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Volume 3 No. 4, October 2008 |
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Preoperative Beta Blocker Induced Controlled Hypotension for Nasal
Surgery
Department of Anesthesiology, Faculty of Medicine, Tanta University,
Egypt
Aim: The purpose of this study was to compare surgical conditions
for nasal surgery under general anesthesia during controlled
hypotension, using either preoperative oral beta blocker atenolol(
50mg twice before surgery) or intraoperative infusion of sodium
nitroprusside (SNP) or esmolol. Patients & Methods: Thirty patients,
assigned to receive either of the drugs as the primary hypotensive
agent, were studied. The same surgeon, blinded to the hypotensive
agents used and the haemodynamic variables, performed all the
operations. The surgeon used a category scale (0-5) to assess
surgical conditions - a value of 2-3 being ideal. Patients were
positioned in 15° reverse Trendelenburg position and the mean
arterial blood pressure (MABP) was reduced in steps of 5 mmHg. The
anesthetist prompted category scale estimations by the surgeon
following a change in any of the haemodynamic variables. Average
category scale (ACS) values were compared between the three groups.
Results: At mild sodium nitroprusside (SNP) induced hypotensive
anesthesia surgical conditions were poor (ACS 3.8 ± 0.53 mean ± SEM),
while in the atenolol and esmolol groups, ideal surgical conditions
(ACS 2.7 ± 0.74 and 2.8±0.63) were recorded at MABP > 60 mmHg. The
combined effects of increased venous drainage due to the reverse
Trendelenburg position, hypotension as well as capillary
vasoconstriction due to unopposed alpha-adrenergic effect on the
mucous membrane vasculature in the atenolol and esmolol groups (as
opposed to vasodilatation in the SNP group) probably caused the
superior surgical conditions. Conclusions: Preoperative oral Beta
blocker was effective in reducing surgical bleeding during nasal
surgery, provide good quality of surgical field, reduce operative
time, simple in use, not need complex technique for infusion, more
convenient for patients and save method for induce mild hypotensive
anesthesia during nasal surgery. 
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