Evaluation and control of waste anesthetic gas in the postanesthesia care unit within patient and caregiver breathing zones

This study (NCT02428413) evaluated waste anesthetic gas (WAG) in the postanesthesia care unit (PACU) and assessed the utility of the ISO-Gard^® mask in reducing nursing exposure to WAG. We hypothesized that WAG levels in the patient's breathing zone upon recovery would exceed the recommended levels, leading to increased exposure of the PACU nurses, with use of the ISO-Gard mask limiting this exposure. A total of 125 adult patients were recruited to participate. Patients were randomized to receive the standard oxygen delivery mask or the ISO-Gard face mask postoperatively. Continuous particulate concentrations were measured using infrared spectrophotometers placed within the patients' and nurses' 6-inch breathing zone. Maximum WAG measurements were obtained every 30 seconds, and the duration of maximum WAG >2 ppm and its proportion relative to the total collection period were calculated. We observed a statistically significant difference in desflurane duration and proportion of maximum WAG >2 ppm in both patient and PACU nurse breathing zones. Therefore, patients and PACU nurses using routine care were exposed to WAG levels >2 ppm during the 1-hour postoperative period, and the ISO-Gard mask effectively reduced the amount of WAG detected in the immediate 1-hour postoperative recovery phase.