Patient-controlled room air insufflation versus automated carbon dioxide delivery for CT colonography

OBJECTIVE. Our objective was to prospectively compare colonic distention and patient comfort at screening CT colonography (CTC) with patient-controlled room air (RA) insufflation versus automated carbon dioxide (CO₂) delivery. SUBJECTS AND METHODS. Two hundred eight adults undergoing CTC were randomized to RA or CO₂ (104 per method). Colonic distention was prospectively assessed by segment using a 4-point scale (1 = optimal, 2 = adequate, 3 = inadequate, 4 = collapsed). Adequacy of combined supine/prone segmental evaluation was also recorded. Patients provided discomfort ratings on a 0-10 scale (0-1 = none/insignificant, 2-3 = minimal, 4-6 = intermediate, 7-10 = significant) before, during, and after the procedure. RESULTS. No significant differences in segmental distention were observed in the prone position between techniques. In the supine position, CO₂ resulted in significantly greater distention in the sigmoid, descending, and transverse segments (p < 0.01). After combined supine/prone assessment, two/104 (1.9%) and three/104 (2.9%) patients were judged to have an inadequately evaluated segment on RA and CO₂, respectively (four sigmoid, one transverse). Mean discomfort scores for RA and CO₂ were 3.97 and 5.08 during the examination (p < 0.01); 0.91 and 0.42 immediately after (p < 0.01); 0.51 and 0.25 15 min later (p < 0.05); and 0.15 and 0.04 2 hours later (p < 0.01), respectively. During active distention, 19 (18.3%) and 33 (31.7%) patients reported significant transient discomfort with RA and CO₂, respectively (p < 0.05). Beyond 15 min, only two (1.9%) patients with RA and no patients with CO₂ had a discomfort level higher than 3. CONCLUSION. Although patient-controlled RA insufflation and automated CO ₂ delivery each resulted in negligible postprocedure discomfort and reliable colonic distention, CO₂ was better for both categories.