Acute hemodynamic effects of inhaled nitric oxide, dobutamine and a combination of the two in patients with mild to moderate secondary pulmonary hypertension

Abstract

Introduction: The use of low-dose dobutamine to maintain hemodynamic stability in pulmonary hypertension may have a detrimental effect on gas exchange. The aim of this study was to investigate whether inhaled nitric oxide (INO), dobutamine and a combination of the two have beneficial effects in patients with end-stage airway lung disease and pulmonary hypertension.

Method: Hemodynamic evaluation was assessed 10 min after the administration of each drug and of their combination, in 28 candidates for lung transplantation.

Results: Administration of INO caused a reduction in mean pulmonary arterial pressure (MPAP), an increase in PaO2 with a significant reduction in venous admixture effect (Qs/Qt).Dobutamine administration caused an increase in cardiac index and MPAP, with a decrease in PaO2 as a result of a higher Qs/Qt. Administration of a combination of the two drugs caused an increase in the cardiac index without MPAP modification and an increase in PaO2 and Qs/Qt.

Conclusion: Dobutamine and INO have complementary effects on pulmonary circulation. Their association may be beneficial in the treatment of patients with mild to moderate pulmonary hypertension.

Figure 1

Flow-pressure diagram showing the difference of MPAP and PAOP (MPAP-PAOP) and cardiac index. The dashed lines indicate the isoresistance lines from 600 to 300 dyne/s/cm⁵. INO, inhaled nitric oxide; MPAP, mean pulmonary arterial pressure; PAOP, pulmonary artery occluded pressure.

Figure 2

Decisional algorithm according to the different values of cardic index and the different values of MPAP and PAOP (MPAP-PAOP) in cases of acute cardiac decompensation. =, low TPG; ↑, moderate TPG; ↑↑, high TPG. INO, inhaled nitric oxide; MPAP, mean pulmonary arterial pressure; PAOP, pulmonary artery occluded pressure; TPG, transpulmonary gradient.