Sequential incremental doses of bisacodyl increase the diagnostic accuracy of colonic manometry

BackgroundColonic manometry is the standard diagnostic modality for evaluating colonic motility in children. Intraluminal bisacodyl is routinely used to trigger high-amplitude propagating contractions (HAPCs), a feature of normal colonic motility. Usually, only a single dose (0.2mg/kg) is suggested. We retrospectively explored whether the use of an additional higher (0.4mg/kg) dose of bisacodyl increases the yield of colonic manometry.MethodsIn 103 children (median age: 8.8years, range 3.2-15.7years) with a diagnosis of slow transit constipation, colonic motility was recorded for 1h before and 1h after each of two incremental doses of bisacodyl (low, L, dose: 0.2mg/kg, max 10mg; high, H, dose: 0.4mg/kg, max 20mg) and the characteristics of HAPCs analyzed.Key ResultsHigh-amplitude propagating contractions were seen in 85 children. H dose significantly increased the proportion of patients with fully propagated HAPCs (H dose: 57/103 [55%], L dose: 27/103 [26%], p<0.001), paralleling the significant decrease in the proportion with partially propagated HAPCs (H dose: 29/103 [28%], L dose: 47/103 [46%], p<0.01). Mean HAPC number significantly increased throughout the colon at H compared to L dose (7.25.05 vs 5.6 +/- 5.1, p<0.05). Finally, the proportion of patients with normal pressure wave morphology of HAPCs significantly increased with higher dose (H dose: 55/85 [65%], L dose: 27/85 [32%], p<0.001).Conclusions & InterferencesAn additional higher dose of bisacodyl during colonic manometry improves colonic neuromuscular function suggesting its use might improve interpretation and decision making in children with slow transit constipation.