Should Certified Registered Nurse Anesthetists (CRNAs) always be supervised?

Supervision of Certified Registered Nurse Anesthetists (CRNAs)

CRNAs should be supervised by physician anesthesiologists in high-risk situations and complex cases to ensure optimal patient safety, though the level of supervision may vary based on patient complexity, procedural risk, and institutional setting.

Rationale for Supervision in High-Risk Scenarios

Current evidence suggests that supervision requirements should be risk-stratified based on several key factors:

Patient Safety Considerations

• The 2023 guidelines on human factors in critical situations highlight that when an anesthesiologist supervises multiple rooms, there is a significant risk of being unavailable during critical situations 1
• The probability of an anesthesiologist being able to intervene when needed ranges from only 87% for short interventions to as low as 40% for longer procedures 1
• Studies show that when an anesthesiologist supervises two rooms simultaneously, on 35% of days it was impossible for them to be available to manage a critical situation 1

Risk-Based Supervision Framework

High-Risk Scenarios Requiring Direct Supervision:

• Patients with complex medical conditions (ASA III or higher)
• Anticipated difficult airway management
• Major surgeries with high risk of hemodynamic instability
• Pediatric patients, especially infants and young children
• Elderly patients with multiple comorbidities
• Emergency surgeries with inadequate pre-operative evaluation

Moderate-Risk Scenarios Requiring Available Supervision:

• ASA II patients with stable comorbidities
• Routine procedures with moderate anesthetic complexity
• Patients with well-controlled chronic conditions

Lower-Risk Scenarios Where Independent Practice May Be Appropriate:

• ASA I patients undergoing minor procedures
• Healthy patients undergoing routine procedures
• Ambulatory/outpatient settings with low-complexity cases

Evidence Supporting Supervision Models

The Pre-Hospital Emergency Medicine Competence guidelines from 2025 provide important context for anesthesia supervision:

• The Association of Anaesthetists of Great Britain and Ireland (AAGBI) "does not support unsupervised administration of anesthesia by non-physicians outside physician-led teams" 2
• The AAGBI specifically highlights "major safety concerns, particularly where non-physicians have administered neuromuscular blocking drugs" 2
• The guidelines emphasize that pre-hospital emergency anesthesia carries more risk than in-hospital anesthesia and should not be undertaken in professional isolation 2

Institutional Considerations

The choice of anesthesia staffing models varies significantly based on:

• Geographic location: Rural facilities use predominantly CRNA models more frequently (61% of rural ambulatory surgical centers) compared to large urban hospitals (only 10%) 3
• Facility type: Hospital vs. ambulatory surgical center
• Surgeon preferences and organizational factors 3

Best Practices for CRNA Practice

When CRNAs are practicing, the following safety measures should be implemented:

• All extubations should be supervised by an anesthesiologist, particularly for "at-risk" patients 1
• Difficult airway equipment should be immediately available 1
• Standard monitoring should be continued in recovery, with capnography available 1
• Clear communication protocols should be established between CRNAs and supervising physicians

Special Considerations

Cardiac Procedures

• The American College of Cardiology Foundation/American Heart Association guidelines recommend that "a fellowship-trained cardiac anesthesiologist (or experienced board-certified practitioner) credentialed in the use of perioperative transesophageal echocardiography is recommended to provide or supervise anesthetic care of patients who are considered to be at high risk" 2

Trauma and Emergency Care

• CRNAs working in rural settings frequently manage airways and stabilize trauma patients, highlighting the need for appropriate training in these skills 4
• The 2007 NCEPOD 'Trauma: Who Cares?' report concluded that "if pre-hospital intubation is to be part of pre-hospital trauma management, then it needs to be in the context of a physician-based pre-hospital care system" 2

Potential Distractions and Safety Concerns

• Personal electronic device use by CRNAs during anesthesia delivery may threaten patient safety and remains understudied 5
• When workload is not adapted to the number of caregivers available, the risk of adverse events increases by 8-34%, and mortality by 43% 1

In conclusion, while CRNAs are highly trained professionals capable of providing excellent anesthesia care, supervision by physician anesthesiologists remains important for high-risk patients and complex procedures to ensure optimal patient safety and outcomes. The level of supervision should be determined by patient factors, procedural complexity, and institutional setting.