Effects of maximizing oxygen delivery on morbidity and mortality in high-risk surgical patients

Objective: To evaluate the effects of maximizing the oxygen delivery on morbidity and mortality in patients >60 yrs of age and/or with chronic diseases of vital organs who underwent major elective surgery. Design: Prospective, randomized, controlled trial, Setting: A 24-bed general intensive care unit of a teaching hospital. Patients: Thirty-seven high-risk patients who underwent major surgery. Interventions: The hemodynamic and oxygen transport variables and outcomes in 18 patients (control group) treated to maintain normal values of oxygen delivery were compared with 19 patients (protocol group) treated to maintain "supranormal" values. Therapy in both groups consisted of volume expansion and, when necessary, dobutamine to reach target values, during the surgery and 24 hrs postoperatively. Measurements and Main Results:We interrupted the study because of a significant difference in the 60-day mortality rate. The mortality rate in the control group was significantly higher when compared with the protocol group (9/18 [50%] vs. 3/19 [15.7%], p <.05), The prevalence of clinical and infectious complications was higher in the control group than in the protocol group (67% and 31% respectively; relative risk, 0.47; 95% confidence interval, 0.226-0.991; p <.05) and there was a trend toward more severe organ dysfunction in nonachievers patients (17/24 [71%] vs, 6/13 [46%], relative risk, 0.65; 95% confidence interval, 0.343-1.237; NS), Conclusion: Older patients with existing cardiorespiratory illness undergoing major surgery have a reduced morbidity and mortality when dobutamine is used to maximize oxygen transport.