Pulmonary blood flow, pressure and resistance following tetraethylammonium and aminophylline

Abstract

The effects of tetraethylammonium chloride (TEAC) and aminophylline on the pulmonary vascular resistance were studied in thoracotomized dogs. Pulmonary arterial blood flow and pressure, and systemic blood pressure were measured simultaneously. Both drugs showed marked hypotensive effects on the systemic vessels. In every instance pulmonary arterial pressures and blood flows were reduced by TEAC given via the pulmonary artery and increased by aminophylline. However, the calculated pulmonary vascular resistance remained essentially unchanged in all experiments. These data challenge the concept that the pulmonary vessels respond to these drugs by active vasodilatation