Specifications

5.2.2 Medigas 3010

Personal exposure data for nurses was collected by the Medigas 3010 during 9 deliveries. Of

these deliveries, data from Deliveries 1, 8 and 9 are suspect because air calibration of the unit

failed meaning the unit could not be re-zeroed and therefore the data was excluded from the

results.

Data for Deliveries 2 to 7 ranged from 0 to 566 ppm. Nitrous oxide does not have a ceiling limit

and therefore 3X (75 ppm of up to 30 minutes) and 5X (125 ppm) excursion limits apply.

Deliveries 3 and 5 did not exceed 5X excursion limit. The remaining deliveries exceeded the

125 ppm ceiling for the following durations: Delivery 2: 12% (6 min) ; Delivery 4: 4% (5 min),

Delivery 6: 14% (17 min) and Delivery 7: 5% (4 min). Large spikes were noted on all the

graphs for these personal samples. Copies of these graphs can be found in Appendix 7 of this

report.

Delivery 2 was monitored at the beginning of the labour and three large spikes were observed.

Monitoring ceased after 47 minutes (3:00 am) because of a low battery warning on the Medigas

unit.

Deliveries 3 and 5 had levels that were below 125 ppm for the entire delivery. Deliveries 4 and

5 were labouring at the same time. The entire labour and delivery was monitored for Delivery 4

and the Medigas 3010 was transferred to the nurse attending to Delivery 5 after the Delivery 4

baby was born. Delivery 5 nitrous oxide use started during the Delivery 4 monitoring and

therefore only the last 20 minutes of gas use was recorded.

The nurse attending to Delivery 6 had the highest and longest exposure to nitrous oxide levels

and was above the 5X excursion limit of 125 ppm for a total of 14% of the delivery (17 min).

Delivery 7 laboured from 5:57 am to 8:51 am, however, the delivery was only monitored using

the Medigas 3010 for the first hour and a half of the delivery because at change of shift the

replacement nurse did not want to wear the unit.