Wednesday, October 1, 2025

Point-of-Care Ultrasound (POCUS): The ICU Physician's Stethoscope

 

Point-of-Care Ultrasound (POCUS): The ICU Physician's Stethoscope

A Comprehensive Review for Critical Care Trainees

Dr Neeraj Manikath , claude.ai

ABSTRACT

Point-of-care ultrasound (POCUS) has emerged as an indispensable diagnostic and monitoring tool in modern intensive care units, fundamentally transforming the bedside assessment of critically ill patients. This review provides a comprehensive overview of essential POCUS applications for critical care physicians, focusing on structured protocols for shock assessment, fluid responsiveness evaluation, and thoracic pathology identification. We examine the Rapid Ultrasound in Shock (RUSH) examination, the Fluid Administration Limited by Lung Sonography (FALLS) protocol, lung ultrasound interpretation, and inferior vena cava (IVC) assessment. Through evidence-based recommendations, practical pearls, and common pitfalls, this article aims to enhance the diagnostic acumen of postgraduate trainees and practicing intensivists. POCUS, when properly utilized, serves as the modern stethoscope—extending the physical examination beyond traditional limitations while maintaining the art of bedside clinical reasoning.

Keywords: Point-of-care ultrasound, POCUS, critical care, RUSH examination, FALLS protocol, lung ultrasound, shock, fluid responsiveness, inferior vena cava

INTRODUCTION

The evolution of critical care medicine has witnessed a paradigm shift from invasive monitoring to non-invasive, real-time bedside diagnostics. Point-of-care ultrasound (POCUS) represents the culmination of this transformation, enabling intensivists to answer critical clinical questions within seconds at the bedside.[1,2] Unlike consultative ultrasonography performed by radiologists or cardiologists, POCUS is goal-directed, hypothesis-driven, and integrated into clinical decision-making in real-time.[3]

The stethoscope, invented by René Laennec in 1816, revolutionized bedside diagnosis by allowing physicians to auscultate internal organs non-invasively.[4] Nearly two centuries later, POCUS has assumed a similar—yet more profound—role, providing visual and hemodynamic data that transcends the limitations of physical examination. Studies demonstrate that POCUS changes management in 40-50% of critically ill patients and improves diagnostic accuracy by up to 25% compared to clinical examination alone.[5,6]

This review focuses on four cornerstone applications of POCUS in the intensive care unit: the RUSH examination for undifferentiated shock, the FALLS protocol for goal-directed fluid therapy, lung ultrasound for respiratory pathology, and IVC assessment for fluid responsiveness. Mastery of these techniques is essential for contemporary critical care practice.

THE RUSH EXAMINATION FOR UNDIFFERENTIATED SHOCK

Historical Development and Rationale

The Rapid Ultrasound in Shock and Hypotension (RUSH) examination was formalized by Weingart and colleagues in 2009-2010 as a systematic, goal-directed approach to the undifferentiated hypotensive patient.[7,8] Recognizing that shock represents a final common pathway of diverse pathophysiologic processes, the RUSH exam provides a structured framework to rapidly identify the etiology and guide resuscitation.

The traditional classification of shock—distributive, cardiogenic, hypovolemic, and obstructive—each has distinct ultrasound findings. The RUSH examination organizes the assessment into three components: "the pump" (heart), "the tank" (volume status and IVC), and "the pipes" (vascular system and bleeding sources).[7]

The Three-Component RUSH Protocol

1. The Pump: Cardiac Assessment

The cardiac evaluation begins with a subcostal view, which is often the most accessible in critically ill patients with mechanical ventilation.[9] Key parameters include:

  • Global contractility: Visual assessment of left ventricular (LV) function provides rapid categorization as hyperdynamic, normal, or severely depressed. While subjective, experienced operators demonstrate excellent correlation with quantitative ejection fraction (EF) measurements.[10]

  • Right ventricular (RV) size and function: RV dilation (RV:LV ratio >0.9-1.0 in apical 4-chamber view) with septal flattening (D-sign) suggests acute cor pulmonale, most commonly from massive pulmonary embolism.[11,12] The McConnell sign (RV free wall akinesis with preserved apical contractility) is specific but insensitive for PE.[13]

  • Pericardial effusion: Even small effusions in the setting of hypotension demand consideration of tamponade. Look for right atrial and right ventricular diastolic collapse, which are sensitive and specific signs.[14,15] Remember that loculated effusions post-cardiac surgery may cause tamponade without classic circumferential fluid.

Pearl: In shock, "eyeball" ejection fraction is sufficient—hyperdynamic (EF >70%), normal (EF 55-70%), moderately reduced (EF 30-55%), or severely reduced (EF <30%). Attempting precise EF calculation wastes time and adds little clinical value.[16]

Oyster: A hyperdynamic heart does NOT exclude cardiogenic shock. Early septic cardiomyopathy and neurogenic shock may present with preserved or elevated EF with inadequate perfusion pressure due to severe vasodilation.[17,18]

2. The Tank: Volume Status Assessment

Assessment of intravascular volume involves IVC visualization (discussed in detail later) and evaluation for hypovolemia or hypervolemia. An IVC diameter <1.5 cm with >50% respiratory collapse suggests hypovolemia in mechanically ventilated patients, while a plethoric IVC (>2.5 cm with minimal collapse) indicates volume overload or elevated right atrial pressure.[19,20]

Hack: If you cannot visualize the IVC subcostally due to bowel gas, try a right lateral approach through the liver. Alternatively, evaluate the internal jugular vein (IJV) in the supine patient—a collapsed IJV suggests hypovolemia, while distension implies elevated central venous pressure.[21]

3. The Pipes: Identifying Bleeding and Vascular Catastrophes

The "pipes" component searches for intraperitoneal, retroperitoneal, and thoracic hemorrhage or vascular emergencies.

  • E-FAST examination: Extended Focused Assessment with Sonography in Trauma (E-FAST) evaluates Morrison's pouch, splenorenal recess, pelvis, and both hemithoraces for free fluid. In trauma, intraperitoneal free fluid has 73-88% sensitivity for hemoperitoneum.[22,23]

  • Abdominal aortic aneurysm (AAA): Measure the aorta in transverse and longitudinal planes. An outer wall diameter >3 cm defines aneurysm. Emergency physicians demonstrate 99% sensitivity for detecting AAA using POCUS.[24]

  • Deep vein thrombosis (DVT): Two-point compression ultrasound of the common femoral vein and popliteal vein has 95-100% sensitivity for proximal DVT.[25] Non-compressibility is the key finding.

Pearl: In undifferentiated shock, always scan the aorta. Up to 30% of ruptured AAAs present without classic triad of pain, hypotension, and pulsatile mass.[26]

Oyster: Free fluid on FAST examination in a pregnant trauma patient may be amniotic fluid, not blood. Correlation with hematocrit, mechanism of injury, and clinical trajectory is essential.[27]

Evidence Base and Outcomes

Multiple studies demonstrate that RUSH-protocol-guided resuscitation improves diagnostic accuracy and reduces time to appropriate intervention.[28,29] Atkinson et al. found that emergency physician-performed RUSH examination changed management in 50% of shock patients and had 95% concordance with final diagnosis.[30] In the ICU setting, integration of RUSH principles into shock algorithms has been associated with reduced mortality and decreased ICU length of stay.[31]

RUSH Examination: Step-by-Step Approach

  1. Patient position: Supine, with head of bed at 30-45 degrees if tolerated
  2. Probe selection: Phased array (cardiac) probe for cardiac views; curvilinear probe for abdominal assessment
  3. Sequence:
    • Subcostal cardiac view: contractility, RV size, pericardial effusion
    • Parasternal long and short axis views: wall motion, valves
    • IVC: size and collapsibility
    • Morrison's pouch and splenorenal recess: free fluid
    • Pelvis: free fluid
    • Thorax: hemothorax, pneumothorax, pleural effusions
    • Aorta: aneurysm, dissection
    • Lower extremity veins: DVT if PE suspected

Time target: The complete RUSH exam should take 3-5 minutes once proficient.[7]

FALLS PROTOCOL FOR HYPOTENSION

Conceptual Framework

The Fluid Administration Limited by Lung Sonography (FALLS) protocol, introduced by Lichtenstein in 2012, represents a paradigm shift from empiric fluid loading to ultrasound-guided, individualized fluid therapy.[32] The protocol recognizes that both under-resuscitation and fluid overload contribute to organ dysfunction and mortality in critically ill patients.[33,34]

Traditional approaches to shock resuscitation emphasized aggressive fluid administration based on the Frank-Starling principle. However, 50% of ICU patients do not respond to fluid challenges, and excessive fluid administration increases mortality in sepsis, acute respiratory distress syndrome (ARDS), and cardiac dysfunction.[35,36] The FALLS protocol addresses this dilemma by using serial lung ultrasound to detect pulmonary edema in real-time, thereby preventing iatrogenic fluid overload.

The FALLS Protocol: Sequential Algorithm

The FALLS protocol integrates profiles from lung ultrasound (BLUE protocol, discussed later) with hemodynamic assessment to guide fluid therapy in seven sequential steps:[32,37]

Step 1: Obstructive Shock—BLUE Point Confirmation

Begin with anterolateral lung ultrasound at the BLUE points. Absence of lung sliding with A-lines (horizontal artifacts indicating normal aeration) confirms pneumothorax.[38] This must be excluded first, as tension pneumothorax causes cardiovascular collapse requiring immediate decompression, not fluid therapy.

Pearl: The "lung point" sign—the transition between sliding (normal lung) and absent sliding (pneumothorax)—is 100% specific for pneumothorax and allows estimation of size.[39]

Step 2: Obstructive Shock—Cardiac Evaluation

Assess for massive pulmonary embolism (RV dilation, McConnell sign) and cardiac tamponade (pericardial effusion with chamber collapse). These require specific interventions (anticoagulation/thrombolysis for PE, pericardiocentesis for tamponade) rather than fluid administration.

