Article Text

Download PDFPDF
Attention and working memory in resident anaesthetists after night duty: group and individual effects
  1. P Bartel1,
  2. W Offermeier2,
  3. F Smith2,
  4. P Becker3
  1. 1Department of Neurology, University of Pretoria and Pretoria Academic Hospital, South Africa
  2. 2Department of Anaesthesiology, University of Pretoria and Pretoria Academic Hospital, South Africa
  3. 3Biostatistics Unit, South African Medical Research Council, Pretoria, South Africa
  1. Correspondence to:
 Dr P Bartel
 Department of Neurology, Pretoria Academic Hospital, Private bag X169, 0001 Pretoria, South Africa;


Aims: To investigate the effects of a single period of night duty on measures of attention and working memory in a group of residents (registrars) in anaesthesiology. Emphasis was placed on individual deficits using a reference point of the equivalent effect of a blood alcohol concentration (BAC) >0.05% determined by other researchers.

Methods: There were 33 subjects aged 26–42 years. Night duty was performed on a weekly basis. Baseline assessments were conducted at either 08 15 or 08 55 preceding night duty and repeated 24–25 hours later, just after the completion of duty. Questionnaires included items regarding duration of sleep and the Stanford Sleepiness Scale. A battery of four reaction time (RT) tasks of increasing difficulty, lasting approximately 35 minutes, was administered on a personal computer. These ranged from simple RT to progressively more complex RT tasks incorporating working memory. A significant change was regarded as >15% deterioration in respect of speed or accuracy.

Results: The mean duration of sleep preceding night duty was 7.04 hours and 1.66 hours during the period of night duty. Intergroup comparisons revealed significant prolongation in mean response speed in the first three tests. Mean accuracy was significantly reduced only in respect of the two more complex tests. A >15% deterioration in response speed occurred in up to 30% of subjects on a single task, rising to 52% (17/33) overall. Deterioration occurred in a patchy distribution in most subjects, involving no more than one or two of the four tasks. As regards accuracy, the prevalence of deterioration increased with task complexity.

Conclusions: Results are in general agreement with previous group analyses. A new dimension was added by the analysis of a broad spectrum of individual response to sleep deprivation. The effects of sleep loss in residents cannot be overlooked, even in a relatively benign work schedule.

  • sleep deprivation
  • psychomotor performance
  • resident anaesthetists
  • BAC, blood alcohol concentration
  • RT, reaction time
  • SSS, Stanford Sleepiness Scale

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Presented in part at the joint congress of the Association of British Neurologists and the Neurological Association of South Africa, 29 Jan–1 Feb 2003, Cape Town, South Africa