Continuous monitoring of mixed venous oxygen saturation during orthotopic liver transplantation.

Hemodynamic management is an important issue concerning anesthesia for orthotopic liver transplantation (OLT). Mixed venous oxygen saturation (SvO2) is considered a good index of tissue oxygenation, but controversy exists about the usefulness of monitoring this parameter in different types of surgery. Therefore, a prospective study was performed to determine changes in SvO2 during OLT and to study the correlation between SvO2 and hemodynamic measurements. Thirty patients undergoing transplantation for end-stage liver disease were divided into two groups: group 1 (n = 15, aged 42 +/- 11 years [mean +/- SD]) without venovenous bypass (VVB), and group 2 (n = 15, aged 43 +/- 10 years) with VVB. SvO2 was greater than 74% throughout the procedure and remained stable during dissection and the anhepatic phase. There was a significant increase in SvO2 after unclamping the portal vein in group 1, whereas a significant decrease was observed during the first hour following reperfusion in group 2. There was no correlation among SvO2 and oxygen consumption, arterial oxygen saturation, (SaO2), or hemoglobin concentrations. A statistically significant correlation was found between SvO2 and cardiac index in both groups (group 1: r = 0.58, P = 0.01; group 2: r = 0.51, P = 0.01), but the correlation was relatively poor. Continuous monitoring of SvO2 may be useful, but cannot substitute for intermittent determinations of other hemodynamic or oxygenation parameters.     

非静脉转流经典原位猪肝移植麻醉

目的 探讨非静脉转流经典原位猪肝移植术的麻醉期管理.方法 将38头猪随机分为两组,分别为供体组和受体组,对实验猪行经口气管内插管+静脉复合麻醉,施行同种异体原位肝移植术.观察其各时相血流动力学、血气、血生化及肝功能的改变.结果 38头猪中35头成功施行气管插管,3头行气管切开.实验猪对麻醉药有较大的耐受量,无肝期麻醉药用量明显减少;无肝期和新肝期血流动力学变化剧烈并伴有代谢性酸中毒,血清K+在新肝期有一过性升高.在肝移植麻醉及手术过程中,平均动脉压(mean arterial pressure,MAP)、中心静脉压(central venous pressure,CVP)、心率(heart rate,HR)、碱剩余(bases excess,BE)、动脉血二氧化碳分压(PaCO:)等均有较大的波动,其中,在无肝期至新肝期后0.5 h变化最剧烈.结论 对实验猪实施经口气管内插管可行;无肝期不需要深麻醉状态;血流动力学改变的处理应以预防为主,随时纠正酸碱平衡紊乱.合理应对无肝期至新肝期后0.5 h期间的循环系统和机体内环境的剧烈变化是麻醉是否成功的关键.     

小型猪原位肝移植模型的建立与评价

目的 探讨建立放弃静脉转流的小型猪原位肝移植模型的可行性。方法 选用广西巴马小型猪(3-6月龄,8-11kg)为实验动物,共实施原位肝移植10例次。供体肝脏游离、冷灌注、切取、修整以及UW保存按常规方法进行。受体术中肝脏游离后夹闭肝上、肝下下腔静脉和门静脉并切除受体肝脏,各血管断端与供肝相应血管进行端端吻合,肝上下腔静脉和门静脉吻合完毕即开放肝脏血流,在此过程中未使用静脉转流,此后吻合肝动脉、胆管。结果 本组10例次肝移植手术后一周存活率90％(9/10),无肝期时间31.3±2.67min,无肝期血压显著下降(MAP4.5±1.58kPa)但肝血流开放后能较快恢复并渐趋平稳。结论 本组结果表明,非静脉转流条件下的小型猪肝移植模型是一操作方便、易于复制同时又具有较好重复性和稳定性的大动物肝移植模型,能应用于肝移植的系列实验研究。     