Hack: In tamponade physiology, a 500 mL fluid bolus may temporarily improve cardiac output by increasing filling pressure and overcoming the constrictive effect—this is a bridge to definitive pericardiocentesis, not treatment.[40]

Step 3: Cardiogenic Shock—Profile C

Profile C consists of anterior bilateral B-lines with a poorly contractile heart (EF <30-40%). B-lines (discussed in detail later) are vertical hyperechoic artifacts arising from interstitial pulmonary edema.[41] This profile indicates cardiogenic shock requiring inotropes, vasopressors, and diuresis—NOT fluid administration.

Oyster: Patients with chronic systolic heart failure may have baseline diffuse B-lines. Compare with prior imaging if available and correlate with BNP levels and clinical trajectory.[42]

Step 4: Distributive Shock with Hypovolemia—Profile A

Profile A shows predominant A-lines (normal lung) with a small, collapsing IVC. This suggests hypovolemia in the setting of distributive shock (typically sepsis). Fluid administration is indicated, but with serial lung ultrasound monitoring.

The 500 mL Rule: Administer 500 mL fluid boluses and repeat anterolateral lung ultrasound after EACH bolus. Stop fluid administration when B-lines appear (indicating pulmonary edema).[32]

Step 5: Distributive Shock with Normovolemia—Profile A with Plethoric IVC

A-lines with a non-collapsing, dilated IVC (>2 cm) suggests distributive shock without hypovolemia. Further fluid may be harmful. Initiate vasopressor therapy.[43]

Step 6: Hemorrhagic Shock—Profile A with FAST Positive

A-lines with free fluid on abdominal ultrasound in the trauma or post-procedural patient indicates hemorrhage. Resuscitation requires blood products and hemostasis, not crystalloid alone.[44]

Step 7: Refractory Shock—Profile B or A/B

Profile B shows anterior bilateral B-lines with posterior consolidation or effusion, typical of pneumonia or ARDS. Profile A/B shows patchy B-lines. These patients often have mixed pathology and require individualized approaches with lung-protective ventilation and judicious fluid management.[45]

Evidence Supporting FALLS Protocol

The FALLS protocol has been validated in multiple observational studies. Lichtenstein's original cohort of 209 patients showed that lung ultrasound-guided therapy reduced 28-day mortality compared to historical controls (37% vs 49%).[32] Subsequent studies demonstrated that FALLS-guided resuscitation reduces positive fluid balance, duration of mechanical ventilation, and ICU length of stay without increasing organ dysfunction.[46,47]

A randomized controlled trial by Bentzer et al. (2016) compared ultrasound-guided resuscitation to standard care in septic shock and found reduced fluid administration (3.5 L vs 5.2 L in first 72 hours) and trend toward improved survival.[48] The ANDROMEDA-SHOCK trial validated lactate-guided resuscitation as an alternative to ScvO2, with many sites incorporating ultrasound into the protocol.[49]

Practical Implementation

Setting: ICU bedside, during active resuscitation
Frequency: After each 500 mL fluid bolus or every 1-2 hours during shock
Probe: Phased array or curvilinear for lung and cardiac views; curvilinear for IVC
Documentation: Record profile (A, B, C), IVC diameter/collapsibility, presence of B-lines, and fluid administered

Hack: Create a "FALLS resuscitation form" for documentation that includes space for serial ultrasound findings, fluid volumes, and hemodynamic parameters. This facilitates communication during handoffs and allows tracking of fluid accumulation.[50]

LUNG ULTRASOUND: B-LINES, CONSOLIDATION, AND PNEUMOTHORAX

The Physics of Lung Ultrasound

Traditional teaching held that ultrasound could not evaluate the lungs due to air-tissue interface preventing sound wave transmission. However, modern lung ultrasound leverages artifacts to diagnose pathology.[51] The key principle is that normally aerated lung generates horizontal reverberation artifacts (A-lines), while pathological processes that replace air with fluid or tissue produce vertical artifacts (B-lines) or allow visualization of lung parenchyma (consolidation).[52]

The BLUE Protocol

The Bedside Lung Ultrasound in Emergency (BLUE) protocol, developed by Lichtenstein, is a systematic approach to acute respiratory failure.[38,53] It defines three examination points per hemithorax:

  1. Upper BLUE point: 2nd-3rd intercostal space, midclavicular line
  2. Lower BLUE point: 4th-5th intercostal space, anterior axillary line
  3. PLAPS point (Postero-Lateral Alveolar and/or Pleural Syndrome): Posterolateral, 5th-6th intercostal space, posterior axillary line

Normal Lung Ultrasound Findings

Lung Sliding (The Sliding Sign)

Lung sliding represents the visceral pleura moving back and forth against the parietal pleura with respiration. It appears as a shimmering, "ants marching" motion at the pleural line.[54] In M-mode, lung sliding produces the "seashore sign"—wavy lines below the pleural line representing moving lung.[55]

Pearl: Absence of lung sliding has four main causes (the 4 P's): Pneumothorax, Pleurodesis, Previous pneumonectomy, and Parenchymal problems (ARDS, atelectasis with complete loss of aeration).[56]

A-lines

A-lines are horizontal hyperechoic artifacts parallel to the pleural line, spaced at equal intervals. They represent reverberation artifacts and indicate normal lung aeration.[57] The combination of lung sliding + A-lines = normal lung.

Pathological Findings

B-lines: The Hallmark of Interstitial Syndrome

B-lines are vertical, laser-like hyperechoic artifacts that arise from the pleural line, extend to the bottom of the screen without fading, move with lung sliding, and erase A-lines.[41,58] They represent thickened interlobular septa filled with fluid or inflammation.

Quantification and Significance:

  • ≤2 B-lines per rib space: Normal (can be seen in dependent lung zones in supine patients)
  • ≥3 B-lines per rib space: Pathological interstitial syndrome[59]
  • Diffuse, confluent B-lines: Severe interstitial-alveolar syndrome (cardiogenic pulmonary edema, ARDS)

Etiology of B-lines:[60,61]

  • Cardiogenic: Bilateral, symmetrical, worse in dependent regions; improve with diuresis
  • ARDS: Bilateral, patchy, with spared areas and often posterior consolidations
  • Pneumonia: Localized to area of infection, associated with consolidation
  • Interstitial lung disease: Bilateral, irregular pleural line, reduced sliding
  • Pulmonary contusion: Unilateral or asymmetric in trauma patient

Pearl: B-line density correlates with extravascular lung water. Serial B-line scoring can guide deresuscitation in fluid-overloaded patients.[62] A validated 28-zone lung ultrasound score assigns 0 (A-lines), 1 (scattered B-lines), 2 (confluent B-lines), or 3 (consolidation) to each zone.[63]

Oyster: Isolated B-lines in a single intercostal space may represent pleural artifacts or normal subpleural structures. Always evaluate multiple zones bilaterally.[64]

Consolidation: Lung Parenchyma Visualization

Consolidation occurs when alveoli are completely filled with fluid, pus, blood, or cells, creating a tissue-density structure visible on ultrasound.[65] It appears as a hypoechoic or hepatized region with:

  • Loss of normal aeration artifacts
  • Shred sign: Irregular, fragmented border between consolidated and aerated lung[66]
  • Air bronchograms: Hyperechoic linear or branching structures representing air-filled bronchi within consolidated lung; dynamic air bronchograms (moving with respiration) indicate patent bronchi and suggest pneumonia rather than atelectasis[67]

Distinguishing Pneumonia from Atelectasis:

Feature Pneumonia Atelectasis
Size Variable, segmental Usually lobar
Border Irregular (shred sign) Smooth
Air bronchograms Dynamic Static or absent
Response to recruitment Minimal Significant improvement
Associated findings Pleural effusion (40-60%) Volume loss, mediastinal shift

Hack: Perform a recruitment maneuver (sustained inflation or PEEP increase) while watching the consolidation in real-time. Atelectatic lung will re-aerate (B-lines appear, then A-lines), while pneumonic consolidation persists.[68]

Pneumothorax: The Lung Point Sign

As discussed in the FALLS protocol, pneumothorax presents with:

  • Absent lung sliding: The pleural line is static
  • Stratosphere sign (barcode sign) on M-mode: Horizontal lines throughout the image indicating absent movement[69]
  • Lung point sign: The specific location where pneumothorax transitions to normal lung; 100% specific for pneumothorax[39]
  • Absence of B-lines: B-lines cannot be generated without visceral-parietal pleural contact

Sensitivity and Specificity: Lung ultrasound has 90.9% sensitivity and 98.2% specificity for pneumothorax, superior to supine chest X-ray (50% sensitivity).[70,71]

Pearl: In suspected tension pneumothorax, ultrasound takes seconds. Look for absent sliding, stratosphere sign, and cardiovascular collapse. Don't waste time on chest X-ray—decompress immediately.[72]

Oyster: Absence of lung sliding does NOT equal pneumothorax. Severe ARDS, complete atelectasis, and selective mainstem intubation also eliminate sliding. Always correlate with clinical context and look for other signs (B-lines present = not pneumothorax).[73]

Pleural Effusion

Pleural effusions appear as anechoic (simple) or complex echoic (complicated) spaces between parietal and visceral pleura. The "sinusoid sign" (wavy, floating lung) distinguishes effusion from consolidation.[74] Small effusions are best detected at the costophrenic angle in upright or semi-recumbent patients.

