Comparison of phenoxybenzamine to sodium nitroprusside in infants undergoing surgery.
OBJECTIVE
The purpose of this study was to compare the effects of a direct-acting arterial dilator, sodium nitroprusside, to an alpha-adrenergic receptor blocker, phenoxybenzamine, in infants with congenital heart defects undergoing cardiac repairs on cardiopulmonary bypass.


METHODS
A prospective, multicenter, observational study.


METHODS
Tertiary care center.


METHODS
Sixty infants scheduled for elective congenital cardiac surgery repair requiring cardiopulmonary bypass.


METHODS
Patients received either sodium nitroprusside 2 to 5 microg/kg/min infusion intraoperatively and in the intensive care unit (n=30 patients) or received phenoxybenzamine 1 mg/kg slowly intravenously at the onset of cardiopulmonary bypass (n=30 patients).


RESULTS
Despite similar mean arterial pressures during cardiopulmonary bypass in both groups, infants who received phenoxybenzamine had a significantly higher flow compared with those who received sodium nitroprusside (180+/-4.8 v 73+/-5.12 mL/kg/min, p<0.0001). Base deficit was significantly larger in the sodium nitroprusside group compared with the phenoxybenzamine group intraoperatively and postoperatively (3.4+/-0.5 v 1.3+/-0.5 mEq/L, p<0.05). The core-to-peripheral temperature gradient was significantly larger in the sodium nitroprusside group compared with the phenoxybenzamine group intra- and postoperatively at all points studied. In the intensive care unit, the left atrial pressure was significantly higher in the sodium nitroprusside group compared with the phenoxybenzamine group (9+/-0.4 v 7+/-0.4 mmHg, p<or=0.0005).


CONCLUSIONS
The use of phenoxybenzamine can maintain organ perfusion on cardiopulmonary bypass and improve peripheral circulation as shown by less base deficit and smaller temperature gradients intraoperatively and in the intensive care unit better than nitroprusside.
Motta
Pablo
P
Department of Cardiothoracic Anesthesia, The Cleveland Clinic Foundation, Cleveland, OH 44145, USA. mottap@ccf.org
Mossad
Emad
E
Toscana
Diego
D
Zestos
Maria
M
Mee
Roger
R
D002315:Cardiopulmonary Bypass / Q000379:methods*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015999:Multivariate Analysis; D009599:Nitroprusside / Q000008:administration & dosage*; D010643:Phenoxybenzamine / Q000008:administration & dosage*; D011446:Prospective Studies; D012867:Skin / Q000098:blood supply / Q000187:drug effects; D012881:Skin Temperature / Q000187:drug effects / Q000502:physiology
D010643:Phenoxybenzamine; D009599:Nitroprusside