Darzi, A

Leff, D

Modi, HN

Singh, H

Yang, G

Spiral - Imperial College Digital Repository

Neural Markers of Sensitivity to Intraoperative Temporal Stress in Surgeons Hemel N. Modi, Harsimrat Singh,  Guang-Zhong Yang, Ara Darzi, Daniel R. Leff Hamlyn Centre for Robotic Surgery, Imperial College London, United Kingdom  Introduction:  Time pressure in the operating room can increase cognitive workload of the operator resulting in disruption of surgical performance1. The ability to stabilise technical performance during stressful intraoperative conditions may relate to activity of the prefrontal cortex (PFC) due to its role in attention, concentration and executive control2. The aim of this study is to determine whether sensitivity to time pressure can be assessed from surgeons’ prefrontal activation patterns.  Methods:  33 surgeons performed a laparoscopic suturing task 5 times (inter-trial rest period 30s) under two conditions: (1) “self-paced” and (2) “time pressure” (max. 2 minutes to tie each knot). A 24-channel fNIRS system (ETG-4000, Hitachi Medical Corp., Japan) was used to record PFC activity with optodes arranged in two 3×3 arrays. 3D coordinates for optode positions were digitized using an electromagnetic probe positioning digitizer (Polhemus, USA). Subjective workload was quantified using the Surgical Task Load Index and continuous heart rate monitoring was used to measure the physiological stress response. Weighted-average normalised performance scores were calculated for each subject in both conditions, and the change in composite performance between conditions was computed to identify those surgeons whose performance was most sensitive to temporal demands. Optical data were pre-processed using HOMER3. Block-averaged time courses were visually inspected to identify channels in each subject in which a pronounced task-induced change in HbO2 occurred.  Results:  Surgeons whose performance deteriorated the most under time pressure showed a task-induced decreased in HbO2 in a number of prefrontal channels. In contrast, those who were better able to maintain stable performance, exhibited a task-induced increase in HbO2 under time pressure (Figure 1).               Conclusions:  fNIRS is a suitable modality by which to study surgeons’ brain function during high fidelity tasks. Although further analysis is required, these preliminary results suggest that stress-induced performance deterioration among surgeons may be due to prefrontal disengagement.   1.  Arora S, Sevdalis N, Nestel D, Woloshynowych M, Darzi A, Kneebone R. The impact of stress on surgical performance: a systematic review of the literature. Surgery. 2010;147:318-30, 30 e1-6. 2.  Miller EK, Cohen JD. An integrative theory of prefrontal cortex function. Annual review of neuroscience. 2001;24:167-202. 3.  Huppert TJ, Diamond SG, Franceschini MA, Boas DA. HomER: a review of time-series analysis methods for near-infrared spectroscopy of the brain. Appl Opt. 2009;48:D280-98. Concentration  Change (µM) Time(s) Time(s) Concentration  Change (µM) Subject 11 Subject 24 Channels indicating:  Increase in HbO2 Decrease in HbO2     HbO2 HbT HHb Figure 1. Regional variations in cortical haemodynamic activity in a surgeon whose performance deteriorates significantly under time pressure (Subject 11) compared with one whose performance remains relatively stable (Subject 24). The grey shaded area represents the trial length. 

Neural markers of sensitivity to intraoperative temporal stress in surgeons

Abstract

Similar works

Full text

Available Versions

Spiral - Imperial College Digital Repository