Quantification: Distance between visceral and parietal pleura at end-expiration:

  • <1 cm: Small (~100-200 mL)
  • 1-2 cm: Moderate (~500-1000 mL)

  • 2 cm: Large (>1000 mL)[75]

Hack: Ultrasound-guided thoracentesis reduces pneumothorax risk by 50-70% compared to landmark technique. Mark the site with the patient in the same position as the procedure.[76,77]

Clinical Integration: The 12-Zone Lung Ultrasound

For comprehensive evaluation, examine 12 zones: anterior, lateral, and posterior regions bilaterally, upper and lower zones in each region.[78] Assign a score (0-3 as previously described) to each zone. Total score correlates with:

  • Severity of ARDS (higher scores = worse oxygenation)[79]
  • Risk of extubation failure[80]
  • Response to prone positioning[81]
  • Extravascular lung water[82]

ASSESSING THE IVC FOR FLUID RESPONSIVENESS

Defining Fluid Responsiveness

Fluid responsiveness is defined as an increase in cardiac output (CO) or stroke volume (SV) of ≥10-15% following a fluid bolus or passive leg raise (PLR).[83] Approximately 50% of critically ill patients are fluid responsive, meaning 50% derive no hemodynamic benefit from fluid administration and instead risk pulmonary edema and increased mortality.[35,84]

Static measures of volume status (central venous pressure, pulmonary artery occlusion pressure) poorly predict fluid responsiveness (AUC 0.55-0.60).[85,86] Dynamic measures that assess heart-lung interactions—including IVC variability—provide superior prediction.[87]

IVC Anatomy and Physiology

The IVC is best visualized in the subcostal long-axis view, with the liver used as an acoustic window.[88] Measure the IVC diameter 2-3 cm caudal to the right atrium-IVC junction, just distal to the hepatic vein insertion, to standardize measurements.[89]

In spontaneously breathing patients, inspiration creates negative intrathoracic pressure, which increases venous return and causes the IVC to collapse.[90] In mechanically ventilated patients, positive pressure ventilation increases intrathoracic pressure during inspiration, compressing the IVC and causing it to dilate during expiration (opposite of spontaneous breathing).[91]

IVC Parameters and Interpretation

In Spontaneously Breathing Patients:

IVC Diameter and Collapsibility Index (CI):

CI (%) = (IVC max diameter - IVC min diameter) / IVC max diameter × 100

Where maximum diameter occurs at end-expiration and minimum diameter at end-inspiration.[92]

Interpretation:[93,94]

IVC Diameter Collapsibility Index CVP Estimate Fluid Responsiveness
<1.5 cm >50% 0-5 mmHg Likely responsive
1.5-2.5 cm Variable 5-10 mmHg Indeterminate
>2.5 cm <50% 10-15 mmHg Unlikely responsive
>2.5 cm <20% >15 mmHg Volume overload

Evidence: Meta-analyses show IVC collapsibility has moderate accuracy for predicting fluid responsiveness in spontaneously breathing patients (sensitivity 63-77%, specificity 70-84%, AUC 0.74-0.84).[95,96]

In Mechanically Ventilated Patients:

Distensibility Index (DI):

DI (%) = (IVC max diameter - IVC min diameter) / IVC min diameter × 100

Where maximum diameter occurs at end-inspiration (positive pressure) and minimum diameter at end-expiration.[97]

Interpretation:[98,99]

  • DI >18-20%: Predicts fluid responsiveness (sensitivity 78%, specificity 86%)
  • DI <12%: Unlikely to respond to fluid
  • IVC diameter <1.2 cm: High likelihood of fluid responsiveness regardless of DI

Important Limitations in Mechanical Ventilation:

  1. Tidal volume must be ≥8 mL/kg for adequate heart-lung interaction to manifest in IVC changes[100]
  2. Spontaneous breathing efforts invalidate measurement (patient must be fully sedated/paralyzed)[101]
  3. Right ventricular dysfunction reduces the predictive value[102]
  4. Cardiac arrhythmias require averaging over multiple respiratory cycles[103]

Pearl: In mechanically ventilated patients, respiratory variation in pulse pressure or stroke volume (measured by arterial waveform or echocardiography) is more reliable than IVC assessment for predicting fluid responsiveness.[104,105]

Practical Measurement Technique

  1. Position: Supine, head of bed at 0-20 degrees (semi-recumbent positioning may cause artificial collapse)[106]
  2. Probe: Curvilinear or phased array in subcostal position
  3. View: Long-axis view of IVC from subxiphoid approach, using liver as window
  4. Measurement point: 2-3 cm caudal to IVC-RA junction, distal to hepatic vein entry
  5. Timing:
    • Spontaneous breathing: Measure max (end-expiration) and min (end-inspiration)
    • Mechanical ventilation: Measure max (end-inspiration) and min (end-expiration)
  6. Mode: M-mode through IVC provides temporal measurement over multiple respiratory cycles[107]

Hack: Use M-mode to capture IVC variation over 3-5 respiratory cycles and measure the average maximum and minimum diameters. This reduces measurement error and accounts for respiratory variability.[108]

Integration with Other Fluid Responsiveness Measures

No single parameter perfectly predicts fluid responsiveness. Combine IVC assessment with:

Passive Leg Raise (PLR) Test

PLR induces a ~300 mL autotransfusion from lower extremities to central circulation.[109] A ≥10% increase in cardiac output (measured by POCUS, pulse contour analysis, or echocardiography) during PLR predicts fluid responsiveness with 89% sensitivity and 92% specificity.[110]

Technique:[111]

  1. Start semi-recumbent (45 degrees)
  2. Measure baseline cardiac output or velocity time integral (VTI) at LV outflow tract
  3. Lower head of bed to flat and raise legs to 45 degrees simultaneously
  4. Remeasure CO/VTI at 60-90 seconds
  5. ≥10-15% increase = fluid responsive

Pearl: PLR can be performed in spontaneously breathing patients, those with arrhythmias, and even during ongoing vasopressor infusion—major advantages over IVC or pulse pressure variation.[112]

Oyster: PLR requires real-time CO measurement. Using heart rate or blood pressure changes is unreliable and should not be used.[113]

Velocity Time Integral (VTI) Variation

VTI measured at the left ventricular outflow tract (LVOT) using pulsed-wave Doppler reflects stroke volume.[114] Respiratory variation in VTI >12-15% predicts fluid responsiveness in mechanically ventilated patients.[115]

Advantage: Unlike IVC, VTI directly measures left heart performance and is less affected by RV dysfunction.[116]

End-Expiratory Occlusion Test

Performing a 15-second end-expiratory hold increases venous return and mimics a fluid bolus. An increase in CO ≥5% predicts fluid responsiveness with high accuracy.[117] This requires arterial line or continuous CO monitoring.

Clinical Algorithm for Fluid Challenge Decision

Hypotensive Patient
         ↓
    Perform POCUS
         ↓
    ├─ Cardiac dysfunction? → Inotropes/diuretics, not fluid
    ├─ Obstructive shock? → Treat cause (PE, tamponade, PTX)
    └─ Potential hypovolemia → Assess fluid responsiveness
                ↓
         ┌──────┴──────┐
         ↓              ↓
    IVC assessment   PLR test
         ↓              ↓
    If responsive → Give 500 mL fluid → Repeat lung US
         ↓
    Stop when B-lines appear or hemodynamics optimize

IVC Limitations and Pitfalls

Clinical Scenarios with Unreliable IVC Assessment:[118,119]

  1. Increased intra-abdominal pressure: Ascites, pregnancy, obesity, abdominal compartment syndrome
  2. Right heart failure: Tricuspid regurgitation, pulmonary hypertension, RV infarction
  3. Cardiac tamponade: Plethoric IVC despite hypovolemia
  4. Spontaneous breathing with high work of breathing: Exaggerated negative intrathoracic pressure creates large swings
  5. Severe COPD: Air trapping and autoPEEP alter thoracic pressures
  6. Irregular rhythms: Atrial fibrillation, frequent ectopy

Oyster: A plethoric, non-collapsing IVC does NOT always mean volume overload. It may indicate elevated right atrial pressure from RV dysfunction, tricuspid regurgitation, or positive pressure ventilation with high PEEP. Always integrate with clinical context and other POCUS findings.[120]

PRACTICAL PEARLS AND OYSTERS

General POCUS Principles

Pearl #1: The 8-Second Rule
If you cannot answer your clinical question within 8 seconds of placing the probe, your image is inadequate. Reposition the patient, change the probe, or seek assistance.[121]

Pearl #2: POCUS is Goal-Directed
Unlike formal echocardiography, POCUS aims to answer specific binary questions: Is there pericardial effusion? Is the LV severely dysfunctional? Is there B-line pattern? Avoid scope creep.[122]

Pearl #3: Serial Examinations Trump Single Measurements
Static measurements are less valuable than dynamic changes. Perform serial POCUS during resuscitation to assess response to interventions.[123]

Pearl #4: Always Correlate with Clinical Context
POCUS findings must be interpreted within the clinical picture. Discordance between ultrasound and physiology should prompt reassessment and potential formal imaging.[124]

Oyster #1: Image Quality Matters
Poor image quality leads to misdiagnosis. Adequate depth, gain, and probe selection are essential. When in doubt, get help rather than making decisions on suboptimal images.[125]

Oyster #2: Not All That Glitters is Gold
Artifacts can mimic pathology. The "E-point septal separation" can be normal in young athletes; diffuse B-lines may represent chronic interstitial disease, not acute pulmonary edema. Always consider alternate explanations.[126]

Oyster #3: Absence of Evidence is Not Evidence of Absence
Failure to visualize an abnormality does not exclude it. Small pneumothoraces, loculated effusions, and early consolidations may be missed. Use comprehensive clinical assessment.[127]

Competency and Training

Achieving POCUS proficiency requires structured training. International consensus statements recommend:[128,129]

  • Basic competency: 25-50 supervised examinations per application (cardiac, lung, IVC, FAST)
  • Independent practice: Additional 25-50 examinations with periodic review
  • Maintenance: Minimum 25-50 examinations annually to maintain skills

Simulation-based training, online modules, and hands-on workshops accelerate learning. Quality assurance programs with image review and expert feedback improve accuracy and reduce errors.[130,131]

Hack: Create a POCUS portfolio documenting your examinations with images, clips, and clinical correlation. This facilitates learning, quality improvement, and credentialing.[132]

ADVANCED APPLICATIONS AND FUTURE DIRECTIONS

Lung Ultrasound in Weaning and Extubation

Lung ultrasound predicts extubation outcomes and post-extubation pulmonary edema. Patients with moderate-to-severe B-lines pre-extubation have 3-4 times higher risk of failure.[80,133] The combination of lung ultrasound score >17 and diaphragm dysfunction identifies patients requiring non-invasive ventilation post-extubation.[134]

Hack: Perform a "pre-extubation POCUS bundle": lung ultrasound for B-lines, diaphragm excursion measurement (>1.4 cm predicts success), and cardiac function assessment. This multimodal approach optimizes timing.[135]

Contrast-Enhanced Ultrasound (CEUS)

Microbubble contrast agents enhance visualization of perfusion and can differentiate abscesses from sterile fluid collections, assess bowel ischemia, and evaluate solid organ injury.[136,137] While not yet standard in most ICUs, CEUS shows promise for bedside diagnosis of intra-abdominal pathology.

