Bispectral Index Monitoring for Sedation in Elective Colonoscopies of Adult Patients: a Randomized Controlled Trial

Randomized double-blind clinical trial in patients undergoing scheduled colonoscopies in endoscopy rooms of the Galdakao-Usánsolo Hospital (Bizkaia, Spain) and Mendaro Hospital (Gipuzkoa, Spain). The investigators will compare the rate of cardiorrespiratory adverse events as well as the anesthetic drugs dosage, need for rescue medication and patient satisfaction among the experimental group in which sedation is guided by BIS and the control group in which the anesthesiologist is blind to the result of the BIS. The investigators hypothesized that BIS monitoring would be associated with better outcomes than clinical observation.

The BIS is the parameter of anesthetic depth monitoring most used today. Its use was approved by the Food and Drug Administration (FDA) in 1996 as an aid to control the effects of certain anesthetic agents. It is validated in the operating room (Recommendation grade A), but not outside it due to lack of conclusive studies.

180 patients are needed to obtain statistically significant differences between both groups. Qualitative variables are expressed in the form of frequencies and percentages and continuous variables in the form of means and standard deviations. Comparisons of percentages will be made by the Chi square test (or Exact Fisher's test, when the expected frequencies are less than 5) and the difference of means in the continuous variables by the t test as well as by the Wilcoxon nonparametric test if the distribution of the variable requires it. The degree of agreement between the BIS and Ramsay scale will be made through the weighted Kappa test. Statistical significance will be assumed when p <0.05. All statistical analyzes will be carried out using SAS V9.4. (SAS institute, Inc., Carey, NC).