Influence of a 30-min break on divided attention and working memory in resident anaesthetists on daily routine

Background. The aim of this study is to test the hypothesis that a standard 30-min break in a routine 7.5 h period of work makes a difference in cognitive function. Methods. In a double-blinded, cross-over trial 30 residents in anaesthesia were randomized to receive or not to receive a 30-min break between the assessment times of 07:30 and 14:00. in a normal working day. After at least 28 days the test was repeated with each resident in the opposite group. Primary outcome measure was the Test for Attentional Performance with the subtest of working memory and divided attention. Secondary outcomes are the Stanford Sleepiness Scale and the State-Trait Anxiety Inventory test. Results. The sleep, caffeine and nicotine habits in both groups were comparable. There was no difference between the two groups in the Test for Attentional Performance, Stanford Sleepiness Scale and the State-Trait Anxiety Inventory. The correlation between recovery through sleep and sleep disturbance in the night before investigation to the Stanford Sleepiness Scale (P < 0.001 and P=0.003) and State-Trait Anxiety Inventory (P < 0.001 and P=0.001) at the 07:30 assessment is significant. For the 14:00 assessment the only significant correlation is between the recovery through sleep with the Stanford Sleepiness Scale (P=0.04) and the State-Trait Anxiety Inventory (P=0.05). Conclusion. A 30-min break during a 7.5 h daily routine did not influence cognitive function tests.