Reversal From Propofol Anesthesia to Midazolam/Fentanyl Sedation Using Water Exchange Insertion Colonoscopy

Abstract

Introduction: Propofol-based anesthesia (P) is rapidly replacing midazolam/fentanyl-based conscious sedation (MF) during colonoscopy. At the same time several technical developments, including more flexible instruments, use of CO2 for insufflation and water exchange during the insertion phase have greatly decreased the discomfort associated with colonoscopy. Goal: To determine whether two half-day observations in water exchange insertion colonoscopy allows successful reversal from P to MF given current patient, nurse and organizational expectations. Setting: Two rural Wisconsin practices (A and B), where up to half of colonoscopies are performed under P (practice A) by a single experienced endoscopist. In practice B reversal from P to MF was encouraged by leadership given P-related expenses. Methods: Prior to preferential use of MF the endoscopist performing screening colonoscopy in practices A and B requested observation of water exchange colonoscopies performed at the University of Minnesota Medical Center. The focus of the observation sessions was on water exchange insertion technique, early rotation of the patient to facilitate endoscope advancement and prophylactic abdominal pressure to prevent loop formation (AJG 2017;112:578). After two observation sessions, the endoscopist started performing water exchange colonoscopy at practice B and at the same time reduced use of P in favor of MF. As before, patients were given the amount of MF to achieve the usual patient level of comfort. Sedation/ anesthesia type and MF doses were obtained by retrospective review of medical records. To prevent bias, 100 successive colonoscopies from practice A from before the conversion from P to MF were compared with 100 successive colonoscopies from practice B after institution of preferential use of MF. Results: In practice A 52/100 (52%) of colonoscopies were done under P anesthesia whereas after preferential use of MF in practice B this was 4/100 (4%; p<0.01). In the 48 patients in practice A the dose of MF when used was significantly higher than the MF dose used in the 96 patients in practice B: Fentanyl 165±31 mcg vs 87±38; Midazolam 3.7±0.8 mg vs 3.0±0.9 (M±SD; p<0.01). Conclusion: (1) Using water exchange insertion technique allowed successful reversal from P to MF colonoscopy in a practice where reduction in the use of P-related expenses was pursued. (2) Water exchange insertion technique significantly reduced the administered doses of midazolam and fentanyl.