Milrinone, not epinephrine, improves left ventricular compliance after cardiopulmonary bypass.
OBJECTIVE
To compare the effects of milrinone versus epinephrine administered after cardiopulmonary bypass (CPB) on left ventricular compliance.


METHODS
Prospective and randomized.


METHODS
University-affiliated hospital.


METHODS
Twenty consenting adult patients.


METHODS
Patients undergoing aortocoronary bypass surgery were randomized to receive 50 microg/kg of milrinone (group M; n = 10) or 0.03 microg/kg/min of epinephrine (group E; n = 10) shortly after separation from CPB. Left ventricular compliance was assessed by observing changes in left ventricular end-diastolic area (LVEDA) in the short-axis view with transesophageal echocardiography, while maintaining a constant left atrial pressure. Measurements were performed (1) before CPB, (2) after separation from CPB, and (3) after either milrinone or epinephrine.


RESULTS
Baseline LVEDA decreased by 20% after CPB in the milrinone group (from 16.6 +/- 3.1 cm2 to 14.3 +/- 2.4 cm2; p < 0.05) and by 22% in the epinephrine group (from 19.4 +/- 4.1 cm2 to 17.2 +/- 3.8 cm2; p < 0.05). LVEDA increased by 15% after milrinone (from 14.3 +/- 2.4 cm2 to 15.6 +/- 2.8 cm2; p < 0.05) but remained unchanged after epinephrine (from 17.2 +/- 3.8 cm2 to 17.1 +/- 4.2 cm2; p = ns).


CONCLUSIONS
Left ventricular compliance was decreased after CPB. The administration of milrinone, but not epinephrine, was associated with a partial return to prebypass values. The exact mechanism of action remains to be determined.
Lobato
E B
EB
Department of Anesthesiology, University of Florida College of Medicine, Gainesville 32610-0254, USA.
Gravenstein
N
N
Martin
T D
TD
D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000368:Aged; D002315:Cardiopulmonary Bypass; D002316:Cardiotonic Agents / Q000627:therapeutic use*; D003187:Compliance; D001026:Coronary Artery Bypass; D017548:Echocardiography, Transesophageal; D004837:Epinephrine / Q000627:therapeutic use*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D020105:Milrinone / Q000627:therapeutic use*; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D016277:Ventricular Function, Left / Q000187:drug effects*
D000318:Adrenergic beta-Agonists; D002316:Cardiotonic Agents; D010726:Phosphodiesterase Inhibitors; D020105:Milrinone; D004837:Epinephrine