Results of a recent study suggest that the use of supraglottic jet oxygenation and ventilation (SJOV) during upper gastrointestinal endoscopy can lower the risk for hypoxia in propofol-sedated patients.
Compared with administration of oxygen through a nasal cannula, SJOV through a nasal tube placed above the glottis significantly reduced the rate of hypoxia from 8.93% to 2.53% (P<0.0001). Moreover, data from the study of 1,781 patients showed only mild side effects with the SJOV approach, including dry mouth and sore throat, without any incidents of barotrauma.
“The combination of SJOV with intravenous general anesthesia using a cocktail of remifentanil-propofol-lidocaine has significantly lower incidence of hypoxia, less respiratory and circulatory response, and higher surgeon satisfaction than traditionally used intravenous remifentanil sedation and topical anesthesia during flexible bronchoscopy,” said Huafeng Wei, MD, PhD, from the Department of Anesthesiology and Critical Care in the Perelman School of Medicine, University of Pennsylvania, in Philadelphia. “SJOV clearly has a favorable risk–benefit ratio and ADVERTISEMENT
“Hypoventilation is the main reason for hypoxia during upper gastrointestinal endoscopy procedures with sedation,” Dr. Wei said. “The key to preventing hypoxia is to maintain normal oxygenation/ventilation during the procedure.”
Methods for Oxygen Delivery
In the multicenter, prospective, single-blind study, Diansan Su, MD, PhD, and colleagues randomly assigned 1,781 outpatients undergoing routine upper gastrointestinal endoscopy procedures who were sedated with propofol to three groups. The first group received supplementary oxygen via nasal cannula (2 L per minute); the second group received supplementary oxygen via the WNJ (2 L per minute); and the third group received SJOV via the WNJ (15 psi; respiratory rate, 20 breaths per minute; and inspiratory to expiratory ratio, 1:2).
As Dr. Su reported at the 2017 annual meeting of the Society of Airway Management, use of SJOV decreased the incidence of hypoxia from 8.93% to 2.53% (P<0.0001).
In addition, severe hypoxia did not occur in the SJOV nasal jet group, while one instance was seen in the nasal jet oxygen group and two instances were observed in the nasal cannula oxygen supply control group.
According to the researchers, SJOV-related minor adverse events increased significantly within a minute after the procedure but decreased 30 minutes later. There was an increased incidence of dry mouth within an hour of WNJ tube use, but no severe complications such as barotrauma or airway traumas were reported.
“Although transtracheal jet ventilation is one of the last steps to save a patient in difficult airway management, it is usually difficult to teach and practice in elective patients, there is a prevalence of barotraumas associated with the technique, and it’s often too late to use,” Dr. Wei said. “Comparatively, SJOV with the WNJ is simple and easy to learn, convenient for elective surgeries, and there is minimal chance of barotraumas because of the supraglottic jet ventilation feature and maintenance of adequate expiration during jet ventilation.”
Similarities to High-Flow Cannula
The moderator of the session, David Wong, MD, professor of anesthesiology at the University of Toronto, asked how Dr. Wei’s WNJ compared to a high-flow nasal cannula in clinical practice.
“I think the methods are similar,” Dr. Wei said. “With a high-flow nasal cannula, you get 100% oxygen, increased oxygen infusion, apneic oxygenation, and you can maintain oxygenation for a long time. The WNJ is similar, offering efficient oxygenation, and often proper ventilation, in apnea patients if the supraglottic jet pulse is adequately adjusted and directing towards [the] vocal cord opening.”
Dr. Wei added, “The ability to monitor [end-tidal carbon dioxide] with the WNJ, though, adds another safety feature to diagnose and treat respiratory suppression early and avoid hypoxia-associated morbidity and mortality.”
“Did you see any incidents of gastric distention?” Dr. Wong asked.
“When we designed this study, that was a big concern, which is why we exposed the gastric area of patients receiving SJOV,” Dr. Wei said. “However, gastric distention was very rare based on our clinical experience up to now.”
Dr. Wei added, “Although the majority of patients do not experience gastric distention, we’re still trying to understand why those few do. Perhaps there is special anatomy that causes this to occur in this group of patients.”