Abstract
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 for home monitoring has limited study. We sought to investigate the feasibility and alarm reliability of home monitoring for four days after orthopedic surgery.
Methods:
Funded by an Intermountain Research & Medical Foundation grant and IRB approved, we conducted a 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 at home for 4 days post-operatively. Oxygen saturation (SpO2), heart rate (HR), breathing frequency (BF), and capnography (EtCO2) were recorded during napping/sleeping. Analysis comparing the number of actionable alarms audible to the subjects/caregivers both with/without delays was performed.
Results:
Three hundred fifty-nine subjects enrolled. When comparing alarms with and without delays, there were 4,770/22,409 low EtCO2, 1,601/6,246 high EtCO2, 460/4,211 low BF, 1,572/6,547 low HR, and 462/5,520 low SpO2 alarms (P-values < .001 comparing all alarms with/without delays per fisher exact test). One hundred seventy (47%) subjects reported the EtCO2 monitor alarmed frequently and was felt to be unreliable. Home visits identified condensation in the capnography cannula line which was likely a factor in EtCO2 and BF false alarms being triggered. Review of aggregate data supported this.
Conclusions:
The accuracy of actionable alarms are of ongoing concern for both in-hospital and home monitoring. Despite using the use of a moisture wicking cannula, moisture in the line impacted reliable BF and EtCO2 values. The Food and Drug Administration had not yet approved pulse oximeters with BF capture for home use. Post-study subject surveys and analyzed alarm data supported low SpO2 being the most reliable alarm. Twenty-six total subjects sought care in an emergency department in response to low SpO2 alarms. Fourteen subjects had a documented diagnosis of an opioid related ischemic event and 12 with a documented diagnosis of a non-opioid related event (eg, pulmonary embolism). Without the use of home monitoring, the declining status of these patients would have likely gone unrecognized and may have led to a poorer outcome. A full manuscript has been submitted for publication.
SpO2: oxygen saturation; BF: breathing frequency; HR: heart rate; Etco2: end tidal carbon dioxide View all access options for this article.Table One: Device Monitor Alarms with/without Delay Settings
off
off
0
0
NA
≤ 85%
30
< 0.0001
off
off
0
0
NA
≤ 6/min
30
< 0.0001
off
off
0
0
NA
≤ 50/min
20
< 0.0001
≥ 50 mmHg
15
< 0.0001
≤ 20 mmHg
15
< 0.0001
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