Inadequate emergence after anesthesia: emergence delirium and hypoactive emergence in the Postanesthesia Care Unit

Study ObjectiveTo evaluate the frequency, determinants, and outcome of inadequate emergence after elective surgery in the Postanesthesia Care Unit (PACU).DesignProspective observational study.Setting12-bed PACU of a tertiary-care hospital in a major metropolitan area.Patients266 adult patients admitted to the PACU.InterventionTo evaluate inadequate emergence, the Richmond Agitation and Sedation Scale (RASS) was administered to patients 10 minutes after their admission to the PACU.MeasurementsDemographic data, perioperative variables, and postoperative length of stay (LOS) in the PACU and the hospital were recorded.Main Results40 (15%) patients showed symptoms of inadequate emergence: 17 patients (6.4%) screened positive for emergence delirium and 23 patients (8.6%) showed hypoactive emergence. Determinants of emergence delirium were longer duration of preoperative fasting (P = 0.001), higher visual analog scale (VAS) scores for pain (P = 0.002), and major surgical risk (P = 0.001); these patients had a higher frequency of postoperative delirium (P = 0.017) and had higher nausea VAS score 6 hours after surgery (P = 0.001). Determinants of hypoactive emergence were duration of surgery (P = 0.003), amount of crystalloids administered during surgery (P = 0.002), residual neuromuscular block (P < 0.001), high-risk surgery (P = 0.002), and lower core temperature on PACU admission (P = 0.028); these patients also had more frequent residual neuromuscular block (P < 0.001) postoperative delirium (P < 0.001), and more frequent adverse respiratory events (P = 0.02). Patients with hypoactive emergence had longer PACU and hospital LOS.ConclusionsPreventable determinants for emergence delirium were higher postoperative pain scores and longer fasting times. Hypoactive emergence was associated with longer postoperative PACU and hospital LOSs.