Ann Acad Med Singap Vol 51 No 2 February 2022 | annals.edu.sg Incidence and risk factors of delirium in post-anaesthesia care unit Yuhe Ke 1 MBBS, Sophia Chew 1 FANZCA, Edwin Seet 2 MMed (Anaes), Wan Yi Wong 3 MMed (Anaes), Vera Lim 3 MMed (Anaes), Nelson Chua 3 MMed (Anaes), Jinbin Zhang 3 MMed (Anaes), Beatrice Lim 3 MMed (Anaes), Vanessa Chua 4 Bsc (Hon), Ne-Hooi Will Loh 4 FFICM, Lian Kah Ti 4 MMed (Anaes) 1 Division of Anaesthesiology and Perioperative Medicine, Singapore General Hospital, Singapore 2 Department of Anaesthesia, Khoo Teck Puat Hospital, Singapore 3 Department of Anaesthesia, Tan Tock Seng Hospital, Singapore 4 Department of Anaesthesia, National University Health System, Singapore Correspondence: A/Prof Lian Kah Ti, Department of Anaesthesia, National University Health System, 5 Lower Kent Ridge Road, Singapore 119074. Email: lian_kah_ti@nuhs.edu.sg ORIGINAL ARTICLE ABSTRACT Introduction: Post-anaesthesia care unit (PACU) delirium is a potentially preventable condition that results in a signifcant long-term effect. In a multicentre prospective cohort study, we investigate the incidence and risk factors of postoperative delirium in elderly patients undergoing major non-cardiac surgery. Methods: Patients were consented and recruited from 4 major hospitals in Singapore. Research ethics approval was obtained. Patients older than 65 years undergoing non-cardiac surgery >2 hours were recruited. Baseline perioperative data were collected. Preoperative baseline cognition was obtained. Patients were assessed in the post-anaesthesia care unit for delirium 30–60 minutes after arrival using the Nursing Delirium Screening Scale (Nu-DESC). Results: Ninety-eight patients completed the study. Eleven patients (11.2%) had postoperative delirium. Patients who had PACU delirium were older (74.6±3.2 versus 70.6±4.4 years, P=0.005). Univariate analysis showed those who had PACU delirium are more likely to be ASA 3 (63.6% vs 31.0%, P=0.019), had estimated glomerular fltration rate (eGFR) of <60mL/min/1.73m 2 (36.4% vs 10.6%, P=0.013), higher HbA1C value (7.8±1.2 vs 6.6±0.9, P=0.011), raised random blood glucose (10.0±5.0mmol/L vs 6.5±2.4mmol/L, P=0.0066), and moderate-severe depression (18.2% vs 1.1%, P=0.033). They are more likely to stay longer in hospital (median 8 days [range 4–18] vs 4 days [range 2–8], P=0.049). Raised random blood glucose is independently associated with increased PACU delirium on multivariate analysis. Conclusion: PACU delirium is common in elderly patients with risks factors presenting for major surgery. Ann Acad Med Singap 2022;51:87-95 Keywords: Geriatrics, major non-cardiac surgery, postoperative delirium Ann Acad Med Singap 2022;51:87-95 https://doi.org/10.47102/annals-acadmedsg.2021297 INTRODUCTION Post-anaesthesia care unit (PACU) delirium is defned as a disorder in thought processes that affect cognition in terms of memory, comprehension and attention. 1 It has a strong association with postoperative delirium, which is present in up to 45% of patients after surgery. 2-5 PACU is a wide-reaching problem, and especially prevalent in elderly patients. Postoperative delirium directly affects clinical outcomes such as hospital length of stay and increased 30-day mortality. 6 Up to 10% of these patients may develop long-term neurocognitive defcits with diminished quality of life, and pose a tremendous socioeconomic burden on family and caregivers. 7,8 Despite its importance, PACU delirium remains under-diagnosed in the perioperative setting. The lack of awareness and established biomarkers could potentially contribute to increased morbidity and mortality in these vulnerable patients. Despite many screening and assessment tools 3 being readily available, few hospitals have institutionalised monitoring protocols. One such scoring tool is the Nursing Delirium Screening Scale