Dex,medetomidine for maintaining Hypotensive Anaesthesia in middle ear surgeries

Middle ear surgeries require hypotensive anaesthesia which is a technique to decrease intraoperative bleeding and improve the quality of the surgical field for better visualization. Dexmedetomidine is a new generation highly selective α-2 adrenoreceptor agonist. It decreases heart rate and arterial blood pressure by reducing norepinephrine and epinephrine plasma levels. The primary objective of our study was to evaluate the effect of loading dose on prevention of stress response during laryngoscopy followed by infusion of dexmedetomidine on haemodynamic parameters, quality of surgical field and post operative sedation. Patients received 1µg/kg body weight of Dexmedetomidine infusion intravenously over 10 min before induction, followed by 0.4 µg/kg/hour infusion during surgery in group D comparing to normal saline in group N. From study we have observed that intravenous infusion of 1µg/kg loading dose followed by continuous infusion 0.4µg/kg/min dexmedetomidine resulted in reduction in isoflurane requirement as compared to saline group. There was statistically significant reduction in pulse rate and blood pressure from base line values after loading dose infusion over 10 min. Dexmedetomidine infusion maintaince a stable haemodynamics including superior quality of surgical field throughout intraoperative period and decreases sympathetic response to intubation. Dexmedetomidine infusion resulted in some degree of sedation postoperatively but there is no statistically significant difference in sedation in comparison to saline group.