An evaluation of multiple clinical variables for hypoxia during colonoscopy

One hundred consecutive patients undergoing routine colonoscopy were evaluated for changes in arterial oxygen saturation levels. All of the patients were monitored with the Nellcor N-200 pulse oximeter (Nellcor Incorporated) by finger probe and received supplemental oxygen when SaO2 levels decreased below 90 per cent. Forty patients demonstrated a decrease in SaO2 to less than 90 per cent after intravenous sedation but prior to colonoscopy, 14 patients demonstrated a decrease in SaO2 to less than 90 per cent during colonoscopy, and 46 patients maintained SaO2 levels greater than 90 per cent at all times. No statistical differences were found when these three groups were compared for age, body surface area, drug dosage, smoking history and a history of pre-existing hypertension, diabetes, arrhythmias, angina or myocardial infarction and pulmonary disease. These data indicate that all patients undergoing colonoscopy should be placed on supplemental oxygen. We further recommend continuous cardiac and pulse oximetry monitoring when available.