Prevention Of Delirium in Elderly With Obstructive Sleep Apnea (PODESA)

Delirium is an acute and fluctuating change in cognitive function, characterized by poor attention and disorganized thinking. Recent studies show that patients with obstructive sleep apnea (OSA) - a sleep disorder characterized by repeated episodes of complete or partial blockage of the upper airway - are at greater risk to develop delirium. It is estimated that 43% of men and 27% of women aged 50-70 years old have OSA. Elderly individuals with this condition are often undiagnosed. Unrecognized OSA may be a treatable cause of postoperative delirium. However, timely access to polysomnography is usually not possible prior to surgery. This multi-centre randomized controlled trial will enroll elderly patients scheduled for elective hip/knee replacement surgery. All participants who have given the consent to participate will be assessed risks of OSA and comorbidity by 3 basic questionnaires- STOP-Bang, Epworth Sleepiness Scale and Charlson Comorbidity index, Cognitive level assess by Mini-Cog and baseline delirium assessment by CAM. STOP-Bang questionnaire is the validated questionnaire to screen the patients for OSA. Score of 3 or higher has sensitivity of detecting OSA of 93% and 100% for moderate and severe OSA respectively. If participant has STOP-Bang score 3 or higher will have a home sleep study with the ApneaLink Air and overnight oximetry. Patients identified to have OSA(AHI ≥10/h) will be randomized to 1) Auto-titrating continuous positive airway pressure (CPAP) applied 1-3 nights before surgery (if possible) and during day/night sleep for 72 hrs after surgery or 2) Control group - routine care. All patients will be evaluated for delirium for 72h after surgery.