The Clinical Studies On Reducing The Intraoperative Transfusion Volume By Low-dose Of Norepinephrine Intravenous Infusion

Objective: Through research to reveal that low-dose of norepinephrine continuously intravenous pump could maintain patient's blood pressure in the surgery of breast under epidural anesthesia and reduce the amount of surgery transfusion to ensure safety and feasibility.Methods: 30 cases of selective patients with breast surgery inⅠ-Ⅱclass of ASA are randomly divided into A and B groups. Two groups of patients have given 0.9% sodium chloride injection with a dose of 8-10ml/kg before anesthesia. Group A is the control group. After the success of epidural punture, give test dose 2% lidocaine 4ml in epidural; after anesthesia plane appears, give 0.5% ropivacaine 7ml,control the anesthesia plane between T1 and T6; intravenous midazolam 0.05mg/kg; intravenous infusion of propofol 3mg/kg.min. If it is necessary to give a second local anesthetic, give 0.5% ropivacaine 4ml for second time and 0.5% ropivacaine 3ml for third time. During the process of surgery, it's indispensible to ensure the amount of liquid which is for physical requirements and the cumulative loss. Crystal and colloid are given by 2:1. Crystal is 0.9% sodium chloride injection while colloid is succinylated gelatin injection and maintain the blood pressure at the level of basic BP±30%. If it is still unable to maintain the ideal BP, give ephedrine 10mg for a single time. Group B is the experimental group. After the success of epidural punture, give test dose 2% lidocaine 4ml in epidural; after anesthesia plan appears, give 0.5% ropivacaine 7ml; intravenous midazolam 0.05mg/kg; intravenous infusion of propofol 3mg/kg.min. If it is necessary to give a second local anesthetic, give 0.5% ropivacaine 4ml for second time and 0.5% ropivacaine 3ml for third time. During the process of surgery, it's only necessary to ensure the amount of physical requirements, while liquid is 0.9% sodium chloride injection, continuously intravenous pump. After ropivacaine, give an immediate infusion of norepinephrine 0.04μg/Kg.min-0.1μg/Kg.min, to maintain the blood pressure at the level of basic BP±30%. If it is still unable to maintain the ideal level, give norepinephrine 10μg for a single time and gradually reduce the amount of norepinephrine infusion up to stop before the end of the surgery. Record after the admission, after the initial administration of 5min, the end of surgery, the moment returned to ICU, 6 hours after surgery, and after a 24-hour MAP, heart rate, oxygen saturation, the amount of local anesthetics, the volume of intraoperative transfusion, postoperative urine, postoperative infusion volume,after a 24-hour renal function, operation time and the dosage of vasoactive drugs. Record the amount and extent of adverse reaction.Results: All 30 cases of patients have a stable blood pressure in the process of surgery, with heart rate in line with the requirements under anesthesia. There is no change in oxygen saturation, no difference in the amount of local anesthetic and renal function has not changed between preoperative and postoperative. Compared between the two groups, there is no difference in age of patients, gender, body weight, duration of surgery, surgical procedure. The infusion volume in the process of surgery in Group B is significantly less than Group A while there is no difference in the infusion volume after surgery. Compared with the preoperative, blood pressure, heart rate and oxygen saturation have not changed in both groups. Group B patients don't present hypotension after surgery. There is no difference in urine volume in the process between the two groups whereas Group B is a little more than Group A during the surgery. There is no difference in the renal function tests between preoperative and postoperative in both groups with no patients'renal function changed significantly, which shows that short-term application of small doses of norepinephrine will not cause renal ischemia, hypoxia and changes in renal function. There is no difference in the incidence rate of adverse reaction during and after surgery between the two groups.Conclusion: In the breast surgery under epidural anesthesia, continuous infusion of small doses of norepinephrine can significantly reduce the volume of transfusion in the process of surgery, which is effective to maintain the stability of the circulatory system during operation, and meanwhile prevent hypotension occuring after surgery. Also it is effective in reducing heart and lung complications caused by excessive transfusion. Another reason is norepinephrine can increase effectively the perfusion of the kidney and urine output, thus it will not cause the hypoxia-ischemia of kidney to the detriment of renal function. To sum up, I think highly of the implementation of epidural anesthesia in breast surgery. There are many advantages in continuous low-dose infusion of norepinephrine which is a safe and effective method.