Prospective, randomized trial of the effect of supranormal oxygen delivery on morbidity and mortality in high risk surgical patients

Introduction

This prospective, controlled study was undertaken to evaluate the response to therapy aimed at achieving supranormal cardiac and oxygen transport values (cardiac index >4.5 l/min/m², oxygen delivery >600 l/min/m², and oxygen consumption >170 l/min/m²) in patients older than (60 or with previous severe cardiorespiratory illnesses, who have undergone elective extensive ablative surgery planned for carcinoma or abdominal aortic aneurism.

Method

Thirty-seven consecutive high risk patients who underwent major surgery were randomized. The postoperative hemodynamic and oxygen transport variables and outcomes in 18 patients (control group) treated to maintain normal hemodynamic values were compared with 19 patients (protocol group) treated to maintain supranormal values. Therapy in both groups consisted of volume expansion, vasopressors, and when necessary, dobutamine (3–30 μg/kg/min), to reach their target values, during the surgery and 24-h postoperative period.

Results

We interrupted the study as a significative difference in mortality rate was seen. The mortality rate in control group (50%) was significantly higher (P < 0.05) when compared with protocol group (1.5.7%). The incidence of clinical and infectious complications was higher in control group (P < 0.05) and organ dysfunction evaluated by SOFA score occurred more frequently in non-achievers.

Conclusions

Patients with a previous cardiorespiratory illness or older patients submitted to extensive surgery had a reduction in morbidity and mortality with the use of supranormal values as therapeutic goals during and after the surgical trauma.