Prehospital Inhaled Methoxyflurane Non-Clinical Occupational Exposure Study

Methoxyflurane is an anesthetic gas and at low doses has shown to help with pain. Methoxyflurane was approved in Canada in 2018. Low-dose methoxyflurane is self-administered by patients via a handheld inhaler. Exhaled methoxyflurane is captured by an activated carbon (AC) chamber fitted to the inhaler in order to minimize environmental and occupational exposure. It provides rapid (\<1 minute), short-term (30-45 minutes) pain relief within six to ten inhalations and has been shown to be effective and safe in emergency care and for minor surgical, radiological, and dental procedures. The current dosing recommendation is 3 ml bottle. However, the frequency at which methoxyflurane treatment can be safely used by paramedics is not established. From the product monograph, a patient's maximum daily dose of 6 mLs and weekly 15 mLs of methoxyflurane. The treatment course of methoxyflurane for patients should not be repeated at an interval of less than 3 months. Despite the activated carbon chamber to capture the exhaled methoxyflurane, when paramedics are supervising patients receiving inhaled analgesia within a confined area (like the back of an ambulance), it is possible that a paramedic may experience intermittent exposure to methoxyflurane vapour. Multiple use of the methoxyflurane Inhaler, with or without the AC chamber, creates additional risk. Elevation of liver enzymes, blood urea nitrogen, and serum uric acid, have been reported in healthcare professionals regularly exposed to methoxyflurane inhalational products. 8 A formal limit regarding levels of occupational exposure to methoxyflurane has not been established. The risk of occupational exposure of methoxyflurane will be evaluated in a controlled laboratory setting, recruiting 30 health, screened (history and blood work) volunteers to participate in the back of an ambulance which meets the Ontario Ministry of Health Standards. The participants will consent and follow a protocol while active samplers are placed in the rear of the ambulance to capture the off-gassing of the methoxyflurane. This will inform the risk of occupational exposure of methoxyflurane to paramedics, as well as, hoping to inform the risk of multiple administrations by paramedics to different patients during a single shift, to ensure a medical directive can be created to support patient care and evaluate and support paramedic safety.

NCT Number	NCT05766397
Lead Sponsor	Ottawa Hospital Research Institute Collaborators: Mayday Fund
Conditions	Occupational Exposure
Enrollment	30 participants
Start Date	2023-09-01
Primary Completion	2024-07-20 (estimated)
Study Completion	2024-09-30 (estimated)
Updated on ClinicalTrials.gov	2024-07-19