TY - JOUR
T1 - Effects of systolic and diastolic positive pleural pressure pulses with altered cardiac contractility
AU - Fessler, H. E.
AU - Brower, R. G.
AU - Wise, R. A.
AU - Permutt, S.
PY - 1992
Y1 - 1992
N2 - Positive pleural pressure (Ppl) decreases left ventricular afterload and preload. The resulting change in cardiac output (CO) in response to these altered loading conditions varies with the baseline level of cardiac contractility. In an isolated canine heart-lung preparation, we studied the effects of positive Ppl applied phasically during systole or diastole on CO and on the cardiac function curve (the relationship between CO and left atrial transmural pressure). When baseline cardiac contractility was enhanced by epinephrine infusion, systolic and diastolic positive Ppl decreased CO equally (1,931 ± 131 to 1,419 ± 124 and 1,970 ± 139 to 1,468 ± 139 ml/min, P < 0.01) and decreased the pressure gradient driving venous return. However, neither shifted the position of the cardiac function curve, suggesting that the predominant effect of positive Ppl was decreased preload. When baseline cardiac contractility was depressed by severe respiratory acidosis, diastolic positive Ppl pulses caused no significant change in CO (418 ± 66 to 386 ± 52 ml/min), the cardiac function curve, or the pressure gradient for venous return. However, systolic positive Ppl pulses increased CO from 415 ± 70 to 483 ± 65 ml/min (P < 0.01) and significantly shifted the cardiac function curve to the left. Thus the effect of Ppl pulsations on CO works through different mechanisms, depending on the state of cardiac contractility.
AB - Positive pleural pressure (Ppl) decreases left ventricular afterload and preload. The resulting change in cardiac output (CO) in response to these altered loading conditions varies with the baseline level of cardiac contractility. In an isolated canine heart-lung preparation, we studied the effects of positive Ppl applied phasically during systole or diastole on CO and on the cardiac function curve (the relationship between CO and left atrial transmural pressure). When baseline cardiac contractility was enhanced by epinephrine infusion, systolic and diastolic positive Ppl decreased CO equally (1,931 ± 131 to 1,419 ± 124 and 1,970 ± 139 to 1,468 ± 139 ml/min, P < 0.01) and decreased the pressure gradient driving venous return. However, neither shifted the position of the cardiac function curve, suggesting that the predominant effect of positive Ppl was decreased preload. When baseline cardiac contractility was depressed by severe respiratory acidosis, diastolic positive Ppl pulses caused no significant change in CO (418 ± 66 to 386 ± 52 ml/min), the cardiac function curve, or the pressure gradient for venous return. However, systolic positive Ppl pulses increased CO from 415 ± 70 to 483 ± 65 ml/min (P < 0.01) and significantly shifted the cardiac function curve to the left. Thus the effect of Ppl pulsations on CO works through different mechanisms, depending on the state of cardiac contractility.
KW - cardiac assist
KW - cardiac output
KW - cardiopulmonary interactions
KW - heart failure
KW - venous return
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U2 - 10.1152/jappl.1992.73.2.498
DO - 10.1152/jappl.1992.73.2.498
M3 - Article
C2 - 1399972
AN - SCOPUS:0026702301
SN - 0161-7567
VL - 73
SP - 498
EP - 505
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 2
ER -