Patterns of intensive care unit emergencies

Objective Little is known about the epidemiology of medical emergencies occurring in the intensive care unit (ICU). The aim of this study is to draw attention to the importance of auditing emergency events in the ICU. We hypothesised that emergency events occurring in the ICU would be clustered during periods of decreased medical and nursing attention and would occur in patients who had a higher illness severity and a greater risk of death. Methods A retrospective observational cohort study was carried out in a 36-bed tertiary intensive care unit. The data capture all intensive care patients admitted to the ICU from 1 January to 1 December 2020. The number of emergency events occurring during each clock hour was correlated with ICU shift staffing patterns. In-hospital mortality and illness severity scores for patients experiencing emergency events were compared with those for all other ICU patients. Results Serious medical emergencies were most frequent during the day, specifically during the morning ICU round (30% of all such events occurred between 08:00 and 12:00 hours), and there were peaks of incidence in the hour following each nursing and medical shift handover (following shift change times at 08:00, 15:00 and 21:00 hours). Agitation-related emergency events were least frequent during the periods of nursing day shift and afternoon shift overlap (07:00-08:00 hours and 13:00-15:00 hours). Patients who experienced serious medical emergency events in the ICU had a higher in-hospital mortality rate (28.3%) compared with the overall ICU mortality of 10.5% (OR = 4.89, 95% CI: 3.04-7.86). Conclusions Patients who deteriorate suddenly in the ICU have greater illness severity and a significantly increased risk of death. The incidence of serious emergency events correlates with patterns of ICU staffing and work routines. This has implications for rostering, clinical workflow and education program design.