Carbon Dioxide Insufflation in Colonoscopy: Safe and Effective in Sedated Patients

Background and Study Aims: Several studies have shown that insufflation of carbon dioxide (CO₂) instead of air during colonoscopy can reduce postprocedural pain. However, CO₂ insufflation might also lead to CO₂ retention in the human body. It was recently shown that this side effect does not occur in unsedated patients, but that sedation leads to impaired respiration. Sedated patients may therefore be more prone to CO₂ retention. This randomized, double-blinded study was designed to investigate whether CO₂ insufflation leads to CO₂ retention in sedated patients.
Patients and Methods: A total of 103 consecutive patients undergoing colonoscopy were randomly assigned to the use of either CO₂ or air insufflation. End-tidal carbon dioxide (ETCO₂), a noninvasive parameter for arterial Pco₂, was recorded before the examination, twice during it, and 10 min after it. Midazolam or pethidine, or both, were used for sedation. The patient’s pain during the examination and 1, 3, 6, and 24 h afterwards was registered using a questionnaire.
Results: CO₂ was used in 52 patients and air insufflation in 51. A total of 52 patients (51 %) received sedation. There were no differences in ETCO₂ between the CO₂ and air group. A slight increase in ETCO₂ was observed in sedated patients, while there was no increase in unsedated patients. CO₂ insufflation significantly reduced pain after the procedure at all time points.
Conclusions: This study indicates that CO₂ insufflation reduces pain and is safe to use in colonoscopy for sedated patients.

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