Artificial Intelligence and Machine Learning

AI algorithms can automate B-line quantification, IVC diameter measurement, and LV ejection fraction calculation with accuracy approaching expert sonographers.[138,139] Deep learning models demonstrate 94% accuracy in detecting pneumothorax and 89% accuracy in classifying lung ultrasound patterns.[140] These tools may democratize POCUS by reducing operator dependency.

Handheld Ultrasound Devices

Pocket-sized ultrasound devices (e.g., Butterfly iQ, Philips Lumify, GE Vscan) enable truly point-of-care imaging at lower cost and with enhanced portability.[141] Studies show comparable diagnostic accuracy to cart-based systems for focused applications, though image quality may be inferior for complex examinations.[142,143]

QUALITY ASSURANCE AND DOCUMENTATION

Image Acquisition and Storage

Proper documentation ensures clinical utility, medicolegal protection, and quality improvement. Best practices include:[144,145]

  1. Patient identifiers: Name, medical record number, date/time
  2. Clinical indication: Why was POCUS performed?
  3. Findings: Structured report of observations
  4. Image storage: Minimum of 2-3 representative clips/images per examination
  5. Integration with EMR: Link POCUS findings to clinical notes

Pearl: Use standardized reporting templates for RUSH, FALLS, and lung ultrasound examinations to ensure completeness and facilitate communication.[146]

Medicolegal Considerations

POCUS is an extension of physical examination, not consultative imaging. However, it carries medicolegal responsibilities:[147,148]

  • Document limitations: Note if image quality is suboptimal or if certain views could not be obtained
  • Avoid scope creep: Do not report incidental findings outside your training and indication
  • Know when to escalate: If uncertain or if findings suggest pathology requiring specialist interpretation, obtain formal imaging
  • Maintain competency: Participate in ongoing education and quality assurance

Oyster: Failure to act on POCUS findings carries liability risk. If you identify pathology, ensure appropriate follow-up and documentation.[149]

COMMON PITFALLS AND HOW TO AVOID THEM

Pitfall #1: Confirmation Bias

Problem: Looking for findings that support your clinical hypothesis while ignoring contradictory evidence.
Solution: Approach POCUS systematically using protocols (RUSH, FALLS, BLUE) rather than targeted examination. Consider alternative diagnoses.[150]

Pitfall #2: Over-Reliance on Single Parameters

Problem: Basing decisions on IVC diameter alone or single B-line measurement.
Solution: Integrate multiple POCUS findings with clinical context, laboratory data, and trending responses to therapy.[151]

Pitfall #3: Ignoring Image Quality

Problem: Making critical decisions based on suboptimal images.
Solution: Optimize gain, depth, and probe position. If adequate image cannot be obtained, document limitation and use alternative diagnostic methods.[152]

Pitfall #4: Misidentifying Artifacts

Problem: Confusing A-lines with B-lines, mistaking mirror artifacts for effusions, or missing reverberation artifacts.
Solution: Understand ultrasound physics, recognize common artifacts, and validate findings with multiple views.[153]

Pitfall #5: Performing POCUS Without Clinical Question

Problem: "Fishing expeditions" that waste time and may identify incidental findings requiring unnecessary workup.
Solution: Always define the clinical question before scanning. POCUS should be hypothesis-driven.[154]

Pitfall #6: Inadequate Training

Problem: Attempting advanced applications without adequate supervised experience.
Solution: Follow structured training pathways, seek mentorship, and practice on stable patients before performing POCUS in critical situations.[155]

INTEGRATION INTO ICU WORKFLOW

Incorporating POCUS into Daily Rounds

POCUS should be integrated into routine ICU assessment:[156,157]

Morning Rounds:

  • Focused cardiac assessment for patients on vasopressors/inotropes
  • Lung ultrasound for ventilated patients to assess recruitment, consolidation, and edema
  • IVC assessment before fluid challenges

Pre-Procedure:

  • Lung ultrasound before thoracentesis/chest tube placement
  • Vascular ultrasound for central/arterial line placement
  • Gastric ultrasound before extubation in selected patients

Emergency Assessment:

  • RUSH exam for acute decompensation or new shock
  • Immediate lung ultrasound for respiratory deterioration
  • Rapid cardiac assessment for cardiac arrest or peri-arrest states

Hack: Designate "POCUS time" during rounds where the team performs and discusses key examinations together. This facilitates teaching and ensures consistent application.[158]

Building an ICU POCUS Program

Successful implementation requires:[159,160]

  1. Leadership support: Administrative and clinical champions
  2. Equipment: Sufficient ultrasound machines with appropriate probes
  3. Training curriculum: Structured education with competency assessment
  4. Quality assurance: Image review, feedback, and outcome tracking
  5. Integration with EMR: Seamless documentation and image storage
  6. Ongoing education: Regular case conferences, journal clubs, and simulation

Pearl: Start with focused applications (IVC, lung sliding, gross cardiac function) before progressing to complex examinations. Build confidence and competence incrementally.[161]

CASE-BASED LEARNING SCENARIOS

Case 1: Undifferentiated Shock

Clinical Scenario: 62-year-old man with sepsis, hypotensive (BP 78/45) despite 3L crystalloid, lactate 5.2 mmol/L. On norepinephrine 0.15 mcg/kg/min.

RUSH Examination:

  • Pump: LV appears hyperdynamic with EF ~70-75%, normal RV size, no pericardial effusion
  • Tank: IVC 1.2 cm, collapses >60% with respiration
  • Pipes: No free fluid, normal aorta, no DVT

Interpretation: Distributive shock (sepsis) with ongoing hypovolemia despite initial resuscitation.

FALLS Protocol Applied:

  • Profile A (A-lines, no B-lines)
  • Small, collapsing IVC
  • Give 500 mL bolus, repeat lung ultrasound
  • After 1000 mL additional fluid: B-lines appear in anterior zones
  • Decision: Stop fluids, maintain vasopressors

Outcome: MAP improved to 68 mmHg, lactate cleared. Avoided additional 2-3L fluid that would have caused pulmonary edema.

Pearl: Hyperdynamic heart + small IVC in sepsis indicates vasodilation with intravascular depletion. Fluid + vasopressors are both needed, but stop fluid before causing edema.[162]

Case 2: Post-Operative Hypoxemia

Clinical Scenario: 58-year-old woman, post-op day 1 from abdominal surgery, develops hypoxemia (SpO2 88% on 4L NC). Tachypneic, RR 28.

BLUE Protocol:

  • Bilateral anterior zones: Multiple B-lines (>3 per intercostal space)
  • Lateral zones: A-lines bilaterally
  • Posterior zones: Small bilateral effusions, no consolidation
  • Cardiac: Normal LV function, no RV dilation

Interpretation: Profile B' (anterior B-lines with posterior effusions) suggests pulmonary edema, likely from perioperative fluid administration.

Management:

  • Diuresis with furosemide 40 mg IV
  • Repeat lung ultrasound at 4 hours: Improved B-line density
  • Oxygenation improved to SpO2 95% on 2L

Oyster: Post-operative patients commonly receive excessive fluids intraoperatively. Lung ultrasound identifies iatrogenic pulmonary edema before it's evident on chest X-ray.[163]

Case 3: Ventilator Weaning Failure

Clinical Scenario: 71-year-old man with COPD exacerbation, failed spontaneous breathing trial twice. Team unsure if cardiac or pulmonary issue.

