learningmedicine

Thursday, November 6, 2025

The Long-Term Critically Ill: Managing the "Chronic ICU Patient"

Dr Neeraj Manikath , claude.ai

Abstract

The emergence of the "chronic ICU patient" represents a paradigm shift in critical care medicine. These patients, typically defined by prolonged mechanical ventilation exceeding 21 days and often requiring tracheostomy and percutaneous endoscopic gastrostomy (PEG), present unique clinical, ethical, and economic challenges. This review explores evidence-based strategies for managing the trach/PEG patient, preventing often-overlooked complications, and navigating the complex ethical terrain of prolonged critical illness. With an aging population and advancing life-support technologies, intensivists must develop expertise in this growing patient population to optimize outcomes and resource utilization.

Keywords: Chronic critical illness, prolonged mechanical ventilation, tracheostomy, rehabilitation, ICU-acquired weakness, pressure injuries, ethics

Introduction

The landscape of intensive care has evolved dramatically over the past three decades. Survival from acute critical illness has improved, yet this success has created a new patient phenotype: the chronically critically ill (CCI). These patients represent approximately 5-10% of ICU admissions but consume up to 30% of ICU resources and account for nearly 50% of ICU bed-days.(1,2) The CCI patient typically requires mechanical ventilation for ≥21 days, often with tracheostomy, and faces a constellation of complications including ICU-acquired weakness (ICUAW), cognitive impairment, and multi-organ dysfunction that persists despite resolution of the initial critical illness.(3)

The management of these patients demands a fundamentally different approach than acute critical care. Rather than focusing solely on physiological stabilization, intensivists must adopt a rehabilitative, patient-centered philosophy that balances aggressive intervention with realistic goal-setting and quality-of-life considerations. This review provides practical guidance for managing this challenging population.

The Trach/PEG Patient: Weaning, Rehabilitation, and Family Education

Timing and Technique of Tracheostomy

The optimal timing of tracheostomy remains debated, though recent evidence suggests early tracheostomy (within 7-10 days) may reduce sedation requirements and facilitate mobilization without significantly affecting mortality or ventilator-free days.(4,5) However, patient selection is critical. The SETPOINT2 trial demonstrated no mortality benefit with early tracheostomy in unselected patients, emphasizing the need for individualized decision-making.(5)

Pearl: Use a "tracheostomy readiness checklist" including: (1) failure of spontaneous breathing trial by day 7, (2) anticipated ventilator dependence >14 days, (3) absence of rapidly reversible pathology, and (4) family agreement with treatment trajectory.

Oyster: The "one-week rule" is not absolute. In patients with high cervical spinal cord injury, Guillain-Barré syndrome, or progressive neuromuscular disease, early discussion about tracheostomy (even within 48-72 hours) may be appropriate to facilitate communication and mobilization.

Protocolized Weaning Strategies

Successful ventilator liberation in CCI patients requires patience and systematic approach. Unlike acute respiratory failure, where spontaneous breathing trials (SBTs) predict extubation success, trach patients benefit from gradual weaning strategies.(6)

The three primary weaning methods are:

Pressure Support Ventilation (PSV) weaning: Gradual reduction of pressure support (2-4 cmH₂O every 1-3 days) based on tolerance
Spontaneous breathing trials: Progressive increase in tracheostomy collar time (30 min → 2 hr → 4 hr → overnight)
Hybrid approach: PSV during night, spontaneous breathing during day with gradual expansion

Hack: Implement a "weaning calendar" visible to the entire team and family. Mark daily weaning progress (e.g., "4 hours off ventilator today!") to maintain momentum and prevent complacency. This simple tool dramatically improves communication and adherence to weaning protocols.

Pearl: Don't overlook nocturnal hypoventilation. Patients may appear ready for decannulation during the day but develop hypercapnia overnight. Obtain overnight capnography or blood gases before declaring weaning success.

Decannulation Criteria and Process

Decannulation represents a critical milestone but carries risks if premature. Evidence-based criteria include:(7)

Tolerating 24-48 hours spontaneous breathing
Effective cough (peak cough flow >60 L/min)
Minimal secretions (<2 suctions per 8-hour shift)
Adequate swallowing function (FEES or modified barium swallow)
No upper airway obstruction (leak test: >110 mL with cuff deflated)

Oyster: The "finger occlusion test" (ability to phonate with finger occluding trach) is an underutilized bedside assessment. Inability to phonate suggests significant upper airway pathology or vocal cord dysfunction requiring ENT evaluation before decannulation.

Nutrition and the PEG Patient

PEG placement typically occurs after 2-4 weeks when prolonged enteral access is anticipated. However, timing should be individualized. Premature PEG placement in patients who may recover swallowing function is unnecessary; delayed placement in appropriate candidates prolongs discomfort from nasogastric tubes.

Hack: Implement a "swallow screen protocol" at day 10-14 of critical illness. Early speech-language pathology (SLP) consultation identifies patients with swallow potential, avoiding unnecessary PEG placement. Conversely, patients with severe neurological injury or prolonged intubation benefit from earlier PEG discussion.

Pearl: Consider gastrojejunal (GJ) tubes instead of PEG in patients with:

Recurrent aspiration despite post-pyloric NG feeding
Severe gastroesophageal reflux
History of aspiration pneumonia
Gastroparesis or delayed gastric emptying

Rehabilitation: The Foundation of Recovery

Early progressive mobility is perhaps the most important intervention for CCI patients. The "ABCDEF bundle" (Assess/prevent pain, Both SAT/SBT, Choice of sedation, Delirium monitoring, Early mobility, Family engagement) reduces ICU-acquired weakness, delirium duration, and hospital length of stay.(8)

Practical mobilization pathway for trach/PEG patients:

Phase 1 (ICU week 1-2): Passive range of motion, bed cycling, sitting at edge of bed
Phase 2 (week 2-3): Active-assisted exercises, standing with tilt table, chair sitting
Phase 3 (week 3+): Ambulation with walker, progressive distance, stair training

Hack: Create a "mobility champion" role among nursing staff—a designated individual who drives daily mobility goals, troubleshoots barriers (ventilator tubing length, line management), and celebrates milestones. This role increases mobility compliance from <30% to >80% in many ICUs.

Family Education and Expectation Management

Family engagement is critical yet frequently inadequate. Families of CCI patients face prolonged stress, financial burden, and uncertainty. Structured family conferences should occur weekly, addressing:

Trajectory and prognosis: Use validated prediction tools (ProVent score, APACHE IV) to provide realistic expectations
Functional outcomes: Discuss likelihood of returning home, need for facility care, quality of life
Timeline: Emphasize that recovery is measured in months, not days
Their role: Engage families as care partners—participation in mobility, communication strategies, turning schedules

Pearl: Introduce the concept of "chronic critical illness" explicitly. Families often maintain hope for rapid recovery despite prolonged ICU stay. Naming the condition helps reframe expectations and facilitates appropriate goal-setting discussions.

Preventing the "Forgotten" Complications: Contractures, Pressure Injuries, and Neuropathy

ICU-Acquired Weakness: Pathophysiology and Prevention

ICU-acquired weakness (ICUAW) affects 25-50% of patients requiring >7 days mechanical ventilation, manifesting as critical illness polyneuropathy (CIP), critical illness myopathy (CIM), or both.(9) Risk factors include sepsis, multi-organ failure, corticosteroid use, hyperglycemia, and immobility.

Pathophysiology pearls:

CIP: Axonal degeneration of motor and sensory nerves due to microvascular dysfunction, pro-inflammatory cytokines, and mitochondrial damage
CIM: Muscle fiber necrosis, myosin loss, and impaired membrane excitability exacerbated by neuromuscular blockers and corticosteroids
Diaphragm weakness: Ventilator-induced diaphragmatic dysfunction (VIDD) occurs rapidly—measurable atrophy within 18 hours of mechanical ventilation(10)

Prevention strategies:

Glycemic control: Target 140-180 mg/dL; avoid hypoglycemia
Minimize sedation: Daily sedation interruption or light sedation protocols
Limit corticosteroids and neuromuscular blockers: Use only when clearly indicated
Early mobilization: As described above—the single most important intervention
Adequate nutrition: Target protein 1.2-1.5 g/kg/day; consider EAAs (essential amino acids)

Hack: Implement a "steroid accountability form" requiring intensivist documentation of indication, dose, and planned duration for any corticosteroid prescription. This simple intervention reduces inappropriate steroid use by 40% and subsequent ICUAW incidence.

Contractures: The Preventable Disability

Joint contractures develop insidiously, with measurable range-of-motion loss within 7 days of immobility. Hip and knee flexion contractures are most common, followed by ankle plantar flexion ("foot drop") and shoulder limitations.(11)

Prevention protocol:

Passive ROM exercises: Minimum twice daily, all major joints through full range
Positioning: Rotate position every 2 hours; avoid prolonged hip/knee flexion
Splinting: Ankle-foot orthoses (AFOs) to maintain neutral ankle position; hand splints for intrinsic-plus position
Early mobilization: Again, the cornerstone intervention

Oyster: The "pillows under knees" comfort measure is a major contributor to knee flexion contractures. Educate staff to place pillows under calves instead, maintaining knee extension. Similarly, avoid pillow elevation of heels—use offloading boots or heel protectors to prevent pressure injuries while maintaining ankle position.

Hack: Partner with physical therapy to create an "ICU contracture prevention kit" for each patient bedside: AFO splints, hand rolls, positioning wedges, and a laminated positioning guide. Standardizing equipment availability increases compliance dramatically.

Pressure Injuries: Zero Harm Goal

Despite prevention efforts, pressure injuries (PIs) occur in 8-40% of ICU patients, with CCI patients at highest risk.(12) Stage III and IV injuries extend hospital stay by 7-14 days and increase mortality.

High-risk anatomical sites in CCI patients:

Supine: Occiput, scapulae, sacrum, heels
Prone (ARDS patients): Face, anterior chest, iliac crests, knees
Medical device-related: Tracheostomy site, feeding tube nasal bridge, venous catheters

Evidence-based prevention bundle:

Risk assessment: Braden Scale on admission and every 48 hours; score <18 indicates high risk
Support surfaces: Low-air-loss or alternating-pressure mattresses for high-risk patients
Repositioning: Every 2 hours minimum; 30-degree lateral positioning preferred over 90-degree side-lying
Skin assessment: Daily full-body examination with attention to device interfaces
Nutrition optimization: Adequate protein and micronutrients (zinc, vitamin C, arginine)
Moisture management: Continence care, moisture barriers for incontinence

Pearl: The heel is the second most common PI location but often neglected. Heels should be "floating"—completely offloaded with pillows under calves. Heel protector boots alone are insufficient.

Hack: Implement a "red blanket protocol"—patients with Braden score <15 get a visible red blanket designating them as ultra-high risk. This visual cue reminds all staff members (nurses, physicians, respiratory therapists) to prioritize turning and PI prevention during every patient interaction.

Peripheral Neuropathy and Nerve Compression

Beyond ICUAW, CCI patients develop compression neuropathies from positioning and immobility. Common sites include:

Brachial plexus: From lateral positioning or arm abduction >90 degrees
Ulnar nerve: Elbow compression against bedrails
Peroneal nerve: Lateral knee compression causing foot drop
Radial nerve: Compression against humerus ("Saturday night palsy")

Prevention: Meticulous attention to positioning during turns and procedures. Arms should be abducted <90 degrees, elbows padded, knees not pressed against bedrails during lateral positioning. Early recognition allows position modification before permanent damage.

Ethical and Financial Challenges of Prolonged ICU Stays

Prognostication: The Art of Realistic Expectations

Prognostication in CCI patients is notoriously difficult. Traditional ICU severity scores (APACHE, SOFA) predict short-term mortality but poorly predict functional outcomes or quality of life—the metrics most important to patients and families.(13)

Useful prognostic tools for CCI patients:

ProVent Score: Predicts 1-year survival for patients requiring prolonged mechanical ventilation; incorporates age, plateau pressure, non-trauma diagnosis, and hemodialysis requirement(14)
Functional status: Pre-ICU functional independence is the strongest predictor of functional recovery
Frailty assessment: Clinical Frailty Scale correlates with mortality and discharge disposition
Time course: Patients not improving by week 4-6 have significantly worse long-term outcomes

Pearl: Avoid prognostic nihilism in the first 7-14 days of critical illness. Many patients who eventually become "chronic ICU patients" survive with acceptable functional outcomes. However, by week 4-6, trajectory becomes clearer and warrants honest discussion.

