Effect of oxygen treatment on heart rate after abdominal surgery

Background: Cardiac complications are common during the postoperative perio d and may be associated with hypoxemia and tachycardia. Preliminary studies in high-risk patients after operation have shown a possible beneficial eff ect of oxygen therapy on arterial oxygen saturation and heart rate. Methods: The authors studied the effect of oxygen therapy on arterial oxyge n saturation and heart rate in 100 consecutive unselected patients randomly and double blindly allocated to receive air or oxygen therapy between the first and fourth day after major abdominal surgery. Results: The median arterial oxygen saturation rate increased significantly from 96% to 99% (P < 0.0001) and the heart rate decreased significantly fr om 85 beats/min to 81 beats/min (P < 0.0001) during oxygen supplementation compared with air administered by a binasal catheter. The greatest decrease in heart rate occurred in patients with the lowest oxygen saturation or th e highest heart rate values before oxygen supplementation. Overall, 73% of this unselected group of patients responded with decreased heart rate durin g supplemental oxygen therapy. No significant differences in changes in hea rt rate after oxygen supplementation were found between patients with or wi thout an epidural catheter or between the postoperative day studied. Conclusion: Postoperative oxygen therapy increased arterial oxygen saturati on and decreased heart rate after uncomplicated abdominal surgery in a cons ecutive unselected group of patients who received routine postoperative car e.