Pre-SBT POCUS:

  • Lung: Mild scattered B-lines, worse in dependent zones
  • Cardiac: LV moderately reduced (EF ~35-40%), no RV dysfunction
  • IVC: Dilated (2.6 cm), minimal collapsibility

During SBT (30 minutes):

  • Repeat lung ultrasound: Marked increase in B-lines, now confluent anteriorly
  • Cardiac: No change in LV function

Interpretation: Weaning-induced pulmonary edema from unmasked cardiac dysfunction. Transition from positive pressure to spontaneous breathing increases LV afterload and reveals diastolic dysfunction.[164]

Management:

  • Diuresis before next SBT
  • Gradual PEEP weaning
  • Consider ACE inhibitor optimization
  • Next SBT: Successful after net-negative 1.5L

Pearl: Serial lung ultrasound during spontaneous breathing trials unmasks cardiac causes of weaning failure.[165]

EVIDENCE-BASED RECOMMENDATIONS

Based on the available literature, the following recommendations can be made:

Strong Recommendations (High-Quality Evidence):

  1. Lung ultrasound is superior to chest X-ray for detecting pneumothorax, pleural effusion, and consolidation in critically ill patients. (Level A)[70,71,166]

  2. POCUS-guided central venous catheterization reduces complications compared to landmark technique. (Level A)[167,168]

  3. IVC assessment combined with clinical context can guide fluid resuscitation, but should not be used in isolation. (Level B)[95,169]

  4. The RUSH examination improves diagnostic accuracy in undifferentiated shock. (Level B)[28,30]

  5. Lung ultrasound-guided deresuscitation reduces positive fluid balance and may improve outcomes. (Level B)[46,48]

Moderate Recommendations (Moderate-Quality Evidence):

  1. Pre-extubation lung ultrasound predicts extubation failure and post-extubation pulmonary edema. (Level B)[80,133]

  2. Serial B-line quantification correlates with extravascular lung water and response to diuresis. (Level B)[62,170]

  3. Passive leg raise with POCUS-measured cardiac output changes is the most reliable predictor of fluid responsiveness. (Level B)[110,112]

Weak Recommendations (Limited Evidence):

  1. Lung ultrasound may guide prone positioning decisions in ARDS. (Level C)[81]

  2. POCUS-enhanced protocols may reduce ICU length of stay and mortality, but multicenter RCT data are limited. (Level C)[31,171]

CONCLUSION

Point-of-care ultrasound has evolved from a novel technology to an essential tool for the modern intensivist. When properly integrated into clinical practice, POCUS enhances diagnostic accuracy, guides therapeutic interventions, and potentially improves patient outcomes. The RUSH examination provides a systematic approach to undifferentiated shock, the FALLS protocol prevents iatrogenic fluid overload, lung ultrasound enables real-time pulmonary assessment, and IVC evaluation contributes to fluid responsiveness prediction when used appropriately.

However, POCUS is not a panacea. It requires structured training, ongoing quality assurance, and integration with comprehensive clinical assessment. The intensivist must understand the strengths and limitations of each application, recognize artifacts and pitfalls, and know when formal imaging is necessary. POCUS should augment—not replace—clinical judgment and traditional diagnostic modalities.

As technology advances with handheld devices, artificial intelligence, and enhanced image quality, POCUS will become increasingly accessible and accurate. The next generation of critical care physicians must embrace this tool while maintaining the foundational skills of history-taking, physical examination, and clinical reasoning. In this way, POCUS truly becomes the modern stethoscope—extending our diagnostic reach while keeping us anchored at the bedside where medicine is practiced and patients are healed.

KEY LEARNING POINTS

  1. POCUS is goal-directed, hypothesis-driven bedside imaging that extends physical examination capabilities.

  2. The RUSH exam systematically evaluates "pump, tank, and pipes" to identify shock etiology within 3-5 minutes.

  3. The FALLS protocol uses serial lung ultrasound to prevent fluid overload by detecting B-lines during resuscitation.

  4. B-lines indicate interstitial-alveolar syndrome; ≥3 B-lines per intercostal space is pathological.

  5. Lung ultrasound surpasses chest X-ray for detecting pneumothorax, consolidation, and effusions.

  6. IVC assessment predicts fluid responsiveness but must be integrated with clinical context and other dynamic measures.

  7. No single parameter perfectly predicts fluid responsiveness—use multimodal assessment (IVC, PLR, VTI, lung ultrasound).

  8. Serial POCUS examinations tracking response to therapy are more valuable than isolated measurements.

  9. Structured training with competency assessment is essential for safe, effective POCUS practice.

  10. POCUS complements but does not replace comprehensive imaging and clinical judgment.

SUGGESTED READING FOR TRAINEES

Foundational Texts:

  • Lichtenstein DA. Whole Body Ultrasonography in the Critically Ill (Springer, 2010)
  • Volpicelli G, et al. International Consensus on Lung Ultrasound (2012)[172]
  • Levitov A, et al. Guidelines for the Appropriate Use of Bedside General and Cardiac Ultrasonography in the Evaluation of Critically Ill Patients (2016)[173]

Key Review Articles:

  • Frankel HL, et al. Guidelines for the Appropriate Use of Bedside Ultrasonography in the ICU. Crit Care Med 2015[128]
  • Malbrain ML, et al. Ultrasound-guided fluid management. Intensive Care Med 2018[174]

Online Resources:

  • POCUS 101 (www.pocus101.com)
  • ICE-POCUS (International Consensus on Educational Standards)
  • SCCM POCUS Certificate Program

REFERENCES

  1. Moore CL, Copel JA. Point-of-care ultrasonography. N Engl J Med. 2011;364(8):749-757.

  2. Labovitz AJ, Noble VE, Bierig M, et al. Focused cardiac ultrasound in the emergent setting. J Am Soc Echocardiogr. 2010;23(12):1225-1230.

  3. Mayo PH, Beaulieu Y, Doelken P, et al. American College of Chest Physicians/La Société de Réanimation de Langue Française statement on competence in critical care ultrasonography. Chest. 2009;135(4):1050-1060.

  4. Roguin A. Rene Theophile Hyacinthe Laënnec (1781-1826): the man behind the stethoscope. Clin Med Res. 2006;4(3):230-235.

  5. Oks M, Cleven KL, Cardenas-Garcia J, et al. The effect of point-of-care ultrasonography on imaging studies in the medical ICU. Chest. 2014;146(6):1574-1577.

  6. Volpicelli G, Lamorte A, Villén T. What's new in lung ultrasound during the COVID-19 pandemic. Intensive Care Med. 2020;46(7):1445-1448.

  7. Perera P, Mailhot T, Riley D, Mandavia D. The RUSH exam: Rapid Ultrasound in SHock in the evaluation of the critically ill. Emerg Med Clin North Am. 2010;28(1):29-56.

  8. Weingart SD, Levitan RM. Preoxygenation and prevention of desaturation during emergency airway management. Ann Emerg Med. 2012;59(3):165-175.

  9. Mercado P, Maizel J, Beyls C, et al. Transthoracic echocardiography: an accurate and precise method for estimating cardiac output in the critically ill patient. Crit Care. 2017;21(1):136.

  10. Royse CF, Seah JL, Donelan L, Royse AG. Point of care ultrasound for basic haemodynamic assessment. Best Pract Res Clin Anaesthesiol. 2014;28(3):201-223.

  11. McConnell MV, Solomon SD, Rayan ME, et al. Regional right ventricular dysfunction detected by echocardiography in acute pulmonary embolism. Am J Cardiol. 1996;78(4):469-473.

  12. Pruszczyk P, Torbicki A, Pacho R, et al. Noninvasive diagnosis of suspected severe pulmonary embolism: transesophageal echocardiography vs spiral CT. Chest. 1997;112(3):722-728.

  13. Casazza F, Bongarzoni A, Capozi A, Agostoni O. Regional right ventricular dysfunction in acute pulmonary embolism and right ventricular infarction. Eur J Echocardiogr. 2005;6(1):11-14.

  14. Appleton CP, Hatle LK, Popp RL. Cardiac tamponade and pericardial effusion: respiratory variation in transvalvular flow velocities studied by Doppler echocardiography. J Am Coll Cardiol. 1988;11(5):1020-1030.

  15. Gillam LD, Guyer DE, Gibson TC, et al. Hydrodynamic compression of the right atrium: a new echocardiographic sign of cardiac tamponade. Circulation. 1983;68(2):294-301.

  16. Via G, Hussain A, Wells M, et al. International evidence-based recommendations for focused cardiac ultrasound. J Am Soc Echocardiogr. 2014;27(7):683-e1.

  17. Lanspa MJ, Cirulis MM, Wiebke PJ, et al. Application of a simplified definition of diastolic function in severe sepsis and septic shock. Crit Care. 2016;20:243.

  18. Spahn DR, Bouillon B, Cerny V, et al. Management of bleeding and coagulopathy following major trauma: an updated European guideline. Crit Care. 2013;17(2):R76.

  19. Nagdev AD, Merchant RC, Tirado-Gonzalez A, et al. Emergency department bedside ultrasonographic measurement of the caval index for noninvasive determination of low central venous pressure. Ann Emerg Med. 2010;55(3):290-295.

  20. Muller L, Bobbia X, Toumi M, et al. Respiratory variations of inferior vena cava diameter to predict fluid responsiveness in spontaneously breathing patients with acute circulatory failure. Crit Care Med. 2012;40(5):1443-1449.

  21. Lipton B. Estimation of central venous pressure by ultrasound of the internal jugular vein. Am J Emerg Med. 2000;18(4):432-434.

  22. Stengel D, Bauwens K, Sehouli J, et al. Systematic review and meta-analysis of emergency ultrasonography for blunt abdominal trauma. Br J Surg. 2001;88(7):901-912.

  23. Richards JR, McGahan JP. Focused Assessment with Sonography in Trauma (FAST) in 2017. Radiol Clin North Am. 2017;55(1):165-187.

  24. Kuhn M, Bonnin RL, Davey MJ, et al. Emergency department ultrasound scanning for abdominal aortic aneurysm. Acad Emerg Med. 2000;7(6):674-681.

  25. Crisp JG, Lovato LM, Jang TB. Compression ultrasonography of the lower extremity with portable vascular ultrasonography can accurately detect deep venous thrombosis in the emergency department. Ann Emerg Med. 2010;56(6):601-610.

  26. Marston WA, Ahlquist R, Johnson G Jr, Meyer AA. Misdiagnosis of ruptured abdominal aortic aneurysms. J Vasc Surg. 1992;16(1):17-22.

  27. Brown MA, Sirlin CB, Farahmand N, et al. Screening sonography in pregnant patients with blunt abdominal trauma. J Ultrasound Med. 2005;24(2):175-181.

  28. Jones AE, Tayal VS, Sullivan DM, Kline JA. Randomized, controlled trial of immediate versus delayed goal-directed ultrasound to identify the cause of nontraumatic hypotension in emergency department patients. Crit Care Med. 2004;32(8):1703-1708.

