title: Impact of carbon dioxide insufflation and water exchange on postcolonoscopy outcomes in patients receiving on-demand sedation: a randomized controlled trial.
abstract: OBJECTIVE
  Water exchange (WE) is the least painful insertion method during colonoscopy. Its impact on postcolonoscopy discomfort has not been well-described. Carbon dioxide (CO2) insufflation consistently reduced postcolonoscopy discomfort. We compared postcolonoscopy outcomes of various combinations of insertion and withdrawal techniques (insertion-withdrawal modality): WE-CO2, WE-air insufflation (WE-AI), and CO2-CO2.
  
  
  METHODS
  A total of 240 patients undergoing on-demand sedation diagnostic colonoscopy were randomized to WE-CO2(n = 79), WE-AI (n = 80), CO2-CO2(n = 81), with postprocedural data collected up to 24 hours. The primary outcome was postcolonoscopy bloating. Other postcolonoscopy outcomes included pain scores, flatus and incontinence episodes, toilet use, interference with normal activities, patient satisfaction, and patient willingness to repeat the procedure.
  
  
  RESULTS
  Demographic and procedural data were comparable. Compared with WE-AI, WE-CO2and CO2-CO2resulted in significantly less bloating (all P < .0005) and lower pain scores (P values ranged from .008 to < .0005) up to 3 hours and fewer flatus episodes up to 6 hours (P values ranged from .003 to < .0005). WE-CO2resulted in less interference with same-day activities compared with WE-AI (P = .043). The differences in postprocedural outcomes were significant, but the magnitude was small. Patient satisfaction and willingness to repeat the procedure were high and comparable among groups. WE was the least painful insertion technique (P < .0005).
  
  
  CONCLUSIONS
  The combination WE-CO2appears to be the optimal choice to decrease pain during the examination and to reduce bloating and other undesired procedural outcomes afterward. If a CO2insufflator is already available, it seems advisable to adopt the combination WE-CO2. In the absence of a CO2insufflator, the cost effectiveness of the addition of withdrawal CO2to WE in diagnostic and nondiagnostic settings needs to be critically assessed. (Clinical trial registration number: NCT02409979.).
authors.affiliation: Digestive Endoscopy Unit, St. Barbara Hospital, Iglesias, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Cadoni
authors.affiliation: Digestive Diseases Center, Vitkovice Hospital, Ostrava, Czech Republic.
authors.forename: Přemysl
authors.initials: P
authors.lastname: Falt
authors.affiliation: Digestive Endoscopy Unit, St. Barbara Hospital, Iglesias, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Gallittu
authors.affiliation: Digestive Endoscopy Unit, St. Barbara Hospital, Iglesias, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Liggi
authors.affiliation: Digestive Diseases Center, Vitkovice Hospital, Ostrava, Czech Republic.
authors.forename: Vit
authors.initials: V
authors.lastname: Smajstrla
authors.affiliation: Sepulveda Ambulatory Care Center, Veterans Affairs Greater Los Angeles Healthcare System, North Hills, California, USA; David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, California, USA.
authors.forename: Felix W
authors.initials: FW
authors.lastname: Leung
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D000368:Aged; D000388:Air; D002245:Carbon Dioxide; D003113:Colonoscopy / Q000009:adverse effects / Q000379:methods*; D016292:Procedural Sedation; D005242:Fecal Incontinence / Q000209:etiology; D005260:Female; D005414:Flatulence / Q000209:etiology; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007327:Insufflation; D008297:Male; D008874:Midazolam / Q000008:administration & dosage; D008875:Middle Aged; D010147:Pain Measurement; D017060:Patient Satisfaction; D014867:Water
chemical_list: D006993:Hypnotics and Sedatives; D014867:Water; D002245:Carbon Dioxide; D008874:Midazolam