Penthrox® (Methoxyflurane) as an Analgesic for Removal of Circular External Fixators and Minor Procedures during the COVID-19 Pandemic

Abstract

Introduction: Methoxyflurane has excellent analgesic properties and is approved for use in the United Kingdom and Ireland since 2015. It is currently used in emergency departments for analgesia during fracture reductions. During the COVID-19 pandemic, with theatre access severely restricted, Penthrox® had the potential to provide adequate pain relief to aid frame and wire removal in the clinic setting. Materials and methods: Patients presenting to the limb reconstruction service elective clinic and requiring frame removal or minor procedures were included in the study. Patients with renal, cardiac or hepatic disease, a history of sensitivity to fluorinated anaesthetic agents and those on any nephrotoxic or enzyme-inducing drugs were excluded. All procedures were performed in an appropriate isolated room in the clinic. Patient demographics, procedure details, visual analogue score, Richmond Agitation Scale and patient satisfaction were recorded. Results: A total of 39 patients were included in the study of which 17 had Ilizarov frames removed, 10 had hexapod removals, nine had heel rings removed and three had an external fixator removed. Eleven patients received additional pain relief in the form of oral analgesia. All patients were satisfied or very satisfied with the experience. One patient required a general anaesthetic for the removal of a wire that could not be removed in the clinic due to bony overgrowth. Conclusion: Patient satisfaction was very high (>95%), and it was possible to perform frame removals and minor procedures in the clinic environment during the COVID-19 pandemic. We see potential for regular use of Penthrox® in the future for the removal of external fixation outside of the operating theatre. Clinical significance: Penthrox as an analgesic for frame adjustments and removals is safe and has the potential for significant financial savings for the National Health Service (NHS).