Simplified technique of orthotopic liver transplantation in pigs

BACKGROUND: Pig models have become common in transplantation immunological research. However, in pigs, clamping of the venous splanchnic system during orthotopic liver transplantation (OLT) is responsible for high morbidity and mortality rates; therefore, the use of venovenous bypass (VVB) is advocated. Because venous bypass can also cause specific complications, a simplified method for OLT in pigs has been developed and evaluated in terms of morbidity and mortality. METHODS: Twenty-three OLTs were performed between pairs of inbred miniature swine. Donor and recipient pairs (weighing 20-35 kg) were selected at 3-6 months of age. In the donor, the portal vein, infrahepatic vena cava, and suprahepatic vena cava were dissected, whereas the hepatic artery was preserved in continuity with the coeliac trunk and the abdominal aorta up to the iliac bifurcation. In situ cold perfusion was then performed. The recipient was prepared simultaneously by another surgical team. After total hepatectomy and complete portal and caval clamping, the suprahepatic vena cava and portal vein were sutured; VVB was not used. After completion of both venous sutures, the liver graft was reperfused. The infrahepatic vena cava was then anastomosed and unclamped. The donor aorta conduit was implanted end-to-side to the recipient infrarenal aorta, and the biliary reconstruction consisted of a cholecystojejunostomy with a Roux-Y loop. RESULTS: Twenty of 23 (87%) animals survived more than 1 week (7-483 days). The mean anhepatic time was 29.6+/-4.12 min. Although severe hypotension was noted during the anhepatic phase, the hemodynamic status rapidly recovered and stabilized after graft reperfusion. CONCLUSION: Simplified technique without VVB is appropriate for successfully achieving OLT in pigs.     

The effects of long-term graft preservation and prostaglandin E1 on intraoperative hemodynamic changes in liver transplantation. A comparison between orthotopic and heterotopic transplantation in the pig.

The study aimed to compare the intraoperative hemodynamic changes during orthotopic liver transplantation (OLT) with those during heterotopic liver transplantation (HLT) after different durations of cold storage of the graft. The effect of prostaglandin E1 (PGE1) on these parameters was also studied. Sixty-nine female Yorkshire pigs underwent either OLT (n = 32) or HLT (n = 37) with a graft stored for 2 hr (n = 31), 24 hr (n = 16), 48 hr (n = 7), or 72 hr (n = 15). In 16 transplantations in the various groups, PGE1 was given intravenously to both donor and recipient animals and it was added to the preservation and flushing solutions. Univariate nonparametric tests (Mann-Whitney and Wilcoxon rank-sum) were used for analysis of cardiac output (CO), mean arterial pressure (MAP), left and right ventricular minute work (LVMW, RVMW), pulmonary capillary wedge pressure (PCWP), and systemic and pulmonary vascular resistance (SVR, PVR), at different intervals during the operative procedure. For the three main variables--i.e., the type of transplantation, the use of PGE1, and the preservation time, multiple regression analysis was performed. During HLT, portal vein clamping lowered MAP and CO, while during the anhepatic phase in OLT, SVR increased and CO dropped. After recirculation of the graft, an increase in PVR and a decrease in SVR were found in both OLT and HLT. At different stages of the surgical procedure, longer graft storage time diminished CO and MAP (P less than 0.001), especially in OLT. PGE1 appeared to reduce the cardiovascular reserves needed to compensate the changes after recirculation of the graft. The observed differences in intraoperative hemodynamics between OLT and HLT can partly be attributed to differences in operative techniques. Extension of the graft preservation period resulted in poor cardiac performance, more so in OLT than HLT. The native liver in HLT might be able to metabolize the presumed myocardial depressant factors, released by the graft upon reperfusion. Prostaglandin E1 did not protect against the reperfusion syndrome.     