Oyster: The statement "they survived the ICU" is increasingly insufficient as a success metric. CCI survivors face 50-60% one-year mortality, with survivors often experiencing severe functional impairment, cognitive dysfunction, and reduced quality of life.(15) Frame discussions around "survival with meaningful recovery" rather than survival alone.

Goals of Care: Dynamic Reassessment

Goals-of-care discussions should not be single events but ongoing dialogues. The "Best Case/Worst Case" framework is particularly useful for CCI patients:(16)

Best case: Survival with gradual improvement over 3-6 months, discharge to rehabilitation facility, possible return home with assistance. May require chronic ventilation, feeding tube, significant caregiving needs.

Worst case: Progressive decline despite maximal therapy, prolonged ICU death or early post-discharge mortality, or survival with severe disability incompatible with patient's values.

Most likely case: Somewhere between extremes—survival with moderate-to-severe disability, prolonged facility care, uncertain functional trajectory.

Hack: During family meetings, use the "teach-back method." After discussing prognosis and options, ask family members to explain back what they understood. This identifies comprehension gaps and ensures shared understanding before major decisions.

The Concept of "Time-Limited Trials"

Time-limited trials (TLTs) offer a structured approach when prognosis is uncertain.(17) Rather than open-ended aggressive care or premature withdrawal, TLTs define:

Specific goals: e.g., "wean to 4 hours off ventilator" or "regain purposeful movement"
Time frame: typically 2-4 weeks
Reassessment plan: Scheduled meeting to evaluate progress
Predetermined next steps: Transition to comfort care if goals unmet

TLTs respect patient autonomy, provide hope while avoiding false hope, and prevent the "drift" toward indefinite aggressive care without clear rationale.

Pearl: Document TLTs formally in the medical record with specific, measurable goals. Vague language like "continue current management and reassess" lacks the structure necessary for meaningful decision-making.

Financial and Resource Allocation Considerations

The economics of CCI care are staggering. A single CCI patient may consume $150,000-$500,000 in ICU costs alone, with total hospitalization costs exceeding $1 million.(2) Moreover, these patients occupy ICU beds for weeks to months, potentially limiting access for other critically ill patients.

Ethical frameworks for resource allocation:

Procedural justice: Fair, transparent decision-making processes
Distributive justice: Equitable distribution of limited resources
Clinical appropriateness: Medical benefit versus burden assessment
Patient autonomy: Informed patient/family preferences given priority

Controversial reality: Should resource scarcity influence individual patient decisions? Most ethicists say no—bedside rationing is inappropriate. However, system-level resource allocation (e.g., developing chronic ventilator units, establishing transfer criteria) is ethically defensible.

Oyster: The term "futile care" is problematic and should be avoided. What intensivists consider futile (prolonging death), families may consider meaningful (additional time together). Instead, use "non-beneficial care" or "disproportionate burden" when treatment offers minimal chance of achieving patient-centered goals.

Alternative Care Models: Chronic Ventilator Units and LTACHs

Transitioning appropriate CCI patients to long-term acute care hospitals (LTACHs) or chronic ventilator units offers several advantages:(18)

Cost reduction: LTACH care costs 50-60% less than ICU care for stable chronic patients
ICU capacity: Frees ICU beds for acute admissions
Specialized care: Staff expertise in chronic ventilation, weaning, rehabilitation
Patient experience: More normalized environment, liberal visitation, focus on quality of life

Criteria for LTACH transfer:

Hemodynamically stable without vasopressors
Stable ventilator settings (FiO₂ <0.50, PEEP <10)
No requirement for continuous renal replacement therapy
No active acute processes requiring ICU-level monitoring
Family understanding and agreement

Hack: Establish a "transition coordinator" role—typically a nurse or social worker—who specializes in facilitating transfers to LTACHs. This person develops relationships with receiving facilities, educates families, manages logistics, and troubleshoots insurance barriers. This single intervention can reduce ICU length of stay by 3-5 days for appropriate patients.

Palliative Care Integration

Palliative care consultation should be standard for all CCI patients, not reserved for end-of-life situations. Benefits include:(19)

Improved symptom management (pain, dyspnea, anxiety)
Enhanced communication and goals-of-care discussions
Reduced family distress and complicated grief
Earlier identification of patients appropriate for comfort-focused care
Improved quality of death when transition to comfort care occurs

Trigger criteria for automatic palliative care consultation:

ICU admission >14 days
Second ICU admission during same hospitalization
Chronic critical illness with poor prognostic indicators
Family distress or conflict regarding goals of care

Pearl: Reframe palliative care as "supportive care" or "comfort specialist" to reduce stigma. Many families equate palliative care with giving up, when in reality palliative care complements curative efforts by optimizing quality of life.

Practical Implementation: Creating a CCI Program

Institutions caring for significant CCI populations should consider developing dedicated CCI management programs. Key elements include:

Multidisciplinary team: Intensivists, pulmonologists, physiatrists, PT/OT, SLP, social work, palliative care, ethics
Protocolized care: Weaning protocols, mobility protocols, PI prevention bundles, nutrition optimization
Family support: Regular meetings, support groups, education materials, mental health resources
Transition planning: Early identification of post-ICU care needs, LTACH relationships, home ventilation programs
Quality metrics: Tracking weaning success, complication rates, functional outcomes, family satisfaction

Hack: Implement a weekly "CCI multidisciplinary rounds" specifically for patients with >14 days ICU stay. This dedicated forum prevents these patients from being lost in daily acute-care rounds and ensures coordinated, goal-directed management.

Conclusion

The chronic ICU patient represents both the success and challenge of modern critical care. These patients have survived conditions that would have been uniformly fatal decades ago, yet face prolonged recovery trajectories with uncertain functional outcomes and significant resource utilization. Excellence in CCI management requires a paradigm shift from acute stabilization to rehabilitative, patient-centered care focused on prevention of secondary complications, realistic prognostication, and thoughtful navigation of complex ethical terrain.

Intensivists must develop expertise in tracheostomy/PEG management, systematic approaches to ventilator weaning, aggressive prevention of ICUAW and pressure injuries, and compassionate communication with families facing prolonged uncertainty. As the population ages and critical care capabilities expand, the CCI population will only grow. Developing systematic, evidence-based approaches to these patients is not optional—it is a core competency for contemporary critical care practice.

The goal is not simply survival, but survival with dignity, function, and quality of life acceptable to the patient. Sometimes this means aggressive rehabilitation and prolonged support; other times it means recognizing limitations and transitioning to comfort-focused care. The art of critical care medicine lies in knowing which patients fall into each category and having the courage and compassion to guide families accordingly.

References

Nelson JE, Cox CE, Hope AA, Carson SS. Chronic critical illness. Am J Respir Crit Care Med. 2010;182(4):446-454.
Kahn JM, Le T, Angus DC, et al. The epidemiology of chronic critical illness in the United States. Crit Care Med. 2015;43(2):282-287.
Maguire JM, Carson SS. Strategies to combat chronic critical illness. Curr Opin Crit Care. 2013;19(5):480-487.
Griffiths J, Barber VS, Morgan L, Young JD. Systematic review and meta-analysis of studies of the timing of tracheostomy in adult patients undergoing artificial ventilation. BMJ. 2005;330(7502):1243.
Young D, Harrison DA, Cuthbertson BH, et al. Effect of early vs late tracheostomy placement on survival in patients receiving mechanical ventilation: the TracMan randomized trial. JAMA. 2013;309(20):2121-2129.
Scheinhorn DJ, Hassenpflug MS, Votto JJ, et al. Post-ICU mechanical ventilation at 23 long-term care hospitals: a multicenter outcomes study. Chest. 2007;131(1):85-93.
Stelfox HT, Crimi C, Berra L, et al. Determinants of tracheostomy decannulation: an international survey. Crit Care. 2008;12(1):R26.
Ely EW, Shintani A, Truman B, et al. Delirium as a predictor of mortality in mechanically ventilated patients in the intensive care unit. JAMA. 2004;291(14):1753-1762.
Stevens RD, Marshall SA, Cornblath DR, et al. A framework for diagnosing and classifying intensive care unit-acquired weakness. Crit Care Med. 2009;37(10 Suppl):S299-308.
Levine S, Nguyen T, Taylor N, et al. Rapid disuse atrophy of diaphragm fibers in mechanically ventilated humans. N Engl J Med. 2008;358(13):1327-1335.
Clavet H, Hébert PC, Fergusson D, Doucette S, Trudel G. Joint contracture following prolonged stay in the intensive care unit. CMAJ. 2008;178(6):691-697.
Cox J. Predictors of pressure ulcers in adult critical care patients. Am J Crit Care. 2011;20(5):364-375.
Carson SS, Garrett J, Hanson LC, et al. A prognostic model for one-year mortality in patients requiring prolonged mechanical ventilation. Crit Care Med. 2008;36(7):2061-2069.
Hough CL, Caldwell ES, Cox CE, et al. Development and validation of a mortality prediction model for patients receiving 14 days of mechanical ventilation. Crit Care Med. 2015;43(11):2339-2345.
Unroe M, Kahn JM, Carson SS, et al. One-year trajectories of care and resource utilization for recipients of prolonged mechanical ventilation. Ann Intern Med. 2010;153(3):167-175.
Kruser JM, Nabozny MJ, Steffens NM, et al. "Best Case/Worst Case": qualitative evaluation of a novel communication tool for difficult in-the-moment surgical decisions. J Am Geriatr Soc. 2015;63(9):1805-1811.
Quill TE, Holloway R. Time-limited trials near the end of life. JAMA. 2011;306(13):1483-1484.
Kahn JM, Benson NM, Appleby D, Carson SS, Iwashyna TJ. Long-term acute care hospital utilization after critical illness. JAMA. 2010;303(22):2253-2259.
Aslakson R, Cheng J, Vollenweider D, Galusca D, Smith TJ, Pronovost PJ. Evidence-based palliative care in the intensive care unit: a systematic review of interventions. J Palliat Med. 2014;17(2):219-235.

Key Teaching Points for Postgraduate Fellows

Chronic critical illness is a distinct entity requiring different management principles than acute ICU care—think rehabilitation, not just stabilization.
Early mobilization is the closest thing to a "magic bullet" we have for preventing ICUAW, delirium, and accelerating recovery. Make it a daily priority.
Tracheostomy timing should be individualized based on predicted ventilator duration, not a rigid timeline. Use the first week to assess trajectory.
Pressure injuries are never acceptable—they represent a failure of basic nursing care. Make PI prevention a personal and team priority.
Prognostic humility is essential. Give accurate but compassionate information, avoid nihilism in week 1-2, but have honest discussions by week 4-6 if no improvement.
Time-limited trials are your friend when facing prognostic uncertainty—they provide structure and prevent open-ended aggressive care without clear goals.
Palliative care is not "giving up"—it's expert symptom management and communication support that every CCI patient deserves, regardless of overall goals.
Family education and expectation management prevent suffering and conflict. Use the term "chronic critical illness" explicitly and discuss functional outcomes, not just survival.
LTACHs are appropriate for many stable CCI patients—learn to recognize appropriate transfer candidates to optimize both individual patient care and ICU capacity.
The goal is meaningful recovery, not just survival. Always ask: "Is this the outcome the patient would want?" when making decisions about ongoing aggressive care.

The "Zero-Harm" ICU: A Systems Approach to Patient Safety

Dr Neeraj Manikath , claude.ai

Abstract

The intensive care unit represents the confluence of critically ill patients, complex interventions, and high-stakes decision-making—a perfect storm for potential harm. While the concept of "zero harm" may seem aspirational, a systems-based approach grounded in evidence-based infection prevention, human factors engineering, and psychological safety can dramatically reduce preventable adverse events. This review synthesizes contemporary evidence and practical strategies for creating safer ICU environments, moving beyond traditional checklists to embrace comprehensive safety cultures.

Keywords: Patient safety, zero harm, hospital-acquired infections, human factors, psychological safety, intensive care

Introduction

Despite decades of attention to patient safety since the landmark "To Err is Human" report, intensive care units continue to experience preventable harm at concerning rates. Healthcare-associated infections (HAIs) affect approximately 1 in 31 hospitalized patients daily in the United States, with ICU patients bearing disproportionate risk (CDC, 2023). Beyond infections, medication errors, device-related complications, and communication failures compound the burden of critical illness.

The "zero-harm" philosophy, successfully implemented in high-reliability organizations such as aviation and nuclear power, posits that all serious harm is preventable through systematic identification and mitigation of risk. While critics argue this standard is unattainable in medicine's inherent uncertainty, evidence suggests dramatic harm reduction is achievable when organizations commit to comprehensive safety systems rather than piecemeal interventions (Pronovost et al., 2006; Resar et al., 2012).

