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

STUDY OBJECTIVE: To evaluate the frequency, determinants, and outcome of inadequate emergence after elective surgery in the Postanesthesia Care Unit (PACU).

DESIGN: Prospective observational study.

SETTING: 12-bed PACU of a tertiary-care hospital in a major metropolitan area.

PATIENTS: 266 adult patients admitted to the PACU.

INTERVENTION: To evaluate inadequate emergence, the Richmond Agitation and Sedation Scale (RASS) was administered to patients 10 minutes after their admission to the PACU.

MEASUREMENTS: Demographic data, perioperative variables, and postoperative length of stay (LOS) in the PACU and the hospital were recorded.

MAIN RESULTS: 40 (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.

CONCLUSIONS: Preventable determinants for emergence delirium were higher postoperative pain scores and longer fasting times. Hypoactive emergence was associated with longer postoperative PACU and hospital LOSs.