Application Of Dobutamine Combined With Nitroglycerin In Partial Hepatic Resection Under Low Central Venous Pressure

BackgroundAccording to GLOBOCAN 2018(Global cancerstatistics 2018),liver cancer is the sixth most common cancer in the world and the fourth leading cause of cancer death.Liver cancer is a serious threat to the lives of patients.At present,there are various treatment methods for various types of liver cancer,including medicine,radiation,surgery,biological therapy,etc.,among which partial hepatectomy is one of the main ways to treat liver cancer.Massive intraoperative bleeding is a common and serious event in liver surgery,which is closely related to the increased incidence of morbidity and mortality after liver surgery.Mass intraoperative blood transfusion is closely related to postoperative mortality and morbidity,and the long-term recurrence rate of the tumor is also significantly increased,the overall survival time and tumor-free survival time are shorter.Therefore,controlling intraoperative bleeding during liver surgery has become the critical point and difficulty of the operation.Contral low central venous pressure(CLCVP)refers to an anesthesia technique that maintains central venous pressure(CVP)at 0 ~ 5 cmH2 O and maintains arterial systolic pressure ≥90 mmHg by various technical means.During liver surgery,blood flow into the liver is often blocked,so intraoperative bleeding mainly comes from hepatic vein reflux bleeding.According to Posue’s law,the amount of bleeding is proportional to the pressure difference between the hepatic vein and the sinus,and the blood vessel The 4th power of the radius is proportional.When the pressure difference between the hepatic vein and the hepatic sinus is small,the reflux pressure decreases,and the small blood vessel radius of the hepatic sinus will decrease or even collapse.The hepatic vein pressure is directly related to the central venous pressure.Therefore,reducing central venous pressure can effectively reduce bleeding during liver surgery.In recent years,studies have found that LCVP can reduce blood loss and shorten the operation time of liver surgery,and the perioperative liver surgery guidelines also strongly recommend the use of low central venous pressure technique during the perioperative period.At present,the main methods to implement the technique of low central venous pressure are the use of anesthesia,the adjustment of body position,the restriction of rehydration,the combination of vasodilators and other means.The common feature of the above methods is to reduce the pressure of the central vein by reducing the volume of the patient’s body or by dilating the venous vessels.However,there are many other factors that can affect central venous pressure,such as cardiac function,intrathoracic pressure,and pulmonary vascular resistance,which have been rarely studied with the use of controlled low central venous pressure.According to Guyton’s theory,venous reflux(VR)is equal to cardiac output(CO),so venous reflux curve and cardiac function curve can be recorded together.The intersection point of venous reflux curve and cardiac function curve is the central venous pressure.In the process of general anesthesia,most anesthetics have an inhibitory effect on cardiac function.In addition,some elderly patients or patients with cardiac insufficiency are found in liver surgery,in which cardiac function is degraded and central venous pressure is increased,which is not conducive to the control of CVP.Dobutamine is a derivative of dopamine,which mainly ACTS on the heart-1 receptor and increases myocardial contractile force.Therefore,the use of dobutamine can theoretically reduce the central venous pressure without reducing the patient’s blood volume.At the same time,due to the enhancement of cardiac function and the reduction of the dependence of low central venous pressure on low volume,the hemodynamic stability and tissue perfusion can be better maintained.And use of dobutamine can increase cardiac output,increase blood flow to the heart of forward,reduce the end systolic ventricular volume,thus increasing diastolic vena cava and the pressure difference of the heart,blood from the hepatic venous return more to the right atrium,reduce the blood hepatic venous sinus,so as to provide the surgeon with better operative field and reduce intraoperative hemorrhage.ObjectiveThe purpose of this study was to investigate the effect of dobutamine on the application of low central venous pressure and its effect on hemodynamics.MethodIn this study,A total of 50 patients with partial liver resection(≥2 hepatic lobes)from March 2019 to November 2019 were collected.They were aged 20-70 years old,ASA grade I-II and child-pugh grade