To Observe the Hemodynamic Stability of Dexmedetomidine in Hypertensive Patients Undergoing Laparoscopic Cholecystectomy.

Laparoscopic surgeries form an essence of today's surgical practice because of its magnification, less cosmetic scar, less postoperative pain, and decreased hospital stay along with less morbidity and mortality.

According to the American Heart Association (AHA), approximately 86 million adults (34%) in the United States are affected by hypertension, which is defined as a systolic blood pressure (SBP) of 140 mm Hg or more or a diastolic blood pressure (DBP) of 90 mm Hg or more, taking anti-hypertensive medication of those with high blood pressure (BP), 78% were aware they were hypertensive, 68% were being treated with anti-hypertensive agents, and only 64% of treated individuals had controlled hypertension.

Anaesthetic management in these patients has become complicated due to cardiopulmonary changes occurring during creation of pneumoperitoneum with CO2 and patient position required for different laparoscopy surgeries. Effects of pneumoperitoneum for laparoscopic surgeries on heart rate and blood pressure was recognized more than 50years ago and the magnitude of the changes was observed to depend on the depth of anesthesia. The cardiovascular, neuroendocrine, and renal changes induced by the CO2 pneumoperitoneum produce a complex pathophysiological state remarkably similar to that in patients with chronic heart failure, though the initiating event is clearly very different. In normotensive subjects these hemodynamic changes are short lived5and probably of little significance. However, these haemodynamic alterations are hazardous to the patients with hypertension, myocardial insufficiency or cerebrovascular disease.

Various pharmacologic and nonpharmacological methods have been tried to limit the pressor response following the creation of pneumoperitoneum. The success rate is variable with different methods because each method has its own merits and demerits. In several clinical trials drugs like opioids, β-blockers, lidocaine, nitrate calcium channel blockers or magnesium have already been used orally or parenterally to obtund this sympathoadrenal response. Recently, there is considerable interest in the use of α2-adrenergic agonists to provide hemodynamic stability during pneumoperitoneum.

Dexmedetomidine famous for its awake sedation is eight times more selective than clonidine for the α2-adrenergic receptors. The ratio of α2:α1 activity of dexmedetomidine is 1620:1. It activates pro-survival kinases and attenuates ischemia and hypoxic injury, including cardio protection. Concurrent infusion during surgery reduces anesthetic consumption by 20-50% , and produces a decrease in heart rate and blood pressure that may be advantageous for hypertensives. Hypertension associated to pneumoperitoneum in normotensive patients has been controlled with the loading dose of dexmedetomidine. So our rational is to see the hemodynamic stability of dexmedatomindine in hypertensive patients undergoing pneumoperitoneum.