Efficiency Studies On Using STOP Questionnaire To Screen The Occurrence Risk Of Hypoxemia In Outpatients Under Colonoscopy

Objective:To access the STOP Questionnaire in screening for hypoxemia in deep sedation for colonoscopy in outpatients.Methods:A single screening test was designed. Consecutive 210 outpatients aged 18-65 years old with ASA class I and II who were to undergo elective colonoscopy with deep sedation were offered participation in December 2009. Before sedation, patients were administered the STOP Questionnaire, a brief survey that stratifies patients into high or low risk of hypoxemia. Deep sedation was induced with propofol by target controlled infusion. Supplemental oxygen (8L/min) was administered by oxygen mask to all patients, who were monitored with continuous pulse oximetry for pulse oxygen saturation (SpO2) and heart rate during the sedation. Hypoxemia was defined as SpO2≤94% anytime during the procedure, regardless of episode duration. We estimated the score of the STOP Questionnaire and the incidence of hypoxemia. SPSS version 15.0 software was used to perform all analyses.Results:A total of 210 consecutive outpatients were offered enrollment. Of these patients, 87 (41.4%) were men and 123 (58.6%) were women.13 patients had hypoxemia (SpO2≤94%). Based on responses to the STOP Questionnaire,32 (15.2%) patients were considered to be at high risk of hypoxemia (score≥2), of whom 10 had hypoxemia (SpO2≤94%). The results of analysis STOP Questionnaire for the incidence of hypoxemia were:sensitivity 76.9%, specificity 88.8%, Youden's index 0. 658, consistency rate 88%, Kappa Value 0.39, positive predictive value 31.3%, negative predictive value 98.3%, area under ROC Curve 0.935.Conclusions:The STOP Questionnaire is a validated and easy-to-use screening tool for hypoxemia in deep sedation for colonoscopy in outpatients. It has high sensitivity and specificity for these patients.