Working Memory Capacity and Surgical Performance While Exposed to Mild Hypoxic Hypoxemia.

Area of Science:

• Aerospace Medicine
• Orthopedic Surgery
• Human Physiology

Background:

• Medical Emergency Response Team (MERT) helicopters operate at high altitudes (3000m).
• Civilian surgical teams may face similar conditions, potentially impacting performance due to mild hypoxia.
• Understanding the effects of acute hypoxia on surgical skills is crucial for aeromedical teams.

Purpose of the Study:

• To investigate the impact of acute normobaric hypoxia (equivalent to 3000m) on orthopedic surgeons' cognitive and practical performance.
• To determine if supplementary oxygen is necessary for surgical teams operating at high altitudes.

Main Methods:

• Ten UK orthopedic surgeons were exposed to normobaric hypoxia (FIo2 ~14.1%) or normoxia for 45 minutes in a double-blind, randomized protocol.
• Cognitive function was assessed using verbal working memory capacity (VWMC) tests.
• Surgical skill was evaluated by applying an orthopedic external fixator to a plastic tibia.

Main Results:

• Hypoxia significantly reduced oxygen saturation (SpO2 87% vs. 98%) but did not affect verbal working memory capacity.
• Surgical performance showed a significant increase in pin-divergence score (frame asymmetry) under hypoxic conditions (4.6 mm vs. 3.0 mm).
• One fixation device applied in hypoxic conditions would have potentially failed early.

Conclusions:

• Acute exposure to 3000m altitude hypoxia for 45 minutes may not impair cognitive function in unacclimated surgeons.
• Surgical performance, specifically frame stability, can be negatively affected by mild hypoxia.
• Further research is needed, but current findings suggest surgery at 3000m may be feasible without supplemental oxygen for short durations.