Oxygen delivery is an important predictor of outcome in patients with ruptured abdominal aortic aneurysms

Abstract

Objective: The purpose of this study was to evaluate the relation of oxygen delivery (DO2) to the occurrence of multiple organ dysfunction (MOD) in patients with ruptured abdominal aortic aneurysms (AAA).

Summary background data: Patients with ruptured AAA are at high risk for the development of MOD and death. Previous reports of high-risk general surgical patients have shown improved survival when higher levels of DO2 are achieved.

Methods: Hemodynamic data were collected at 4-hour intervals on 57 consecutive patients (mean age, 70.5 years) who survived 24 hours after repair of infrarenal ruptured AAA. Patients were resuscitated to standard parameters of perfusion (pulse, blood pressure, urine output, normal base deficit). MOD was determined based on six organ systems. Standard parametric (analysis of variance, t tests) and nonparametric (chi square, Wilcoxon) tests were used to compare hemodynamic data, red blood cell requirements, colon ischemia, and organ failure for patients with and without MOD.

Results: Patients who developed MOD had a significantly lower cardiac index and DO2 for the first 12 hours; the difference was most significant at 8 hours. Logistic regression analysis demonstrated that the strongest predictors of MOD were DO2, early onset of renal failure, and total number of red blood cells transfused.

Conclusions: DO2 is an earlier and better predictor of MOD after ruptured AAA than previously identified risk factors. Failure to achieve a normal DO2 in the first 8 hours after repair is strongly associated with the development of MOD and a high mortality. Strategies to restore normal DO2 may be useful to improve outcome in these high-risk patients.