Inhaled methoxyflurane and intranasal fentanyl for prehospital management of visceral pain in an Australian ambulance service.
OBJECTIVE
This study analysed the analgesic effect and changes in vital signs associated with administration of inhaled Methoxyflurane (MTX) and/or intranasal Fentanyl (INF) for prehospital management of visceral pain.


METHODS
A retrospective, observational study reviewing 1024 randomly selected records of patients with presumed visceral pain administered MTX (465), INF (397) or both (162) by the Western Australian Ambulance Service between January 2004 and February 2006. Clinical variables assessed included systolic blood pressure, pulse rate, respiration rate and Glasgow Coma Scale score. Pain was assessed utilising Visual/Verbal Analogue Scale pain scores.


RESULTS
Overall effects on vital signs appeared favourable 5 min after use and at hospital arrival with either agent alone or in combination. As sole agents, MTX produced the greatest initial pain scores reduction (2.0 (1.7 to 2.2) vs 1.6 (1.4 to 1.8)) (mean (95% CI), and INF provided greater pain reduction by hospital arrival (3.2 (2.9 to 3.5) vs 2.5 (2.1 to 2.9)). While both agents were effective, INF provided a greater pain score reduction for cardiac (3.0 (2.6 to 3.4) vs 2.3 (1.8 to 2.8)), female (3.4 (2.9 to 4.0) v 2.5 (2.0 to 3.0)) and age 75+ patients (3.2 (2.5 to 3.8) vs 1.8 (1.0 to 2.5)). Combined use of agents was not advantageous.


CONCLUSIONS
MTX and INF are effective agents for providing visceral pain analgesia in the prehospital setting. While MTX provided a more rapid onset of pain relief, INF provided superior analgesia after subsequent doses and in female, cardiac and older patients.
Johnston
Steven
S
School of Nursing, Midwifery and Postgraduate Medicine, Edith Cowan University, Joondalup, Perth, Western Australia, Australia. steven.johnston@ecu.edu.au
Wilkes
Garry J
GJ
Thompson
Jennifer A
JA
Ziman
Mel
M
Brightwell
Richard
R
D000280:Administration, Inhalation; D000281:Administration, Intranasal; D000293:Adolescent; D000328:Adult; D000368:Aged; D000552:Ambulances; D000701:Analgesics, Opioid / Q000008:administration & dosage; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage*; D005392:First Aid / Q000379:methods; D006801:Humans; D008297:Male; D008733:Methoxyflurane / Q000008:administration & dosage*; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis / Q000188:drug therapy*; D010147:Pain Measurement; D012189:Retrospective Studies; D016896:Treatment Outcome; D055986:Vital Signs / Q000187:drug effects*; D014904:Western Australia; D055815:Young Adult
D000701:Analgesics, Opioid; D008733:Methoxyflurane; D005283:Fentanyl