Introduction:

Colonoscopy remains the most important method for screening programs for colorectal cancer, its impact in reducing the incidence and mortality of this disease is due to the possibility of detecting and resecting precancerous lesions. The detection rate of polyps is directly proportional to the adenoma detection rate. Different techniques have been described that facilitate cecal intubation and improve the visualization of the mucosa. The technique of minimum water exchange combines the original concept of water exchange, in wich the air from the colonic lumen is aspirated to later infuse water; however, in this technique, the amount of water infused is less, by constant pressure on the button of the air/water valve of the endoscope, sucking when necessary.

Objectives:

To compare the detection rate of polyps with minimal exchange colonoscopy (CIM) and conventional colonoscopy with ambient air (CC). Secondary objectives: Compare the rate and time of cecal cannulation, the requirements of sedative drugs and patient satisfaction.

Material and methods:

Prospective, controlled and randomized study. The patients were randomized by means of an electronic program in 2 groups: first group with the conventional technique, second group with minimum exchange technique, patients did not know the type of technique used. The dose that was used for the sedative medication was at the discretion of the anesthesiologist. A chronometer was applied to measure the cecal cannulation time. Prior to discharge, the patient was asked to complete the GHAA-9mc form and the Likert scale was applied to define the discomfort perceived during the procedure.

Exclusion criteria:

Poor intestinal preparation (Boston scale <6 points), suspected intestinal perforation or occlusion, previous colon surgery, severe gastrointestinal bleeding, documented colorectal cancer, penetrating or stenosing inflammatory bowel disease, patients who did not accept the procedure. The calculation of the sample size was made with the Win episcope version 2.0 program. 84 patients were studied (42 for each group). Demographic data are described using the mean and standard deviations. The Fisher’s exact test and the Chi-square test were used to compare categorical data. Student test was applied to compare the means of the numerical variables. A value of p <0.05 was considered significant. All data were processed with the SPSS 23 program (IBM SPSS Statistics)

Results:

The general characteristics of the patients were similar between the two groups; the mean age was 58.5 ± 12.6 in the MIC group and 57.2 ± 13.6 in the CC group. We did not find differences in the polyp detection rate between the groups studied, for the MIC group the detection rate was 14.4%, and for the group C.C. the rate was 21.5%, with a greater proportion of detection of polyps in right hemicolon, there were no differences in the rate of cecal cannulation between both groups (95.2% vrs 92.9%); however, with the CIM technique the cecal cannulation time was shorter (695 sec vrs 869 sec) and they required less maneuvers such as position changes or abdominal compression to reach the cecum. The dose of drugs used during sedation was higher in the C.C. (p <0.05). Patient satisfaction with the GHAA-9mc scale was greater in the minimal exchange colonoscopy group than in the C.C. (35.6 ± 3 vrs 29.9 ± 3, p <0.001). Regarding the Likert scale to determine the degree of discomfort perceived by the patient, the CIM group had a higher proportion of patients with very good or excellent grades (33 and 31% respectively).

Conclusions:

The colonoscopy technique of minimal water exchange showed no superiority in the detection rate of polyps, nor in the rate of cecal cannulation; however, there is a shorter cannulation time, less requirement for position changes, abdominal compression, sedative medication doses and greater patient satisfaction.

        · resumo em Espanhol     · texto em Espanhol     · Espanhol ( pdf )