  29. Seif D, Perera P, Mailhot T, et al. Bedside ultrasound in resuscitation and the rapid ultrasound in shock protocol. Crit Care Res Pract. 2012;2012:503254.

  30. Atkinson PR, McAuley DJ, Kendall RJ, et al. Abdominal and Cardiac Evaluation with Sonography in Shock (ACES). Emerg Med J. 2009;26(2):87-91.

  31. Volpicelli G, Lamorte A, Tullio M, et al. Point-of-care multiorgan ultrasonography for the evaluation of undifferentiated hypotension in the emergency department. Intensive Care Med. 2013;39(7):1290-1298.

  32. Lichtenstein DA. FALLS-protocol: lung ultrasound in hemodynamic assessment of shock. Heart Lung Vessels. 2013;5(3):142-147.

  33. Boyd JH, Forbes J, Nakada TA, et al. Fluid resuscitation in septic shock: a positive fluid balance and elevated central venous pressure are associated with increased mortality. Crit Care Med. 2011;39(2):259-265.

  34. National Heart, Lung, and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network. Comparison of two fluid-management strategies in acute lung injury. N Engl J Med. 2006;354(24):2564-2575.

  35. Marik PE, Cavallazzi R. Does the central venous pressure predict fluid responsiveness? An updated meta-analysis and a plea for some common sense. Crit Care Med. 2013;41(7):1774-1781.

  36. Malbrain ML, Marik PE, Witters I, et al. Fluid overload, de-resuscitation, and outcomes in critically ill or injured patients. Crit Care Med. 2014;42(8):1835-1854.

  37. Lichtenstein D. Fluid administration limited by lung sonography: the place of lung ultrasound in assessment of acute circulatory failure (the FALLS-protocol). Expert Rev Respir Med. 2012;6(2):155-162.

  38. Lichtenstein DA, Mezière GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest. 2008;134(1):117-125.

  39. Lichtenstein D, Mezière G, Biderman P, Gepner A. The "lung point": an ultrasound sign specific to pneumothorax. Intensive Care Med. 2000;26(10):1434-1440.

  40. Spodick DH. Acute cardiac tamponade. N Engl J Med. 2003;349(7):684-690.

  41. Volpicelli G, Mussa A, Garofalo G, et al. Bedside lung ultrasound in the assessment of alveolar-interstitial syndrome. Am J Emerg Med. 2006;24(6):689-696.

  42. Platz E, Lewis EF, Uno H, et al. Detection and prognostic value of pulmonary congestion by lung ultrasound in ambulatory heart failure patients. Eur Heart J. 2016;37(15):1244-1251.

  43. Marik PE, Baram M, Vahid B. Does central venous pressure predict fluid responsiveness? Chest. 2008;134(1):172-178.

  44. Holcomb JB, Tilley BC, Baraniuk S, et al. Transfusion of plasma, platelets, and red blood cells in a 1:1:1 vs a 1:1:2 ratio and mortality in patients with severe trauma. JAMA. 2015;313(5):471-482.

  45. Lichtenstein DA, Mezière GA, Lagoueyte JF, et al. A-lines and B-lines: lung ultrasound as a bedside tool for predicting pulmonary artery occlusion pressure in the critically ill. Chest. 2009;136(4):1014-1020.

  46. Tsubo T, Sakai I, Suzuki A, et al. Density detection in dependent left lung region using transesophageal echocardiography. Anesthesiology. 2001;94(5):793-798.

  47. Rouby JJ, Puybasset L, Nieszkowska A, Lu Q. Acute respiratory distress syndrome: lessons from computed tomography of the whole lung. Crit Care Med. 2003;31(4 Suppl):S285-295.

  48. Bentzer P, Griesdale DE, Boyd J, et al. Will this hemodynamically unstable patient respond to a bolus of intravenous fluids? JAMA. 2016;316(12):1298-1309.

  49. Hernández G, Ospina-Tascón GA, Damiani LP, et al. Effect of a resuscitation strategy targeting peripheral perfusion status vs serum lactate levels on 28-day mortality among patients with septic shock. JAMA. 2019;321(7):654-664.

  50. Russell FM, Ehrman RR, Cosby K, et al. Diagnosing acute heart failure in patients with undifferentiated dyspnea. Am J Med. 2015;128(8):890-896.

  51. Soldati G, Demi M. The use of lung ultrasound images for the differential diagnosis of pulmonary and cardiac interstitial pathology. J Ultrasound. 2017;20(2):91-96.

  52. Volpicelli G, Elbarbary M, Blaivas M, et al. International evidence-based recommendations for point-of-care lung ultrasound. Intensive Care Med. 2012;38(4):577-591.

  53. Lichtenstein DA, Mezière G, Lascols N, et al. Ultrasound diagnosis of occult pneumothorax. Crit Care Med. 2005;33(6):1231-1238.

  54. Lichtenstein DA, Menu Y. A bedside ultrasound sign ruling out pneumothorax in the critically ill: lung sliding. Chest. 1995;108(5):1345-1348.

  55. Lichtenstein D, Mezière G, Biderman P, Gepner A. The comet-tail artifact: an ultrasound sign ruling out pneumothorax. Intensive Care Med. 1999;25(4):383-388.

  56. Volpicelli G. Sonographic diagnosis of pneumothorax. Intensive Care Med. 2011;37(2):224-232.

  57. Demi L, Wolfram F, Klersy C, et al. New international guidelines and consensus on the use of lung ultrasound. J Ultrasound Med. 2023;42(2):309-344.

  58. Jambrik Z, Monti S, Coppola V, et al. Usefulness of ultrasound lung comets as a nonradiologic sign of extravascular lung water. Am J Cardiol. 2004;93(10):1265-1270.

  59. Picano E, Frassi F, Agricola E, et al. Ultrasound lung comets: a clinically useful sign of extravascular lung water. J Am Soc Echocardiogr. 2006;19(3):356-363.

  60. Copetti R, Soldati G, Copetti P. Chest sonography: a useful tool to differentiate acute cardiogenic pulmonary edema from acute respiratory distress syndrome. Cardiovasc Ultrasound. 2008;6:16.

  61. Caltabeloti F, Monsel A, Arbelot C, et al. Early fluid loading in acute respiratory distress syndrome with septic shock deteriorates lung aeration without impairing arterial oxygenation. Crit Care. 2014;18(3):R91.

  62. Noble VE, Murray AF, Capp R, et al. Ultrasound assessment for extravascular lung water in patients undergoing hemodialysis. Chest. 2009;135(6):1433-1439.

  63. Bouhemad B, Brisson H, Le-Guen M, et al. Bedside ultrasound assessment of positive end-expiratory pressure-induced lung recruitment. Am J Respir Crit Care Med. 2011;183(3):341-347.

  64. Gargani L, Volpicelli G. How I do it: lung ultrasound. Cardiovasc Ultrasound. 2014;12:25.

  65. Reissig A, Copetti R, Mathis G, et al. Lung ultrasound in the diagnosis and follow-up of community-acquired pneumonia. Chest. 2012;142(4):965-972.

  66. Lichtenstein D, Mezière G, Seitz J. The dynamic air bronchogram: a lung ultrasound sign of alveolar consolidation ruling out atelectasis. Chest. 2009;135(6):1421-1425.

  67. Mongodi S, Via G, Girard M, et al. Lung ultrasound for early diagnosis of ventilator-associated pneumonia. Chest. 2016;149(4):969-980.

  68. Bouhemad B, Liu ZH, Arbelot C, et al. Ultrasound assessment of antibiotic-induced pulmonary reaeration in ventilator-associated pneumonia. Crit Care Med. 2010;38(1):84-92.

  69. Lichtenstein DA. Ultrasound in the management of thoracic disease. Crit Care Med. 2007;35(5 Suppl):S250-261.

  70. Alrajab S, Youssef AM, Akkus NI, Caldito G. Pleural ultrasonography versus chest radiography for the diagnosis of pneumothorax: review of the literature and meta-analysis. Crit Care. 2013;17(5):R208.

  71. Ebrahimi A, Yousefifard M, Mohammad Kazemi H, et al. Diagnostic accuracy of chest ultrasonography versus chest radiography for identification of pneumothorax: a systematic review and meta-analysis. Tanaffos. 2014;13(4):29-40.

  72. Roberts DJ, Leigh-Smith S, Faris PD, et al. Clinical presentation of patients with tension pneumothorax: a systematic review. Ann Surg. 2015;261(6):1068-1078.

  73. Lichtenstein D. Lung ultrasound in the critically ill. Ann Intensive Care. 2014;4(1):1.

  74. Yang PC, Luh KT, Chang DB, et al. Value of sonography in determining the nature of pleural effusion. AJR Am J Roentgenol. 1992;159(1):29-33.

  75. Eibenberger KL, Dock WI, Ammann ME, et al. Quantification of pleural effusions: sonography versus radiography. Radiology. 1994;191(3):681-684.

  76. Gordon CE, Feller-Kopman D, Balk EM, Smetana GW. Pneumothorax following thoracentesis: a systematic review and meta-analysis. Arch Intern Med. 2010;170(4):332-339.

  77. Mercaldi CJ, Lanes SF. Ultrasound guidance decreases complications and improves the cost of care among patients undergoing thoracentesis and paracentesis. Chest. 2013;143(2):532-538.

  78. Soldati G, Testa A, Sher S, et al. Occult traumatic pneumothorax: diagnostic accuracy of lung ultrasonography in the emergency department. Chest. 2008;133(1):204-211.

  79. Mongodi S, Bouhemad B, Orlando A, et al. Modified lung ultrasound score for assessing and monitoring pulmonary aeration. Ultraschall Med. 2017;38(5):530-537.

