Comparison of a single intravenous dose of magnesium sulphate or dexmedetomidine for attenuation of pressor response during selective neck dissection in head and neck malignancy:A double-blinded randomized interventional clinical trial

Primary tumour excision and selective neck dissection is the mainstay of treatment of oral cancers. The head and neck region is highly innervated and vascular and surgical stimulus causes an acceleration of the heart rate and blood pressure, resulting in increased bleeding and decreased visibility of the surgical field. 

Controlled hypotensive anaesthesia is an accepted method of providing a drier operative field, better visualization, more accurate dissection and reduced blood loss. Management of the intraoperative pressor response during surgical stimulus in head and neck surgeries continues to be a challenge. Inhalational anaesthetics combined with various intravenous agents are used to provide controlled hypotension during surgery.

Various drugs have been used to reduce the pressor responses to noxious stimuli. Among these, the efficacy of dexmedetomidine, an α 2-adrenoreceptor agonist that reduces the heart rate and cardiac output, hence the blood pressure has been established. Magnesium Sulphate too reduces the blood pressure by inhibiting catecholamine release and arteriolar vasodilation. Studies comparing magnesium sulphate with dexmedetomidine shows conflicting conclusions of the advantage of one over the other. There are not many studies comparing the effect of these two drugs during selective neck dissection dissections. We would like to compare magnesium sulfate as a safe, effective and less expensive alternative to dexmedetomidine in our patient population undergoing head and neck surgery. Hence the need for this study.