Association Between Perioperative Sleep Disorders and Post‐Operative Delirium in Cardiac Surgeries: A Systematic Review and Meta‐Analysis

Post-operative delirium (POD) is an acute deterioration in cognitive function and highly prevalent after cardiac surgery (CS; up to 55%). Perioperative sleep disorders (PSD) are also commonly noted in surgical patients (up to 60%). The primary aim of our systematic review is to determine the association between PSD and POD in CS patients during their hospital stay. We searched five databases (PubMed, CINAHL, Web of Science, Scopus, and EMBASE) to identify studies evaluating the association between PSD and POD amongst CS (any open-heart CS) patients, without time and geographic restriction. Original articles that focused on adults undergoing cardiac surgeries and assessed sleep and POD were included. We conducted a meta-analysis using a random effects model to determine the effect of sleep quality on POD. Thirty-three studies were included (63% observational designs); most studies originated from China (33%). The most frequently used subjective and objective sleep assessment tools were the Pittsburgh Sleep Quality Index (PSQI) (33%) and polysomnography (18%). After pooling observational data, we identified an incidence of POD ranging from 3.6% to 73%. Increased PSQI scores (standard threshold > 5) were associated with a greater likelihood of POD occurrence (standardised mean difference [SMD] = 0.73, p > 0.05). Lower total sleep time (SMD = -0.68, p < 0.05) was associated with an increased risk of POD. Poor sleep quality, insomnia, and sleep-disordered breathing are prevalent forms of PSD and are major risk factors for POD following CS. Additional research is warranted to clarify when sleep quality normalises after cardiac surgery and how targeted interventions can accelerate this recovery.