What is the role of Point-of-Care Ultrasound (POCUS) in anesthesia care?

Role of Point-of-Care Ultrasound (POCUS) for Anesthesiologists

POCUS has evolved from a procedural tool into an essential diagnostic and monitoring modality that anesthesiologists should integrate across all perioperative phases—preoperative assessment, intraoperative management, and postoperative care—to rapidly diagnose hemodynamic instability, guide procedures, assess aspiration risk, and monitor treatment response. 1, 2

Core Applications in Anesthesia Practice

Procedural Guidance (Foundational Skill Level)

• Vascular access: POCUS facilitates safer central line placement and is particularly valuable for challenging venous and arterial catheter placements 3, 4
• Regional anesthesia: Ultrasound-guided central neuraxial and peripheral nerve blocks have become standard practice, with nerve visualization improving block success rates 5, 4
• Airway management: Ultrasound can confirm endotracheal tube placement and assess airway anatomy preoperatively 1, 5

Preoperative Risk Assessment

• Gastric ultrasound: Critical for assessing aspiration risk by evaluating gastric content and volume, directly impacting anesthetic planning 1, 4
• Cardiac evaluation: Preoperative focused cardiac ultrasound (FoCUS) identifies previously undiagnosed cardiac dysfunction, valvular disease, or pericardial effusion that may alter anesthetic management 2, 5
• Lung assessment: Preoperative lung ultrasound detects pleural effusions, consolidations, or interstitial syndrome that increase perioperative respiratory risk 1, 4

Intraoperative Hemodynamic Management

When faced with intraoperative hypotension or shock, use a systematic POCUS protocol to rapidly differentiate causes:

• Cardiac assessment using parasternal long axis, parasternal short axis (basal/mid-papillary/apical), apical four chamber, and subcostal four chamber views to visually estimate left ventricular ejection fraction 2
• Identify specific cardiac pathology: pericardial effusion, cardiac tamponade (look for right atrial/ventricular collapse), massive pulmonary embolism (right ventricular dilation and dysfunction), or severe hypovolemia (kissing ventricle sign) 2, 4
• Volume responsiveness: Assess inferior vena cava collapsibility and cardiac chamber size to guide fluid resuscitation decisions 3, 4

Respiratory Emergencies

For intraoperative or postoperative hypoxemia, POCUS rapidly identifies the cause:

• Pneumothorax: Absence of lung sliding with A-lines and identification of lung point 6, 2
• Pulmonary edema: Bilateral B-lines (≥3 per intercostal space in multiple zones) indicate interstitial syndrome 6, 4
• Pleural effusion: Anechoic fluid collection above the diaphragm with atelectatic lung floating within 2, 4
• Consolidation: Tissue-like appearance of lung with air bronchograms suggests pneumonia or atelectasis 6, 1
• Diaphragm assessment: Diaphragm ultrasound evaluates diaphragmatic function and can predict extubation success 4

Trauma and Emergency Settings

• Extended FAST examination (Focused Assessment with Sonography for Trauma) identifies intra-abdominal hemorrhage, pneumothoraces, and hemothoraces in hypotensive trauma patients 1, 2
• This application is particularly valuable in the operating room when a patient deteriorates unexpectedly or arrives directly from the emergency department 2

Training and Competency Considerations

Different POCUS applications require varying levels of training expertise, which should guide implementation:

• Basic level: Vascular access, gastric ultrasound, simple lung pathology (pneumothorax, pleural effusion) 7, 3
• Intermediate level: Focused cardiac assessment, comprehensive lung ultrasound, FAST examination 7, 3
• Advanced level: Detailed cardiac function assessment, complex hemodynamic evaluation, transesophageal echocardiography 7

Training methods that have proven effective include:

• Model/simulation-based lecture series for teaching ultrasound to anesthesiology residents 1
• E-learning and traditional didactics are equally effective for teaching specific applications like lung ultrasound and FAST 1
• Structured expert demonstration combined with hands-on practice 1

Clinical Decision-Making Framework

Use the I-AIM protocol (Indication, Acquisition, Interpretation, Medical decision making) to ensure consistent and reliable POCUS utilization: 1

1. Indication: Define the specific clinical question (e.g., "Is hypotension due to hypovolemia, cardiac dysfunction, or tamponade?")
2. Acquisition: Obtain appropriate views using standardized techniques
3. Interpretation: Recognize pathological findings and their limitations
4. Medical decision making: Integrate POCUS findings with clinical context to guide management

Critical Caveats and Limitations

Understand that POCUS is a focused examination, not a comprehensive diagnostic study:

• POCUS should not replace comprehensive echocardiography when detailed cardiac assessment is needed 3
• Operator skill significantly affects diagnostic accuracy; recognize your limitations and seek expert consultation when findings are unclear 8
• POCUS cannot distinguish between cardiogenic and non-cardiogenic pulmonary edema based on lung findings alone—integrate cardiac assessment with lung findings 6

Common pitfalls to avoid:

• Do not delay definitive imaging or treatment while attempting POCUS if you lack proficiency 8
• Indeterminate results should prompt formal radiology consultation rather than delaying diagnosis 8
• Always correlate POCUS findings with clinical context; isolated findings without clinical correlation can mislead 3, 1

Evidence for Clinical Impact

POCUS improves diagnostic accuracy and clinical outcomes in perioperative settings:

• When added to standard diagnostic pathways, POCUS leads to significantly more correct diagnoses compared to standard pathways alone 7, 3
• POCUS reduces time to diagnosis (40 vs. 60 minutes) in acute settings 3
• The American College of Physicians recommends using POCUS when there is diagnostic uncertainty in patients with acute dyspnea in emergency or inpatient settings (conditional recommendation, low-certainty evidence) 7

POCUS consistently improves sensitivity for detecting:

• Congestive heart failure 7, 3
• Pneumonia 7, 3
• Pulmonary embolism 7, 3
• Pleural effusion 7, 3
• Pneumothorax 7, 3

Governance and Quality Assurance

Establish clear scope of practice and quality assurance mechanisms:

• Define which POCUS applications are within your competency based on training level 7
• Maintain image documentation for quality review and medicolegal purposes 7
• Participate in ongoing competency assessment and continuing education 7
• Understand institutional credentialing requirements for POCUS practice 7

Emerging Applications

Novel POCUS applications continue to expand the anesthesiologist's diagnostic capabilities:

• Venous excess ultrasound (VExUS) for assessing venous congestion and guiding fluid management 4
• Multi-organ POCUS evaluation protocols for undifferentiated shock or cardiac arrest 4
• Integration of POCUS into enhanced recovery after surgery (ERAS) pathways 9

In ambulatory settings specifically, POCUS can prevent surgery cancellations and delays by:

• Rapidly assessing aspiration risk with gastric ultrasound 9
• Identifying previously undiagnosed cardiac or pulmonary pathology that requires optimization 9
• Confirming adequate vascular access before induction 9