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Volume 3 No. 4, October 2008 |
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Acute Normovolemic Hemodilution versus Controlled Hypotensive Anesthesia in Major Orthopedic Surgery Sabry M Amin, Sameh M Fathy, Attia. G. Ibrahim& Yasser Mohamed Amr
Department of Anesthesiology, Faculty of Medicine, Tanta University,
Egypt
Aim: The purpose of this study was to investigate the efficacy and
safety of controlled hypotension versus ANH as blood conservation
methods during major orthopedic surgery. Patients & Methods: Forty
patients, assigned to receive either ANH (HT= 30%) or controlled
hypotension. General anesthesia was induced by fentanyl 2µgm/kg
intravenously, thiopental Na 5mg/kg intravenously and atracurim
0.5mg/kg. After induction of anesthesia but before surgery, the
patients were classified into two groups according to the technique
of blood conservation used: Group I (20 patients) acute normovolemic
hemodilution. The volume of blood withdrawn has been replaced
simultaneously by infusion of identical volume of hydroxyethyl
starch 6% in order to maintain normovolemia. Group II (20patients):
controlled hypotensive anesthesia. Results: A mean of 1000 ml blood
was predonated (20 % of the total blood volume) in hemodilution
group. Blood loss was, significantly higher in ANH group. The total
loss was 1500mL (ANH) vs. 1200 mL (in hypotensive group), (p <
0.05). The average amount of blood transfusion was 262.5 ml (ANH
group) vs. 187.5 ml (hypotensive group). 50 % went through surgery
without receiving blood (ANH) vs. 60% (hypotensive group). No renal,
neurological or cardiopulmonary complications were registered. Also
there was slight but significant metabolic acidosis. The acidosis
was metabolic in origin because PaCO2 was kept constant and (Bic)
and (BE) decreased significantly and it was not lactic acidosis as
serum lactate remains within normal limit. It is considered as
hyperchloermic metabolic acidosis as serum chloride significantly
increased. Conclusions: Both ANH and hypotensive anesthesia can be
used safely in patients undergo major orthopedic surgery however,
Deliberate hypotension was the most effective means of reducing
intraoperative bleeding and the time for this procedure was shorter
than for normovolaemic haemodilution combined with autotransfusion.
Also there was slight but significant metabolic acidosis.  |
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