Role of Low Dose Preoperative Dexmedetomidine in Preventing Tourniquet Induced Hypertension in Paediatric Orthopaedic upper Limb Surgeries during General Anaesthesia.

ABSTRACT

Background: Pneumatic Tourniquets are commonly used in orthopaedic surgery of the extremities to reduce bleeding and to provide a clear field to the surgeon, but severe pain often complicates the tourniquet inflation. Although the mechanism of tourniquet induced hypertension (TIH)is not well understood, the autonomic nervous system plays an important role. Hence, Dexmedetomidine, a potent a2-adrenoceptor agonist may prevent hyper adrenergic responses and can be of prophylactic value for tourniquet induced hypertension. Methods: Forty American Society of Anesthesiologists (ASA) physical status class I and II children, aged 5-12 years, posted for Orthopaedic surgery of upper limbs under general anaesthesia with tourniquet application were included in the study. They were randomly assigned to receive intravenous Dexmedetomidine (Group D; n=20) or normal saline (Group C; n=20) before tourniquet inflation. Incidence of TIH, Mean Arterial blood pressure and heart rate were recorded. Results: There were no significant differences between the baseline characteristics. The incidence of TIH in group D was significantly less than the group C (20%) as compared to group D (70%).There was significant increase in the heart rate of placebo group after 30 minutes of tourniquet inflation while there was minimal variability of heart rate in the group D. In the group D, arterial pressure was not significantly changed, but in the group C, the arterial pressure was significantly increased after 20 minutes of tourniquet inflation. No significant adverse effects were noted in any group. Conclusion: Preoperative low dose intravenous Dexmedetomidine prevents tourniquetinduced hypertension in paediatric patients undergoing general anaesthesia for upper limb surgeries.