Temporal Demands Increase Workload and Degrade Surgical Performance

Authors: Modi HN, Leff DR, Singh H, Darzi A

AIMS:Complications thatarisein the operating theatre may place added cognitive strain on surgeons, requiring them to perform operative manoeuvresswiftly yet accurately. The purpose of this study is to determine the impact of a temporalstressoron surgeons’technical performance during a laparoscopic suturing task.

METHODS:In a randomised cross-over study, 27 higher surgical trainees (ST3 – post-CCT level; median age 32 years; 21 males) were asked to suture a 2cm defect in a Penrose drain using an intracorporeal technique under two conditions: (1) “self-paced”, in which trainees took as long as they needed to tie each knot,and (2) “time pressure”, in which subjects were given a maximum of 2 minutes to tie each knot. Subjective workload was quantified using the Surgical Task Load Index (SURG-TLX) andcontinuous heart rate monitoring was used to measure the physiological stress response. Technical skill was assessed by measuring a task progression score, an accuracyscore [distance (mm) between needle entry/exit points and pre-marked points on the drain], leak volume (ml), and tensile strength (N) of the knots.

RESULTS: Each traineecreated five knotsin a self-paced manner andfive knots under time-pressure, producing a total of 270 knots for analysis. The results(Table 1) demonstrate that time-pressure led to a statistically significant increase in subjective workload (p<0.001) and heart rate (stress) (p<0.05).Performing the task under a temporal demand also led to a deterioration in performance, exemplified by inferior task progression (p<0.001), greater leak volumes (p<0.05), and lower tensile strengths of knots (p<0.01).

CONCLUSIONS:Time-pressure stressors increase trainees’ subjective workload and negatively impact technical skills. Future work will focus on developing strategies to help trainees cope with excessive cognitive load in the operating theatre, thereby optimisingperformance and maximisingpatient safety.

Table 1. Workload, stress and performance parameters
Outcome measure / Self-paced condition / Time-pressure condition / P value
SURG-TLX score (au) / 147.63 (38.38)† / 191.89 (45.27)† / <0.001
Heart rate (bpm) / 89.75 (102.60)‡ / 90.62 (118.68)‡ / 0.042
Progression score (au) / 6.0 (5.0-6.0)‡ / 4.8 (2.4-6.0)‡ / <0.001
Accuracyscore (mm) / 1.9 (0.7-7.8)‡ / 3.0 (0.6-11.4)‡ / 0.09
Leak volume (ml) / 17.3 (2.02)† / 18.7 (2.51)† / 0.015
Tensile strength (N) / 34.85 (18.64)† / 13.53 (19.83)† / 0.008
† mean (standard deviation) for parametric data; ‡ median(range) for non-parametric data
P value indicates paired samples t-test for parametric data and Wilcoxon Signed Rank test for non-parametric data. Significant values are in bold.
Abbreviations: SURG-TLX (Surgical Task Load Index); au (arbitrary units); mm (millimetres); ml (millilitres); N (Newtons); bpm (beats per minute)