Delirium in Survivors of Cardiac Arrest Treated With Mild Therapeutic Hypothermia

BACKGROUND: Mild therapeutic hypothermia is recommended for comatose patients resuscitated from cardiac arrest. However, the prevalence of delirium and its associated risk factors have not been assessed in survivors of cardiac arrest treated with therapeutic hypothermia. OBJECTIVE: To determine the prevalence of and risk factors for delirium among survivors of cardiac arrest who were treated with therapeutic hypothermia. METHODS: A retrospective observational study of patients treated with therapeutic hypothermia after cardiac arrest from 2007 through 2014. Baseline demographic data and daily delirium assessments throughout the intensive care unit stay were obtained. The association between duration of delirium and various risk factors was assessed. RESULTS: Of 251 patients, 107 (43%) awoke from coma. Among the 107 survivors, all had at least 1 day of delirium during their intensive care unit stay. Median number of days of delirium was 4.0 (interquartile range, 2.0-7.5). Multivariable analysis revealed that age (odds ratio, 1.72; 95% CI, 1.0-2.95; P = .05), time from cardiopulmonary resuscitation to return of spontaneous circulation (odds ratio 1.52; 95% CI, 1.11-2.07; P = .01), and total dose of prewarming propofol (odds ratio, 0.02; 95% CI, 0.00-0.48; P = .02) were associated with duration of delirium. CONCLUSIONS: All survivors of cardiac arrest treated with mild therapeutic hypothermia had at least 1 day of delirium. Age and time from initiation of cardiopulmonary resuscitation to return of spontaneous circulation were associated with prolonged delirium, whereas exposure to propofol was protective against delirium. These findings are limited to this unique cohort and may not be generalizable to different populations.