Implementation of home blood pressure monitoring in preoperative anaesthesia assessment clinic

Elevated preoperative blood pressure (BP) is a common problem and often results in late surgery cancellation and wastage of theatre resources. High BP readings in the preoperative anaesthetic assessment clinic (PAAC) could be the result of the white coat effect (WCE) and may not reflect patients' baseline BP. A preliminary audit conducted in our hospital revealed a significant number of unnecessary referrals to the general practitioners (GPs) and the emergency department (ED) based on high BP readings in PAAC alone.This study aimed to determine the prevalence of WCE in elective surgical patients and develop a workflow to reduce unnecessary referrals and case cancellations.A multidisciplinary team established a new hypertension workflow by introducing home BP monitoring and involving internal medicine specialists in perioperative care. 214 patients with clinic BP higher than 160/90 mm Hg in PAAC were recruited. They were instructed to check their home BP twice a day with a machine on loan from PAAC and seek medical assistance if their home BP exceeded 160/90 mm Hg. WCE was diagnosed when the discrepancy between the average clinic BP and home BP exceeded 20/10 mm Hg.WCE was observed in 92.1% of patients (162/176, 95% CI 87.0 to 95.6) and 57.4% of those with WCE (57.4%, 95% CI 49.7 to 64.8) had normal home BP measurement. None of the patients had surgery cancelled due to high BP readings on the day of the operation, and the number of unnecessary GP/ED referrals was significantly reduced after implementation of the new workflow.The comprehensive perioperative workflow using home BP monitoring offers an effective and feasible method to detect WCE. This approach has saved healthcare resources and improved patient satisfaction.