Changes in pulse oximetry levels and factors affecting oxygen saturation during routine upper gastrointestinal endoscopy with or without sedation.

BACKGROUND/AIMS We aimed to investigate whether endoscopy or midazolam as premedication causes oxygen desaturation and to determine factors which may affect the occurrence of oxygen desaturation. METHODS Totally 200 patients with various indications (103 men and 97 women), who presented to the Endoscopy Unit of Dicle University Hospital for upper gastrointestinal endoscopy examination, were included in the study. Anamnesis and anthropometric values of the patients were taken. Preoperative oxygen saturation, hemoglobin levels and heart rate per minute were recorded. Patients with initial oxygen saturation levels <90% were excluded. Patients were divided into two groups. The first group included 100 patients who underwent endoscopic examination without sedation and the second group included 100 patients who underwent endoscopic examination with sedation [midazolam (2-5 mg)]. At the end of endoscopy, intravenous flumazenil (0.2 mg) was administered to the premedication patients. Patients were monitored for oxygen saturation and heart rate starting before the sedation and oropharynx anesthesia and lasting until 1 min after the end of the procedure. During the endoscopic examination, minimum oxygen saturation and maximum heart rate values were recorded. The duration of the oxygen saturation <90% was recorded throughout the procedure and the relation of this time with the total time of the endoscopic examination was evaluated. RESULTS The mean age of the 200 patients included in the study was 45 and 44 years for Group 1 and Group 2, respectively. No differences were found between the two groups in terms of body mass index, smoking, hemoglobin and basal maximum pulse rate, duration of endoscopy, minimum basal oxygen saturation, duration of hypoxia and time to hypoxia. No relation was determined between oxygen desaturation and gender, duration of the endoscopy, basal pulse rate or hemoglobin level. It was found that smoking made significant contributions to the oxygen desaturation. CONCLUSION Midazolam premedication for upper gastrointestinal system endoscopy is a reliable procedure and does not contribute an additional risk in individuals without serious comorbidities. Smoking habits should be taken into account in endoscopy patients.