Abstract
Background: Fatigue related to sleep deprivation has a degrading effect on human performance. In critical care health settings this represents a potential hazard to the safety of patients. This thesis aimed to identify and assess possible effects of acute clinician fatigue using a measure with direct relevance to safe and effective clinical performance. The focus was on critical care clinicians, particularly those who work in the high risk and somewhat isolated setting of intensive care patient air transfer. The specific research objectives for the thesis were to assess the degree of fatigue the clinicians experience in the course of routine duties, develop and test a meaningful method of measuring clinical performance, and assess the effect of routinely-experienced levels of fatigue on clinical performance.
Methods: In an initial field-based study doctors and flight nurses from two intensive care inter-hospital transport teams routinely completed subjective fatigue report forms before and after patient transport missions, over a 4 month period. Multivariate hierarchical linear and logistic models were used to evaluate the influence of various mission characteristics on post-mission fatigue. In the next phase of the research an existing non-technical skills measurement system was adapted to the aeromedical setting, using data collected directly from clinician groups and published literature. It was evaluated by: surveying experienced clinicians; testing it in the field; and undertaking a clinical simulation study, to determine whether the tool distinguished the different levels of performance expected in clinicians experienced versus inexperienced in patient transfer. Rank-based statistical tests were used to examine performance differences and associations between assessment approaches. Finally, a second clinical simulation study utilising a randomised crossover design compared the non-technical performance of individual clinicians when they were fatigued versus non-fatigued. Within-subject differences in performance were analysed using paired t-tests. Analysis of covariance was used to examine the relationship between possible covariates and within-subject performance differences, while controlling for the effect of scenario order (fatigued or non-fatigued first).
Results: Results from the initial field-based research showed there was at least one clinician reporting severe fatigue on 11.2% of routine interhospital transport missions. Fatigue levels were influenced by clinicians’ baseline fatigue, their workload, and working during any part of the night. From the second phase of research the adapted aeromedical non-technical skills framework showed good face and content validity, and the ability to distiguish between differing performance levels, with clinicians experienced in interhospital transport performing more highly than those without experience, according to both non-technical skills ratings (Mann-Whitney U, p = 0.001) and independently observed general performance ratings (Mann-Whitney U, p = 0.003). Self ratings did not distinguish experienced from inexperienced transport clinicians (Mann-Whitney U, p = 0.32). The main finding from the third phase of research was that the non-technical skills performance scores of clinicians were higher when they were in non-fatigued versus fatigued states (mean difference with 95%CI, 2.8 [2.2 - 3.4]), as assessed by raters blinded to the fatigue status of the clinicians.This finding remained consistent when controlling for an order effect and examining the impact of a number of possible co-variates. There was no difference in self-ratings of clinical performance between non-fatigued and fatigued states (Wilcoxon signed-ranks test, p = 0.153).
Conclusion: In critical care settings clinicians’ non-technical skills are recognised as being directly linked to safe and effective treatment of patients. The findings of the research undertaken here support a conclusion that non-technical skills performance is degraded at levels of fatigue clinicians routinely experience. In addition, clinicians may fail to recognise their performance is compromised. Non-technical skills frameworks provide an ideal foundation for assessing a range of clinically-relevant behaviours, and could be routinely incorporated into critical care training programmes and practice. In combination with an active fatigue-education approach, they could also be used to identify and develop methods for managing or mitigating fatigue effects in critical care settings.