Effect Of Combined General-epidural Anesthesia On Stress In Patients With Tumor Undergoing HIFU Treatment

Background and Objective: High-intensity focused ultrasound(HIFU) is a noninvasive tumor therapy. This method keeps away from such complications as bleeding of organs and tissue, infection, visible trauma ect. But most of patients undergoing HIFU treatment were malignant tumor cases with many coexist diseases. Because the patients' clinic physiological changes such as high temperature in biological focal region(BFR), fever of body, heightened of blood pressure, increased of heart rate and arrhythmia frequently, interfere HIFU therapy, HIFU had to be ceased temporarily for another treatment. We assuming that BFR, fever of body, fluctuating of circulation and coagulative necrosis of tissue and cell could turn into stressors of HIFU,which leads the stress. Many investigators have shown that control of stress could reduce the patients' perioperative morbidity rates. Many authors have reported that general anesthesia combined with thoracic epidural block could significantly decrease the stress of patients undergoing thoracic and abdomen procedures. In the world, it has not been reported that general anesthesia combined with thoracic epidural block could decrease the stress of patients with tumor undergoing HIFU therapy. This study compared effects of the general anesthesia combined with thoracic epidural block and general anesthesia on stress in patients with tumor undergoing HIFU procedure, to observe circulatory response .concentrations of plasma norepinephrine(NE), epinephrine(E),cortisol(Cor) and β-EP ect. in order to evaluate the levels of the stress. The aim was to find evidences of selections of anesthesia and to investigate how to reduce the stress and complications of HIFU procedure.Methods: 28 ASAâ…  ^â…¡ adult patients scheduled for HIFU procedure, whose mean age and weight were 58 ± 20yr and 60 ± 9.6Kg, respectively, were randomly allocated into general anesthesia combined with thoracic epidural block group(GEA group,n=14) and general anesthesia group (GA group,n=14). The patients were premedicated with intramuscular atropine and lumial sodium. In GEA group epidural block was performed before anesthesia induction at T8-9 and epidural catheter was advanced cephalad for 3cm in epidural space with epidural block level between T4 and T10. Anesthesia was induced with propofol 1.5-2.0mg/kg, fentanyl 2μg/kg and vecuronium 0.1mg/kg. After tracheal intubation, the patients were mechanically ventilated with 50%O₂. Anesthesia was maintained with propofol TCI infusion, vecuronium and epidural infusion of 0.375% ropivacain. After the procedures, PCEA with 0.125% ropivacain, plus fentanyl 4μg/ml was started. In group GA the induction and maintenance of anesthesia were more of the same except epidural infusion. Peripheral venous blood samples were taken at T0 (before anesthesia), T1 (after anesthesia), T2 (during HIFU procedure), T3(after HIFU procedure), T4(post-operative day 1), for determination of plasma NE, E,serum Cor, blood glucose and 6-EP, at the same time, systolic arterial blood pressure (SBP, DBP) and HR, Bis, rectum temperature(Tr), extubation time, incidents during procedure and VAS of post-operative day 1 were recorded.Results: The two groups of patients were similar respect to age, male/female ratio, weight, therapeutic times, volume income and ASA physical status. In GEA goup there were no significant changes in plasma NE, E, serum Cor, blood glucose, 8-EP, systolic arterial blood pressure (SBP, DBP), and HR. The score of visual analog scale (VAS) was significantly lower than that in GA group(p<0.05). There were no arrhythmias during the procedure. But in GA group there was a large increase in plasma NE, E, serum Cor, blood glucose, 8-EP, systolic arterial blood pressure (SBP, DBP, and HR during and after therapy(p<0.01 or p<0.05). The GA group had significantly higher levels of the above-mentioned internal secretion than GEA group at this time. The plasma B-EP increased at T3 (after HIFU procedure ) and raised continuously, and reached peak value at T4. The rectum temperature(Tr) of two groups were increased during HIFU procedure. The speed of decline of the rectum temperature was slower in GA group than that in GEA group.Conclusions: 1) It was considered that HIFU is a noninvasion operation according to its special type of "ablate" of tumor. But to evaluate HIFU procedure, it is do not a noninvision procedure because of strong stress, which was induced undergoing HIFU treatment in general anesthesia patients with tumor. Fever was an important stressor in this procedure, in addition, nociceptive reflex signal origin from BFR, conducting via neurofiber was stressor too. Afer HIFU procedure, the patients had a medium pain in epigastric, so needs analgetic. 2) General anesthesia combined with thoracic epidural block could reduce the stress of patients with tumor undergoing HIFU therapy. There were such advantages as early of wakening, short of extubation time and preferable postoperative rehabilitation. PCEA could effectively be applied to relieve postoperative pain and stress. 3) It is recommended that general anesthesia combined with thoracic epidural block could be employed in HIFU procedure.