Prehospital Analgesia in Adults Using Inhaled (PAIN) Methoxyflurane Study

The aim of this multi-centred study is to evaluate the prehospital use of methoxyflurane in patients ≥ 18 years of age presenting with moderate to severe pain (verbal numeric pain rating scale (NPRS) ≥ 4) secondary to trauma (which is defined as a physical injury of sudden onset and severity which requires immediate medical attention) as compared to other current therapies available to paramedics (NSAIDS and Opioids).

This will be a prehospital prospective stepped-wedge open-label, non-blinded, cluster randomized trial, enrolling patients with trauma related moderate to severe pain (numerical pain rating scale ≥4). It will be composed of three phases, involving a total of seven Ontario paramedic services. Our 24-month study will consist of the three following phases: 1) a 6-month setup and training period, followed by phase 2) the stepped-wedge trial (8-months) and phase 3) a 9-month period for data analysis and knowledge dissemination.

The verbal numeric pain rating scale (NPRS) is a subjective measure in which individuals rate their pain on an eleven-point numeric scale. The scale is comprised of values ranging from 0 (no pain at all) to 10 (worst imaginable pain). After ethics approvals have been secured for all sites, and after the initial 4-week observation period (where paramedics will provide standard care) one paramedic service will be randomized, using a number generator which the study team will be blinded, to the intervention condition (Methoxyflurane). Additional paramedic services will subsequently be randomized, and notified one by one at 4 week intervals until all seven paramedic services have been randomized to the intervention arm. Data will be collected for all eligible patients in each paramedic service for a total duration of 8 months. The study will be conducted in seven paramedic services in Eastern Ontario and will enrol patients who have been treated by paramedics, trained and authorized in the use and administration of methoxyflurane.

Eastern Ontario comprises 35 300 km2 and has a total regional population of 1.76 million. There are eight base hospitals in Ontario that provide medical direction, leadership and advice in the provision of prehospital emergency care. The Regional Paramedic Program for Eastern Ontario (RPPEO) is the base hospital which provides oversight to the seven included paramedic services. These paramedic services are comprised of 944 paramedics (738 of which are Primary Care Paramedics and 256 who are Advanced Care Paramedics). In summary, this study will comprise seven land paramedic services, operating in a catchment area of 10 rural counties and 4 cities, with 18 acute care hospitals and 1 university hospital.