Oxygen saturation monitoring during endoscopy.

The role of monitoring during endoscopy is not clearly defined. We have prospectively investigated continuous arterial oxygen saturation (SaO2) monitoring in 326 patients undergoing upper endoscopy (EGD) and 90 undergoing colonoscopy. Automated blood pressure recording was evaluated in 278 of these patients. SaO2 desaturation (less than 90%) occurred in 17.8% of patients undergoing EGD and 12.9% undergoing colonoscopy. Systolic blood pressure abnormalities (greater than 200 or less than 90 mmHg) occurred in 19.8% of EGD patients and 19.6% of colonoscopy patients. Treatment based on these abnormalities was required in 4.3% of patients during EGD and 8.8% during colonoscopy. A history of pulmonary or cardiac disease predicted increased risk during colonoscopy, while cardiac disease and age 60 years or above predicted desaturation during EGD. Pulse oximetry and automated blood pressure monitoring was especially valuable during endoscopy in the elderly and patients with cardiac or pulmonary disease. It may be used as a guide to therapeutic intervention and to avert major cardiopulmonary complications.