Randomised clinical study comparing the effectiveness and physiological effects of hypertonic and isotonic polyethylene glycol solutions for bowel cleansing.

OBJECTIVES: Bowel cleansing is necessary before colonoscopy, but is a burden to patients because of the long cleansing time and large dose volume. A low-volume (2 L) hypertonic polyethylene glycol-ascorbic acid solution (PEG-Asc) has been introduced, but its possible dehydration effects have not been quantitatively studied. We compared the efficacy and safety including the dehydration risk between hypertonic PEG-Asc and isotonic PEG regimens. DESIGN: This was an observer-blinded randomised study. Participants (n=310) were allocated to receive 1 of 3 regimens on the day of colonoscopy: PEG-Asc (1.5 L) and water (0.75 L) dosed with 1 split (PEG-Asc-S) or 4 splits (PEG-Asc-M), or PEG-electrolyte solution (PEG-ES; 2.25 L) dosed with no split. Dehydration was analysed by measuring haematocrit (Ht). RESULTS: The cleansing time using the hypertonic PEG-Asc-S (3.33±0.48 hours) was significantly longer than that with isotonic PEG-ES (3.05±0.56 hours; p<0.001). PEG-Asc-M (3.00±0.53 hours) did not have this same disadvantage. Successful cleansing was achieved in more than 94% of participants using each of the 3 regimens. The percentage changes in Ht from baseline (before dosing) to the end of dosing with PEG-Asc-S (3.53±3.32%) and PEG-Asc-M (4.11±3.07%) were significantly greater than that with PEG-ES (1.31±3.01%). CONCLUSIONS: These 3 lower volume regimens were efficacious and had no serious adverse effects. Even patients cleansed with isotonic PEG-ES showed significant physiological dehydration at the end of dosing. The four-split PEG-Asc-M regimen is recommended because of its shorter cleansing time without causing serious nausea. TRIAL REGISTRATION NUMBER: UMIN000013103; Results.

Carbon dioxide insufflation for colonoscopy: evaluation of gas volume, abdominal pain, examination time and transcutaneous partial CO2 pressure.

BACKGROUND: Insufflation with carbon dioxide (CO(2)) in colonoscopy has not been widely adopted and, consequently, limited data are available on insufflated gas volume and blood pCO(2). The aim of this study was to compare CO(2) and air as an insufflation agent in patients undergoing colonoscopy without sedation in terms of insufflated gas volume, pCO(2), pain and examination time. METHODS: This was a randomized, double-blind, control trial. Consecutive patients presenting for colonoscopy, excluding those with lung or malignant disease, were randomized into two groups: insufflation with air or with CO(2), respectively. Insufflated gas volume, pain, pCO(2) and examination time were assessed. RESULTS: The study cohort comprised 120 patients (66 randomized to CO(2) group). No significant difference in insufflated gas volumes was found between the CO(2) and air groups. The mean pCO(2) measured before, during (the peak value) and 30 min after colonoscopy were 40, 43 and 40 mmHg, respectively, in both groups. The pain scores in the air group were significantly greater than those in the CO(2) group until 3 h after the examination. There was a significant faster cecal intubation time and a trend toward shorter examination time in the CO(2) group. CONCLUSIONS: The CO(2) gas volume used in our study (14.0 L) was much greater than that reported by others (8.3 L), but the pCO(2) values were still within the normal reference range, indicating the safety of CO(2) insufflation over a greater range of CO(2) gas volume. Among our patients, CO(2) insufflation was associated with relatively less pain and a shorter examination time. Based on our results, we recommend that CO(2) become the standard gas for insufflation in patients undergoing colonoscopy without sedation.