原位肝移植围术期血液酸碱和电解质变化

目的探讨原位肝移植围术期血液酸碱、电解质变化及麻醉处理。方法18例终末期肝病行原位肝移植术患者,分别于无肝前期、无肝期10、20、30min、新肝期10、20、30min测定动脉血pH、PaO2、PaCO2和肺动脉混合静脉血HCO3-、SvO2、K 、Ca2 、Na 和Hct。结果与无肝前期时相比,无肝期20min时pH值明显升高(P<0.05),随后在新肝期10、20min时逐渐下降;而PaCO2和HCO3-自无肝期20min以后都保持不同程度的升高(P<0.05或P<0.01)。新肝期10、20、30min时Hct和PaO2均明显升高(P<0.05或P<0.01),血Na 浓度均明显降低(P<0.05),血K 浓度在无肝期10min时升高(P<0.05),而新肝期10min时又明显降低(P<0.05);血Ca2 浓度基本保持稳定,只是在无肝期30min时比无肝前期时略有升高(P<0.05)。SVO2在无肝前期时较高,但在无肝期30min时较无肝前期时显著降低(P<0.05),在新肝期又回升至无肝前期时水平。结论原位肝移植术中酸碱和电解质变化较大,围术期适时监测血酸碱、电解质变化有助于维持血流动力学的稳定和预防再灌注综合征的发生。     

Vasopressor agents without volume expansion as a safe alternative to venovenous bypass during cavaplasty liver transplantation

BACKGROUND: Cavaplasty orthotopic liver transplantation (OLT) offers advantages for hepatectomy and implantation and eliminates the risk of outflow obstruction. However, it does require clamping of the cava. This study describes the use of a vasopressor without fluid expansion or venovenous bypass (VB) for hemodynamic control during the anhepatic phase. METHODS: The cavaplasty OLT technique was used routinely. A vasopressor was administered if the mean arterial blood pressure (MAP) was less than 60 mm Hg after clamping of the cava. If the MAP did not reach 60 mm Hg after adjusting the dosage of the vasopressor, femoro-axillary VB would be used. VB was also indicated for preexisting cardiac disease or for massive hemorrhage from severe portal hypertension and extensive adhesions. RESULTS: Among all the 121 adult cavaplasty OLTs, 33 were supported with VB and 50 received a vasopressor. The remaining 38 were excluded. However, baseline variables were well matched, except that preexisting cardiac disease was more frequent in the VB group. The median dosage of epinephrine was 0.07 microg/kg/min (range 0.01-0.6). The VB and vasopressor groups were similar in the reduction in mean MAP and the accumulation in arterial lactate upon clamping as well as in the central venous pressure upon unclamping. Postreperfusion hypotension was more frequent in the VB than in the vasopressor group (27.3% vs. 4.0%, P=0.006). There was no primary graft nonfunction or intraoperative right heart failure. One patient in the vasopressor group required postoperative temporary dialysis. Ninety-day patient and graft survival for the VB and vasopressor groups were 97.0% vs. 98.0% and 97.0% vs. 94.0%, respectively. CONCLUSION: Modest doses of vasopressor without volume expansion or VB can maintain hemodynamic stability during the anhepatic phase of cavaplasty OLT.     

非转流原位肝移植术患者术中血浆胶体渗透压的变化

目的 分析非转流原位肝移植术患者术中血浆胶体渗透压的变化.方法 择期经典非转流原位肝移植术患者30例,年龄35～60岁,ASA Ⅱ～Ⅳ级,肝功能Child-Push分级B或C级.静脉注射咪达唑仑、舒芬太尼、异丙酚及维库溴铵行麻醉诱导,静脉输注异丙酚,吸入异氟醚,并间断静脉注射舒芬太尼及维库溴铵维持麻醉.术中静脉输注入血白蛋白注射液及新鲜冰冻血浆等液体,无肝前期维持血红蛋白浓度70～80 g/L,尿量1 ml·kg-1·h-1,中心静脉压4～7 mm Hg;无肝期维持血红蛋白浓度80～100 g/L,尿量0.5 mll·kg-1·h-1,中心静脉压0～3 mm Hg;新肝期维持尿量1-2 ml·kg-1·h-1,中心静脉压4～10 him Hg.于建立肘正中静脉通路时(T0)、切皮即刻(T1)、无肝前期60 min(T2)、无肝即刻(T3)、无肝期30 mm(T4)、新肝即刻(T5)、新肝期30 min(T6)及术毕(T7)时取静脉血样5 ml,测定血浆胶体渗透压、血浆晶体渗透压及血清白蛋白浓度.结果 与T0时比较,T2-6时血浆胶体渗透压、T2-7时血清白蛋白浓度及T4-7时血浆晶体渗透压均升高(P<0.05或0.01),但仍在正常范围内.结论 非转流原位肝移植术中常规液体管理可维持正常血浆胶体渗透压,提示常规液体管理方案是可行的.     

