Monitoring the exposure to Sevoflurane on an outpatient operating room of a regional hospital.
On an outpatient surgery room from a regional hospital, a monitoring programme for exposure to Sevoflurane was designed and executed. The reason for this study was a temporarily reduced ventilation in the surgery room.
The surgery room is used for short procedures in children, in particular the removal of tonsils and placement of tubes in eardrums. During these surgical operations, the patients are anesthetized for a short period. For reasons of efficiency, administration of anesthetic gas is done with a facemask, which might lead to exposure of the personnel.
Personal air samples were taken to determine the concentration of anesthetic gases in the breathing zone. The results were compared to the Occupational Exposure Levels (OELs) for Sevoflurane to check whether there is a potential health risk. No limits for this substance exist in the Netherlands. The limit values applied were Finnish (2007: 8-hour time weighted average (TWA) of 83 mg/m3, 15-min TWA of 170 mg/m3).
The results of the individual measurements (from 2006-2009) are shown in the graph below (in Dutch). The colored lines represent the 10%, 25%, and 100% OEL.
Analysis shows a probability of exceedance of the OEL (83 mg/m3) of 24%. The upper limit (95th percentile) of all measurements is 153 mg/m3. Given the cyclical nature of the work with Sevoflurane, brief high exposure levels are most likely to occur. Considering the 95 percentile, exposure of the (assistant) anesthetist to levels higher than the 15-min TWA OEL (170 mg/m3) during these short periods are conceivable.
In response to these findings, a double face mask was introduced for administration of the anesthetic gas in order to reduce the occupational exposure. Besides, additional reducement of the exposure is expected when implementing the planned ventilation system. Personal exposure measurements after implementation are needed to demonstrate this.