ايجاد هيپوتانسيون حين بيهوشي با استفاده از دوزهاي مختلف كلونيدين خوراكي

INDUCTION OF DELIBERATE HYPOTENSION DURING ANAESTHESIA BY USING VARIOUS DOSES OF ORAL CLONIDINE

The main purpose of deliberate hypotension is to decrease the need for blood transfusion in major surgical procedures or to improve the operating condition and field in microscopic surgeries . Mean arterial pressure of 50 - 55 mm.Hg is considered a safe range for deliberate hypotension . Different techniques and drugs are used for inducing hypotension. For this purpose in halational anesthetics, vasodilators, t; - blockers and many other drugs are used. Clonidine is a selective Alfa 2 - adrenoreceptor agonist that not only decreases sympathetic function centrally , but also lowers norepinephrine release peripherally in presynaptic Alfa 2 - receptors. We used clonidine to decrease the blood pressure in ENT surgical patients . The principal goal of this study was to determine the appropriate dose of oral clonidine as a premedication for intraoperative induced hypotension . This clinical trial study was a prospective one and a total of 106 healthy patients (15 - 50 years old ) were studied . They received clonidine in three different doses and were compared with a control group (no hypotensive drug preoperatively ) . Blood pressure was maintained in the minimal range ( MAP - 55 mm.Hg ) intraoperatively in all groups by increasing halothane , opiod doses and finally using TNG infusion , if necessary . The results showed that 4 - 5 mcg/kg clonidine can decrease blood pressure significantly without any important side effects .