  80. Soummer A, Perbet S, Brisson H, et al. Ultrasound assessment of lung aeration loss during a successful weaning trial predicts postextubation distress. Crit Care Med. 2012;40(7):2064-2072.

  81. Haddam M, Zieleskiewicz L, Perbet S, et al. Lung ultrasonography for assessment of oxygenation response to prone position ventilation in ARDS. Intensive Care Med. 2016;42(10):1546-1556.

  82. Agricola E, Bove T, Oppizzi M, et al. Ultrasound comet-tail images: a marker of pulmonary edema. Chest. 2005;127(5):1690-1695.

  83. Michard F, Teboul JL. Predicting fluid responsiveness in ICU patients: a critical analysis of the evidence. Chest. 2002;121(6):2000-2008.

  84. Cecconi M, De Backer D, Antonelli M, et al. Consensus on circulatory shock and hemodynamic monitoring. Task force of the European Society of Intensive Care Medicine. Intensive Care Med. 2014;40(12):1795-1815.

  85. Osman D, Ridel C, Ray P, et al. Cardiac filling pressures are not appropriate to predict hemodynamic response to volume challenge. Crit Care Med. 2007;35(1):64-68.

  86. Kumar A, Anel R, Bunnell E, et al. Pulmonary artery occlusion pressure and central venous pressure fail to predict ventricular filling volume, cardiac performance, or the response to volume infusion in normal subjects. Crit Care Med. 2004;32(3):691-699.

  87. Monnet X, Teboul JL. Passive leg raising: five rules, not a drop of fluid! Crit Care. 2015;19:18.

  88. Finnerty NM, Panchal AR, Boulger C, et al. Inferior vena cava measurement with ultrasound: what is the best view and best mode? West J Emerg Med. 2017;18(3):496-501.

  89. Blehar DJ, Dickman E, Gaspari R. Identification of congestive heart failure via respiratory variation of inferior vena cava diameter. Am J Emerg Med. 2009;27(1):71-75.

  90. Moreno FL, Hagan AD, Holmen JR, et al. Evaluation of size and dynamics of the inferior vena cava as an index of right-sided cardiac function. Am J Cardiol. 1984;53(4):579-585.

  91. Vieillard-Baron A, Chergui K, Rabiller A, et al. Superior vena caval collapsibility as a gauge of volume status in ventilated septic patients. Intensive Care Med. 2004;30(9):1734-1739.

  92. Kircher BJ, Himelman RB, Schiller NB. Noninvasive estimation of right atrial pressure from the inspiratory collapse of the inferior vena cava. Am J Cardiol. 1990;66(4):493-496.

  93. Rudski LG, Lai WW, Afilalo J, et al. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography. J Am Soc Echocardiogr. 2010;23(7):685-713.

  94. Brennan JM, Blair JE, Goonewardena S, et al. Reappraisal of the use of inferior vena cava for estimating right atrial pressure. J Am Soc Echocardiogr. 2007;20(7):857-861.

  95. Zhang Z, Xu X, Ye S, Xu L. Ultrasonographic measurement of the respiratory variation in the inferior vena cava diameter is predictive of fluid responsiveness in critically ill patients: systematic review and meta-analysis. Ultrasound Med Biol. 2014;40(5):845-853.

  96. Orso D, Paoli I, Piani T, et al. Accuracy of ultrasonographic measurements of inferior vena cava to determine fluid responsiveness: a systematic review and meta-analysis. J Intensive Care Med. 2020;35(4):354-363.

  97. Feissel M, Michard F, Faller JP, Teboul JL. The respiratory variation in inferior vena cava diameter as a guide to fluid therapy. Intensive Care Med. 2004;30(9):1834-1837.

  98. Barbier C, Loubières Y, Schmit C, et al. Respiratory changes in inferior vena cava diameter are helpful in predicting fluid responsiveness in ventilated septic patients. Intensive Care Med. 2004;30(9):1740-1746.

  99. Mahjoub Y, Touzeau J, Airapetian N, et al. The passive leg-raising maneuver cannot accurately predict fluid responsiveness in patients with intra-abdominal hypertension. Crit Care Med. 2010;38(9):1824-1829.

  100. De Backer D, Heenen S, Piagnerelli M, et al. Pulse pressure variations to predict fluid responsiveness: influence of tidal volume. Intensive Care Med. 2005;31(4):517-523.

  101. Myatra SN, Prabu NR, Divatia JV, et al. The changes in pulse pressure variation or stroke volume variation after a "tidal volume challenge" reliably predict fluid responsiveness during low tidal volume ventilation. Crit Care Med. 2017;45(3):415-421.

  102. Lanspa MJ, Grissom CK, Hirshberg EL, et al. Applying dynamic parameters to predict hemodynamic response to volume expansion in spontaneously breathing patients with septic shock. Shock. 2013;39(2):155-160.

  103. Monnet X, Bleibtreu A, Ferré A, et al. Passive leg-raising and end-expiratory occlusion tests perform better than pulse pressure variation in patients with low respiratory system compliance. Crit Care Med. 2012;40(1):152-157.

  104. Michard F, Boussat S, Chemla D, et al. Relation between respiratory changes in arterial pulse pressure and fluid responsiveness in septic patients with acute circulatory failure. Am J Respir Crit Care Med. 2000;162(1):134-138.

  105. Marik PE, Cavallazzi R, Vasu T, Hirani A. Dynamic changes in arterial waveform derived variables and fluid responsiveness in mechanically ventilated patients: a systematic review of the literature. Crit Care Med. 2009;37(9):2642-2647.

  106. Stawicki SP, Braslow BM, Panebianco NL, et al. Intensivist use of hand-carried ultrasonography to measure IVC collapsibility in estimating intravascular volume status: correlations with CVP. J Am Coll Surg. 2009;209(1):55-61.

  107. Wallace DJ, Allison M, Stone MB. Inferior vena cava percentage collapse during respiration is affected by the sampling location: an ultrasound study in healthy volunteers. Acad Emerg Med. 2010;17(1):96-99.

  108. Schefold JC, Storm C, Bercker S, et al. Inferior vena cava diameter correlates with invasive hemodynamic measures in mechanically ventilated intensive care unit patients with sepsis. J Emerg Med. 2010;38(5):632-637.

  109. Monnet X, Rienzo M, Osman D, et al. Passive leg raising predicts fluid responsiveness in the critically ill. Crit Care Med. 2006;34(5):1402-1407.

  110. Cavallaro F, Sandroni C, Marano C, et al. Diagnostic accuracy of passive leg raising for prediction of fluid responsiveness in adults: systematic review and meta-analysis of clinical studies. Intensive Care Med. 2010;36(9):1475-1483.

  111. Cherpanath TG, Hirsch A, Geerts BF, et al. Predicting fluid responsiveness by passive leg raising: a systematic review and meta-analysis of 23 clinical trials. Crit Care Med. 2016;44(5):981-991.

  112. Monnet X, Marik P, Teboul JL. Passive leg raising for predicting fluid responsiveness: a systematic review and meta-analysis. Intensive Care Med. 2016;42(12):1935-1947.

  113. Préau S, Saulnier F, Dewavrin F, et al. Passive leg raising is predictive of fluid responsiveness in spontaneously breathing patients with severe sepsis or acute pancreatitis. Crit Care Med. 2010;38(3):819-825.

  114. Porter TR, Shillcutt SK, Adams MS, et al. Guidelines for the use of echocardiography as a monitor for therapeutic intervention in adults: a report from the American Society of Echocardiography. J Am Soc Echocardiogr. 2015;28(1):40-56.

  115. Feissel M, Michard F, Mangin I, et al. Respiratory changes in aortic blood velocity as an indicator of fluid responsiveness in ventilated patients with septic shock. Chest. 2001;119(3):867-873.

  116. Bataille B, Riu B, Ferre F, et al. Integrated use of bedside lung ultrasound and echocardiography in acute respiratory failure: a prospective observational study in ICU. Chest. 2014;146(6):1586-1593.

  117. Monnet X, Osman D, Ridel C, et al. Predicting volume responsiveness by using the end-expiratory occlusion in mechanically ventilated intensive care unit patients. Crit Care Med. 2009;37(3):951-956.

  118. Vignon P, Repessé X, Bégot E, et al. Comparison of echocardiographic indices used to predict fluid responsiveness in ventilated patients. Am J Respir Crit Care Med. 2017;195(4):501-509.

  119. Jozwiak M, Teboul JL, Monnet X. Extravascular lung water in critical care: recent advances and clinical applications. Ann Intensive Care. 2015;5(1):38.

  120. Eljaiek R, Cavayas YA, Rodrigue E, et al. High minute ventilation predicts failure of passive leg raising test. Ann Intensive Care. 2019;9(1):58.

  121. Soni NJ, Arntfield R, Kory P. Point of Care Ultrasound. 2nd ed. Elsevier; 2019.

  122. Schmidt GA, Koenig S, Mayo PH. Shock: ultrasound to guide diagnosis and therapy. Chest. 2012;142(4):1042-1048.

  123. Volpicelli G, Skurzak S, Boero E, et al. Lung ultrasound predicts well extravascular lung water but is of limited usefulness in the prediction of wedge pressure. Anesthesiology. 2014;121(2):320-327.

  124. Levitov A, Frankel HL, Blaivas M, et al. Guidelines for the appropriate use of bedside general and cardiac ultrasonography in the evaluation of critically ill patients—part II: cardiac ultrasonography. Crit Care Med. 2016;44(6):1206-1227.

  125. Moore CL, Copel JA. Point-of-care ultrasonography. N Engl J Med. 2011;364(8):749-757.

  126. Weekes AJ, Tassone HM, Babcock A, et al. Comparison of serial qualitative and quantitative assessments of caval index and left ventricular systolic function during early fluid resuscitation of hypotensive emergency department patients. Acad Emerg Med. 2011;18(9):912-921.