A.Patients were randomly divided into nitroglycerin group(N group)and dobutamine + nitroglycerin group(D group)using a randomized table generated by Excel program.All patients were routinely monitored for electrocardiogram,pulse oxygen saturation,blood pressure and exhaled carbon dioxide Puncture and intubation of radial artery was performed under local anesthesia and FloTrac/Vigileo equipment was connected to continuously monitor invasive arterial blood pressure,CI,CO and SVV.Puncture and catheterization of the right internal jugular vein under local anesthesia were connected with transducers to continuously monitor the central venous pressure.Transducers measuring invasive arterial pressure and central venous pressure were placed in the midaxillary line at the 4th intercostal level.Narcotrend was monitored intraoperatively under general anesthesia with endotracheal intubation.All patients received continuous infusion of lactated ringer’s solution(1-2ml/kg/h)from the beginning of surgery to the end of partial hepatectomy with restricted fluid transfusion.In group N of the control group,intravenous infusion of nitroglycerin was started at 0.3ug / kg / min from the beginning of surgery to completion of hepatectomy and hemostasis.CVP and blood pressure were continuously monitored,and the rate of nitroglycerin infusion was gradually increased according to CVP and blood pressure(increased by 0.1ug/kg/min every 5min),the goal is to reduce CVP to 5cmH2 O.If the systolic blood pressure was < 90 mmHg during the increase of nitroglycerin,the increase of nitroglycerin dose was stopped and fluid challenge stategy was performed with 3ml/kg crystallol.At this time,CVP was recorded as the patient’s minimum tolerance CVP,and the level of CVP was maintained until the partial liver resection was completed.In the experimental group D,dobutamine was continuously pumped to 3ug/kg/min from the beginning of surgery to the completion of liver resection and hemostasis,and intravenous infusion was started with nitroglycerin at 0.3ug/kg/min.Nitroglycerin dose regulation and CVP target were as in group N.Fluid resuscitation was initiated after partial hepatectomy to make SVV < 13,or CVP reach 8 cmH2 O.The surgeon in charge of the surgery grades the surgical field without knowing the patient group using the following criteria.The amount of bleeding was assessed according to the suction volume of the aspirator,the weight of the gauze pad and the bleeding in the surgical field.The data of heart rate,average pressure,central venous pressure,cardiac index,cardiac displacement,and stroke volume variation were recorded at entry(T0),after induction(T1),15 min after operation(T2),at the beginning of hepatectomy(T3),after hepatectomy(T4),and after operation(T5),respectively.After induction(T1),after hepatectomy(T4),and after surgery(T5),blood gas analysis was performed on the artery and the central vein,and PH,PCO2,PO2,BE,SO2,Hb,Hct% and lactic acid values were recorded.Before operation and 1,3,and 7 days after operation,blood was drawn for liver function,biochemical eight tests and alanine aminotransferase,aspartate aminotransferase,albumin,total bilirubin,creatinine,urea nitrogen were recorded.Result1.There were no statistically significant differences in gender,age,height,weight,BMI,surgical method,tumor site,tumor size,operative time,intraoperative infusion volume and urine volume between group N and group D(P >,0.05).2.SV and CI of T3 in group D were higher than that in group N,and the comparison between the two groups was statistically significant(p < 0.05).The CVP of group D and group N at T2 was(6.4±2.1)cmH2O and(7.8±2.2)cmH2O respectively,and the comparison between the two groups was statistically significant(p < 0.05).3.The score of operative field in group D was significantly better than that in group N,with a statistical difference(P < 0.05).Intraoperative blood loss in group D and group N was(223.0±115.5)ml and(404.8±219.6)ml respectively,and the comparison between the two groups was statistically significant(P < 0.05).4.There was no significant difference in lactic acid,BE,ScvO2,PH and HCO3-of T1,T4 and T5 between the two groups(P >,0.05),and they were all within the normal range.5.There was no significant difference in ALT,AST,ALB,TBIL,Cr and BUN of D0,D1,D3 and D7 between the two groups(P >,0.05).Conclusion1.In the controlled low central venous pressure technique,continuous infusion of dobutamine combined with 3ug/kg/min is more conducive to the control of CVP,maintaining circulatory stability and reducing intraoperative blood loss.2.The proper implementation of the controlled low central venous pressure technique has no significant effect on tissue perfusion and liver and kidney function.