Perfusion of the Wedged Pulmonary Artery Catheter as a Method of Assessing Pulmonary Vasomotion

The perfused wedged catheter technique was used (a) with the catheter passed in the conventional manner and (b) with the catheter introduced directly into a pulmonary artery and wedged, through a thoracotomy. An important source of artifact in the transcandiac wedged catheter is demonstrated to be cardiac effect on the catheter resistance. Using the directly wedged catheter, through the open chest, nitrogen-breathing hypoxia caused vasodilation in the wedge segment. Serotonin, epinephrine, nor-epinephnine, acetylcholine and hypercapnia caused vasoconstriction. The constrictor effect of epinephrine and nor-epinephrine was blocked or reversed by tolazoline, but not the effect of serotonin or hypercapnia. The perfused wedged catheter is a valuable tool for the experimental evaluation of pulmonary vasomotion.