Aim: Inadequate emergence after anesthesia in the adult patient may be distinguished by the patients' activity level into two subtypes: emergence delirium and hypoactive emergence. The aim of this study was to determine the incidence of inadequate emergence in its different forms, to identify causative factors and to examine the possible influence on postoperative length of stay in the recovery room and in the hospital.
Methods: In this prospective observational study, 1868 non-intubated adult patients who had been admitted to the recovery room were analyzed. Inadequate emergence was classified in its different forms according to the Richmond agitation and sedation scale (RASS) 10 minutes after admission to the recovery room. Emergence delirium was defined as a RASS score >or=+1, and hypoactive emergence was defined as a RASS score <or=-2.
Results: Of the 1,868 patients, 153 (8.2%) displayed symptoms of inadequate emergence: 93 patients (5.0%) screened positive for emergence delirium, and 60 patients (3.2%) showed hypoactive emergence. Significant risk factors for emergence delirium were premedication with benzodiazepines, induction of anesthesia with etomidate, younger as well as older age (age below 40 years and over 64 years), higher postoperative pain scores (NRS 6-10) and musculoskeletal surgery. Risk factors for hypoactive emergence were younger age, long duration of surgery and intraabdominal surgery. Patients with hypoactive emergence had a significantly increased length of stay in the hospital.
Conclusion: Inadequate emergence after anesthesia is a frequent complication. Preventable risk factors for emergence delirium were induction of anesthesia with etomidate, premedication with benzodiazepines and higher postoperative pain scores. Hypoactive emergence was less frequent than emergence delirium and was associated with a longer postoperative hospital stay.