Venous oxygen saturation during normovolaemic haemodilution in the pig

BACKGROUND: Hypovolaemia may be considered to represent a volume-restricted cardiac output (CO), but CO varies inversely with the haemoglobin concentration (Hb) and a maximal mixed venous oxygen saturation (SvO2) may be a better target for volume administration than a maximal CO. METHODS: In 10 anaesthetized pigs, volume loading with 6% hydroxyethyl starch was performed to obtain a maximal SvO2 followed by normovolaemic haemodilution with 6% hydroxyethyl starch. RESULTS: Volume loading increased SvO2 from 55.0+/-5.2% to 64.8+/-9.0% (mean+/-SD) associated with an increase in CO (2.3+/-0.4 to 3.5+/-0.9 l/min) and central venous oxygen saturation (ScvO2; 68.2+/-9.3% to 79.4+/-7.2%; P<0.05). Heart rate (HR), mean arterial (MAP), central venous (CVP), pulmonary arterial mean (PAMP), and occlusion pressures (PAOP) increased as well (P<0.05). In contrast, during progressive haemodilution, SvO2 and ScvO2 remained statistically unchanged until the haemoglobin concentration had decreased from 5.5+/-0.4 to 2.9+/-0.2 mM, while CO and HR increased at a haemoglobin value of 4.4+/-0.4 and 4.0+/-0.4 mM and CVP and PAOP decreased at a haemoglobin of 4.0+/-0.4 and 2.9+/-0.2 mM, respectively (P<0.05) leaving MAP unaffected. CONCLUSION: This study found that volume loading increased cardiac output and mixed and central venous oxygen saturations in parallel, but during normovolaemic haemodilution an increase in cardiac output left mixed and central venous oxygen saturations statistically unchanged until haemoglobin concentration was reduced by approximately 50%. Accordingly, volume therapy should be directed to maintain a high venous oxygen saturation rather than a change in cardiac output.     

The Relationship Between Inhalational Anesthetic Requirements and the Severity of Liver Disease in Liver Transplant Recipients According to Three Phases of Liver Transplantation

Purpose

Orthotopic liver transplantation (OLT) patients are known to show decreased intraoperative anesthetic requirements compared with patients undergoing other liver surgeries. The aim of this study was to determine the relationship between inhalational anesthetic requirements and the severity of liver disease among OLT patients.

Methods

Fifty patients undergoing first living donor OLT were divided into 2 groups: model for end-stage liver disease (MELD) score <20 (low-MELD group; n = 25) versus, MELD score ≥20 (high-MELD group; n = 25). Anesthesia was maintained with desflurane and inspired concentration was titrated to maintain the bispectral index between 40 and 50. Neither intraoperativel opioid nor epidural or intrathecal analgesia was used. End-tidal desflurane concentration (ETdes) was measured every 5 minutes and averaged in 30-minute intervals. These values were divided into 3 phases: preanhepatic (P 0.5 hour, P 1 hour, and P 1.5 hours), anhepatic (A 0.5 hour, A 1 hour, A 1.5 hours, and A 2 hours), and postreperfusion (R 0.5 hour, R 1 hour, R 1.5 hours, R 2 hours, R 2.5 hours, and R 3 hours). Results were compared between the 2 groups.