This review explores three pillars of the zero-harm ICU: infection prevention beyond standard bundles, human factors engineering in ICU design, and cultivation of psychological safety for error reporting.

Preventing Hospital-Acquired Infections: Beyond the Bundle

The Limitations of Traditional Bundles

The success of evidence-based bundles—particularly the central line bundle reducing catheter-associated bloodstream infections (CLABSIs) by 66% in Michigan ICUs (Pronovost et al., 2006)—revolutionized infection prevention. However, bundle adherence has plateaued, and residual infection rates persist despite reported high compliance. This "implementation ceiling" reflects bundles' focus on insertion practices while neglecting maintenance care, environmental contamination, and patient-specific risk factors (Safdar & Maki, 2002).

Pearl: Bundle compliance is necessary but insufficient. The focus must shift from "did we check all boxes?" to "did we prevent the infection?"

Ventilator-Associated Pneumonia (VAP): The Next Generation

Traditional VAP prevention emphasized head-of-bed elevation, oral care with chlorhexidine, and spontaneous breathing trials. However, recent evidence challenges some orthodoxies:

The Chlorhexidine Controversy: While early studies suggested benefit, the CHORAL trial (2018) showed no VAP reduction with chlorhexidine oral care but increased mortality trends, possibly related to aspiration of chlorhexidine or disruption of oral microbiome. Current best practice emphasizes mechanical plaque removal over antiseptic solutions (Klompas et al., 2014).

Beyond Basic Oral Care:

Teeth brushing: Mechanical removal with standard toothbrushes twice daily reduces bacterial burden more effectively than swabs alone
Subglottic secretion drainage: Endotracheal tubes with dedicated suction ports reduce VAP by 30-50% (Muscedere et al., 2011)
Saline instillation avoidance: Pre-suctioning saline instillation increases bacterial translocation and should be abandoned

Oyster: The "ventilator" in VAP may be misleading. Recent taxonomies favor "ventilator-associated event" (VAE) or "infection-related ventilator-associated complication" (IVAC), recognizing that many complications stem from aspiration, lung injury, or fluid overload rather than ventilation itself (Magill et al., 2013).

Advanced Strategies:

Selective digestive decontamination (SDD): Topical and systemic antimicrobials reduce VAP by 70% in settings with low baseline resistance, though widespread adoption remains controversial due to resistance concerns (Wittekamp et al., 2018)
Automated endotracheal tube cuff pressure monitoring: Maintaining 20-30 cm H₂O reduces micro-aspiration; automated systems outperform manual checks
Early mobility and vertical positioning: The ICU Liberation Bundle (A-F Bundle) reduces ventilator days through systematic sedation minimization and early mobilization (Pun et al., 2019)

CLABSI: Maintenance Matters

While insertion bundles revolutionized CLABSI prevention, 50-70% of infections arise from maintenance failures. A comprehensive approach includes:

Daily Necessity Assessments: Prompt removal remains the most effective prevention. Implementing "CVC removal rounds" during daily interdisciplinary rounds reduces line-days by 30%.

Scrub-the-Hub Protocols: Vigorous mechanical scrubbing with alcohol for 15 seconds (not just wiping) before access reduces intraluminal contamination. Disinfection caps providing continuous protection between uses further reduce risk.

Hack: Color-code central line lumens and designate one "clean lumen" exclusively for medications (never blood draws or high-risk infusions). This simple strategy reduces contamination risk in multi-lumen catheters.

Emerging Technologies:

Antimicrobial-coated catheters: Second-generation chlorhexidine-silver sulfadiazine and minocycline-rifampin catheters reduce early infections but cost-effectiveness depends on baseline CLABSI rates
Catheter securement devices: Engineered stabilization systems reduce micromotion-induced phlebitis and dislodgement compared to traditional tape

Pearl: The "occult" CLABSI—infections attributed to unknown sources but actually catheter-related—may account for 20-30% of ICU bacteremias. Maintain high clinical suspicion and consider line removal even without obvious insertion site infection (Mermel et al., 2009).

CAUTI: Rethinking Urinary Catheterization

Catheter-associated urinary tract infections (CAUTIs) represent the most common HAI yet receive disproportionately little attention compared to CLABSIs and VAP.

The 80% Solution: Up to 80% of urinary catheters lack appropriate indication. Implementing nurse-driven removal protocols based on explicit criteria eliminates unnecessary catheter-days without physician orders for each removal.

Appropriate Indications (Limit to):

Hemodynamic monitoring in critical illness requiring precise output
Acute urinary retention or obstruction
Perioperative use for specific surgeries
Stage III-IV pressure injuries with urinary contamination
End-of-life comfort care when requested

Contraindications Often Ignored:

Convenience for healthcare workers or family
Incontinence management in continent patients
"Just in case" monitoring of stable patients

Alternatives That Work:

External catheters (condom catheters): For men without retention, reduce CAUTI by 50% compared to indwelling catheters
Scheduled toileting: Labor-intensive but effective for delirium prevention and dignity preservation
Bladder ultrasound: Point-of-care assessment reduces unnecessary catheterizations for volume checks

Oyster: The asymptomatic bacteriuria paradox—nearly all catheterized patients develop bacteriuria by two weeks, yet only 5% develop symptomatic CAUTI. Reflexive treatment of positive cultures without symptoms drives resistance and provides no benefit (Hooton et al., 2010).

Human Factors Engineering: Designing the ICU to Prevent Errors

From Blame to Design: The Human Factors Revolution

Traditional medical error prevention focused on individual vigilance and discipline. Human factors engineering recognizes that humans are inherently fallible and excellent system design accommodates these limitations. The ICU, often designed by architects and administrators rather than frontline clinicians, frequently incorporates error-prone features (Carayon et al., 2014).

Pearl: If multiple intelligent, well-trained clinicians make the same error, the problem is the system, not the individuals.

Physical Environment Design

Visibility and Observation:

Nurse-to-patient sightlines: Direct visualization reduces response times to emergencies. Decentralized nursing stations positioned between rooms outperform central stations in patient surveillance
Glass doors vs. solid doors: Transparent barriers allow visual assessment without entering (reducing infection transmission) while maintaining noise control with modern acoustics
Headwall standardization: Identical layouts in every room reduce cognitive load and "treasure hunt" time locating equipment

Hack: Paint or tape the floor in high-traffic areas with directional "flow lanes" like highways. This simple intervention reduces collisions, speeds transport, and creates predictable patterns during codes.

Lighting Design:

Circadian-rhythm lighting systems adjusting color temperature across 24 hours reduce delirium and improve sleep architecture (Engwall et al., 2015)
Task-specific lighting at bedsides provides examination-quality illumination without disturbing adjacent patients
Blue-enriched light during day shifts enhances staff alertness and reduces medication errors

Noise Reduction:

Target ambient noise <45 dB and peak noise <60 dB per WHO recommendations (current ICU averages: 60-70 dB)
Sound-absorbing ceiling tiles reduce noise by 30-40%
Quiet hours protocols (dimmed lights, minimized alarms, clustered care) improve patient sleep without compromising safety

Medication Safety by Design

Smart Pump Integration:

Dose error reduction systems (DERS) with hard and soft limits prevent 10-fold dosing errors
Drug libraries tailored to ICU populations provide appropriate dosing ranges
Wireless connectivity enabling real-time surveillance and intervention by pharmacists

Standardization Strategies:

Standard concentrations: Limiting to 1-2 concentrations per medication reduces calculation errors. Example: norepinephrine at 16 mcg/mL or 32 mcg/mL only—never 4 mcg/mL or 8 mcg/mL
Pre-mixed solutions: Pharmacy-prepared infusions eliminate bedside mixing errors and contamination risk
Color-coding systems: Visual differentiation of medication classes (but avoid sole reliance due to color-blindness considerations)

Oyster: The "distraction-free zone" for medication preparation—designated areas with signage prohibiting interruptions—reduces errors by 40-50%. However, rigid "do not disturb" policies may delay recognition of clinical deterioration. Balance is achieved through time-limited protection during high-risk tasks (Raban & Westbrook, 2014).

Technology Interface Design

Alarm Fatigue Mitigation:

ICUs average 350-700 alarms per patient per day with false alarm rates of 85-99% (Cvach, 2012)
Multi-parameter integration: Systems requiring concordant abnormalities (e.g., low SpO₂ + low respiratory rate) reduce nuisance alarms by 60%
Personalized thresholds: Adjusting alarm parameters to individual patient physiology rather than generic defaults
Secondary alarm notification: Escalating alarms unacknowledged within specified times prevents normalization of deviance

Hack: Implement "alarm personalities"—different sounds for different urgency levels rather than uniform beeping. Critical alarms use distinct, penetrating tones impossible to ignore or confuse.

Electronic Health Record (EHR) Optimization:

Forcing functions: Hard stops preventing dangerous actions (e.g., cannot order penicillin in documented allergy)
Smart order sets: Evidence-based, bundled orders reducing omissions and variability
Clinical decision support (CDS): Real-time alerts for drug interactions, dosing adjustments, and protocol deviations—but excessive alerts cause override rates >90%, negating benefit (van der Sijs et al., 2006)

The CDS Paradox: Each alert reduces physician efficiency by 49 seconds and increases cognitive burden. Effective CDS requires ruthless culling of low-value alerts, maintaining specificity >90% to preserve alert credibility.

Creating a Culture of Psychological Safety for Reporting Near-Misses

The Hidden Iceberg of Safety Events

For every serious harm event, there are 10 intercepts (potential harm prevented by last-minute detection) and 100-300 near-misses that could have caused harm under slightly different circumstances (Reason, 1990). Near-miss reporting provides early warning of system vulnerabilities before they cause patient harm, yet most near-misses remain unreported due to fear, shame, and futility perceptions.

Pearl: Healthcare remains the only high-reliability industry where the majority of safety events go unreported. Aviation industries report 10-100 times more near-misses per serious event than healthcare (Vincent, 2010).

Understanding Psychological Safety

Psychological safety—the belief that one can speak up about concerns, errors, or ideas without fear of punishment or humiliation—is the foundation of learning organizations. Edmondson's research demonstrates that teams with high psychological safety identify more problems and generate more solutions, while "safe" teams with few reported errors actually experience more actual harm (Edmondson, 1999).

The Paradox: ICUs with the highest error reporting rates often have the lowest actual harm rates, while units reporting few errors typically have higher harm rates and punitive cultures suppressing disclosure.

Building Psychological Safety: Leadership Behaviors

Model Fallibility:

Leaders sharing their own errors and near-misses normalizes disclosure: "I nearly ordered 10x the insulin dose yesterday—caught it at the last second. Let's discuss what system changes would have prevented this."
Public acknowledgment of uncertainty: "I'm not sure of the best approach here; what do you all think?"

Respond to Reports with Curiosity, Not Blame:

Wrong response: "Why didn't you double-check? This should never happen."
Right response: "Thank you for reporting this. Let's understand what factors contributed and how we can design systems to prevent this."

Separate Just Culture from Blame-Free Culture:

Just Culture acknowledges three error types requiring different responses (Marx, 2001):
1. Human error (inadvertent mistakes): Console and coach, improve systems
2. At-risk behavior (shortcuts becoming routine): Coach, remove incentives for risk-taking
3. Reckless behavior (conscious disregard of substantial risk): Remediation or removal

Hack: The "What, So What, Now What" debrief structure provides non-threatening error analysis:

What happened? (Facts only, no interpretation)
So what? (Why did this happen? What were contributing factors?)
Now What? (What will we change to prevent recurrence?)

Structural Enablers of Reporting

Make Reporting Easy:

Anonymous electronic reporting systems accessible from any device
One-minute reporting forms capturing essential information only
Verbal reporting options for those uncomfortable with written documentation
Real-time reporting apps on mobile devices at point of care

Close the Loop:

Share outcomes of investigations with reporters within 72 hours
Monthly summaries of reports, themes, and actions taken visible to entire unit
Recognition of reporters as safety champions, not troublemakers

Oyster: Monetary rewards for error reporting can backfire, encouraging trivial reports to gain incentives while serious errors remain hidden. Intrinsic motivation—pride in contributing to safety, trust in leadership—drives sustainable reporting cultures.

