Determine the effect of Dexmedetomidine in Attenuating Arterial Pressure increase during Laparoscopic Cholecystectomy

AIM OF THE STUDY: To study the effect of dexmedetomidine in attenuating the arterial pressure increase due to pneumoperitoneum in patients posted for elective laparoscopic cholecystectomy. BACKGROUND: Dexmedetomidine is a alpha 2 adrenoreceptor agoinst being increasingly used in anaesthesia and critical care as they not only decrease the sympathetic tone and attenuate the stress responses to anesthesia and surgery, but also causes sedation and analgesia. Already Clonidine, a similar alpha 2 agonist was proved in attenuating arterial pressure increase during laproscopic surgeries. So we investigated whether IV dexmedetomidine attenuates the hemodynamic stress response to pneumoperitoneum by changing neurohormonal responses during laproscopic cholecystectomy. MATERIAL AND METHODS: After obtaining ethical committee approval from Govt Kilpauk Medical College, 40 patients with average of 18-60 years undergoing elective laproscopic cholecystectomy are to be randomized into two Groups of 20 each. Patients to be premedicated with glycopyrrolate 0.2 mg IM one hour before surgery and fentanyl 2mcg/kg IV before induction. The trachea intubated after induction of anaesthesia with propofol 1.5- 2 mg/kg and vecuronium 0.1 mg/kg. Anaesthesia maintained with 1-1.5% sevoflurane and 2:4 O2/N2O at 6lit/min. After induction study Group to receive IV dexmedetomidine 0.5 mcg/kg bolus followed by 0.5μg/kg/hr infusion and control Group to receive normal saline at same infusion rate. After completion of surgery, pneumoperitoneum deflated slowly and after the patient had adequate respiratory attempts patient reversed with glycopyrrolate and neostigmine IV. Arterial pressure and heart rate are measured before induction, pre pneumoperitoneum, at pneumoperitoneum (P0), at 5 min, 10 min, 20 min, 30 min after pneumoperitoneum and post surgery. Serum noradrenaline samples are taken pre pneumperitoneum and at 10 minute pneumoperitoneum. RESULTS: We observed, that the systolic, diastolic and mean arterial pressure increased abruptly after induction of pneumoperitoneum and this response sustained during the entire pneumoperitoneum period in the control Group (Group A). In the dexmedetomidine Group (Group B) hemodynamic responses to the induction of pneumoperitoneum were effectively blunted and the heart rate and blood pressure levels when compared to the control Group (Group A). In the control Group (Group A) the 10 minute serum noradrenaline values were significantly higher than the pre pneumoperitoneal values suggesting that all these hemodynamic changes are due to release of catecholamines. In the study Group (Group B), the noradrenaline levels taken 10 minutes after induction of pneumoperitoneum were significantly not increased when compared with the pre pneumoperitoneal values suggesting that dexmedetomidine effectively suppressed the hemodynamic responses by its central sympatholytic action. CONCLUSION: We conclude that intravenous administration of dexmedetomidine as an adjunct before induction of pneumoperitoneum in laparoscopic cholecyctectomy effectively attenuates the arterial pressure increase due to pneumoperitoneal response.