During Laparoscopic cholecystectomy, carbon dioxide (CO2) pneumoperitoneal laparoscopic surgery, CO2-pneumoperitoneum activates the sympathoadrenomedullary system to increase the release of catecholamines such as epinephrine (E) norepinephrine (NE) and dopamine (DA). During stress, E and NE are secreted by the adrenal medulla into blood circulation to promote glycogenolysis to increase blood glucose, speed up lipolysis and accelerate heartbeats. Stellate g anglion block (SGB) reters to the blockade of sympathetic nerves including the large area covered by middle cervical, vertebral arterial. stellate ganglions and ther pre- and post- ganglions. SGB affects both peripheral and central nervous systems. In the peripheral system. the sympathetic pre- and post-ganglionic fibers in the innervated areas of stellate ganglion are affected. Therefore, the control of vascular dilatation and constriction, muscular movement, bronchial smooth muscle relaxation and contraction, and pain conduction, by sympathetic nerves is inhibited. In the central nervous system, the hypothalamus is mainly involved in the regulation of systemic autonomic nervous, immune and endocrine systems, and to maintain homeostasis.

CO2-pneumoperitoneum causes severe stress-related homeostatic disorders including arrhythmia and blood pressure changes. This study will examine the effects of stellate ganglion block (SGB) on hemodynamics and stress response in patients undergoing CO-pneumoperitoneal surgery.

Laparoscopic surgery is being increasingly recognized for its advantages of minimal invasiveness. mild postoperative pain, short length of hospitalization and rapid recovery and is widely used in general surgery, obstetrics. gynecology and urology. Laparoscopic cholecystectomy (LC) has become the gold standard for surgically treating benign diseases of the gallbladder.

During carbon dioxide (CO2) pneumoperitoneal laparoscopic surgery, CO2-pneumoperitoneum activates the sympathoadrenomedullary system to increase the release of catecholamines such as epinephrine (E) norepinephrine (NE) and dopamine (DA). During stress, E and NE are secreted by the adrenal medulla into blood circulation to promote glycogenolysis to increase blood glucose, speed up lipolysis and accelerate heartbeats. Stellate g anglion block (SGB) reters to the blockade of sympathetic nerves including the large area covered by middle cervical, vertebral arterial. stellate ganglions and ther pre- and post- ganglions. SGB affects both peripheral and central nervous systems. In the peripheral system. the sympathetic pre- and post-ganglionic fibers in the innervated areas of stellate ganglion are affected. Therefore, the control of vascular dilatation and constriction, muscular movement, bronchial smooth muscle relaxation and contraction, and pain conduction, by sympathetic nerves is inhibited. In the central nervous system, the hypothalamus is mainly involved in the regulation of systemic autonomic nervous, immune and endocrine systems, and to maintain homeostasis.

CO2-pneumoperitoneum causes severe stress-related homeostatic disorders including arrhythmia and blood pressure changes. This study will examine the effects of stellate ganglion block (SGB) on hemodynamics and stress response in patients undergoing CO-pneumoperitoneal surgery.

Inclusion Criteria:

• Aged 18 -60 years
• american society of anesthesiologists status I-II
• Scheduled for elective laparoscopic cholecystectomy

Exclusion Criteria:

• Patients with chronic renal dysfunction.
• Patients with hypo/hyper-thyroidism.
• Patients with diseases of the autonomic and central nervous systems.
• Patients with cardiopulmonary dysfunction.
• Patients with history of treatment with long-term oral tranquilizers.