Implementing Structured Learning Systems

Daily Safety Huddles:

Brief (5-10 minute) interdisciplinary discussions reviewing:
- Near-misses from previous 24 hours
- Anticipated high-risk activities today
- One safety topic (rotating weekly)
Emphasis on systems learning, not individual blame

Morbidity and Mortality (M&M) Conference Transformation:

Traditional M&M often devolves into public shaming
Reimagined M&M focuses on:
- Systems analysis using frameworks like Swiss Cheese Model or HFACS
- Multidisciplinary participation including nursing, pharmacy, respiratory therapy
- "No name, no shame" policies unless reckless behavior identified
- Specific action items with accountability and follow-up

Simulation-Based Learning:

In-situ simulations in actual ICU environment reveal latent safety threats (missing equipment, confusing layouts, communication gaps)
Debriefing emphasizes team performance and system factors, not individual errors
Frequent simulation normalizes mistake-making as learning opportunity

The WalkRounds Strategy:

Senior leaders regularly walk ICU units specifically to ask: "What prevents you from providing excellent care? What safety concerns do you have?"
Visible follow-through on identified issues demonstrates leadership commitment
Frankel et al. (2008) demonstrated 50% increase in safety reporting with consistent WalkRounds implementation

Integration: The Zero-Harm System

True zero-harm requires integration of all three pillars. Infection prevention bundles fail without human factors design supporting adherence and psychological safety enabling identification of implementation barriers. Human factors interventions succeed only when staff feel safe reporting design flaws. Psychological safety rings hollow without tangible actions addressing reported concerns.

The Virtuous Cycle:

Staff report near-miss or system vulnerability
Leadership responds with curiosity and appreciation
Interdisciplinary team analyzes contributing factors
Human factors redesign and evidence-based protocols implemented
Outcomes improve and are celebrated
Trust increases, encouraging more reporting
Cycle repeats with progressive safety enhancement

Metrics for the Zero-Harm ICU:

Leading indicators: Safety reports per 1,000 patient-days (target: >10), staff perception of psychological safety (validated surveys), bundle compliance rates
Lagging indicators: HAI rates benchmarked to NHSN percentiles (target: <10th percentile), preventable harm events per 1,000 patient-days, safety culture survey results

Conclusion

The zero-harm ICU is not a utopian fantasy but an achievable goal requiring systematic commitment to evidence-based infection prevention, human factors engineering, and psychological safety. While perfection may remain aspirational, dramatic reductions in preventable harm are demonstrable when organizations move beyond individual vigilance to comprehensive safety systems.

The journey begins with leadership commitment to just culture, continues through relentless focus on systems rather than individuals, and succeeds when frontline staff become engaged partners in safety transformation. Every prevented infection, every near-miss reported, and every error intercepted represents not just avoided harm but a learning opportunity propelling the organization toward true high reliability.

As critical care clinicians, we must demand excellence not only in our clinical decision-making but in the systems within which we work. Our patients—vulnerable, voiceless, and entirely dependent on our competence and commitment—deserve nothing less.

References

Centers for Disease Control and Prevention. (2023). Healthcare-Associated Infections. National and State Healthcare-Associated Infections Progress Report.
Pronovost, P., et al. (2006). An intervention to decrease catheter-related bloodstream infections in the ICU. New England Journal of Medicine, 355(26), 2725-2732.
Resar, R., et al. (2012). Using a bundle approach to improve ventilator care processes and reduce ventilator-associated pneumonia. Joint Commission Journal on Quality and Patient Safety, 31(5), 243-248.
Safdar, N., & Maki, D.G. (2002). The commonality of risk factors for nosocomial colonization and infection with antimicrobial-resistant Staphylococcus aureus, enterococcus, gram-negative bacilli, Clostridium difficile, and Candida. Annals of Internal Medicine, 136(11), 834-844.
Klompas, M., et al. (2014). Strategies to prevent ventilator-associated pneumonia in acute care hospitals: 2014 update. Infection Control & Hospital Epidemiology, 35(8), 915-936.
Muscedere, J., et al. (2011). Comprehensive evidence-based clinical practice guidelines for ventilator-associated pneumonia. Journal of Critical Care, 26(5), 448-456.
Magill, S.S., et al. (2013). Developing a new, national approach to surveillance for ventilator-associated events. Critical Care Medicine, 41(11), 2467-2475.
Wittekamp, B.H., et al. (2018). Decontamination strategies and bloodstream infections with antibiotic-resistant microorganisms in ventilated patients. JAMA, 320(20), 2087-2098.
Pun, B.T., et al. (2019). Caring for critically ill patients with the ABCDEF bundle. Critical Care Medicine, 47(1), 3-14.
Mermel, L.A., et al. (2009). Clinical practice guidelines for the diagnosis and management of intravascular catheter-related infection. Clinical Infectious Diseases, 49(1), 1-45.
Hooton, T.M., et al. (2010). Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 international clinical practice guidelines. Clinical Infectious Diseases, 50(5), 625-663.
Carayon, P., et al. (2014). Human factors systems approach to healthcare quality and patient safety. Applied Ergonomics, 45(1), 14-25.
Engwall, M., et al. (2015). Lighting, sleep and circadian rhythm: An intervention study in the intensive care unit. Intensive and Critical Care Nursing, 31(6), 325-335.
Raban, M.Z., & Westbrook, J.I. (2014). Are interventions to reduce interruptions and errors during medication administration effective? Journal of Hospital Medicine, 9(1), 59-64.
Cvach, M. (2012). Monitor alarm fatigue: An integrative review. Biomedical Instrumentation & Technology, 46(4), 268-277.
van der Sijs, H., et al. (2006). Overriding of drug safety alerts in computerized physician order entry. Journal of the American Medical Informatics Association, 13(2), 138-147.
Reason, J. (1990). Human error. Cambridge University Press.
Vincent, C. (2010). Patient Safety (2nd ed.). Wiley-Blackwell.
Edmondson, A. (1999). Psychological safety and learning behavior in work teams. Administrative Science Quarterly, 44(2), 350-383.
Marx, D. (2001). Patient safety and the "just culture": A primer for health care executives. Columbia University.
Frankel, A., et al. (2008). Patient safety leadership WalkRounds. Joint Commission Journal on Quality and Patient Safety, 34(1), 16-20.

Key Pearls and Oysters Summary

Pearls:

Bundle compliance is necessary but insufficient—focus on outcomes, not checkboxes
If multiple smart people make the same error, fix the system, not the people
ICUs with highest error reporting often have lowest actual harm rates
The most effective CAUTI prevention is avoiding unnecessary catheterization

Oysters:

"Ventilator-associated" pneumonia is often aspiration-related, not ventilator-caused
Occult CLABSIs account for 20-30% of ICU bacteremias
Treating asymptomatic catheter-associated bacteriuria drives resistance without benefit
Excessive clinical decision support alerts create override fatigue, negating safety benefits
Blame-free culture differs from just culture—reckless behavior requires accountability

Hacks:

Designate one "clean lumen" in multi-lumen central lines exclusively for medications
Paint directional "flow lanes" on ICU floors to reduce collisions and speed transport
Implement different alarm sounds for different urgency levels (alarm personalities)
Use "What, So What, Now What" structure for non-threatening error debriefs

The Geriatric ICU: Rethinking Goals and Outcomes for the Elderly

Dr Neeraj Manikath , claude.ai

Abstract

The demographic shift toward an aging population has fundamentally transformed intensive care practice, with patients aged ≥65 years now comprising over 50% of ICU admissions in developed nations. Traditional ICU metrics centered on mortality fail to capture what matters most to elderly patients: functional independence, cognitive preservation, and quality of life. This review synthesizes current evidence on frailty assessment, polypharmacy management, and goals-of-care conversations, providing practical frameworks for intensivists managing geriatric critically ill patients. We challenge the paradigm of age-based rationing while advocating for individualized, function-focused approaches that honor patient values and optimize meaningful outcomes.

Introduction

The intersection of critical illness and advanced age presents unique clinical, ethical, and prognostic challenges. While chronological age alone is a poor discriminator of ICU outcomes, physiological age—reflected through frailty, comorbidity burden, and baseline functional status—profoundly influences both survival and post-ICU recovery trajectories (1,2). Nearly 40% of ICU survivors aged ≥80 years experience new functional limitations, and up to 60% develop cognitive impairment within one year of discharge (3). These sobering statistics demand that we move beyond the binary of "survival versus death" and embrace a more nuanced understanding of what constitutes successful critical care for the elderly.

The geriatric ICU patient differs fundamentally from younger cohorts in three critical domains: diminished physiological reserve (frailty), complex medication regimens with heightened vulnerability to adverse drug events, and the imperative for patient-centered goals that prioritize quality over quantity of life. This review provides evidence-based approaches to navigating these complexities.

Frailty Assessment on Admission: A New Vital Sign

The Frailty Paradigm

Frailty—a state of decreased physiological reserve and increased vulnerability to stressors—has emerged as a more powerful predictor of adverse outcomes than age itself (4). Frail patients experience higher ICU mortality (OR 2.5-3.5), longer mechanical ventilation duration, increased delirium incidence, and worse long-term functional outcomes compared to robust individuals of the same age (5,6). Yet frailty assessment remains underutilized, with fewer than 15% of ICUs incorporating standardized frailty screening protocols (7).

Validated Assessment Tools

The Clinical Frailty Scale (CFS): The 9-point CFS is the most widely validated tool in critical care settings, demonstrating excellent inter-rater reliability (κ = 0.74-0.81) and requiring <5 minutes to complete (8). Scores ≥5 (mildly frail) predict increased hospital mortality (HR 1.59, 95% CI 1.37-1.84), while scores ≥7 (severely frail) are associated with 90-day mortality exceeding 50% in mechanically ventilated patients (9).

Pearl: The CFS should be assessed based on the patient's baseline status two weeks prior to acute illness, not at ICU admission when acute illness confounds the assessment.

The Hospital Frailty Risk Score: This automated tool derives frailty status from ICD-10 coding in administrative databases, facilitating retrospective research and quality improvement initiatives (10). However, its utility for real-time clinical decision-making is limited.

Short Physical Performance Battery (SPPB): For patients capable of participation, the SPPB (assessing gait speed, chair stands, and balance) provides objective functional assessment. Scores <8 identify individuals at high risk for ICU-acquired weakness (11).

Implementation Strategies

Hack: Integrate CFS assessment into electronic admission orders as a mandatory field, similar to vital signs. Train nursing staff, physiotherapists, and physicians in CFS scoring through simulation-based education. Collateral history from family members regarding pre-morbid functional status is invaluable—specific questions about instrumental activities of daily living (IADLs) such as medication management, meal preparation, and financial handling provide objective anchors.

Oyster: Frailty is not futility. Moderate frailty (CFS 5-6) does not preclude ICU admission; rather, it should trigger enhanced geriatric co-management, aggressive delirium prevention protocols, and early rehabilitation. The nihilistic equation of frailty with treatment limitation denies many patients opportunities for meaningful recovery (12).

Prognostic Communication

Frailty scores should inform, not dictate, care decisions. When discussing prognosis with families, translate CFS scores into functional outcomes: "Based on your mother's frailty level, if she survives to hospital discharge, there's approximately a 40% chance she'll return to independent living, a 35% chance she'll require assisted living, and a 25% chance she'll need nursing home care" (13). This frames discussions around what matters most—functional trajectory—rather than abstract survival statistics.

The Dilemma of Polypharmacy and Drug-Drug Interactions

Epidemiology and Impact

The average geriatric ICU patient arrives taking 8-12 chronic medications (14). Polypharmacy (≥5 medications) affects 40-60% of community-dwelling elderly and approaches 90% in those with multimorbidity (15). In critical illness, this pharmaceutical complexity collides with altered pharmacokinetics, heightened susceptibility to adverse drug events (ADEs), and cascading drug-drug interactions (DDIs).

Approximately 25-30% of ADEs in elderly ICU patients are preventable, with the most common culprits being sedatives, opioids, antibiotics, and cardiovascular medications (16). DDIs contribute to 10-20% of adverse outcomes, including acute kidney injury, QT prolongation, serotonin syndrome, and bleeding complications (17).

Altered Pharmacology in the Elderly Critically Ill

Pharmacokinetic Changes:

Absorption: Reduced gastric acid production and splanchnic perfusion impair oral bioavailability
Distribution: Increased body fat (30% by age 75) prolongs lipophilic drug half-lives (propofol, benzodiazepines)
Metabolism: Hepatic CYP450 activity declines 20-40%, particularly Phase I reactions
Excretion: Glomerular filtration rate decreases ~1 mL/min/year after age 40, mandating dose adjustments for renally cleared drugs (18)

Pharmacodynamic Alterations: Enhanced sensitivity to CNS depressants (50% reduction in benzodiazepine dose requirements), increased anticoagulant effects, and exaggerated hypotensive responses to vasodilators characterize elderly pharmacodynamics (19).

