1.
Almitrine, an agonist of peripheral chemoreceptors, has been shown to be effective in lowering PaCO2 in patients with
chronic obstructive lung disease. The aim of this investigation was to evaluate the pulmonary haemodynamic response to
almitrine in clinically stable patients with
chronic airflow obstruction and chronic
hypercapnia (PaCO2 7.1 +/- 0.5 kPa, mean +/- SD). 2. Seven men, aged from 55 to 64 years, had the following values for pulmonary function (means +/- SD): FEV1.0 0.67 +/- 0.16 litre; VC 2.12 +/- 0.52 litres; FEV1.0/VC 33 +/- 8%. They had haemodynamic monitoring during 1 h of
almitrine (1 mg/kg intravenously) and
solvent (placebo) in a random fashion while receiving 28%
oxygen. Before infusion, six patients had evidence of
pulmonary hypertension and the mean pulmonary artery pressure (PAP) for all seven patients was 4.3 +/- 1.6 kPa (mean +/- SD); the pulmonary vascular resistance (PVR) was 0.61 +/- 0.22 kPa 1(-1)s (mean +/- SD). 3. There were no significant changes from baseline values during placebo. During
almitrine, however, the PAP and right ventricular
stroke work (mean +/- SD) increased significantly at 30 min (6.0 +/- 2.1 kPa, P less than 0.001, 0.38 +/- 0.12 J, P less than 0.05, respectively) with maximum increase of PVR at 45 min (1.01 +/- 0.34 kPa 1(-1)s, P less than 0.001, mean +/- SD). The lowest PaCO2 (mean +/- SD) was observed at the end of the infusion (5.7 +/- 0.5 kPa, P less than 0.001). 4. These results confirm the benefit of
almitrine in lowering PaCO2 in patients with
chronic airflow obstruction who have chronic
hypercapnia but also demonstrate significant pulmonary vasoconstriction.