Pulmonary artery catheter monitoring during single-lung ventilation in dogs.

The effect of pulmonary artery (PA) catheter insertion on cardiac output measurements and the effect of single-lung ventilation on data derived from catheters placed in both the right and left pulmonary arteries were examined in 17 anesthetized mongrel dogs. Serial tricarboncyanine dye measurements of cardiac output were taken at baseline and after insertion of each of two PA catheters, one catheter in each lung, to detect possible changes in cardiac output due to instrumentation. In the second part of the study, single-lung ventilation was achieved through a Kottmeier double-lumen tube. Right and left paired values of thermodilution cardiac output, PA systolic pressure, and PA PO2 were compared during ventilation of both lungs, during right lung ventilation, during return to ventilation of both lungs, and during left lung ventilation. Mean dye-dilution cardiac outputs were not significantly different after one or two catheters were inserted. Paired right and left values were similar for thermodilution cardiac output, PA PO2, and pulmonary systolic pressure, regardless of ventilation conditions. Even during single-lung ventilation, data obtained from PA catheters in the ipsilateral and contralateral lung were equivalent in supine dogs.