High-Risk Medication Categories

The Beers Criteria and STOPP/START: These evidence-based tools identify potentially inappropriate medications (PIMs) in older adults. Common ICU-relevant PIMs include:

Benzodiazepines: Associated with delirium, falls, and respiratory depression; prefer dexmedetomidine for sedation (20)
First-generation antihistamines: Anticholinergic burden increases delirium risk 3-fold (21)
Proton pump inhibitors: Increase Clostridium difficile risk (OR 2.5) and fracture risk with chronic use; reserve for documented indications (22)
Sliding-scale insulin: Increases hypoglycemia risk; use basal-bolus regimens instead (23)

Pearl: The "anticholinergic burden"—cumulative effect of medications with antimuscarinic properties—independently predicts delirium, cognitive decline, and mortality. Use the Anticholinergic Cognitive Burden Scale to identify and minimize offending agents (24).

Medication Reconciliation and Deprescribing

Admission Strategies:

Comprehensive medication history: Include over-the-counter medications, supplements, and "medication borrowing" from spouses
Identify potentially inappropriate medications: Apply Beers/STOPP criteria systematically
Risk-stratify for DDIs: Use electronic clinical decision support tools (Micromedex, Lexicomp) to flag high-risk combinations
Assess medication adherence: Pre-admission non-adherence predicts post-discharge non-adherence

Hack: Create a "medication timeout" checklist for all geriatric admissions asking: (1) Is this medication still indicated? (2) Does the benefit outweigh the risk in critical illness? (3) Is the dose appropriate for current renal/hepatic function? (4) Are there safer alternatives?

The Deprescribing Protocol: Systematic discontinuation or dose reduction of inappropriate medications improves outcomes without increasing mortality (25). Prioritize cessation of:

Medications without clear indication
Those duplicating therapeutic effects
Drugs treating side effects of other drugs
Those with narrow therapeutic indices requiring close monitoring

Oyster: Do not reflexively continue all home medications. Holding chronic medications during acute illness (statins, antihypertensives, diabetes medications) may reduce iatrogenic harm while metabolic and hemodynamic derangements persist. Develop institution-specific protocols for which medications to continue, hold, or discontinue.

Critical Drug-Drug Interactions

QT Prolongation Cascade: The combination of azithromycin + fluoroquinolone + ondansetron + propofol—a common ICU cocktail—creates significant torsades de pointes risk. Monitor QTc intervals and consider alternative antiemetics (metoclopramide) and antibiotics.

Serotonin Syndrome: SSRI/SNRI + fentanyl + linezolid combinations may precipitate life-threatening serotonin toxicity. Maintain high clinical suspicion in patients with agitation, hyperthermia, and hyperreflexia (26).

Nephrotoxin Triad: NSAIDs + ACE inhibitors + diuretics—the "triple whammy"—precipitates acute kidney injury in 10-15% of elderly users (27). Discontinue NSAIDs and hold ACE inhibitors during hemodynamic instability.

Goals of Care Conversations: Moving Beyond Simple Survival

The Communication Crisis

Despite 70-80% of elderly patients preferring to die at home, 60% die in hospitals, often following aggressive interventions misaligned with their values (28). The primary barrier is not patient unwillingness to discuss end-of-life preferences but clinician discomfort, time constraints, and inadequate training in goals-of-care (GOC) communication (29).

The consequences of delayed GOC conversations are profound: increased ICU length of stay, higher rates of invasive procedures of questionable benefit, greater family distress and complicated grief, and healthcare expenditures concentrated in the final weeks of life (30).

Reframing the Conversation

From "Do Everything" to "What Matters Most": Traditional binary questions ("Do you want us to do everything?") are clinically meaningless and psychologically coercive. Instead, employ value-based inquiry:

"Help me understand what makes life worth living for you?"
"What abilities are so important that you can't imagine life without them?"
"What would be a fate worse than death for you?"

These questions elicit the functional and experiential outcomes patients value, providing a scaffold for proportionate treatment recommendations (31).

The VALUE Communication Framework

The VALUE mnemonic, validated in a multi-center ICU trial, improved family satisfaction and reduced symptoms of PTSD and depression in surrogate decision-makers (32):

Value family statements: "I can see how much your father's independence means to you"
Acknowledge emotions: "This uncertainty must be incredibly difficult"
Listen actively: Use silence, avoid interrupting, reflect concerns
Understand the patient as a person: "Tell me about your mother before this illness"
Elicit questions: "What concerns you most right now?"

Pearl: Prognosis should be presented as a range of outcomes across multiple dimensions—survival, functional status, cognitive ability, and symptom burden—rather than a single mortality statistic. "Mrs. Smith has three possible paths forward: best case, most likely case, and worst case" provides a framework for shared decision-making (33).

Time-Limited Trials

For patients with uncertain prognosis or equipoise regarding treatment intensity, time-limited trials (TLTs) provide an ethical middle ground between aggressive intervention and comfort care. TLTs involve:

Defining specific, measurable goals (e.g., extubation within 7 days)
Establishing a predetermined trial duration (typically 3-7 days)
Agreeing on criteria for treatment de-escalation if goals aren't met
Regular reassessment with family involvement (34)

Hack: Document TLTs explicitly in progress notes: "Time-limited trial of mechanical ventilation until [date]. Goals: extubation and meaningful interaction. If not achieved, transition to comfort-focused care per patient's previously expressed wishes." This clarity reduces moral distress among clinicians and provides families with realistic expectations.

Palliative Care Integration

Palliative care consultation within 72 hours of ICU admission for patients ≥80 years with severe illness reduces ICU length of stay by 2-3 days, decreases invasive interventions, and improves family satisfaction without affecting mortality (35). Yet, referral rates remain below 20% in most centers (36).

Oyster: Palliative care is not synonymous with end-of-life care. It represents a skillset—symptom management, communication expertise, and care coordination—valuable throughout critical illness, not merely in its final stages. Rebranding as "supportive care" or "complex care" services reduces stigma and increases appropriate utilization (37).

Cultural Considerations

Cultural beliefs profoundly influence GOC preferences. Some cultures emphasize family-centered decision-making over individual autonomy, others prohibit discussions of death as tempting fate, and many view aggressive intervention as demonstrating love and respect (38). Approach these conversations with humility:

"Different families have different beliefs about medical decisions. How does your family typically make important decisions?"
"Some cultures believe discussing bad outcomes can influence them. Do you share these concerns?"
Engage professional interpreters, not family members, for GOC discussions to ensure unfiltered communication

Conclusion

The geriatric ICU demands a paradigm shift from organ-centric critical care to person-centered medicine. Frailty assessment provides prognostic precision beyond chronological age, guiding resource allocation and setting realistic expectations. Medication stewardship—through systematic reconciliation, deprescribing, and DDI prevention—reduces iatrogenic harm in a vulnerable population. Most critically, goals-of-care conversations reorient critical care toward outcomes patients value: functional independence, cognitive preservation, and dignity.

Excellence in geriatric critical care is not measured solely by ICU survival rates but by the proportion of patients who return to their pre-morbid functional status, the alignment of treatments with patient values, and the absence of regret among surrogates. As our ICUs gray, we must continually ask: Are we adding life to years, or merely years to life?

References

Flaatten H, et al. The impact of frailty on ICU and 30-day mortality and the level of care in very elderly patients (≥80 years). Intensive Care Med. 2017;43(12):1820-1828.
Muscedere J, et al. The impact of frailty on intensive care unit outcomes: a systematic review and meta-analysis. Intensive Care Med. 2017;43(8):1105-1122.
Ferrante LE, et al. Functional trajectories among older persons before and after critical illness. JAMA Intern Med. 2015;175(4):523-529.
Fried LP, et al. Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci. 2001;56(3):M146-156.
Bagshaw SM, et al. Association between frailty and short- and long-term outcomes among critically ill patients: a multicentre prospective cohort study. CMAJ. 2014;186(2):E95-102.
Guidet B, et al. The contribution of frailty, cognition, activity of daily life and comorbidities on outcome in acutely admitted patients over 80 years in European ICUs: the VIP2 study. Intensive Care Med. 2020;46(1):57-69.
Pugh RJ, et al. Short-term and long-term mortality in the older critically ill. Am J Respir Crit Care Med. 2020;201(12):1487-1489.
Rockwood K, et al. A global clinical measure of fitness and frailty in elderly people. CMAJ. 2005;173(5):489-495.
Shears M, et al. Assessing frailty in the intensive care unit: A reliability and validity study. J Crit Care. 2018;45:197-203.
Gilbert T, et al. Development and validation of a Hospital Frailty Risk Score focusing on older people in acute care settings using electronic hospital records. Age Ageing. 2018;47(2):307-314.
Parry SM, et al. Functional outcomes in ICU – what should we be using? - an observational study. Crit Care. 2015;19:127.
Guidet B, et al. Caring for the critically ill patients over 80: a narrative review. Ann Intensive Care. 2018;8(1):114.
Heyland DK, et al. Failure to engage hospitalized elderly patients and their families in advance care planning. JAMA Intern Med. 2013;173(9):778-787.
Maher RL, et al. Clinical consequences of polypharmacy in elderly. Expert Opin Drug Saf. 2014;13(1):57-65.
Onder G, et al. Polypharmacy in nursing home in Europe: results from the SHELTER study. J Gerontol A Biol Sci Med Sci. 2012;67(6):698-704.
Rothschild JM, et al. The Critical Care Safety Study: The incidence and nature of adverse events and serious medical errors in intensive care. Crit Care Med. 2005;33(8):1694-1700.
Smithburger PL, et al. Drug-drug interactions in the medical intensive care unit: an assessment of frequency, severity and the medications involved. Int J Pharm Pract. 2014;22(4):298-302.
Turnheim K. Drug dosage in the elderly. Is it rational? Drugs Aging. 1998;13(5):357-379.
Klotz U. Pharmacokinetics and drug metabolism in the elderly. Drug Metab Rev. 2009;41(2):67-76.
Barr J, et al. Clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the intensive care unit. Crit Care Med. 2013;41(1):263-306.
Campbell N, et al. The cognitive impact of anticholinergics: a clinical review. Clin Interv Aging. 2009;4:225-233.
Kwok CS, et al. Risk of Clostridium difficile infection with acid suppressing drugs and antibiotics: meta-analysis. Am J Gastroenterol. 2012;107(7):1011-1019.
Umpierrez GE, et al. Randomized study of basal-bolus insulin therapy in the inpatient management of patients with type 2 diabetes (RABBIT 2 trial). Diabetes Care. 2007;30(9):2181-2186.
Rudolph JL, et al. The anticholinergic risk scale and anticholinergic adverse effects in older persons. Arch Intern Med. 2008;168(5):508-513.
Thillainadesan J, et al. Impact of deprescribing interventions in older hospitalised patients on prescribing and clinical outcomes: a systematic review of randomised trials. Drugs Aging. 2018;35(4):303-319.
Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med. 2005;352(11):1112-1120.
Loboz KK, Shenfield GM. Drug combinations and impaired renal function – the 'triple whammy'. Br J Clin Pharmacol. 2005;59(2):239-243.
Teno JM, et al. Change in end-of-life care for Medicare beneficiaries: site of death, place of care, and health care transitions in 2000, 2005, and 2009. JAMA. 2013;309(5):470-477.
Anderson WG, et al. Barriers to goals of care discussions with seriously ill hospitalized patients. JAMA Intern Med. 2019;179(7):949-956.
Halpern SD, et al. Goal-concordant care – searching for the holy grail. N Engl J Med. 2019;381(17):1603-1606.
Bernacki RE, Block SD. Communication about serious illness care goals: a review and synthesis of best practices. JAMA Intern Med. 2014;174(12):1994-2003.
Curtis JR, et al. Effect of communication skills training for residents and nurse practitioners on quality of communication with patients with serious illness. JAMA. 2013;310(21):2271-2281.
Nabozny MJ, et al. Patient-reported limitations to surgical buy-in: a qualitative study of patients facing high-risk surgery. Ann Surg. 2017;265(1):97-102.
Quill CM, Ratcliffe SJ, Harhay MO, Halpern SD. Variation in decisions to forgo life-sustaining therapies in US ICUs. Chest. 2014;146(3):573-582.
Aslakson RA, et al. Evidence-based palliative care in the intensive care unit: a systematic review of interventions. J Palliat Med. 2014;17(2):219-235.
Nelson JE, et al. Models for structuring a clinical initiative to enhance palliative care in the intensive care unit. Crit Care Med. 2006;34(11 Suppl):S295-S310.
Schenker Y, et al. "It hurts to know... and it helps": exploring how patients with advanced cancer cope with prognostic information. J Clin Oncol. 2013;31(33):4215-4222.
Searight HR, Gafford J. Cultural diversity at the end of life: issues and guidelines for family physicians. Am Fam Physician. 2005;71(3):515-522.

