Dosimetry as a Lagging Indicator of Occupational Exposure to Nitrous Oxide in Pediatric Sedation: A Collaborative...

Nitrous oxide (N2O) is commonly used in pediatric procedural sedation. It is an attractive option to facilitate intravenous line placement, as it does not extend sedation recovery from subsequently administered agents. Although debate exists regarding health consequences of occupational exposure now that scavenging of exhaled gases is common, cooperation of pediatric patients to maximize engineering controls is not guaranteed and can contribute to repeated exposure over the course of a clinician's career. There is no global consensus on personal exposure limits, but the National Institute for Occupational Safety and Health published U.S. guidelines. A dosimetry survey of our sedation team during a short N2O procedure for intravenous line placement exceeded the National Institute for Occupational Safety and Health Recommended Exposure Limit (REL) of 25 parts per million. We designed a process improvement initiative to reduce occupational exposure below the Recommended Exposure Limit on serial surveys.

A continuous flow, titratable, full-face mask N2O delivery system with scavenging by a central vacuum connection was used. A retrospective chart review of N2O procedures performed before the initial dosimetry survey revealed practice trends in provider behavior during N2O administration. Initiation of N2O gas flow and maintenance of face mask seal on an uncooperative patient were identified as two sources of variability. Two-handed face-masking technique, initiation of N2O gas flow only after masking, and continued masking for 2 min of exhaled scavenging were standardized and socialized as best practices. Subsequent dosimetry surveys of the sedation team were coordinated by Industrial Hygiene.

Pre- and post-intervention phases were 17 months each and included 92 and 201 N2O patients, respectively. Six dosimetry surveys occurred in the post phase. Intravenous line placement was the typical procedure surveyed. Dosimetry results for all team members during surveys 1-4 were below the REL, with 14 of 16 samples falling below the level of quantitation. Elevated dosimetry results in survey 5 prompted reevaluation of work practices and equipment. A loose component on the delivery system was discovered, corrected, and incorporated as a pre-procedure check. With no further changes to work practices, dosimetry results were below the REL for survey 6.

We layered work practice changes atop engineering controls to reduce occupational exposure levels for medical team members. We utilized dosimetry as a lagging indicator, prompting frequent reassessments of our equipment and processes that we might not otherwise have performed. Pediatric sedation programs are encouraged to consider whether Industrial Hygiene resources might provide synergy to process improvement efforts with inhalational sedation agents.