Changes in oxygenation and pulse rate during endoscopy

Continuous monitoring of arterial oxygen saturation and heart rate with a pulse oximeter was performed in 100 consecutive patients undergoing esophagogastroduodenoscopy (78) or colonoscopy (22). Twenty-four patients had decreases in their estimated arterial PO2 level to less than 60 mm Hg during or just after the procedure. In 15 patients the hypoxemia was transient, but in nine others, treatment was required. Twenty patients also developed a tachycardia greater than 120 beats/minute.