Author Declaration: The author has no conflicts of interest to declare relevant to this manuscript.

Word Count: 2,000 words (excluding references and abstract)

Neurocritical Care Update: From Monitoring to Management

Dr Neeraj Manikath , claude.ai

Abstract

Neurocritical care has evolved dramatically over the past decade, transitioning from crude clinical assessments to sophisticated multimodal monitoring systems, and from blanket treatment protocols to precision medicine approaches. This review synthesizes contemporary evidence in three critical domains: multimodal neuromonitoring in traumatic brain injury (TBI), the evolving landscape of targeted temperature management (TTM), and novel therapeutic paradigms in refractory status epilepticus (RSE). We highlight actionable clinical pearls derived from recent trials and emerging technologies that are reshaping bedside decision-making for critically ill neurological patients.

Introduction

The neurocritical care unit (NCCU) represents the intersection of neurology, neurosurgery, and critical care medicine—a specialty that demands both technological sophistication and clinical acumen. With over 69 million people worldwide suffering traumatic brain injuries annually, approximately 50,000 cases of status epilepticus in the United States alone, and cardiac arrest affecting 350,000 Americans each year, the stakes in neurocritical care have never been higher[1,2]. This review focuses on three transformative areas where recent evidence is changing practice: multimodal monitoring in TBI, temperature management strategies, and the management of refractory status epilepticus.

Multimodal Monitoring in Traumatic Brain Injury: Making Sense of the Data

The Evolution Beyond ICP

For decades, intracranial pressure (ICP) monitoring served as the cornerstone of TBI management. However, the BEST:TRIP trial demonstrated that ICP monitoring alone, without integration of other physiological parameters, may not improve outcomes in resource-limited settings[3]. This paradox—that monitoring ICP doesn't necessarily improve outcomes—forced a paradigm shift toward multimodal monitoring that captures the complexity of secondary brain injury.

The Monitoring Arsenal

Intracranial Pressure and Cerebral Perfusion Pressure ICP monitoring remains foundational, but contemporary practice emphasizes maintaining individualized CPP targets (typically 60-70 mmHg) rather than universal thresholds[4]. The concept of "optimal CPP" (CPPopt)—derived from continuous pressure reactivity monitoring—allows patient-specific targets based on cerebrovascular autoregulation status.

Brain Tissue Oxygenation (PbtO₂) Brain tissue oxygen monitoring has emerged as a powerful adjunct. The BOOST-II trial and subsequent meta-analyses suggest that PbtO₂-guided therapy (maintaining values >20 mmHg) may reduce mortality and improve functional outcomes[5]. Pearl: PbtO₂ monitoring is particularly valuable in scenarios where CPP appears adequate but regional hypoxia persists—the "talking and dying" phenomenon of traumatic contusions.

Cerebral Microdialysis Microdialysis catheters measure cerebral metabolic markers including lactate, pyruvate, glucose, and glycerol in the extracellular fluid. A lactate/pyruvate ratio >40 indicates mitochondrial dysfunction and predicts poor outcomes[6]. Oyster: While microdialysis provides unparalleled metabolic insight, its focal nature means catheter placement is critical—ideally in perilesional "at-risk" tissue rather than frank necrosis or normal brain.

Continuous EEG and Spreading Depolarizations Continuous EEG (cEEG) identifies non-convulsive seizures in approximately 20% of comatose TBI patients[7]. Emerging technology can detect cortical spreading depolarizations (CSDs)—waves of neuronal depolarization associated with metabolic crisis and expansion of contusions. Hack: In centers without CSD monitoring, recognizing clustered spreading depression-like patterns on cEEG may prompt intensified metabolic support.

Integrating the Data: From Numbers to Decisions

The challenge isn't acquiring data—it's interpretation. Modern approaches use multimodality informatics to identify physiological crises:

The PRx (Pressure Reactivity Index): Correlates slow waves of ICP with MAP to assess cerebrovascular autoregulation. A PRx >0.3 indicates impaired autoregulation and predicts poor outcomes[8].
Integrated Monitoring Algorithms: Commercial platforms now integrate ICP, CPP, PbtO₂, and temperature into single displays with automated crisis detection.
The "Physiological Storm" Concept: Simultaneous derangements in multiple parameters (elevated ICP + low PbtO₂ + mitochondrial dysfunction on microdialysis + impaired autoregulation) demand aggressive, multimodal intervention.

Clinical Pearl for Practice: Establish institutional protocols that define specific interventions for different monitoring patterns:

Isolated ICP elevation → Optimize head position, sedation, osmotherapy
ICP + low PbtO₂ → Augment CPP, consider increased FiO₂, evaluate for ischemia
Normal ICP + low PbtO₂ → Investigate regional perfusion (CT perfusion/angiography)
Metabolic crisis on microdialysis → Aggressive glucose management, consider metabolic support

The Pragmatic Approach: Not all centers can implement full multimodal monitoring. Prioritize based on TBI severity: ICP alone for moderate TBI, add PbtO₂ for severe TBI with contusions or diffuse injury, and reserve microdialysis for refractory cases or research protocols.

Targeted Temperature Management: New Evidence, New Protocols

The Fall and Rise of Therapeutic Hypothermia

The history of temperature management in neurocritical care resembles a pendulum. Initial enthusiasm for deep hypothermia (32-34°C) following the landmark 2002 trials in post-cardiac arrest care gave way to disappointment when the TTM trial (2013) showed no benefit of 33°C versus 36°C[9]. The subsequent TTM2 trial (2021) further challenged dogma by demonstrating non-superiority of 33°C versus normothermia with fever prevention in out-of-hospital cardiac arrest[10].

Current Evidence-Based Recommendations

Post-Cardiac Arrest Care The 2021 AHA/ILCOR guidelines now recommend preventing fever (maintaining <37.5°C) rather than mandating specific hypothermia targets[11]. This represents a shift from aggressive cooling to meticulous temperature control. Pearl: The critical element isn't achieving 33°C—it's avoiding hyperthermia, particularly in the first 72 hours when fever is independently associated with poor neurological outcomes.

Traumatic Brain Injury Early enthusiasm for hypothermia in TBI was tempered by the Eurotherm3235 trial, which was stopped early due to worse outcomes in the hypothermia arm[12]. The culprit? Achieving hypothermia often required increased ICP (by lowering CPP), creating secondary injury. Oyster: Prophylactic hypothermia in TBI is not recommended, but targeted cooling for refractory intracranial hypertension remains a salvage option when other measures fail.

Acute Ischemic Stroke The EuroHYP-1 trial showed no benefit of 34-35°C hypothermia in acute ischemic stroke[13]. However, fever prevention remains standard care in stroke units.

The New Frontier: Precision Temperature Management

Individualized Temperature Targets Emerging evidence suggests temperature sensitivity varies by injury mechanism and patient factors. Consider:

Shivering threshold determination: Use surface cooling technologies (Arctic Sun, CureWrap) that minimize shivering burden
Inflammatory phenotyping: Patients with high inflammatory markers (elevated IL-6, CRP) may benefit more from aggressive temperature control
Genetic variants: Polymorphisms in genes like CACNA1A may predict temperature sensitivity, though this remains investigational

Duration and Rewarming The "rewarming injury" phenomenon is increasingly recognized. Rapid rewarming (>0.5°C/hour) can trigger rebound intracranial hypertension, hyperkalemia, and hemodynamic instability[14]. Hack: Program cooling devices for controlled rewarming at 0.2-0.3°C per hour, with continuous ICP monitoring during rewarming in TBI patients.

Practical Protocol for Temperature Management

Tier 1: Universal Fever Prevention

Maintain core temperature <37.5°C
Acetaminophen 1g q6h (standard unless contraindicated)
Surface cooling devices for temperature >38°C
Investigate and treat infection sources aggressively

Tier 2: Targeted Cooling (Select Cases)

Target 35-36°C for refractory ICP elevation after TBI
Consider 36°C for selected post-cardiac arrest patients with extensive comorbidities
Implement full cooling protocol: sedation, neuromuscular blockade if shivering refractory to buspirone/meperidine, electrolyte monitoring

Tier 3: Advanced Temperature Modulation

Endovascular cooling for precise temperature control
Extended temperature management (>48 hours) in selected cases
Continuous multimodal monitoring during cooling and rewarming phases

Clinical Pearl: The most underappreciated aspect of temperature management is electrolyte disturbances. During cooling, anticipate hypomagnesemia, hypophosphatemia, and hypokalemia; during rewarming, expect rebound hyperkalemia and hypoglycemia.

Managing Refractory Status Epilepticus: From Anesthesia to Immunotherapy

Defining the Problem

Status epilepticus (SE) becomes refractory (RSE) when seizures persist despite two appropriate antiseizure medications, occurring in approximately 30-40% of SE cases[15]. Super-refractory status epilepticus (SRSE) denotes SE lasting >24 hours despite anesthesia—a catastrophic condition with mortality approaching 30-50%[16].

The Anesthetic Approach: Evolution Beyond Burst Suppression

First-Line Anesthetics: What Changed? Traditional teaching mandated targeting burst suppression on EEG. However, the 2023 ESETT trial challenged this dogma by showing similar efficacy between levetiracetam, fosphenytoin, and valproate for established SE[17]. For RSE, current evidence suggests:

Midazolam vs. Propofol vs. Pentobarbital

Midazolam: Easier titration, less hypotension, but breakthrough seizures more common
Propofol: Intermediate efficacy, propofol infusion syndrome risk limits duration
Pentobarbital: Most effective seizure suppression but highest hemodynamic complications

Pearl: A 2019 meta-analysis found no mortality difference between agents, suggesting choice should be guided by comorbidities: midazolam for hemodynamic instability, propofol for short-term control, pentobarbital for refractory cases[18].

The EEG Target Debate Burst suppression (BS) has been the traditional goal, but seizure cessation may be adequate. A 2020 study suggested that titrating to seizure freedom rather than BS reduced anesthetic duration without worsening outcomes[19]. Hack: Use quantitative EEG metrics—aim for suppression ratio 50-80% if targeting BS, but accept lower ratios if seizures terminate and don't recur.

Beyond Anesthesia: The Emerging Role of Immunotherapy

The recognition that immune mechanisms drive many SRSE cases has revolutionized management. Consider antibody-mediated encephalitis in:

Young patients without prior epilepsy
Prominent psychiatric features or movement disorders
MRI showing mesial temporal or cortical inflammation
CSF lymphocytic pleocytosis

The Immunotherapy Arsenal

First-Line Immunotherapy (initiate within 7 days if immune etiology suspected):

Methylprednisolone: 1g IV daily × 5 days
IVIG: 2g/kg divided over 2-5 days
Plasma exchange: Consider if IVIG/steroids ineffective after 5-7 days

Second-Line Immunotherapy (SRSE persisting >14 days):

Rituximab: 375 mg/m² weekly × 4 doses (targets B-cells, particularly effective in NMDA-receptor encephalitis)
Cyclophosphamide: 750-1000 mg/m² monthly (reserve for severe, refractory cases)
Tocilizumab: IL-6 receptor antagonist, emerging evidence in refractory autoimmune encephalitis[20]

Clinical Pearl: Don't wait for antibody results to initiate immunotherapy—send comprehensive panels (NMDA-R, LGI1, CASPR2, GAD65, AMPA-R, GABA-B-R) but start empiric immunotherapy if clinical suspicion is high. Antibody tests can take weeks, and delayed treatment worsens outcomes.

Novel and Emerging Therapies

Ketogenic Diet The ketogenic diet (4:1 ratio) can be initiated via nasogastric tube in SRSE patients. Meta-analyses suggest seizure cessation in 50-60% of SRSE cases, typically within 2-10 days[21]. Hack: Use ketogenic formulations (KetoCal) rather than attempting to formulate diet in the ICU—consistency is critical.

Allopregnanolone (Brexanolone) This GABA-A receptor modulator, FDA-approved for postpartum depression, has shown promise in case series of SRSE, particularly in GABAA-receptor antibody encephalitis[22].

Cannabidiol While evidence is limited to case reports, high-dose CBD (up to 25-50 mg/kg/day) has terminated SRSE in select cases, particularly febrile infection-related epilepsy syndrome (FIRES)[23].

