Wearable alert system for detecting postoperative hypotension

Project Summary This project aims to develop a low-cost, comfortable, and easy-to-use wearable alert system that tracks continuous BP non-invasively in patients to notify caregivers of hypotensive events in the postoperative setting. Postoperative hypotension (POH), when a patient’s mean arterial pressure (MAP) falls to unsafe levels, commonly lt70 mmHg, can occur frequently in the time span between leaving the operating room and prior to discharge from the hospital. POH is a serious and common condition that has been shown to be independently associated with poor patient outcomes such as acute kidney injury, stroke, hospital re-admission, myocardial injury, and death.1–9 During surgery and recovery in the post anesthesia care unit (PACU) or the intensive care unit (ICU), a patient’s hemodynamics are closely monitored to support timely interventions and treatment. However, once the patient is transferred to a lower ward for recovery, patient monitoring is dramatically reduced. The current method to monitor a patient’s BP in the general ward, which relies on intermittent spot-checks performed manually every 4-6 hours by the nurse using an oscillometric BP cuff, is insufficient for detecting POH events. A recent study showed that almost 50% of hypotensive events went undetected by routine vital assessments. There is an unmet need for a technology that comfortably monitors a patient’s BP in the postoperative setting. Our core technology is able to non-invasively measure rapid BP changes at any location with a palpable pulse. The proposed project aims build upon the core technology to create a wearable alert system that informs caregivers of postoperative hypotensive episodes. To do so, a machine learning (ML) classifier for detection of hypotensive episodes will be developed through monitoring in the ICU. This ML classifier will undergo feasibility testing in the PACU and then a pilot study in the general ward. Successful completion of the proposed aims will result in a proof- of-concept wearable alert system that continuously monitors BP in the postoperative environment in a low-profile, wireless, and comfortable manner. Such a technology has huge potential to change clinical practice through earlier detection of patient deterioration, allowing more timely intervention and ultimately improved patient outcomes.