NITROUS-OXIDE INHALATION AS SEDATION FOR FLEXIBLE SIGMOIDOSCOPY

Background: Flexible sigmoidoscopy is usually performed without sedati on in screening programs for colorectal cancer. Most patients report s ome degree of discomfort or pain during the procedure. The aim of this study was to evaluate self-administered nitrous oxide as a method to reduce patient discomfort, thereby improving the procedure and conceiv ably increasing patient compliance and motivation. Methods: in a doubl e-blind, randomized, placebo-controlled study, 38 patients undergoing sigmoidoscopy self-administered 60% nitrous oxide (n = 18) or oxygen ( n = 20) by mask. The endoscopist recorded the depth of insertion of th e sigmoidoscope, duration of the procedure, and time to patient recove ry. Patients scored the degree of pain and discomfort felt during the examination. Results: There were no significant differences between th e groups with regard to patients' age, gender, pain or discomfort, dur ation of procedure, or depth of insertion. Recovery time was significa ntly longer in the nitrous oxide group (3.3 +/- 0.6 minutes vs 0.5 +/- 0.5 minutes; p = 0.02), but this finding was of no practical or clini cal consequence. Conclusions: The addition of ''on demand'' nitrous ox ide did not improve sigmoidoscopy performance or diminish pain and dis comfort. However, further studies using improved administration techni ques and larger study groups are justified in the search for ways to i ncrease compliance with and motivation for colorectal cancer screening .