Background
During the procedure of general anesthesia, the anesthesiologists sometimes have to do another task in clinical settings. However it is unclear whether anesthesiologist can simultaneously do both anesthetic procedure (primary task) and mental workload (secondary task). We hypothesized that the capacities of anesthesiologists to deal with mental workloads differ based on their clinical experience. The aim of this study was to reveal the effect of anesthesiologist’s mental workload to anesthetic procedure during induction of general anesthesia. 

Methods
Twenty-two participants were categorized into anesthesiology residents (RA group; n = 13) and board certified anesthesiologists (CA group; n = 9). Subjects participated in 3 simulated scenarios (Scenario A: baseline, Scenario B: simple addition tasks, Scenario C: combination of simple addition tasks and treatment of unexpected arrhythmia). We used simple 2-digit integer additions every 5 seconds as a secondary task during the induction of general anesthesia. The rate of correct answers to 40 addition questions was calculated. Four kinds of key actions involved in the induction of general anesthesia were also evaluated in each scenario.
Results
The correct answer rate was not significantly different between both groups (RA: 0.853 ± 0.162 vs. CA: 0.945 ± 0.046, p = 0.07, 95%CI -0.193 to 0.010) and the scores of key actions were similar between the two groups (RA: 3.6 ± 0.65 vs. CA: 4.0 ± 0.00, p=0.07) in scenario B. In scenario C, the correct answer rate was significantly higher in the CA vs. the RA group (RA: 0.370 ± 0.050 vs. CA: 0.736 ± 0.051, p<0.01, 95%CI -0.518 to -0.215) as was the score of key actions (RA: 2.7 ± 1.3 vs. CA: 4.0 ± 0.00, p=0.005) for maintenance of anesthesia. 
Conclusion
In a serious clinical situation, anesthesiologists might not be able to adequately perform both the primary and secondary tasks. These results means mental workload of the primary task is close to the participant’s maximal capacity. This tendency is more apparent in young anesthesiologists.

Influence of mental workload on the performance of anesthesiologists during induction of general anesthesia: a patient simulator study