Surgery at Sea: The Effect of Simulated High Sea States on Surgical Performance

The US Navy initiated design concepts for a Medical Mission Module Support Container (M3SC), a mobile operating room capable of rapid installation aboard maneuverable ships within proximity of active combat units. The M3SC provides an alternative echelon of care in the current trauma system by decreasing the time between point of injury, arrival, and surgical intervention. The mobile ships used as M3SC platforms, however, are more susceptible to oceanic conditions that can induce detrimental physiologic motion sickness in medical personnel and patients aboard the vessels. This study investigated the effects of different sea-state motion conditions on the performance of surgical teams.

Six four-person surgical teams performed 144 procedures in an M3SC aboard a Stewart motion table that simulated motion profiles of sea states 0, 3, and 4. A modified human-worn partial- task surgical simulator was used as a surgical surrogate to simulate the four most common, wartime, improvised explosive device injuries in the past 10 years. Electroencephalographs and heart rate variability (HRV) data were collected from surgeons and surgical technologists during each procedure to assess real-time physiologic responses to motion. Two postprocedure surveys, a Surgical Task Load Index and a Motion Sickness Assessment Questionnaire, were given to assess subjective responses of workload stress and motion-induced kinetosis. Surgical subject matter experts quantified surgical performance after each procedure by measuring blood loss and orthopedic pin placement to evaluate each intervention.

Motion did not significantly influence overall performance (ρ = .002). Surgical procedure was the strongest predictor of performance. HRV was used to measure stress and was increased in surgical technologists; however, HRV was decreased for surgeons and technologists in motion. There was a significant interaction between role and motion (ρ = .002): Surgeons had higher workloads than did surgical technologists and neither demonstrated differences between motion and no motion. Surgeons demonstrated significantly decreased workloads under motion conditions (ρ = 0.002); however, surgeons perceived their workload to be higher. We attribute this to their increased critical thinking and physical execution of procedures. Surgeons and surgical technologists showed a trend toward HRV suppression within the motion conditions. This may indicate a coping response to the increased stress of the motion setting. Procedure and team dynamic were the strongest predictors of overall performance, suggesting a learning curve exists and that added focus on training should be enforced.

Based on data collected in this study, similar surgical procedures should be implemented aboard these classes of ships. By doing so, injured military personnel would have more timely access to care. Surgical team members were aware of craft motion, used compensatory measures, and exhibited some physiological response.