Association of Oral Intake and Transient Mixed Venous Oxygen Desaturation in Patients Undergoing Fast-Track Postoperative Care After Open-Heart Surgery

Objective The impact of early resumption of oral intake after cardiac surgery on hemodynamics has not been characterized. The authors examined the effects of early oral intake on the oxygen supply-demand relationship in patients undergoing on-pump cardiac surgery in an early recovery after surgery program. Design Prospective data were collected in postcardiac surgical patients in a multidisciplinary intensive care unit (ICU) during an 18-month period. Setting Single institution study. Participants Forty-three patients who underwent either mitral or aortic valve repair and were successfully liberated from ventilatory support within 10 hours after surgery. Interventions Patients were either allowed to resume oral intake on the morning of the first postoperative day or not at the discretion of the surgical team after extubation. Measurements and Main Results The oxygen supply-demand relationship was assessed continuously with cardiac index and mixed venous oxygen saturation (SvO 2 ). Among the subjects, 22 patients were allowed to eat, and transient SvO 2 decrease was noted in 13 patients. All transient SvO 2 decreases occurred in the patients with early oral intake. The hemodynamic status and oxygen supply-demand relationship did not differ between the patients with and without transient SvO 2 decrease. All the subjects were discharged successfully from the ICU on the first postoperative day, and the length of hospital stay was similar irrespective of SvO 2 decrease after early oral intake. Conclusions Early oral intake shortly after extubation was associated with transient but significant SvO 2 decrease in patients who underwent fast-track recovery after open-heart surgery. Because this phenomenon did not negatively affect the postoperative outcome, early oral intake may not be harmful.