Effect Of Ultrasound-guided Stellate-ganglion Block On Regional Cerebral Oxygen Saturation In The Patients Undergoing Arthroscopic Shoulder Surgery In The Beach Chair Position

Background:With the rapid development of sports medicine,arthroscopy technology is well known and accepted by the public because of its advantages of small wound and fast recovery.The shoulder joint capsule is loose and unstable,which is easy to be injured under the impact of external force.The shoulder arthroscope is mainly used to treat shoulder diseases such as rotator cuff injury and fracture.The shoulder joint is the largest and most flexible joint of the upper limb.In the shoulder arthroscopic surgery,because the beach chair position is more consistent with the exposure of the shoulder joint's anatomical structure,and is not easy to damage the nerve,most of the shoulder arthroscopic surgery in recent years use the beach chair position.Because of its special position,beach chair position will lead to other problems.Under general anesthesia,patients are prone to general hypotension when they are in the beach chair position.Due to gravity,the blood flow in the brain is more reduced,and the brain is at risk of ischemia and hypoxia.At present,more and more cases also reveal the shortcomings of beach chair position,so the safety of beach chair position is controversial.The local cerebral oxygen saturation measured by near-infrared spectroscopy can provide non-invasive continuous data about the balance between oxygen supply and demand in brain tissue,so as to detect and timely deal with cerebral perfusion deficiency in the early stage,which can help reduce the risk of preventable brain injury.At present,it is widely used in the research of Beach chair safety^[1,2].Some studies have found that stellate ganglion block can expand the blood vessels in its control area and increase the blood flow.It has been reported that it can increase the blood flow of anastomosed arteries after aneurysm operation^[3],improve the turbulence of brain oxygen metabolism during cardiopulmonary bypass during cardiac and large vessel operation^[4].Whether stellate ganglion block can be applied to shoulder arthroscopic operation in beach chair position has not been reported yet.There are relevant reports.Therefore,the purpose of this study is to explore the effects of stellate ganglion block on hemodynamics and local cerebral oxygen saturation,so as to provide more suggestions for the beach chair position shoulder arthroscopy.Objective:1.To investigate the effect of ultrasound-guided stellate-ganglion block onhemodynamics in the patients undergoing arthroscopic shoulder surgery in the beachchair position.2.To investigate the effect of ultrasound-guided stellate-ganglion block?SGB?onregional cerebral oxygen saturation in the patients undergoing arthroscopic shouldersurgery in the beach chair position.Methods:A total of forty patients of both sexes,aged18?70yr,of American Society of Anesthesiologists physical status I or II,scheduled for elective arthroscopic shoulder surgery in the beach chair position,were divided into 2 groups?n=20 each?using a random number table:control group?group C?and stellate-ganglion block group?group S?.In the operating room?OR?,patients in Group S received ultrasound guided SGB with 6 ml of 0.25%ropivacaine and patients in group C received ultrasound guided SGB with 6 ml saline.Then the two groups performed the same operation.After SGB,patients were changed to beach chair position for 10 minutes,and then patients were lying in the supine position and induction of anesthesia was initiated.5 minutes after endotracheal intubation,patients were prepared in the beach chair position for surgery.The HR,SBP,DBP,MAP,r SO₂were recorded 5 minutes after entering the OR(T_p1),5minutes after SGB and BCP(T_b1),5 minutes after anesthesia induction and before BCP(T_p2),5 minutes after BCP(T_b2)and immediately after BCP,at 3,6,9,12,15,18,21,24,27and 30 min after BCP.Results:Compared with the r SO₂at T_p2,the r SO₂was significantly decreased at T_1-10in the operated side and at T_4-10in the non-operated side in group C and S?P<0.05?.There was no significant difference in r SO₂at each time between the two groups.Compared with group C,the HR of group S was higher in T_b1,T_p2and T_b2?P<0.05?.Conclusion:Ultrasound-guided stellate ganglion block could not increase the regional cerebral oxygen saturation in the patients undergoing arthroscopic shoulder surgery in the beach chair position,and had little effect on hemodynamics?except heart rate?.