A two-center randomized controlled trial of water-aided colonoscopy versus air insufflation colonoscopy.
OBJECTIVE
Water-aided colonoscopy includes water immersion and water exchange. Several small single-center studies have suggested that the use of water rather than air insufflation during colonoscopy reduces pain on insertion. The aim of this study was to investigate whether water-aided colonoscopy is less painful than air insufflation in a large cohort of patients.


METHODS
This was a two-center, randomized controlled trial. Consecutive patients who agreed to start colonoscopy without premedication were included. Sedation was administered on demand. Water-aided colonoscopy was performed using water immersion in the early phase of the study, and subsequently water exchange was used. The primary endpoint was cecal intubation with pain scores of ≤ 2 and sedation with no or ≤ 2 mg midazolam. Secondary outcomes were pain score at discharge, cecal intubation rate and time, and adenoma detection rate (ADR).


RESULTS
A total of 672 patients were randomized to water exchange (n = 338) or air insufflation (n = 334). The primary endpoint was achieved in more patients in the water exchange group (83.8 % vs. 62 %; P < 0.0005). On-demand sedation was also required less (11.5 % vs. 26.0 %; P < 0.0005) and mean pain score was lower (1.3 vs. 2.3; P < 0.0005) in the water exchange group. The cecal intubation rates were comparable. Water exchange had a significantly higher overall ADR (25.8 % vs. 19.1 %; P = 0.041), proximal ADR (10.1 % vs. 4.8 %; P = 0.014), and proximal < 10 mm ADR (7.7 % vs. 3.9 %; P = 0.046); proximal ADR was also higher in screening-only patients in the water exchange group (18.9 % vs. 7.4 %; P  = 0.015). No detailed analysis was possible for the air insufflation vs. water immersion comparison.


CONCLUSIONS
The current results confirmed that water exchange minimized the requirement for sedation and increased the ADR.
Digestive Endoscopy Unit, S. Barbara Hospital, Iglesias, Carbonia-Iglesias Province, Italy.
Sergio
S
Cadoni
Digestive Endoscopy Unit, S. Barbara Hospital, Iglesias, Carbonia-Iglesias Province, Italy.
Paolo
P
Gallittu
Digestive Endoscopy Unit, N. S. di Bonaria Hospital, San Gavino Monreale, Villacidro-Sanluri Province, Italy.
Stefano
S
Sanna
Digestive Endoscopy Unit, N. S. di Bonaria Hospital, San Gavino Monreale, Villacidro-Sanluri Province, Italy.
Viviana
V
Fanari
Digestive Endoscopy Unit, N. S. di Bonaria Hospital, San Gavino Monreale, Villacidro-Sanluri Province, Italy.
Maria L
ML
Porcedda
Department of Surgery, University of Cagliari, Cagliari, Cagliari Province, Italy.
Matteo
M
Erriu
Sepulveda Ambulatory Care Center, Veterans Affairs Greater Los Angeles Healthcare System, North Hills, California, USA.
Felix W
FW
Leung
D015746:Abdominal Pain / Q000209:etiology*; D000236:Adenoma / Q000175:diagnosis*; D000368:Aged; D000388:Air; D002432:Cecum; D003110:Colonic Neoplasms / Q000175:diagnosis*; D003113:Colonoscopy / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007327:Insufflation / Q000009:adverse effects / Q000379:methods*; D007441:Intubation, Gastrointestinal; D008297:Male; D008875:Middle Aged; D061646:Operative Time; D010147:Pain Measurement; D011446:Prospective Studies; D014867:Water
D006993:Hypnotics and Sedatives; D014867:Water