Comparison of High-flow Oxygen With or Without Nasal Positive Airway Pressure (PAP) During Propofol Sedation for Colonoscopy in an Ambulatory Surgical Center: a Prospective Randomized Controlled Trial

This study involves the oxygenation, continuous positive airway pressure, and ventilation of a subject via nasal mask and oxygenation via a closed facemask. The interventions directly related to this study are that of supplement oxygen, bag-mask ventilation, and continuous nasal CPAP intra-operatively and in the recovery unit.

Patients will be randomized in groups of ten to one of two groups using a random number table.

Group A: standard care with a nasal cannula. Group B: SuperNO2VA™EtCO2. For each anesthetic case, a preoperative history and physical and intraoperative record will be documented.

Once in the endoscopy suite, the patients will have baseline vital signs, EtCO2 and oxygen levels measured. Continuous monitoring of heart rate, end tidal CO2 (EtC02), O2 saturation, and every 3-minutes BP monitoring will be obtained. For patients randomized to group A, the anesthesia provider will supply oxygen via nasal cannula at 10LPM. For patients randomized to group B, the anesthesia provider will attach the SuperNO2VA™ EtCO2's circuit port to the hyperinflation bag with the oxygen flow rate to 10 L/min, and the adjustable pressure-limiting (APL) valve completely closed. Initial propofol bolus of 0.5-1.0 mg/kg actual body weight will be administered for sedation. No other sedative or analgesic will be permitted besides propofol. MOAA/S scores will be assessed by the anesthesiologist and medical team and recorded by the research assistant. If the patient's MOAA/S score is ≥ 4, additional 20-50 mg boluses will be administered every 30 - 90 seconds until a MOAA/S score <4 is reached. Once a MOAA/S <4 is reached the endoscopist will insert the colonoscope into the rectum. Sedation will be titrated to maintain a MOAA/S <4 throughout the procedure. If the patient's MOAA/S score ≥4, additional 20-50 mg boluses of propofol will be administered every 30-90 seconds until the MOAA/S is <4. The measurements recorded during colonoscopy for both groups will be: time of administration of sedation; incidence, severity, and duration of oxygen desaturation; number, duration and reason for performing the airway maneuver(s); duration of the procedure; total dose of medication; blood pressure, heart and respiratory rate, and oxygen saturation; time to full recovery; and patient cooperation. The research assistant will document their patient's depth of sedation, cooperation with procedure, and safety.

Endoscope techniques performed during the procedure such as biopsies, dilation, polypectomy, etc. will be tracked. Techniques to facilitate proximal passage of the endoscope such as moving the patient or abdominal pressure will also be noted. If the anatomic extent desired to complete the colonoscopy is not reached (i.e., colon stricture, excessive looping of the instrument), then the patient will be withdrawn from the study.