386: The Incidence of Hypoxia and Respiratory Depression During Emergency Department Chemical Restraint of Patients With Psychomotor Agitation

Abstract

This is a prospective observational study to describe the incidence of hypoxia and respiratory depression in patients chemically restrained for psychomotor agitation in the emergency department (ED). Any patient over the age of 18 with psychomotor agitation who was to be chemically restrained with a benzodiazepine and/or a phenothiazine was eligible for enrollment. Routine management of these patients in our ED requires that they receive electronic monitoring of SpO2 and ETCO2. The ETCO2 monitor used recorded SpO2 and ETCO2 every 5 seconds, this data was saved and downloaded into Excel. A trained research associate recorded demographic data, history of drug or ETOH abuse, medical and psychiatric history. They also recorded HR and BP every 5 minutes, any physician intervention for hypoxia and/or respiratory depression, or adverse events. Hypoxia was defined as a SpO2 of <92% for >15 seconds, respiratory depression was defined as an ETCO2 of >50 mmHg, a change of 10% above or below baseline, or a loss of waveform for >15 seconds. 59 patients enrolled, 9 patients were excluded due to >35% data loss, leaving 50 patients for analysis. 21/50 patients developed hypoxia during their chemical restraint (42%). 28/50 developed respiratory depression during their chemical restraint (56%). 19/21 patients that developed hypoxia had an ETCO2 change. Of the 19 patients that developed hypoxia with a corresponding ETCO2 change. 15/19 had these changes before the onset of hypoxia. The mean length of time between the onset of an ETCO2 change to the onset of hypoxia was 5 minutes (SD +3.34 min). The average Ramsay sedation score was 4.36 (SD 0.57). The sensitivity of ETCO2 to predict the onset of a hypoxic event in this population is 90.48%, the sensitivity is 75.86%. 9 patients received an intervention for respiratory depression and hypoxia (5 verbal, 4 physical, 6 got supplemental O2). 37 pts had a history of concurrent drug or ETOH abuse; 24 patients had a concurrent psychiatric history. None of these patients had an adverse event. Almost half of the patients in this study exhibited hypoxia and/or respiratory depression. Most of the incidences of hypoxia were preceded by respiratory depression. Few of these events were recognized by their treating physicians. No adverse events were noted.