Abstract
Objective: We hypothesized that remifentanil continuous infusion during colonoscopy in spontaneous respiration may give benefits in terms of quality of sedation and recovery compared to propofol, and that patients’ ventilatory drive and consciousness could be accurately evaluated by the continuous measurement of end-tidal CO2 (EtCO2), and of Bispectral Score (BIS) respectively. Methods: One-hundred and eighty patients scheduled for colonoscopy were randomized in two groups: 76 patients were included in Groupcontrol (propofol 0.5 mg/kg bolus plus infusion 1 mg/kg/h) and 78 patients in Gruopremi (0.5 mcg/Kg/1 min bolus plus infusion 0.08 mcg/kg/min, progressively reduced to 0.03 mcg/kg/min). Cardiovascular and respiratory variables were measured before induction and every 3 min throughout the procedure. Sedation level was estimated by BIS and Observer’s Assessment of Alertness/Sedation Scale (OAA/S). Respiratory function was evaluated by arterial oxygen saturation (SaO2) and EtCO2. Recovery from sedation and hospital discharge criteria were assessed by Modified Aldrete Score System (APRS) 30 min after colonoscopy completion. Results: Remifentanil was effective and well tolerated during colonoscopy. Hemodynamic parameters remained stable throughout the study steps in both groups. In Groupremi OAA/S and BIS score were higher (p<0.001), and EtCO2 (p<0.5) lower that in Groupcontrol. Recovery time was faster in the Groupremi (p<0.01). Conclusions: Our data show that analgosedation with remifentanil allowed to obtain a good quality colonoscopy without respiratory and hemodynamic impairment and with faster recovery than moderate sedation propofol/fentanyl. Moreover, BIS and EtCO2 monitoring proved to be well suited to evaluate the trend variations of patients’ sedation level and respiratory drive.
Highlights
Colonoscopy is one of the most commonly performed outpatient procedures for diagnosis and treatment of gastrointestinal disorders, usually performed under moderate sedation in the ambulatory setting [1]
The target level of sedation in Groupcontrol was moderate sedation, 30% of those patients moved to deep sedation during the procedure, with the lowest values of Bispectral Score (BIS) 55% and OAA/S of 2 reached on T3
The American Society of Anesthesiologists (ASA) guidelines on “Sedation and anesthesia in GI endoscopy” approved by the American Society of Gastroenterology Endoscopy (ASGE) established that the physiological monitoring needed for sedation during colonoscopy should include pulse oximetry, electrocardiography, and intermittent blood pressure measurement, while extended monitoring techniques that may provide sensitive measures of patient’s ventilatory function and level of sedation (BIS), are optional [22]
Summary
Colonoscopy is one of the most commonly performed outpatient procedures for diagnosis and treatment of gastrointestinal disorders, usually performed under moderate sedation in the ambulatory setting [1]. Colonoscopy in spontaneous ventilation patients may carry a higher risk as opposed to anesthesia inside the operating room [2]. Potential problems that can arise with Non-Operating Room Anesthesia (NORA) are hypothermia, aspiration of gastric content, hypovolemia, airways management difficulties, anaphylaxis, postoperative nausea and vomiting, and procedure related complications [3]. The use of adequate monitoring tools and of manageable drugs is essential to decrease the complication rate [2]. Capnometry is widely used in anesthetic practice as non-invasive tool for respiratory monitoring. Some warnings on the possible inaccuracy of EtCO2 sampling in such condition, due to the risk of mixing of expired gas with ambient air, have been aroused, in the last decades new capnometers designed for EtCO2 measurement in non-intubated patients, were introduced in clinical practice that were found reliable mostly to evaluate the time course of EtCO2 in every single patient [5]
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