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.
Keyword :
Dexmedetomidine, General anaesthesia, Tourniquet induced hypertension.