Upper gastrointestinal endoscopy: a prospective randomized study comparing continuous supplemental oxygen via the...

We have examined the efficacy of supplemental oxygen in preventing episodes of significant arterial desaturation (SpO2 less than 90%) during upper gastrointestinal endoscopy. We have compared the effects of 2 liters.min-1 of oxygen given orally via the bite-guard with the same flow rate via nasal cannulas and have also examined the effects of pre-oxygenation. Results of this study at a flow rate of 2 liters.min-1 have been compared with previously published results at a flow rate of 3 liters.min-1. Although in this study fewer episodes of desaturation were seen in the orally supplemented group compared with the nasal group, the difference observed was not statistically significant. Pre-oxygenation significantly reduced episodes of desaturation (SpO2 less than 90%, p less than 0.01) and prevented SpO2 falls below 85% in all patients studied. Supplemental oxygen given at a rate of 2 liters.min-1 was as effective as that given at a rate of 3 liters.min-1 in preventing significant desaturation, as previously defined, during the procedure. We therefore recommend the use of supplemental oxygen at a flow rate of 2 liters.min-1 in all high risk patients and conclude that the oral route has practical advantages and is at least as effective as nasal cannulas.