Cardiorespiratory changes during upper gastrointestinal endoscopy

To determine the changes in oxygen saturation, blood pressure and heart rate during various endoscopic procedures and to find out the risk factors for these changes.

Forty patients without cardiorespiratory disorders were recruited. Oxygen saturation, blood pressure and pulse rate were monitored during endoscopy using pulse oximeter and automated blood pressure monitor. These were recorded from baseline until 5 minutes after the procedure. The important variables, which were evaluated in relation to these changes, included age, gender, duration of the procedure and drug/dosages.

Baseline mean oxygen saturation was 96.8 +/- 1.55%. It decreased significantly to 94.53 +/- 3.30%(p= 0.002) during insertion of probe. Mild to moderate hypoxia was found in 19 (47.5%) patients. Severe hypoxia was found in 5 (12.5%) patients. The variables that reached statistical significance for desaturation were age greater than 50 years and duration longer than 27 minutes. Changes in pulse rate were significant post-sedation, during probe insertion, during scoping, at removal of probe and immediately post-procedure (p < 0.02). The mean change in systolic blood pressure was not significant throughout the procedure when compared to baseline, however 14 (35%) patients developed transient hypertension.

Mild to moderate hypoxia is common during endoscopic procedures and of no serious consequence. However severe hypoxia is less common. We recommend a non-invasive monitoring in patients with age greater than 50 years and procedure longer than 27 minutes.