Specifications

18
5.2.3 Passive Dosimeter Badges
Passive dosimeters were given to 2 to 4 nurses at the beginning of their shift. In total 31 badges
were used in this study. Three were blanks, exposure to nitrous oxide was captured for 16 of the
badges and the remainder were worn but exposure to nitrous oxide did not occur during the shift.
In the exposed badges (nitrous oxide exposure occurred during the shift) the values ranged from
1.3 ppm to 15.1 ppm for full shift readings (either 8 or 12 hour shifts). With the exception of
BP19, all of the badges were lower than the WCB OF BC standard of 12.5 ppm (25 ppm * 0.5
for a 12 hour shift) and 6 were above the action level of 6.25 ppm. BP 19 had a value of 15.1
ppm. This nurse was exposed to nitrous oxide for one delivery during her shift. BP 11 had an
average exposure of 4.1 ppm and the nurse had one delivery during the 8 hour shift but her
patient did not use nitrous oxide. A graph and table of these results can be found in Appendix 5
of this report.
5.2.4 Overall results
Nurses wearing the Medigas 3010 were often also wearing a passive dosimeter. The nurse
attending to Delivery 5 and wearing BP 13 had the lowest average of 1.3 ppm and the Medigas
3010 exposure did not exceed 125 ppm at any point in the delivery. Delivery 6, BP 19, had the
highest average and it also corresponded to the greatest amount of time over 125 ppm during the
delivery.
Delivery 3, BP 10, and Delivery 4, BP 14, had similar lengths of exposure and similar average
exposures (6.3 ppm and 6.7 ppm) according to the passive dosimeters but the Medigas average
exposures were 8.3 ppm and 37.9 ppm respectively. Both of the two nurses attended only one
delivery during their shifts.
5.2.5 Ventilation Testing
The forced air supply to Room 339 was measured using a Balometer. The results for the three
locations were 220 cfm, 215 cfm and 105 cfm giving a total of 540 cfm supply. Chris
Thompson, Systems Engineer LMH, reported that the nitrous oxide scavenging system flow rate