Visual Attention of Anaesthetists during Simulated Critical Incidents

Schulz CM, Schneider E, Fritz L et al.

British Journal of Anaesthesia 2011; 106(6): 807-13.

Aim of Study

To assess the distribution of visual attention (VA) in anaesthetists delivering general anaesthesia.

Design & Location

Exploratory, randomized, cross-over trial. Germany.


* Convenience sample of 15 anaesthetists

* All wore head-mounted, eye-tracking camera systems while inducing general anaesthesia at a high fidelity simulator

* Tracker recorded dwell time and gaze

* Environment was categorised into different regions of interest (ROI): monitoring tasks, manual tasks, other.

* Two groups:

  • Group A = Resident doctors of first or second year
  • Group B = Resident doctors of third, fourth or fifth year, staff, or senior anaesthetists.

* Occurrence of a critical evident was randomised in session 2; consisted of a severe anaphylactic reaction after the administration of a hypnotic.

* Simulator scripts were programmed to ensure similar conditions

  • Script A = uneventful sessions
  • Script B = Critical incidents

Primary Outcome

* Group B spent less time on monitoring and other tasks and increased time related to manual tasks, when compared to uneventful session.

* Group A acted inversely.

Secondary Outcomes

* ROI with highest VA were patient monitor (21% uneventful, 30% in critical)

* During critical incident, VA dedicated to patient monitor increased from 20% to 30%.


* No power calculation

* Generalized estimation equations


* 4 participants did not complete 3rd sessions – 11 completed all 3.

* In 6 of 22 data sets, video data was unusable due to technical issues.

* During critical incident, VA dedicated to patient monitor increased from 20% to 30%. (p=0.003)

* Between 7.9& and 11.3% of the VA was dedicated to regions not identified in ROI classification

% distribution of VA



* Increase in VA for patient monitor during critical incident suggest that individuals actively directed their attention in order to have sufficient awareness of situation – patient monitors play an important role for the maintenance of situation awareness while inducing anaesthesia.

* ROI sequence of respiratory mask – patient thorax – respiratory mask – patient thorax was the most frequent scan path only in group B. Authors thought it was a basic technique that should be present in both groups. Should this be a training focus for anaesthesia novices?

Stated Limitations from Study

* Low sample size.

* Simulators are different to real life settings and do not provide qualitative differences, such as skin colour changes.

* Carrying an eye tracker may introduce bias.

* Bias may also be present, as participants could have been anticipating a critical incident and therefore attention and vigilance are heightened, which may alter VA.

* Six of the twenty-two videos, the video data was not useable due to technical reasons.

* The median years of experience in Group B was 3 years and therefore they cannot be defined as an expert sample.

* The eye tracker only captured the visual aspect of spatial distribution of attention and can’t record other measures e.g. auditory, haptic.

Discussion from Journal Club Meeting/Change of Practice

Agreed that possibly the skill of visual and tactile management of the patient has somewhat declined since the introduction of more forms of monitoring but is this such a bad thing?

How do we get our novices to become more hands on?

Agreed that it is a combination of both monitoring and hands on to develop skills to manage patients

Encourage use of more simulation as good practice for difficult scenarios that trainees may not come across.

Summary by Dr H Sivadhas. Journal Club 12 October 2017.

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