Supplemental Oxygen and Oxygen Desaturations in Colonoscopies

Sedation procedures such as colonoscopies involve administering drugs to patients that reduce awareness and pain without complete loss of consciousness. A side effect of these drugs is respiratory depression, where the patient's breathing becomes more shallow and less frequent. Another side effect is partial or complete obstruction of the airway by the airway tissue, inhibiting the flow of oxygen to the lungs. When a patient experiences significant respiratory depression or airway obstruction, they may not receive adequate oxygen, which may result in low hemoglobin oxygen saturation (SpO2), which is generally monitored with a probe on a finger. This may lead to inadequate oxygenation of tissues or organs and can lead to permanent organ damage or even death in severe cases.

The current standard approach to prevent oxygen desaturation during procedural sedation is supplemental oxygen therapy, usually administered through a nasal cannula or oxygen mask. The traditional method is continuous flow oxygen therapy, where a constant flow of oxygen is given. Research has demonstrated that while this does improve overall oxygen saturation levels during sedation, oxygen desaturation and apnea still frequently occur.

An FDA-cleared intelligent oxygen delivery device (Sovant, Dynasthetics LLC) that is relatively new to the market provides a new approach to supplemental oxygen delivery called synchronized flow, which delivers variable-volume pulses of high-flow oxygen only as the patient inhales. The volumes of the pulses are based on a set flow rate and the patients respiratory rate. Research has shown that higher oxygen concentrations reach the lungs when using synchronized flow delivery as opposed to continuous flow oxygen delivery, but research has yet to demonstrate that synchronized flow reduces oxygen desaturation events.

Research has demonstrated that continuous positive airway pressure (CPAP) therapy, which involves directing air flow into a tight-fitting mask over the patient's nostrils and/or mouth to stent open the airway, effectively reduces oxygen desaturation and apnea when administered with a non-invasive ventilator. However, non-invasive ventilators used for administering PAP therapy are expensive, large, require special training to operate, and often are not available in areas of the hospital where sedation procedures take place, making this a less-practical approach.

We have developed a smaller low-cost CPAP system for sedation as an additional software feature and disposable integrated into the FDA-cleared intelligent oxygen delivery device that also administers continuous flow and synchronized flow supplemental oxygen (Sovant, Dynasthetics LLC). The aim of the study is to administer supplemental oxygen to colonoscopy patients using these three different administration methods (continuous flow, synchronized flow, and CPAP therapy) and evaluate differences in oxygen desaturation (SpO2 < 90%) and apnea (10 seconds or more without respiration) events. We aim to evaluate the effectiveness of synchronized flow oxygen delivery compared to continuous flow oxygen delivery in reducing oxygen desaturation and apnea. We also aim to evaluate whether our compact and low-cost CPAP system can also effectively reduce oxygen desaturation and apnea compared to the current standard practice of continuous flow delivery.

Inclusion criteria

• Adult patient
• No life threatening conditions
• Undergoing colonoscopy procedures and receiving procedural sedation at the University of Utah Health clinic in South Jordan, Utah.

Exclusion criteria

• Inability/refusal of subject to provide informed consent.
• Less than 18 years of age.
• Standard colonoscopy exclusion criteria used at the GI lab at the University of Utah.
• Patients known or suspected to be pregnant.
• Patients with an ASA physical status of IV (A patient with severe systemic disease that is a constant threat to life) or V (A moribund patient who is not expected to survive without the operation).
• Patients known to have acute respiratory distress syndrome, severe COPD, or cardiovascular disease.
• If their oxygen saturation measured by pulse oximetry (SpO2) is below 93% while breathing room air prior to the procedure.
• Patients with severe medical condition(s) that in the view of the acting physician prohibits participation in the study.