Pulse oximetry during gastrointestinal endoscopic procedures

To determine the changes in oxygen saturation, blood pressure and pulse rate during various endoscopic procedures and to find out the risk factors for these changes.Observational study.Department of Gastroenterology, Shaikh Zayed Postgraduate Medical Institute, Lahore, Pakistan from June 2001 to December 2001 were included in the study.Oxygen saturation, blood pressure and pulse were monitored during various endoscopic procedures using pulse oximeter. These changes were recorded from the start until 5 minutes after the procedure. The important variables which were evaluated in relation to these changes included age, gender, history of smoking, associated chronic obstructive airway disease (COAD), coronary artery disease (CAD), duration of procedure, elective versus emergency and diagnostic versus therapeutic procedures.Base line mean oxygen saturation was 98.1+/-0.98 %. The saturation decreased to 93.5+/-4.8 % (p=0.002) during the procedures and returned to base line after the procedures. Mild to moderate hypoxia was found in 59 (20.2%) patients. Severe hypoxia was found in 32 (11.5%) patients. Of these 21(65.6%) patients were having history of COAD. No patient developed serious complications. The changes in blood pressure and pulse were not significant. The variables which reached statistical significance for desaturation were age50 years, history of smoking, emergency procedures, therapeutic procedures and associated COAD. Diabetes mellitus (DM) and hypertension (HTN) alone, CAD and duration of procedures did not affect oxygen saturation.Mild to moderate hypoxia is common during endoscopic procedures and of no serious consequence. Severe hypoxia is less common and is associated with underlying risk factors. Continuous monitoring is required in patients with age50 years, history of smoking, emergency procedures, therapeutic procedures and history of COAD. Routine monitoring with pulse oximetry may not be required in patients with no risk factors.