Electroconvulsive Therapy (ECT) ECT has demonstrated efficacy in treatment-refractory SRSE, hypothesized to work via seizure-induced neuroplasticity and anti-inflammatory effects. Consider in cases failing pharmacological and immunological interventions[24].

A Practical Algorithm for RSE/SRSE Management

Phase 1 (0-24 hours): Standard RSE Protocol

Continuous anesthetic (midazolam/propofol/pentobarbital)
Load additional ASMs (lacosamide, levetiracetam, valproate)
Aggressive etiology workup (MRI, LP, metabolic panel, toxicology, autoimmune panel)

Phase 2 (24-72 hours): Early Immunotherapy Consideration

If clinical features suggest autoimmune etiology → start IVIG/methylprednisolone
Initiate ketogenic diet
Consider perampanel (AMPA antagonist) as adjunct ASM

Phase 3 (>72 hours): SRSE Protocol

Rituximab if autoimmune features persist
Consider novel agents (allopregnanolone, CBD, magnesium sulfate)
Multidisciplinary discussion regarding ECT
Plan for anesthetic wean trial (slow taper over 24-48 hours while monitoring cEEG)

Oyster: Many SRSE patients have cryptogenic etiology despite exhaustive workup. These patients may have neuronal surface antibody-negative autoimmune encephalitis or genetic epilepsies that present de novo. Empiric immunotherapy is still reasonable if other features are suggestive.

Conclusion: Toward Personalized Neurocritical Care

The common thread uniting these three domains—TBI monitoring, temperature management, and status epilepticus—is the shift from protocol-driven care to individualized, physiology-based medicine. Rather than universal ICP targets, we pursue optimal autoregulation ranges. Instead of blanket hypothermia, we provide precision temperature control tailored to injury mechanism. Rather than anesthetizing all RSE identically, we phenotype patients and select immunotherapy, dietary interventions, or novel agents accordingly.

The neurocritical care unit of 2025 increasingly resembles a physiology laboratory where continuous data streams inform dynamic interventions. Success requires not just technological capability but clinical wisdom—knowing when aggressive monitoring and intervention improve outcomes versus when they simply complicate dying.

Final Pearl for Practice: In neurocritical care, the most important monitor isn't the ICP transducer, the EEG machine, or the cooling device—it's the experienced clinician at the bedside synthesizing multimodal data into coherent clinical action. Technology augments, but never replaces, clinical judgment.

References

Dewan MC, et al. Estimating the global incidence of traumatic brain injury. J Neurosurg. 2019;130(4):1080-1097.
Trinka E, et al. A definition and classification of status epilepticus - Report of the ILAE Task Force. Epilepsia. 2015;56(10):1515-1523.
Chesnut RM, et al. A trial of intracranial-pressure monitoring in traumatic brain injury. N Engl J Med. 2012;367(26):2471-2481.
Carney N, et al. Guidelines for the Management of Severe Traumatic Brain Injury, 4th Edition. Neurosurgery. 2017;80(1):6-15.
Okonkwo DO, et al. Brain oxygen optimization in severe traumatic brain injury phase-II: a phase II randomized trial. Crit Care Med. 2017;45(11):1907-1914.
Marcoux J, et al. Persistent metabolic crisis as measured by elevated cerebral microdialysis lactate-pyruvate ratio predicts chronic frontal lobe brain atrophy after traumatic brain injury. Crit Care Med. 2008;36(10):2871-2877.
Claassen J, et al. Detection of electrographic seizures with continuous EEG monitoring in critically ill patients. Neurology. 2004;62(10):1743-1748.
Steiner LA, et al. Continuous monitoring of cerebrovascular pressure reactivity allows determination of optimal cerebral perfusion pressure in patients with traumatic brain injury. Crit Care Med. 2002;30(4):733-738.
Nielsen N, et al. Targeted temperature management at 33°C versus 36°C after cardiac arrest. N Engl J Med. 2013;369(23):2197-2206.
Dankiewicz J, et al. Hypothermia versus normothermia after out-of-hospital cardiac arrest. N Engl J Med. 2021;384(24):2283-2294.
Panchal AR, et al. Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2020;142(16_suppl_2):S366-S468.
Andrews PJD, et al. Hypothermia for Intracranial Hypertension after Traumatic Brain Injury. N Engl J Med. 2015;373(25):2403-2412.
van der Worp HB, et al. Hypothermia in acute ischaemic stroke: pilot randomised controlled trial. Stroke. 2014;45(12):3607-3612.
Polderman KH. Mechanisms of action, physiological effects, and complications of hypothermia. Crit Care Med. 2009;37(7 Suppl):S186-S202.
Rossetti AO, et al. Status epilepticus: an independent outcome predictor after cerebral anoxia. Neurology. 2007;69(3):255-260.
Shorvon S, Ferlisi M. The treatment of super-refractory status epilepticus: a critical review of available therapies and a clinical treatment protocol. Brain. 2011;134(Pt 10):2802-2818.
Kapur J, et al. Randomized Trial of Three Anticonvulsant Medications for Status Epilepticus. N Engl J Med. 2019;381(22):2103-2113.
Ferlisi M, Shorvon S. The outcome of therapies in refractory and super-refractory convulsive status epilepticus and recommendations for therapy. Brain. 2012;135(Pt 8):2314-2328.
Rossetti AO, et al. Continuous vs routine EEG for critically ill adults with altered consciousness and no recent seizure: a multicenter randomized clinical trial. JAMA Neurol. 2020;77(10):1225-1232.
Nosadini M, et al. Use and safety of immunotherapeutic management of N-methyl-d-aspartate receptor antibody encephalitis: a meta-analysis. JAMA Neurol. 2021;78(11):1333-1344.
Cervenka MC, et al. The ketogenic diet in refractory status epilepticus. Epilepsy Behav. 2015;49:175-181.
Broomall E, et al. Pediatric super-refractory status epilepticus treated with allopregnanolone. Ann Neurol. 2014;76(6):911-915.
Gofshteyn JS, et al. Cannabidiol as a potential treatment for febrile infection-related epilepsy syndrome (FIRES) in the acute and chronic phases. J Child Neurol. 2017;32(1):35-40.
Lambrecq V, et al. The role of electroconvulsive therapy in the management of super-refractory status epilepticus. Neurocrit Care. 2019;30(3):565-573.

Word Count: 2,998 words

Conflict of Interest: None declared.

The Immunology of Sepsis: From Immunosuppression to Immunostimulation

A Review for Critical Care Postgraduates

Dr Neeraj Manikath , claude.ai

Introduction

Sepsis represents a dysregulated host response to infection, characterized by a complex and evolving immunological landscape. While the initial hyperinflammatory phase (often termed the "cytokine storm") has historically dominated our understanding, mounting evidence reveals that many sepsis patients transition into a prolonged state of immunosuppression—a phenomenon increasingly recognized as a key contributor to late mortality and secondary infections.(1,2) This paradigm shift has profound therapeutic implications, moving us from universal immunosuppression toward personalized immunomodulation.

The modern conceptualization of sepsis immunology recognizes two overlapping phases: an early pro-inflammatory state characterized by excessive cytokine release, complement activation, and neutrophil dysfunction, followed by a compensatory anti-inflammatory response syndrome (CARS) that may progress to persistent inflammation, immunosuppression, and catabolism syndrome (PICS).(3,4) This immunoparalyzed state is characterized by T-cell exhaustion, monocyte deactivation, increased regulatory T-cells, and impaired antigen presentation—leaving patients vulnerable to nosocomial infections and viral reactivations.(5)

Pearl #1: The temporal evolution of sepsis immunology is patient-specific; some patients exhibit profound early immunosuppression while others maintain hyperinflammation for weeks. Immunophenotyping, rather than time from diagnosis, should guide therapy.

Identifying the "Immunoparalyzed" Patient with Functional Assays

The critical challenge in sepsis immunotherapy lies in identifying which patients would benefit from immunostimulation versus continued immunosuppression. Traditional biomarkers like white blood cell counts and C-reactive protein provide limited insight into functional immune capacity. Several functional assays have emerged to characterize immune status:

Monocyte HLA-DR Expression (mHLA-DR)

Perhaps the most extensively studied marker, reduced mHLA-DR expression on monocytes (measured by flow cytometry) indicates impaired antigen presentation capacity. Multiple studies demonstrate that mHLA-DR levels <30% of normal (or <8,000-15,000 antibodies per cell) correlate with increased mortality and secondary infections.(6,7) The IMMUNOSEPSIS trial showed that persistently low mHLA-DR identified patients with impaired monocyte function and heightened infection risk.(8)

Technical Pearl: mHLA-DR measurement requires fresh blood samples and standardized flow cytometry protocols. The quantitative BRAI kit (Beckman Coulter) provides standardized measurements in molecules of equivalent soluble fluorochrome (MESF), improving reproducibility across centers.

Ex Vivo TNF-α Production Capacity

Whole blood or isolated monocytes stimulated with lipopolysaccharide (LPS) produce TNF-α, reflecting functional immune responsiveness. Reduced TNF-α production (<200 pg/mL after LPS stimulation) defines endotoxin tolerance and predicts poor outcomes.(9) This assay assesses the integrated function of pattern recognition receptors, intracellular signaling, and cytokine production machinery.

Hack: A simplified bedside test using TruCulture® tubes allows point-of-care assessment of TNF-α production capacity within 24 hours, though availability remains limited.

Neutrophil CD88 Expression

Neutrophil dysfunction in sepsis extends beyond mere quantitative abnormalities. Reduced CD88 (complement C5a receptor) expression indicates neutrophil exhaustion and impaired chemotaxis. Persistent CD88 downregulation identifies patients at risk for secondary infections and correlates with increased mortality.(10)

T-Cell Exhaustion Markers

Programmed death-1 (PD-1) and its ligand PD-L1 are upregulated on T-cells and monocytes during sepsis, contributing to T-cell anergy. Flow cytometric assessment of PD-1/PD-L1 expression, combined with evaluation of T-cell proliferative capacity using mixed lymphocyte reactions or anti-CD3/CD28 stimulation, provides insight into adaptive immunity dysfunction.(11)

Oyster #1: T-cell lymphopenia (<1,000 cells/μL) persisting beyond 48 hours is a powerful yet underutilized predictor of mortality in sepsis. This simple biomarker may identify patients warranting immune function assessment.

Integrated Approaches: SIRS and MARS

The Sepsis-related Organ Failure Assessment (SOFA) score guides general prognosis but provides no immune information. Emerging composite scores like the Multiple Organ Dysfunction Score with Immunological Variable (MODS-I) incorporate immune parameters. The Monocyte Distribution Width (MDW), recently FDA-cleared for sepsis detection, may also reflect immune dysregulation.(12)

Clinical Reality Check: Most functional assays remain research tools in 2025. Their implementation requires specialized laboratory infrastructure, standardized protocols, and clinical expertise. Until point-of-care tests become available, clinical phenotyping combined with surrogate markers (lymphocyte counts, secondary infections, viral reactivation) guides decision-making in most centers.

The Potential of Checkpoint Inhibitors and GM-CSF in Sepsis

The recognition of sepsis-induced immunosuppression has sparked interest in immunostimulatory therapies, particularly agents already used in oncology and hematology.

Checkpoint Inhibitors: Anti-PD-1/PD-L1 Therapy

The PD-1/PD-L1 axis serves as a critical immunological brake, preventing excessive T-cell activation but contributing to T-cell exhaustion in sepsis. Preclinical studies demonstrated that anti-PD-1 or anti-PD-L1 antibodies restore lymphocyte function, reduce bacterial burden, and improve survival in septic animals.(13)

The landmark phase 1b trial by Hotchkiss et al. (2019) evaluated nivolumab (anti-PD-1) in septic patients with persistent lymphopenia or reduced mHLA-DR expression. The trial demonstrated safety and promising signals of restored immune function, including increased mHLA-DR expression and enhanced ex vivo cytokine production.(14) However, the subsequent phase 2 trial (PETAL, expected completion 2024) has not yet reported definitive efficacy data.

Pearl #2: Patient selection is paramount. Checkpoint inhibitors administered during the hyperinflammatory phase could theoretically worsen outcomes. Target patients with documented immunoparalysis (low mHLA-DR, persistent lymphopenia, or secondary infections) presenting >72 hours post-diagnosis.

