Portable inhaled methoxyflurane is feasible and safe for colonoscopy in subjects with morbid obesity and/or obstructive sleep apnea

Nam Q Nguyen; Leanne Toscano; Matthew Lawrence; Vinh-An Phan; Rajvinder Singh; Peter Bampton; Robert J Fraser; Richard H Holloway; Mark N Schoeman

doi:10.1055/s-0034-1392366

Portable inhaled methoxyflurane is feasible and safe for colonoscopy in subjects with morbid obesity and/or obstructive sleep apnea

Endosc Int Open. 2015 Oct;3(5):E487-93. doi: 10.1055/s-0034-1392366. Epub 2015 Jun 24.

Authors

Nam Q Nguyen¹, Leanne Toscano¹, Matthew Lawrence², Vinh-An Phan¹, Rajvinder Singh³, Peter Bampton⁴, Robert J Fraser⁴, Richard H Holloway¹, Mark N Schoeman¹

Affiliations

¹ Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
² Colo-Rectal Surgical Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
³ Department of Gastroenterology, Lyell McEwin Hospital, Elizabeth Vale, South Australia, Australia.
⁴ Department of Gastroenterology, Flinders Medical Centre, Bedford Park, South Australia, Australia.

Abstract

Background and study aims: Colonoscopy with inhaled methoxyflurane (Penthrox) is well tolerated in unselected subjects and is not associated with respiratory depression. The aim of this prospective study was to compare the feasibility, safety, and post-procedural outcomes of portable methoxyflurane used as an analgesic agent during colonoscopy with those of anesthesia-assisted deep sedation (AADS) in subjects with morbid obesity and/or obstructive sleep apnea (OSA).

Patients and methods: The outcomes of 140 patients with morbid obesity/OSA who underwent colonoscopy with either Penthrox inhalation (n = 85; 46 men, 39 women; mean age 57.2 ± 1.1 years) or AADS (n = 55; 27 men, 28 women; mean age, 54.9 ± 1.1 years) were prospectively assessed.

Results: All Penthrox-assisted colonoscopies were successful, without any requirement for additional intravenous sedation. Compared with AADS, Penthrox was associated with a shorter total procedural time (24 ± 1 vs. 52 ± 1 minutes, P < 0.001), a lower incidence of hypotension (3 /85 vs. 23 /55, P < 0.001), and a lower incidence of respiratory desaturation (0 /85 vs. 14 /55, P < 0.001). The patients in the Penthrox group recovered more rapidly and were discharged much earlier than those in the AADS group (27 ± 2 vs. 97 ± 5 minutes, P < 0.0001). Of those who underwent colonoscopy with Penthrox, 90 % were willing to receive Penthrox again for colonoscopy. More importantly, of the patients who underwent colonoscopy with Penthrox and had had AADS for previous colonoscopy, 82 % (28 /34) preferred to receive Penthrox for future colonoscopies. Penthrox-assisted colonoscopy cost significantly less than colonoscopy with AADS ($ 332 vs. $ 725, P < 0.001), with a cost saving of approximately $ 400 for each additional complication avoided.

Conclusions: Compared with AADS, Penthrox is highly feasible and safe in patients with morbid obesity/OSA undergoing colonoscopy and is associated with fewer cardiorespiratory complications. Because of the advantages of this approach in regard to procedural time, recovery time, and cost benefit in comparison with AADS, further evaluation in a randomized trial is warranted.