Right ventricular response to high-dose almitrine infusion in patients with severe hypoxemia related to acute respiratory distress syndrome

Objective: To evaluate the effects of high-dose almitrine infusion on gas e xchange and right ventricular function in patients with severe hypoxemia re lated to acute respiratory distress syndrome (ARDS). Design: Prospective study. Setting: Medicosurgical intensive care department (ten beds). Patients: Nine patients with ARDS and severe hypoxemia (PaO2/FIO2 ratio, <1 50 torr [20 kPa]). Intervention: High-dose almitrine infusion (16 <mu>g/kg/min for 30 mins). Measurements and Main Results: Gas exchange and hemodynamic parameters were recorded before and after almitrine infusion. Right ventricular function w as evaluated by using a fast response thermistor pulmonary artery catheter that allowed measurement of right ventricular ejection fraction and calcula tion of right ventricular end-diastolic and end-systolic volumes. Almitrine did not significantly alter arterial oxygenation and intrapulmonary shunt. Almitrine increased mean pulmonary arterial pressure (MPAP) from 31 +/- 4 to 33 +/- 4 mm Hg (p < .05), pulmonary vascular resistance index from 353 /- 63 to 397 +/- 100 dyne.sec/cm(5).m(2) (p < .05), and right ventricular e nd-systolic volume index from 71 +/- 22 to 77 +/- 21 mL/m(2) (p < .05); alm itrine decreased right ventricular ejection fraction from 36% +/- 7% to 34% +/- 8% (p < .05). Stroke volume index and cardiac index did not change. Th e almitrine-induced changes in right ventricular ejection fraction were clo sely correlated with the baseline MPAP (r(2) = .71, p < .01). Conclusion: In patients with severe hypoxemia related to ARDS, high-dose al mitrine infusion did not improve arterial oxygenation and impaired the load ing conditions of the right ventricle. The decrease in right ventricular ej ection fraction induced by almitrine was correlated with the baseline MPAP. Thus, high-dose almitrine infusion may be harmful in ARDS patients with se vere hypoxemia and pulmonary hypertension.