Adolescent ; Child ; Child, Preschool ; Female ; Heart Failure ; drug therapy ; Humans ; Infant ; Male ; Milrinone ; adverse effects ; pharmacology ; therapeutic use ; Phosphodiesterase Inhibitors ; therapeutic use

AIMTo study the effects of rhBNP and milrinone on the cardiac hemodynamics and renal function in anesthetized dogs.

METHODSThe actions of rhBNP given cumulatively i.v. 10, 30 and 100 ng.kg-1 for 30 min and milrinone of single dose (100 micrograms.kg-1, i.v.) on cardiac hemodynamics and renal function were studied in anesthetized open-chest dogs.

RESULTSIn anesthetized dogs (n = 7) intravenous infusion of rhBNP at 10-100 ng.kg-1, caused decreases in mean arterial pressure (MAP), left ventricular systolic pressure (LVSP), LVdp/dtmax, pulmonary arterial pressure (PAP), left ventricular end diastolic pressure (LVEDP), total peripheral resistance (TPR) and renal vascular resistance (RVR) dose-dependently, without significant changes in cardiac output (CO), LV(dp/dt)/P, renal blood flow (RBF) and heart rate (HR), increases in urinary volume and sodium excretion. In anesthetized dogs (n = 6), there were remarkable decreases in MAP, LVEDP, PAP, TPR, RBF, RVR and urinary volume following the MIL (100 micrograms.kg-1, i.v.), with significant increases of LVSP, +/- LVdp/dtmax, HR and CO, but no marked changes in urinary volume and sodium excretion.

CONCLUSIONrhBNP reduces the pre-load and after-load in the anaesthetized dogs but showed no distinct effect on the contractility of the heart. Positive inotropic and chronotropic actions have been demonstrated after intravenous injection of milrinone 100 micrograms.kg-1 in anesthetized dogs.

Anesthesia ; Animals ; Cardiotonic Agents ; pharmacology ; Dogs ; Drug Interactions ; Female ; Heart ; drug effects ; physiology ; Hemodynamics ; Kidney ; drug effects ; physiology ; Male ; Milrinone ; pharmacology ; Natriuretic Peptide, Brain ; pharmacology ; Recombinant Proteins ; pharmacology ; Sodium ; blood ; urine ; Urine

This investigation evaluated the effect of continuous milrinone infusion on right ventriclular (RV) function during off-pump coronary artery bypass graft (OPCAB) surgery in patients with reduced RV function. Fifty patients scheduled for OPCAB, with thermodilution RV ejection fraction (RVEF) <35% after anesthesia induction, were randomly allocated to either milrinone (0.5 microgram/kg/min) or control (saline) group. Hemodynamic variables and RV volumetric data measured by thermodilution method were collected as follows: after anesthesia induction (T1); 10 min after heart displacement for obtuse marginal artery anastomosis (T2); after pericardial closure (T3). Cardiac index and heart rate increased and systemic vascular resistance significantly decreased in milrinone group at T2. Initially lower RVEF of milrinone group was eventually comparable to control group after milrinone infusion. RVEF did not significantly change at T2 and T3 in both groups. RV end-diastolic volume in milrinone group consistently decreased from the baseline at T2 and T3. Continuous infusion of milrinone without a bolus demonstrated potentially beneficial effect on cardiac output and RV afterload in patients with reduced RV function during OPCAB. However, aggressive augmentation of intravascular volume seems to be necessary to maximize the effect of the milrinone in these patients.
Ventricular Function, Right/*drug effects ; Phosphodiesterase Inhibitors/*pharmacology ; Milrinone/*pharmacology ; Middle Aged ; Male ; Humans ; Heart Rate/drug effects ; Female ; Echocardiography, Transesophageal ; *Coronary Artery Bypass, Off-Pump ; Blood Pressure/drug effects ; Aged