The Effect of Ischemia and Isoproterenol on the Pulmonary Circulation in Dogscolon; Analysis by Digital Intravenous Angiography

摘要

Slutsky RA, Gerber KH, Higgins CB. The effect of ischemia and isoproterenol on the pulmonary circulation in dogscolon; analysis by digital intravenous angiography.To assess the effects of ischemia and isoproterenol on the pulmonary circulation, eight open-chest dogs were studied by digital intravenous angiography. Dogs were instrumented with a left circumflex (LCX) coronary flow probe and occluder, left atrial catheter (three dogs), aortic catheter for pressure recordings, and electrocardiogram (ECG) leads to provide a gating signal. Both indicator dilution techniques and standard area-length measures of the central circulation were employed for determination of cardiac output, pulmonary blood volume (PBV), and pulmonary transit time (PTT). PTT lengthened after subtotal (2.7 plusmn; 1.6 to 3.2 plusmn; 1.2 seconds, P .05) and total LCX occlusion (4.0 plusmn; 1.0 seconds, P .01 vs. control) and declined during isoproterenol administration (1.9 plusmn; 0.7, P .05 vs. control). PBV increased gradually with ischemia (from control value of 177 plusmn; 75 ml to 179 plusmn; 57 ml at subtotal occlusion to 241 plusmn; 59 at total occlusion) but was significantly greater only with total occlusion (P .01). Isoproterenol produced increases in PBV (197 plusmn; 46 ml, P .05 vs. control) due to increases in cardiac output (PTT shortened). In general, prolongations of PTT and increases in PBV were associated with gradual increases in LA pressure. The authors conclude that intravenous digital angiography may be used to assess hemodynamic changes in the pulmonary circulation. Acute ischemic heart failure is associated with increases in PBV (mean increase of 36percnt;) and prolongation in PTT (mean increase of 48percnt;).