Background

Administering anesthesia is a complex task in which either human or equipment failure can have disastrous consequences. An improved understanding of the nature of the anesthesiologist's job could provide a more rational basis for improvements in provider training as well as the design of anesthesia equipment. The objective of this study was to develop a set of techniques to evaluate anesthesiologist performance and to determine what information could be obtained from performing real-time task assessment and workload analysis tests in the operating room.

Methods

The methodology used included time-motion analysis, secondary task probing, and subjective workload assessment. The time-motion data was subjected to subsequent analysis to generate quantitative measures such as task duration (time spent focused on an individual task) and task density (the number of tasks initiated per minute). The latency of response to a "vigilance light" was used as a secondary task probe. Finally, both the observer and the subjects themselves scored workload at 10-15-min intervals throughout the case. Two groups of anesthesia providers performing general endotracheal anesthesia for simple ambulatory surgical cases (1-4 h duration) were examined using this methodology. In the first group, 3rd-yr anesthesia residents and experienced certified registered nurse anesthetists (n = 11) performed cases under limited supervision by an attending anesthesiologist. In the second group, novice residents in their first 8 weeks of training (n = 11) performed similar cases under nearly constant attending supervision.

Results

The two groups seemed to manifest different patterns of task behavior, task density, subjective workload, and latency of response to the vigilance task. Response latency to the vigilance task increased at times of increased workload (e.g., during induction of anesthesia). The experienced (less supervised) providers spent significant amounts of time observing the monitors and the surgical field, whereas the novice subjects spent more time conversing with the supervising attending. Despite performing fewer tasks per minute (lower task densities), the novice subjects exhibited longer latencies of response to the vigilance light and increased subjective workload. Novice subjects also had longer task duration values. For example, postintubation, novices focused on their monitors for an average of twice as long as did experienced subjects (13 +/- 2 vs. 7 +/- 1 s) before moving on to another task.

Conclusions

These techniques permitted an objective description of task characteristics, workload, and vigilance in anesthesia personnel under actual work conditions. This methodology could aid in understanding the factors that affect anesthesiologists' performance and may prove useful in assessing the progress of training.