predictive factors of arterial blood oxygen desaturation during upper gastrointestinal endoscopy in nonsedated patients

introduction: hypoxemia can occur during upper gastrointestinal endoscopy with or without pharmacological sedation. pulse oximetry saturation (spo2) levels were assessed in patients attending for routine unsedated diagnostic upper gastrointestinal endoscopy to identify factors associated with oxygen desaturation. methods: a total of 300 patients who underwent upper gastrointestinal endoscopy without sedation were monitored with continuous pulse oximetry. factors related to the patient, the examination, and the monitoring data that could predict severe desaturation were evaluated. results: mild desaturation (spo2 between 1-4%) was found in 143(47.7%) of the patients, while severe desaturation (spo2≥5%) and hypoxemia occurred in 65 (21.7%) of patients, 40 (61.5%) of those had previous illnesses (p<0.001). the variables found to predict severe desaturation were basal spo2 <95%, chronic obstructive pulmonary disease, anemia, age more than 60 years and coronary artery disease. conclusion: the decrease in spo2 is related to increase in age, basal sao2 < 95%, respiratory disease, coronary artery disease, and anemia, .we recommend continuous monitoring of spo2 in these high-risk patients undergoing upper gastrointestinal endoscopy.