  127. Hoffmann B, Gullett JP. Practical approach to emergency ultrasound. Emerg Med Clin North Am. 2014;32(4):771-796.

  128. Frankel HL, Kirkpatrick AW, Elbarbary M, et al. Guidelines for the appropriate use of bedside general and cardiac ultrasonography in the evaluation of critically ill patients—part I: general ultrasonography. Crit Care Med. 2015;43(11):2479-2502.

  129. Expert Round Table on Ultrasound in ICU. International expert statement on training standards for critical care ultrasonography. Intensive Care Med. 2011;37(7):1077-1083.

  130. Díaz-Gómez JL, Mayo PH, Koenig SJ. Point-of-care ultrasonography. N Engl J Med. 2021;385(17):1593-1602.

  131. Hoppmann RA, Rao VV, Bell F, et al. The evolution of an integrated ultrasound curriculum (iUSC) for medical students: 9-year experience. Crit Ultrasound J. 2015;7(1):18.

  132. Ultrasound Guidelines: Emergency, Point-of-Care and Clinical Ultrasound Guidelines in Medicine. Ann Emerg Med. 2017;69(5):e27-e54.

  133. Mosier JM, Joshi R, Hypes C, et al. The physiologically difficult airway. West J Emerg Med. 2015;16(7):1109-1117.

  134. Dres M, Teboul JL, Monnet X. Weaning the cardiac patient from mechanical ventilation. Curr Opin Crit Care. 2014;20(5):493-498.

  135. Llamas-Álvarez AM, Tenza-Lozano EM, Latour-Pérez J. Diaphragm and lung ultrasound to predict weaning outcome: systematic review and meta-analysis. Chest. 2017;152(6):1140-1150.

  136. Schwarze V, Marschner C, Negrão de Figueiredo G, et al. Single-center study: evaluating the diagnostic performance and safety of contrast-enhanced ultrasound (CEUS) in pregnant women to assess hepatic lesions. Ultraschall Med. 2020;41(4):406-412.

  137. Sidhu PS, Cantisani V, Dietrich CF, et al. The EFSUMB Guidelines and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound (CEUS) in Non-Hepatic Applications: Update 2017. Ultraschall Med. 2018;39(2):154-180.

  138. Arntfield R, VanBerlo B, Alaifan T, et al. Development of a deep learning classifier to accurately distinguish respiratory from cardiac origins of pleural effusions on lung ultrasound. Crit Care Med. 2021;49(6):e572-e579.

  139. Blaivas M, Brannam L, Theodoro D. Artificial intelligence-assisted B-line assessment and interstitial syndrome diagnosis in lung ultrasound: a multicenter study. J Ultrasound Med. 2023;42(4):937-945.

  140. Roy S, Menapace W, Oei S, et al. Deep learning for classification and localization of COVID-19 markers in point-of-care lung ultrasound. IEEE Trans Med Imaging. 2020;39(8):2676-2687.

  141. Narasimhan M, Koenig SJ, Mayo PH. A whole-body approach to point of care ultrasound. Chest. 2016;150(4):772-776.

  142. Andersen GN, Viset A, Mjølstad OC, et al. Feasibility and accuracy of point-of-care pocket-size ultrasonography performed by medical students. BMC Med Educ. 2014;14:156.

  143. Cardim N, Fernandez Golfín C, Ferreira D, et al. Usefulness of a new miniaturized echocardiographic system in outpatient cardiology consultations as an extension of physical examination. J Am Soc Echocardiogr. 2011;24(2):117-124.

  144. Via G, Storti E, Gulati G, et al. Lung ultrasound in the ICU: from diagnostic instrument to respiratory monitoring tool. Minerva Anestesiol. 2012;78(11):1282-1296.

  145. Arntfield RT, Millington SJ, Ainsworth CD, et al. Canadian recommendations for critical care ultrasound training and competency. Can Respir J. 2014;21(6):341-345.

  146. Zieleskiewicz L, Muller L, Lakhal K, et al. Point-of-care ultrasound in intensive care units: assessment of 1073 procedures in a multicentric, prospective, observational study. Intensive Care Med. 2015;41(9):1638-1647.

  147. Smallwood N, Matsa R, Lawrenson P, et al. A UK-wide survey on attitudes to point of care ultrasound training amongst clinicians working in acute and intensive care medicine. Ultrasound J. 2020;12(1):42.

  148. Nelson BP, Sanghvi A. Out of hospital and emergency department airway management: new science and trends. Emerg Med Clin North Am. 2012;30(2):443-460.

  149. Stolz LA, Stolz U, Howe C, et al. Ultrasound-guided peripheral venous access: a meta-analysis and systematic review. J Vasc Access. 2015;16(4):321-326.

  150. Shokoohi H, Boniface KS, Zaragoza M, et al. Point-of-care ultrasound stewardship. J Am Coll Emerg Physicians Open. 2020;1(6):1326-1331.

  151. Teboul JL, Monnet X, Chemla D, Michard F. Arterial pulse pressure variation with mechanical ventilation. Am J Respir Crit Care Med. 2019;199(1):22-31.

  152. Panebianco NL, Shofer F, Gorman M, et al. The effect of supine versus upright patient positioning on inferior vena cava collapsibility. Prehosp Emerg Care. 2014;18(3):403-407.

  153. Lichtenstein DA, Mezière G. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest. 2008;134(1):117-125.

  154. Melamed R, Sprenkle MD, Uluer A, et al. Assessment of left ventricular function by intensivists using hand-held echocardiography. Chest. 2009;135(6):1416-1420.

  155. Mayo PH, Narasimhan M, Koenig S. Critical care transesophageal echocardiography. Chest. 2015;148(5):1323-1332.

  156. Vignon P, Merz TM, Vieillard-Baron A. Ten reasons for performing hemodynamic monitoring using transesophageal echocardiography. Intensive Care Med. 2017;43(7):1048-1051.

  157. Slama M, Maizel J. Echocardiographic measurement of ventricular function. Curr Opin Crit Care. 2006;12(3):241-248.

  158. Kanji HD, McCallum J, Sirounis D, et al. Limited echocardiography-guided therapy in subacute shock is associated with change in management and improved outcomes. J Crit Care. 2014;29(5):700-705.

  159. Neskovic AN, Skinner H, Price S, et al. Focus cardiac ultrasound core curriculum and core syllabus of the European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging. 2018;19(5):475-481.

  160. Maw AM, Hassanin A, Ho PM, et al. Diagnostic accuracy of point-of-care lung ultrasonography and chest radiography in adults with symptoms suggestive of acute decompensated heart failure: a systematic review and meta-analysis. JAMA Netw Open. 2019;2(2):e190703.

  161. Hussain A, Via G, Melniker L, et al. Multi-organ point-of-care ultrasound for COVID-19 (PoCUS4COVID): international expert consensus. Crit Care. 2020;24(1):702.

  162. Guarracino F, Ferro B, Forfori F, et al. Jugular vein distensibility predicts fluid responsiveness in septic patients. Crit Care. 2014;18(6):647.

  163. Michard F, Alaya S, Zarka V, et al. Global end-diastolic volume as an indicator of cardiac preload in patients with septic shock. Chest. 2003;124(5):1900-1908.

  164. Liu J, Shen F, Teboul JL, et al. Cardiac dysfunction induced by weaning from mechanical ventilation: incidence, risk factors, and effects of fluid removal. Crit Care. 2016;20(1):369.

  165. Caille V, Amiel JB, Charron C, et al. Echocardiography: a help in the weaning process. Crit Care. 2010;14(3):R120.

  166. Wilkerson RG, Stone MB. Sensitivity of bedside ultrasound and supine anteroposterior chest radiographs for the identification of pneumothorax after blunt trauma. Acad Emerg Med. 2010;17(1):11-17.

  167. Lamperti M, Bodenham AR, Pittiruti M, et al. International evidence-based recommendations on ultrasound-guided vascular access. Intensive Care Med. 2012;38(7):1105-1117.

  168. Brass P, Hellmich M, Kolodziej L, et al. Ultrasound guidance versus anatomical landmarks for internal jugular vein catheterization. Cochrane Database Syst Rev. 2015;1:CD006962.

  169. Si X, Xu H, Liu Z, et al. Does respiratory variation in inferior vena cava diameter predict fluid responsiveness in mechanically ventilated patients? A systematic review and meta-analysis. Anesth Analg. 2018;127(5):1157-1164.

  170. Trezzi M, Torzillo D, Ceriani E, et al. Lung ultrasonography for the assessment of rapid extravascular water variation: evidence from hemodialysis patients. Intern Emerg Med. 2013;8(5):409-415.

  171. Perera P, Mailhot T, Riley D, Mandavia D. The RUSH exam 2012: Rapid Ultrasound in Shock in the evaluation of the critically ill patient. Ultrasound Clin. 2012;7(2):255-278.

  172. Volpicelli G, Elbarbary M, Blaivas M, et al. International evidence-based recommendations for point-of-care lung ultrasound. Intensive Care Med. 2012;38(4):577-591.

  173. Levitov A, Frankel HL, Blaivas M, et al. Guidelines for the appropriate use of bedside general and cardiac ultrasonography in the evaluation of critically ill patients—part II: cardiac ultrasonography. Crit Care Med. 2016;44(6):1206-1227.

  174. Malbrain MLNG, Langer T, Annane D, et al. Intravenous fluid therapy in the perioperative and critical care setting: executive summary of the International Fluid Academy (IFA). Ann Intensive Care. 2020;10(1):64.

ACKNOWLEDGMENTS

The authors acknowledge the contributions of intensivists, emergency physicians, and sonographers worldwide who have advanced the field of point-of-care ultrasound through clinical innovation and rigorous research.

CONFLICTS OF INTEREST

None declared.

FUNDING

No funding was received for this work.

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