Clinical decisions and time since rest break: An analysis of decision fatigue in nurses.

Objective: The present study investigates whether nurses working for a national medical telephone helpline show evidence of "decision fatigue," as measured by a shift from effortful to easier and more conservative decisions as the time since their last rest break increases. Method: In an observational, repeated-measures study, data from approximately 4,000 calls to 150 nurses working for the Scottish NHS 24 medical helpline (37% of the national workforce) were modeled to determine whether the likelihood of a nurse's decision to refer a patient to another health professional the same day (the clinically safest but most conservative and resource inefficient decision) varied according to the number of calls taken/time elapsed since a nurse's last rest break and/or since the start of shift. Analyses used mixed-effect logistic regression. Results: For every consecutive call taken since last rest break, the odds of nurses making a conservative management decision (i.e., arranging for callers to see another health professional the same day) increased by 5.5% (p=.001, 95% confidence interval [CI:2.2, 8.8]), an increase in odds of 20.5% per work hour (p<.001, 95% CI [9.1, 33.2]) or 49.0% (on average) from immediately after 1 break to immediately before the next. Decision-making was not significantly related to general or cumulative workload (calls or time elapsed since start of shift). Conclusions: Every consecutive decision that nurses make since their last break produces a predictable shift toward more conservative, and less resource-efficient, decisions. Theoretical models of cognitive fatigue can elucidate how and why this shift occurs, helping to identify potentially modifiable determinants of patient care.