Enhancement of hypoxic pulmonary vasoconstriction by low dose almitrine bismesylate in normal humans.

Abstract

The effect of almitrine bismesylate on hypoxic pulmonary vasoconstriction (HPV) remains controversial. We therefore investigated in a double-blind, placebo-controlled, randomized design the effects of low dose of almitrine bismesylate (4 micrograms/kg/min given intravenously) on blood gases, pulmonary hemodynamics, and ventilation-perfusion (VA/Q) distributions in normal subjects breathing a hypoxic mixture (FIO2, 0.125), room air (FIO2, 0.21), and oxygen (FIO2, 1.0) in a random sequence. In the placebo group (7 subjects), no change was recorded. In the almitrine group (10 subjects), arterial PO2 improved during hypoxia (from 42 +/- 2 to 47 +/- 1 mm Hg, p less than 0.05, mean +/- SEM) and normoxia (from 99 +/- 3 to 104 +/- 2, p less than 0.05). Pulmonary arterial mean pressure and pulmonary vascular resistance index increased with almitrine during hypoxia, respectively, from 20 +/- 1 to 23 +/- 1 mm Hg (p less than 0.01) and from 207 +/- 22 to 283 +/- 35 dyne.s.cm-5.m2 (p less than 0.01), and during normoxia, respectively, from 12 +/- 1 to 14 +/- 1 mm Hg (p less than 0.05) and from 90 +/- 11 to 137 +/- 13 dyne.s.cm-5.m2 (p less than 0.05). The VA/Q distribution improved during hypoxia, with a shift of the blood flow distribution to better oxygenated lung units with higher VA/Q ratios. We conclude that in normal humans low dose of almitrine improves gas exchange by an enhancement of HPV.

• Authors: C Mélot, P Dechamps, R Hallemans, P Decroly, P Mols
• Journal: The American review of respiratory disease (Am Rev Respir Dis) Vol. 139 Issue 1 Pg. 111-9 (Jan 1989) ISSN: 0003-0805 [Print] United States
• PMID: 2912330 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Piperazines
• Almitrine
• Oxygen

Topics

• Adult
• Almitrine
• Blood Pressure (drug effects)
• Double-Blind Method
• Female
• Humans
• Hypoxia (physiopathology)
• Male
• Oxygen (blood)
• Piperazines (administration & dosage, pharmacology)
• Pulmonary Circulation (drug effects)
• Random Allocation
• Vascular Resistance (drug effects)
• Vasoconstriction (drug effects)
• Ventilation-Perfusion Ratio (drug effects)