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 (13 < 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 CO2 delivery each resulted in negligible postprocedure discomfort and reliable colonic distention, CO2 was better for both categories.