Hemodynamic profile and vasoactive drugs in acute respiratory distress syndrome

Introduction

Acute respiratory distress syndrome (ARDS) is characterized by diffuse inflammatory response in the lungs with refractory hypoxemia. The maintenance of hemodynamic stability is a key point for tissue perfusion in this syndrome.

Objective

To determine the hemodynamic profile and the response to vasopressor therapy in ARDS patients, and its relationship with mortality.

Materials and methods

All patients who met American–European Consensus criteria for ARDS between January 1999 and December 2002 were included in the analysis, dividing into survivors (SV) and nonsurvivors (NSV). The following data were collected prospectively: age, Acute Physiology and Chronic Health Evaluation (APACHE) II score at admission and at diagnosis, heart rate, mean arterial pressure, central venous pressure, mean pulmonary artery pressure, pulmonary artery occlusion pressure, systemic vascular resistance index and pulmonary vascular resistance index, left and right ventricular stroke work index, cardiac index, and doses of dopamine, dobutamine and norepinephrine, between the first and seventh days. The differences between groups were analyzed with a t test and considered significant with P < 0.05.

Results

One hundred and ten patients met the ARDS criteria, of which 96 were managed with a pulmonary artery catheter and included in the analysis. In SV and NSV, the mean age was 36 ± 16 and 51 ± 19 years (P = 0.0001), and the APACHE II score at admission was 16.6 ± 6.3 and 20.1 ± 8.3 (P = 0.031) and that at ARDS diagnosis was 17.1 ± 5.5 and 22.3 ± 6.7 (P = 0.001), respectively. The hemodynamic profile and doses of the vasoactive drugs are presented in Table 1.

Table 1

Conclusions

NSV were older and sicker according to the APACHE II score than SV, and they presented significant vasopressor dependency in the first 4 days. The absence of statistical difference in hemodynamics is probably due to purposeful interventions aimed to optimize the cardiovascular status of patients based on invasive hemodynamic data, and not related to the pulmonary artery catheter's inability to change patient outcome. The need for higher doses in the vasopressor reflects a vasodilatory state that could contribute to mortality.