This study aims to assess the impact of the use of sedation on the overall quality of the colonoscopy, therefore addressing each and every one of its dimensions, namely: scientific and technical quality, perceived quality and safety.

In recent decades there has been a notable increase in the use of a range of gastrointestinal endoscopy procedures - colonoscopy particularly -, more so in recent years with the implementation of colorectal cancer screening programs.

Colonoscopy can cause discomfort and even pain. In order to reduce these effects and facilitate the procedure, patients are usually administered iv sedation.

Numerous studies have assessed the impact of sedation on patient discomfort and anxiety, on the undesirable effects of the colonoscopy, and even on certain aspects relating to its scientific and technical quality. There have not, however, been any studies evaluating the effects of sedation on the overall quality of the procedure.

The overall quality of every medical act can be defined according to four dimensions: accessibility, or how easily the patient can obtain the assistance required without physical or bureaucratic barriers; scientific and technical quality, or the provision of the best possible assistance with the most up-to-date knowledge and technical resources; perceived quality, or the patient's degree of satisfaction with the care provided; and safety, or the absence of undesirable side effects. Doctors have typically assessed the quality of a procedure based on its scientific and technical quality and its safety. The investigators have strived to conduct good, complication-free techniques based on cutting-edge scientific knowledge, but have often overlooked the other dimensions.

This study aims to assess the impact of the use of sedation on the overall quality of the colonoscopy, therefore addressing each and every one of its dimensions, namely: scientific and technical quality, perceived quality and safety. Since sedation during the procedure has no impact on accessibility, the study will not assess this dimension.

Subjects and Methods:

Prospective case-control study. The study will include consecutive ambulatory patients referred to our Endoscopy Unit for a first-time colonoscopy. Patients will be excluded when they have had previous colonoscopies, have an anesthetic risk above ASA III (American Society of Anesthesia classifications) allergy to the drugs used or if they are undergoing antiplatelet or anticoagulant therapy contraindicated for the procedure, pregnant woman and patients unable to understand the questionnaires.

Prior to inclusion demographic data, clinical background and indication for the colonoscopy will be collected on each patient.

Thereafter patients will be randomly assigned to colonoscopy without sedation or with conscious sedation with iv midazolam and fentanyl dosed according to age, weight and baseline conditions.

The procedures will be conducted by four endoscopists with ample experience in endoscopy and sedation (over 7000 colonoscopies each).

1. Data collected during the endoscopy will include:

   1. The degree of cleanliness of the colon according to the Boston scale; defined as the adequate preparation of at least 2 points in each region of the colon);
   2. Whether or not colonoscopy is completed up to the cecum;
   3. Time needed for insertion up to the cecum and for withdrawal;
   4. The complications that might arise during the procedure and recovery period (early complications). To this end, patients' oxygen saturation and heart rate will be continuously monitored from the beginning of the procedure until their discharged and their blood pressure will be taken every 5 minutes. Non-sedated patients will be discharged from the Unit immediately after the procedure, and sedated patients when they reach a score of 9 or 10 on the Aldrete scale.
   5. Adenomas resected, based on pathology reports. All of the biopsies will be examined by a pathologist specialized in gastrointestinal pathology.

2. Thirty days after the Endoscopy, patients will be interviewed by telephone by staff with no involvement in the study (call center) and asked to respond to two questionnaires.

   1. The ASGE (American Society of Gastrointestinal Endoscopy) endoscopy satisfaction survey (GHAA 9-me), previously translated into Spanish and validated by our team.
   2. A survey on complications suffered in the 30 days following the procedure (late complications), previously used in earlier studies.

3. Assessment of quality criteria:

   1. Six indicators will be used to assess the scientific and technical quality of each procedure. The first three will assess their technical aspects: percentage of colonoscopies completed up to the cecum; time required to reach the cecum; and withdrawal time. The remaining three are results indicators: percentage of patients with adenomas; total number of adenomas per patient; and total number of advanced adenomas. These indicators were previously validated in our setting.

      Since the use or not of sedation during the procedure does not affect the cleanliness of the colon, this indicator will be used as a control variable.

   2. Perceived quality will be assessed using the ASGE (American Society of Gastrointestinal Endoscopy) satisfaction survey, previously translated into Spanish and adapted and validated. Total scores, scores for the procedure (item 7 on the survey) and the number of patients rating the procedure "excellent" will be analyzed.

   3. Safety will be assessed following the same method used in previous research, analyzing early complications (those occurring during the procedure and recovery phase) and late complications (those occurring in the 30 days after the procedure).

Statistical Analyses:

Results will be expressed as mean ± standard deviation. Comparisons between groups will be performed using the Chi-squared test for ordinal variables and Student's t-test for quantitative variables. Results with a p value <0.05 will be considered statistically significant. Logistic regression will be used to determine the impact of sedation on the quality indicators studied.

Inclusion Criteria:

• Consecutive ambulatory patients referred to our Endoscopy Unit for a first-time colonoscopy.

Exclusion Criteria:

• Patients with previous colonoscopies.
• Patients with anesthetic risk above ASA III,
• Patients with allergy to the drugs used.
• Patients undergoing antiplatelet or anticoagulant therapy.
• Pregnant woman.
• Patients unable to understand the questionnaires.

Prospective case-control study. The study will include . Patients will be excluded when they have had previous colonoscopies, have an anesthetic risk above ASA III, allergy to the drugs used or if they are undergoing antiplatelet or anticoagulant therapy contraindicated for the procedure