Effects of norepinephrine and dobutamine on pressure load-induced right ventricular failure.
OBJECTIVE
A transient increase in pulmonary arterial (PA) pressure can persistently depress right ventricular (RV) contractility. We investigated the effects norepinephrine and dobutamine on RV-PA coupling in this model of RV failure.


METHODS
Prospective, controlled, randomized animal study.


METHODS
University research laboratory.


METHODS
Twenty-two anesthetized dogs.


METHODS
Animals underwent transient (90-min) PA constriction to induce persistent RV failure. They were randomly assigned to control, norepinephrine, or dobutamine group. Norepinephrine was administered at 0.1 and 0.5 microg x kg x min or dobutamine at 5 and 10 microg x kg x min.


RESULTS
We measured PA distal resistance and proximal elastance by pressure-flow relationships and vascular impedance. We also measured RV contractility by the end-systolic pressure-volume relationship (Ees), PA effective elastance by the end-diastolic to end-systolic relationship (Ea), and RV-PA coupling efficiency by the Ees/Ea ratio. The transient PA constriction persistently increased PA resistance and elastance, increased Ea from 0.8+/-0.1 to 2.7+/-0.3 mmHg/mL, decreased Ees from 1.1+/-0.1 to 0.5+/-0.1 mm Hg/mL, and decreased Ees/Ea from 1.2+/-0.1 to 0.2+/-0.1. Norepinephrine restored arterial pressure, increased RV contractility, and increased but did not normalize RV-PA coupling and cardiac output. Dobutamine restored arterial pressure, markedly increased RV contractility, and normalized RV-PA coupling and cardiac output. Compared with norepinephrine, dobutamine decreased PA resistance and elastance and increased RV contractility and RV-PA coupling.


CONCLUSIONS
A transient increase in PA pressure persistently worsens PA hemodynamics, RV contractility, RV-PA coupling, and cardiac output. Dobutamine restores RV-PA coupling and cardiac output better than norepinephrine because of its more pronounced inotropic effect.
Kerbaul
François
F
Laboratory of Physiology, Free University of Brussels, Belgium.
Rondelet
Benoît
B
Motte
Sophie
S
Fesler
Pierre
P
Hubloue
Ives
I
Ewalenko
Patricia
P
Naeije
Robert
R
Brimioulle
Serge
S
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D002316:Cardiotonic Agents / Q000494:pharmacology*; D004280:Dobutamine / Q000494:pharmacology*; D004285:Dogs; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D009200:Myocardial Contraction / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology*; D011669:Pulmonary Wedge Pressure / Q000187:drug effects / Q000502:physiology; D013318:Stroke Volume / Q000187:drug effects* / Q000502:physiology; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology; D018497:Ventricular Dysfunction, Right / Q000503:physiopathology*
D002316:Cardiotonic Agents; D004280:Dobutamine; D009638:Norepinephrine