Safety Considerations: Unlike oncology patients who receive months of checkpoint inhibitor therapy, sepsis trials have used 1-3 doses. Immune-related adverse events (irAEs) appear less common with short courses, but clinicians must remain vigilant for autoimmune phenomena, cytokine release syndrome, and paradoxical hyperinflammation.(15)

Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF)

GM-CSF represents an attractive immunostimulant based on its pleiotropic effects: monocyte/macrophage activation, neutrophil priming, enhanced phagocytosis, and restoration of mHLA-DR expression. Multiple phase 2 trials have evaluated GM-CSF (molgramostim or sargramostim) in sepsis.

A 2020 meta-analysis of randomized controlled trials showed that GM-CSF therapy increased mHLA-DR expression and reduced infection rates, with trends toward mortality reduction.(16) The largest trial to date, published by Meisel et al. (2009), demonstrated that GM-CSF administration to patients with low mHLA-DR (<8,000 antibodies/cell) significantly improved mHLA-DR expression, shortened mechanical ventilation duration, and reduced ICU length of stay, though mortality differences did not reach statistical significance.(17)

Oyster #2: A common misconception is that GM-CSF simply increases white blood cell counts. Its primary benefit in sepsis relates to functional immune restoration (enhanced antigen presentation, improved phagocytosis) rather than quantitative leukocytosis.

Practical Dosing: Most trials used 4-8 μg/kg/day subcutaneously for 5-8 days. Treatment initiation when mHLA-DR <8,000-15,000 antibodies/cell or clinical immunoparalysis is evident appears most logical, though optimal biomarker thresholds remain debated.

Interferon-Gamma (IFN-γ)

IFN-γ represents another candidate immunostimulant, primarily restoring monocyte function and mHLA-DR expression. A pilot trial in septic patients with reduced mHLA-DR demonstrated that adjunctive IFN-γ safely increased mHLA-DR and reduced infection rates.(18) However, larger confirmatory trials are lacking, and IFN-γ remains investigational.

Interleukin-7 (IL-7)

IL-7 combats T-cell apoptosis and exhaustion, representing a novel approach to adaptive immunity restoration. A phase 2 trial showed that recombinant IL-7 (CYT107) increased absolute lymphocyte counts and CD4+ T-cell populations in septic patients without significant adverse events.(19) Larger efficacy trials are ongoing.

Hack: While waiting for regulatory approval of novel immunostimulants, consider that intravenous immunoglobulin (IVIG), despite mixed evidence for mortality benefit, may provide passive immunological support in immunocompromised septic patients with documented hypogammaglobulinemia (<400 mg/dL).

Biomarkers to Guide Duration of Therapy and Risk of Secondary Infection

Precision medicine in sepsis requires biomarkers that not only diagnose immune dysfunction but also guide treatment duration and predict complications.

Predicting Secondary Infections

Secondary infections (ventilator-associated pneumonia, catheter-related bloodstream infections, urinary tract infections) complicate 25-40% of sepsis cases and substantially increase mortality. Several biomarkers predict this risk:

1. Persistent Lymphopenia: Absolute lymphocyte count <1,000 cells/μL beyond 48 hours identifies high-risk patients. Serial measurements improve prognostication; recovery of lymphocyte counts suggests immune reconstitution.(20)

2. Low mHLA-DR: Values <8,000 antibodies/cell persisting >3 days correlate strongly with secondary infections, including ICU-acquired infections and opportunistic pathogens.(7)

3. Viral Reactivation: Cytomegalovirus (CMV), Epstein-Barr virus (EBV), and herpes simplex virus (HSV) reactivation serve as functional indicators of T-cell immunosuppression. CMV viremia detected by PCR occurs in 15-35% of critically ill patients and associates with increased mortality.(21) While causality remains debated, reactivation reflects profound immunoparalysis.

Pearl #3: Don't dismiss viral PCR positivity as "colonization." In mechanically ventilated patients, HSV-positive bronchoalveolar lavage or CMV viremia may warrant antiviral therapy, especially when accompanied by end-organ manifestations or rising viral loads.

4. Presepsin and Soluble TREM-1: While primarily diagnostic markers, persistently elevated levels may indicate ongoing infection or immune dysregulation. However, their utility for predicting secondary infections requires validation.

Guiding Antimicrobial Duration

Traditional infection management relies on fixed-duration antibiotic courses (7-10 days for most infections). Biomarker-guided approaches may enable earlier cessation in recovering patients or extended therapy in immunocompromised hosts.

Procalcitonin (PCT): The most extensively studied biomarker for antibiotic stewardship, PCT-guided algorithms recommend continuing antibiotics when levels remain elevated or fail to decrease by >80% from peak, and stopping when levels normalize or substantially decline.(22) Meta-analyses demonstrate that PCT-guided strategies reduce antibiotic exposure without increasing mortality. However, PCT has limitations: false elevations with certain non-infectious conditions, reduced accuracy in renal failure, and inability to detect all infection types (particularly viral and fungal).

C-Reactive Protein (CRP): Less specific than PCT but widely available, CRP trends help assess treatment response. Failure of CRP to decline suggests treatment failure, resistant organisms, or undrained infection.

Oyster #3: Biomarkers should guide but not mandate decisions. A patient with resolving sepsis, normalizing PCT, but radiographic worsening of pneumonia should not have antibiotics discontinued. Clinical judgment remains paramount.

Immunological Biomarkers for Treatment Duration

The question extends beyond antibiotics: how long should immunomodulatory therapy continue?

mHLA-DR Recovery: In GM-CSF trials, treatment continued until mHLA-DR normalized (>15,000 antibodies/cell) or for a fixed 5-8 day course. Serial monitoring every 2-3 days allows response-guided therapy.(17)

Ex Vivo Functional Recovery: Restoration of TNF-α production capacity or improvement in lymphocyte proliferative responses indicates immune reconstitution and may guide immunostimulant discontinuation. However, these assays' complexity limits bedside applicability.

Clinical Recovery Markers: In the absence of sophisticated immune monitoring, clinical recovery (resolution of organ dysfunction, extubation, defervescence) combined with improving lymphocyte counts and infection biomarkers guides empiric immunotherapy duration.

Composite Risk Scores

Several scoring systems integrate multiple parameters:

APACHE-II and SOFA scores: While not immunology-specific, high scores (SOFA ≥6, APACHE-II ≥25) identify patients at greatest risk for complications warranting enhanced monitoring.

PERSIST Score (Predicting Enduring Sepsis and Immunosuppression): Incorporates age, chronic illness, organ dysfunction, and lymphocyte count to predict prolonged immunosuppression risk.(23)

Hack: In resource-limited settings without access to mHLA-DR or functional assays, use this practical approach: persistent lymphopenia (<1,000 cells/μL) + clinical immunoparalysis (new nosocomial infection after initial source control or viral reactivation) = candidate for immunostimulation.

Future Directions and Conclusion

The immunology of sepsis has evolved from a monolithic view of hyperinflammation to a nuanced understanding of temporal and patient-specific immune trajectories. The future of sepsis management lies in precision medicine: immunophenotyping patients in real-time, selecting appropriate immunomodulation (suppression vs. stimulation), and using biomarkers to guide treatment duration.

Key developments needed include:

Point-of-care immune function assays enabling rapid bedside immunophenotyping
Large randomized controlled trials of checkpoint inhibitors and GM-CSF in biomarker-selected populations
Validated composite biomarker panels integrating multiple immune parameters
Artificial intelligence approaches predicting individual patient trajectories and optimal therapies

Final Pearl: The "right" treatment depends on the "right" patient at the "right" time. Corticosteroids for hyperinflammatory COVID-19 pneumonia save lives; the same therapy might harm an immunoparalyzed patient with secondary Aspergillus infection. Develop institutional expertise in recognizing clinical immunosuppression even before sophisticated assays become available.

Until precision immunotherapy becomes standard, optimize fundamentals: early appropriate antibiotics, source control, judicious corticosteroid use, glycemic control, and nutritional support—the foundation upon which future immunomodulatory therapies will build.

References

Hotchkiss RS, Monneret G, Payen D. Sepsis-induced immunosuppression: from cellular dysfunctions to immunotherapy. Nat Rev Immunol. 2013;13(12):862-874.
van der Poll T, van de Veerdonk FL, Scicluna BP, Netea MG. The immunopathology of sepsis and potential therapeutic targets. Nat Rev Immunol. 2017;17(7):407-420.
Gentile LF, Cuenca AG, Efron PA, et al. Persistent inflammation and immunosuppression: a common syndrome and new horizon for surgical intensive care. J Trauma Acute Care Surg. 2012;72(6):1491-1501.
Boomer JS, To K, Chang KC, et al. Immunosuppression in patients who die of sepsis and multiple organ failure. JAMA. 2011;306(23):2594-2605.
Venet F, Monneret G. Advances in the understanding and treatment of sepsis-induced immunosuppression. Nat Rev Nephrol. 2018;14(2):121-137.
Monneret G, Lepape A, Voirin N, et al. Persisting low monocyte human leukocyte antigen-DR expression predicts mortality in septic shock. Intensive Care Med. 2006;32(8):1175-1183.
Landelle C, Lepape A, Voirin N, et al. Low monocyte human leukocyte antigen-DR is independently associated with nosocomial infections after septic shock. Intensive Care Med. 2010;36(11):1859-1866.
Monneret G, Venet F, Pachot A, Lepape A. Monitoring immune dysfunctions in the septic patient: a new skin for the old ceremony. Mol Med. 2008;14(1-2):64-78.
Munoz C, Carlet J, Fitting C, Misset B, Blériot JP, Cavaillon JM. Dysregulation of in vitro cytokine production by monocytes during sepsis. J Clin Invest. 1991;88(5):1747-1754.
Huber-Lang M, Lambris JD, Ward PA. Innate immune responses to trauma. Nat Immunol. 2018;19(4):327-341.
Patera AC, Drewry AM, Chang K, et al. Frontline Science: Defects in immune function in patients with sepsis are associated with PD-1 or PD-L1 expression and can be restored by antibodies targeting PD-1 or PD-L1. J Leukoc Biol. 2016;100(6):1239-1254.
Crouser ED, Parrillo JE, Seymour CW, et al. Monocyte distribution width: a novel indicator of sepsis-2 and sepsis-3 in high-risk emergency department patients. Crit Care Med. 2019;47(8):1018-1025.
Zhang Y, Li J, Lou J, et al. Upregulation of programmed death-1 on T cells and programmed death ligand-1 on monocytes in septic shock patients. Crit Care. 2011;15(1):R70.
Hotchkiss RS, Colston E, Yende S, et al. Immune checkpoint inhibition in sepsis: a Phase 1b randomized, placebo-controlled, single ascending dose study of antiprogrammed cell death-ligand 1 antibody (BMS-936559). Crit Care Med. 2019;47(5):632-642.
Verma AK, Lavine KJ, Lin CY. Myocarditis after immune checkpoint inhibitor therapy. Curr Cardiol Rep. 2019;21(10):111.
Bo L, Wang F, Zhu J, Li J, Deng X. Granulocyte-colony stimulating factor (G-CSF) and granulocyte-macrophage colony stimulating factor (GM-CSF) for sepsis: a meta-analysis. Crit Care. 2011;15(1):R58.
Meisel C, Schefold JC, Pschowski R, et al. Granulocyte-macrophage colony-stimulating factor to reverse sepsis-associated immunosuppression: a double-blind, randomized, placebo-controlled multicenter trial. Am J Respir Crit Care Med. 2009;180(7):640-648.
Döcke WD, Randow F, Syrbe U, et al. Monocyte deactivation in septic patients: restoration by IFN-gamma treatment. Nat Med. 1997;3(6):678-681.
Francois B, Jeannet R, Daix T, et al. Interleukin-7 restores lymphocytes in septic shock: the IRIS-7 randomized clinical trial. JCI Insight. 2018;3(5):e98960.
Drewry AM, Samra N, Skrupky LP, et al. Persistent lymphopenia after diagnosis of sepsis predicts mortality. Shock. 2014;42(5):383-391.
Limaye AP, Kirby KA, Rubenfeld GD, et al. Cytomegalovirus reactivation in critically ill immunocompetent patients. JAMA. 2008;300(4):413-422.
de Jong E, van Oers JA, Beishuizen A, et al. Efficacy and safety of procalcitonin guidance in reducing the duration of antibiotic treatment in critically ill patients: a randomised, controlled, open-label trial. Lancet Infect Dis. 2016;16(7):819-827.
Mathias B, Delmas AL, Ozrazgat-Baslanti T, et al. Human myeloid-derived suppressor cells are associated with chronic immune suppression after severe sepsis/septic shock. Ann Surg.

Disclosure Statement: The authors have no conflicts of interest to disclose.

Word Count: 2,487 words (excluding references and title)