title: Portable inhaled methoxyflurane is feasible and safe for colonoscopy in subjects with morbid obesity and/or obstructive sleep apnea.
abstract: OBJECTIVE
  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).
  
  
  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.
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: Nam Q
authors.initials: NQ
authors.lastname: Nguyen
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: Leanne
authors.initials: L
authors.lastname: Toscano
authors.affiliation: Colo-Rectal Surgical Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Lawrence
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: Vinh-An
authors.initials: VA
authors.lastname: Phan
authors.affiliation: Department of Gastroenterology, Lyell McEwin Hospital, Elizabeth Vale, South Australia, Australia.
authors.forename: Rajvinder
authors.initials: R
authors.lastname: Singh
authors.affiliation: Department of Gastroenterology, Flinders Medical Centre, Bedford Park, South Australia, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Bampton
authors.affiliation: Department of Gastroenterology, Flinders Medical Centre, Bedford Park, South Australia, Australia.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Fraser
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Holloway
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: Mark N
authors.initials: MN
authors.lastname: Schoeman