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October 16, 2018
10/16/2018 3:15:00 PM - 10/16/2018 4:45:00 PM
Room North, Room 22
Characterization of Respiratory Compromise and the Potential Clinical Utility of Capnography in the Post Anesthesia Care Unit
Frances F. Chung, M.B.,B.S., Michael Mestek, Ph.D., Peter R. Lichtenthal, M.D.
Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
Disclosures: F.F. Chung: Funded Research; Self; Ontario Ministry of Health and Long term Care Innovation Grant, University Health Network Foundation, Acacia, Medtronics. Honoraria; Self; UpToDate. M. Mestek: Salary; Self; Medtronic employee. Equity Position; Self; Medtronic equity. P.R. Lichtenthal: None.
BACKGROUND: Respiratory compromise is a common postoperative patient safety concern and occurs, in part, due to unrecognized respiratory adverse events (RAE) (1). Closed claims analyses suggest that critical respiratory events could largely be avoided through better patient monitoring and response (2). Compared with the ward setting, there are limited prospective data characterizing such events in the Post Anesthesia Care Unit (PACU). The purpose of this study was to determine the frequency and duration of RAE identified by combined pulse oximetry and capnography monitoring. METHODS: With IRB approval, we enrolled 250 patients at 2 sites. 172 patients met the following PACU inclusion criteria: 1) > 18 years old, 2) ASA score II-IV, 3) procedures > than 1.5 hours under general anesthesia, 4) intraoperative opioids, & 5) discharged from PACU to an inpatient setting with validated device data. Blinded pulse oximetry and capnography data were collected for a minimum of 45 minutes using the FDA-cleared Capnostream 20p (Medtronic, USA). Standard of care monitoring was maintained at each site that did not include capnography. RAE (Table 1) were classified using monitor alarm events using alarm thresholds considered appropriate to notify an MD (Level I notifications) and those considered appropriate to notify an RN (Level II notifications). Observer validated alarmed events were quantified by total number, frequency per minute and reported by type and level, together with 95% confidence intervals (Table 2). Clinician reported RAE were recorded in the PACU and 24 hours post PACU. RESULTS: 172 patients were included in the per protocol analysis. 163 (95%) patients had a Level II notification and 135 (78%) had an escalation to Level I notification. Monitored RAE included hypercapnia (9% Level II; 1% Level I), hypocapnia (38% Level II; 28% Level I); hypoxemia (33% Level II; 21% Level I), apnea (26% Level II; 66% Level I), bradypnea (57% Level II; 31% Level I); tachypnea (38% Level II; 3% Level I). Twenty-four clinically reported RAE were reported on 22 patients (10%). Three patients required unplanned intervention with CPAP (2 in PACU & 1 post-PACU); 2 received Narcan (1 in PACU & 1 post-PACU). There were no clinician-reported serious adverse outcomes reported (e.g., re-intubation, unexpected ICU transfer, pulmonary arrest). CONCLUSIONS: These data indicate that respiratory adverse events are frequent in the PACU and the combination of capnography and pulse oximetry monitoring gives additional clinical information on hypercapnia, hypocapnia and respiratory rate. Further interventional studies are warranted to determine if these early warnings to respiratory adverse events reduce adverse patient outcomes. References 1. Lam T et al. Anesth & Analg; 2017; 125:2019-2029. 2. Lee LA et al. Anesthesiology; 2015; 122:659-665.
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