Preliminary Outcomes of High-Risk Opioid, Post-Operative, Orthopedic Patient Home Monitoring: Emergency Department Visits

Background: Patients receiving opioids are at risk of morbidity and mortality due to opioid-induced respiratory depression (OIRD). Monitoring systems with alarms may avert clinically relevant OIRD in the home. The feasibility of such systems for home monitoring has limited study. Methods: Funded by an Intermountain Research & Medical Foundation grant, we began an IRB approved quantitative, prospective, non-randomized, single cohort study from September 28, 2019 – October 31, 2020. Subjects meeting high-risk opioid inclusion criteria and prescribed opioids were included. A monitoring device was utilized by orthopedic surgery subjects in the home for 4 days post-operatively. Pulse oximetry (SpO2), heart rate (HR), breathing frequency, and capnography (EtCO2) were recorded during napping/sleeping. Upon device return, emergency department visits were analyzed to determine reasons for visits and discharge diagnoses. Results: Three hundred fifty-nine subjects enrolled. There were 26 (7%) subjects who visited the emergency department due to patient/caregiver reported low SpO2 alarms. This was confirmed by analysis of alarm data upon monitor return. Twenty-four total subjects/caregivers were alerted to declining patient status by alarms triggered by low SpO2 which prompted patients to seek care at the emergency department. One patient was found non-arousable by a home caregiver in response to monitor alarms requiring nasal naloxone administration, resuscitation, and ultimate survival. A second patient was diagnosed with opioid-induced hypoxic renal failure requiring ICU admission and dialysis. One subject was diagnosed with opioid-induced non-ST elevated myocardial infarction. Conclusions: The accuracy of actionable alarms are of ongoing concern for both in-patient and home monitoring. Analysis of recorded monitor data and patient responses indicated EtCO2 was the least reliable alarm. Despite using a moisture wicking cannula, condensation in the line impeded accurate capture of breathing frequency and EtCO2. At the time of this study the Food and Drug Administration had not approved pulse oximeters with breathing frequency capture for use in the home. Post-study subject surveys and data analysis supports SpO2 being the most reliable alarm in this study population and in the home environment. The use of home monitoring was determined to be feasible and facilitated the identification of the declining status in patients which allowed intervention to prevent poor outcomes. A full manuscript has been submitted for publication.Table 1: ED Visits and Opioid Related and Non-Opioid Related Diagnoses with Home Monitoring n = 359 # (%)Sleep study requested by patient18 (5.0)ED visits26 (7.2)Subjects with ED Visits & ED Documented Opioid Related Diagnosisn = 26#(%)Opioid induced cardiac ischemia6 (23.1)Opioid induced neurologic ischemia (e.g., stroke, seizure, transient ischemic attack)4 (15.4)Opioid induced renal ischemia1 (<1)Opioid induced hypoxia/dyspnea/impending respiratory failure11 (11.5))Total14 (53.8)Subjects with ED Visits and ED Documented Non-Opioid Related Discharge Diagnosesn = 26# (%)Non-opioid related pulmonary embolism3 (11.5)*Other (e.g., wound issues, pain control, bronchitis, vocal cord paralysis)9 (34.5)Total12 (46.2)*Non-opioid related event; however, all 3 subjects reported no symptoms but visited the ED due to frequent audible alarming of low SpO2 on pulse oximeter.