OXYGEN SUPPLEMENTATION DURING UPPER GASTROINTESTINAL ENDOSCOPY - A COMPARISON OF 2 METHODS

The optimal method of oxygen supplementation during upper gastrointest inal endoscopy has not been clearly defined. The aim of this study was to compare oxygen supplementation via nasal prongs with that via a ca theter passed into the low oropharynx to eliminate the effect of mouth breathing. Patients were stratified according to the American Society of Anesthesiologists (ASA) classification of physical status into low er-risk (ASA 1 and 2) and higher-risk (ASA 3) groups. The lower-risk g roup received intranasal, intrapharyngeal, or no oxygen supplementatio n, and higher-risk patients received either intranasal or intrapharyng eal oxygen. Continuous arterial oxygen saturation (SpO(2)) was recorde d, using a pulse oximeter, before and during endoscopy. Critical desat urations (SpO(2) less than or equal to 90%), minimum SpO(2) during end oscopy, and maximum desaturation from the baseline oxygen on air, were evaluated. There was no significant difference in the number of patie nts desaturating, mininum SpO(2), or in the maximum desaturation from the baseline between the groups receiving intranasal or intrapharyngea l oxygen supplementation. In lower-risk patients receiving no suppleme ntary oxygen (n = 27), ten patients (37 %) desaturated, compared,vith one of 52 patients (2 %) receiving supplementary oxygen (p < 0.001). T here was also a significant difference between these groups in the min imum SpO(2) (91 % vs 97 %, p < 0.001) and the maximum desaturation fro m the baseline (- 5.2 % vs + 0.7 %, p < 0.001) during endoscopy. We co nclude that the intranasal and intrapharyngeal methods of oxygen suppl ementation are of similar efficacy, and that supplementary oxygen sign ificantly decreases the incidence of critical arterial oxygen desatura tion that occurs even in healthy patients undergoing upper gastrointes tinal endoscopy.