Effects of 24 h working on-call on psychoneuroendocrine and oculomotor function: A randomized cross-over trial
Introduction
On-call duty (OCD) is a common pattern of working schedule among physicians in European hospitals (Baldwin et al., 2003, Council of the European Union, 2007). For continuous night shift workers, as air traffic controllers or emergency physicians it is well known that they are prone to errors while working night shifts (Smith-Coggins et al., 1994). OCD combines day and night work, and includes extended work hours, frequent stressful situations, sleep deficit and desynchronisation of the circadian rhythm (Akerstedt, 2007). Furthermore, it provides a possibility to maintain compliance with restricting regulatory guidelines although accompanied by risks for the physician's health (Rauchenzauner et al., 2009). In the early 70s, Friedman and colleagues found a reduced ability to judge electrocardiogram (ECG) print-outs during OCD (Friedman et al., 1971). Self-injuries and motor vehicle crashes after extended work hours are known to reflect the negative short-term effects on physician's safety (Barger et al., 2005, Ayas et al., 2006). In 2003, the American Accreditation Council for Graduate Medical Education reacted to the growing concerns about patients’ safety treated by sleep deprived physicians and limited continuous clinical work to 24 h. Time and again OCD shift-systems are the substance of a public dialogue although the clinical importance of sleep curtailment still remains unclear due to the lack of studies conducted in clinical care environments (Gaba and Howard, 2002). The main focus of clinical research deals with performance decrements after nightshift in view of an optimal treatment of patients. However, the physician's emotional state influences the patient-physician interaction and the communication between doctor and patient plays an important role in economic health care issues (Epstein et al., 2005). Data concerning the immediate effects of OCD on the emotional status are sparse and often focus on negative feelings often neglecting affects on positive emotions (Crowley et al., 2004, Rose et al., 2008).
This is a sub study of a trial investigating cardiovascular stress response during OCD (Rauchenzauner et al., 2009). The aims of this study were to:
- 1.
Investigate changes in mood, cognitive performance in relation to sympathetic-adrenomedullary axis (SMA) and the hypothalamic-pituitary-adrenocortical axis (HPA) over a 24 h period during OCD as compared to a regular working day (non on call, NOC)
- 2.
Determine the causative factors of the observed changes (e.g. sleep deprivation, repeated awakenings by phone calls or the on-call shift itself)
- 3.
Identify impairment of neurocognitive function after OCD by analysis of saccadic latency distributions.
Section snippets
Study design (Fig. 1)
Participants were residents and senior physicians of the Department of Internal Medicine, Neurology and Otorhinolaryngology at the University Hospital Innsbruck. Each physician completed two days (24 h) of data collection in a randomized within-person cross-over design as reported previously (Rauchenzauner et al., 2009). To avoid a residual effect of OCD on NOC the minimal interval between OCD and NOC was defined as 7 days at least. Randomization was performed by an external advisor.
The
Results
Forty-four physicians were assessed for eligibility and 40 colleagues agreed to participate in the study. Thereof, seven study participants were lost to follow-up [cancelled consent of participation (n = 4), aborted night shift (n = 1), refused to participate (n = 1), moved away from Innsbruck (n = 1)]. Since three colleagues had to be excluded from analysis due to manifest cardiac abnormality (n = 1) or alcohol consumption on control day (n = 2), 9 female and 21 male physicians remained for data analysis (
Discussion
This is the first randomized cross-over trial investigating changes in cognitive performance and mood related to objective parameters of stress in physicians doing OCD. We found a significant reduction in cognitive performance and alterations in emotional state. These findings were associated with an activation of the SMA-axis and a reduction in short latencies during saccadometry as a sign of fatigue.
Cognitive performance was significantly reduced after OCD when compared to NOC. The d2-test
Conclusion
24 h OCD impairs cognitive performance associated with a distinctive emotional change showing elevated mood. This is accompanied by alterations of both the SMA- and the HPA-axis, which may counteract an impaired oculomotor system. 32 h on-call duties are still legal practice in Austrian hospitals and when one considers another possible 8 h of patient contact these findings are clinically relevant with respect to a balanced patient-interaction and the accuracy of medical decisions.
Role of the funding source
The study was supported by Landessanitätsdirektion für Tirol, Österreich.
Conflict of interest
The authors declare no conflict of interest.
Acknowledgement
We thank all participants of this study for their patience and collegiality during data acquisition.
Glossary
- AW
- awakenings
- CP
- concentration performance
- ECG
- electrocardiogram
- EWL
- Eigenschaftswoerterliste
- fOCD
- first nightshift
- GD
- general deactivation
- HPA
- hypothalamic pituitary-adrenocortical
- LATER
- Linear Approach to Threshold with Ergodic Rate
- NOC
- not on-call
- OCD
- on-call duty
- OCD/m
- OCDs per month
- OP
- overall performance
- PRA
- performance related activation
- SMA
- sympathetic-adrenomedulary
- TIB
- time in bed
- TST
- total sleep time
- TWT
- total wake time
- VLF
- spectral power in very low frequency
References (50)
Altered sleep/wake patterns and mental performance
Physiol. Behav.
(2007)- et al.
Cognitive impairments and mood disturbances in growth hormone deficient men
Psychoneuroendocrinology
(1996) - et al.
The pharmacology of wakefulness
Metabolism.
(2006) - et al.
Cardiovascular and endocrine responses to experimental stress: effects of mental effort and controllability
Psychoneuroendocrinology
(1998) - et al.
Acute psychological stress reduces working memory-related activity in the dorsolateral prefrontal cortex
Biol. Psychiatry
(2009) - et al.
Intra-individual patterns of hormonal and affective adaptation to work demands: an n = 2 study of junior doctors
Biol. Psychol.
(1996) - et al.
Relationship of day versus night sleep to physician performance and mood
Ann. Emerg. Med.
(1994) - et al.
Effect of sleep deprivation on surgeons’ dexterity on laparoscopy simulator
Lancet
(1998) - et al.
Saccadometry: a novel clinical tool for quantification of the motor effects of subthalamic nucleus stimulation in Parkinson's disease
Exp. Neurol.
(2009) - et al.
The use of quantitative oculometry in the assessment of Huntington's disease
Exp. Brain Res.
(2006)