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Purpose: To evaluate emergence agitation and delirium signs in general anesthesia (GA) and postanesthesia care units (PACUs), and associated risk factors.
Methods: Adult patients (n = 380) exposed to GA were recruited over a period of 1 year and five months for this study, and were assessed for emergence delirium (ED) using Richmond Agitation- Sedation Scale (RASS). Confusion Assessment Method for Intensive Care Unit (CAM-ICU) was used to assess delirium signs on admission to, and during stay in PACU at 30 min, 1 h, and at discharge. Signs consistent with delirium were classified as hyperactive or hypoactive based on a positive CAM-ICU assessment and RASS score. Multivariable logistic regression was used to assess potential risk factors for delirium such as age, American Society of Anesthesiologists (ASA) classification, and opioid and benzodiazepine (BZD) exposure during stay in PACU.
Results: Emergence delirium (ED) occurred in 69 (18.2 %) patients out of which 41 (59.4 %) were also CAM-ICU +ve on admission to PACU, with 22 (31.9 %), 11 (15.9 %), and 6 (8.7 %) CAM-ICU +ve at 30 min, 1 h, and at discharge from PACU, respectively. Therefore, 28 (7.4 %) patients had ED with no associated signs of delirium. A total of 117 (30.8 %) patients had signs of delirium (CAM-ICU +ve) during admission to PACU, 58.1 % of whom had hypoactive features based on their RASS scores. Signs of delirium during stay in PACU were observed in 64 (16.8 %) patients, while 61 (16.1 %), 28 (7.4 %), and 14 (3.7 %) patients were CAM-ICU +ve at 30 min, 1 h, and at discharge from PACU, respectively. The results of multivariate logistic regression showed that total perioperative opioid administration (fentanyl equivalent) was independently associated with signs of delirium during stay in PACU, after relevant covariate adjustment (p = 0.03). However, age, BZD exposure (midazolam equivalent), and ASA classification did not show significant association with signs of delirium during stay at PACU. The result of sensitivity analysis showed that duration of anesthesia was independently associated with signs of delirium during stay in PACU.
Conclusion: The results of this study suggest that in patients undergoing GA, signs of delirium are common in the immediate postoperative period, with incidence highest on arrival at the PACU and decreasing gradually during stay in PACU. Hypoactive features are common and more prominent during stay in PACU, when compared to hyperactive features.
Keywords: Emergence delirium, Anesthesia, Post-anesthesia care unit, Hypoactive features, Association