Published online by Cambridge University Press: 28 June 2012
Transcutaneous cardiac pacing (TCP) is a promisingprehospital intervention, but there are little data available regarding protocols to improve patient tolerance to TCP. A 50:50 nitrous oxide:oxygen analgesic mixture aho is a commonly employed prehospital intervention. In this randomized, prospective study, we compared the discomfort experienced by 18 healthy subjects when paced in two triah at the capture threshold: one following breathing of a 50:50 nitrous oxide:oxygen mixture; and the second breathing only room air. Discomfort was rated on an analog scale from 1 (minimal discomfort) to 10 (severe pain). Of the 18 subjects, 15 (83%) reported that nitrous oxide improved the tolerance to pacing at capture threshold. The median pain scores at capture threshold in the nitrous oxide and room air group were 3.8 and 5.0 respectively (P<.05). Nine of the subjects tolerated TCP for the maximum allotted time of 30 seconds in each trial; six tolerated TCP for a longer time period in the nitrous oxide trial; three tolerated TCP longer in the room air trial. These data suggest that inhalation of a 50:50 nitrous oxide:oxygen mixture may improve tolerance to TCP in the conscious patient.