Results

The demographic and intraoperative data were similar between the 2 groups. ETdes to maintain comparable anesthetic depth was significantly lower during the preanhepatic and anhepatic phases in the high-MELD than the low-MELD group, but there was no significant difference during the postreperfusion period.

Conclusions

OLT patients with high MELD scores showed less inhalational anesthetic requirements during the preanhepatic and the anhepatic periods than those with low MELD scores.     

Causes of renal dysfunction during the anhepatic phase in patients for orthotopic liver transplantation and their postoperative renal function

This study was carried out to clarify causes of renal dysfunction during the anhepatic phase in orthotopic liver transplantation (OLT) with venovenous bypass and to show how the deterioration impacted on postoperative renal function. The 44 consecutive patients with normal preoperative renal function who underwent OLT in Royal Prince Alfred Hospital were classified into two groups according to creatinine clearance (Ccr) during the anhepatic phase. Group 1 consisted of 27 patients whose Ccr levels levels were kept above 60 ml.min-1.m-2 and group 2 consisted of 17 patients under 60 ml.min-1.m-2. In group 2, preoperative International Normalized Ratio for prothrombin was higher and blood transfusion volume before revascularization was significantly lager than group 1. There were significant differences in haemodynamics just before revascularization (mean arterial pressure 95 +/- 14 vs 83 +/- 14 mmHg, pulmonary artery wedge pressure 16 +/- 5 vs 11 +/- 5 mmHg, cardiac index 4.6 +/- 1.3 vs 4.0 +/- 0.9 l.min-1.m-2, group 1 vs group 2, mean +/- SD, P < 0.05). Serum creatinine levels in group 2 were significantly higher postoperatively. It is suggested that bleeding due to insufficient preoperative coagulability caused haemodynamic instability which deteriorated renal function during the anhepatic phase and the deterioration impacted on postoperative renal function.     

原位肝移植术的麻醉管理

目的探讨成年原位肝移植术病人围手术期血流动力学、内环境变化和麻醉管理方法。方法52例晚期肝病行背驮式原位肝移植术病人，采用静吸复合全身麻醉。术中监测血流动力学、血气、生化指标、凝血功能、体温、尿量及出血量等。根据成人原位肝移植术无肝前期、无肝期、新肝期的特点及术中具体情况，给予相应的处理。结果52例行肝移植术病人无术中死亡。围手术期血液动力学基本平稳。pH值和BE等代谢性指标变化较大；所有病人手术期间血游离Ca^2 均偏低。术中体温变化不大。结论肝移植手术期间血流动力学、凝血因子、电解质和酸碱平衡等变化复杂，应加强麻醉管理和监测，并积极实施血液保护措施。     

肝移植术后早期血流动力学及氧代谢的变化

目的 观察原位肝移植术后早期全身血流动力学及氧代谢的变化，并探讨与术后早期预后的相关关系。方法 29例终末期肝病的患者接受了首次原位肝移植术。所有病例均于术中放置Swan-Ganz导管，术后48h内，每8h监测1次心率（HR）、平均动脉压（MAP）、心输出量（CO）、肺动脉压（PAP）、肺动脉楔压（PAWP）、中心静脉压（CVP）、全身血管阻力（SVR）、肺血管阻力（PVR）、左室每搏作功指数（LVSWI）、右室每搏作功指数（RVSWI）及氧供（DO2）、氧耗（VO2）、氧摄取率（O2Ext)、静脉血氧饱和度（SvO2)。对这些数据进行回顾性的分析并比较存活与死亡病例的差异。结果 存活者与死亡者术后均呈现持续高的CO、DO2、VO2及SvO2；低的SVR、O2Ext。术后24h HR开始明显下降，而MAP、CVP则明显增加；LVSWI自术后16h开始增加。存活者术前急性生理慢性健康评分（APACHEⅡ）低于死亡者；HR下降更明显；LVSWI高于死亡者；MPAP低于死亡者。结论 肝移植患者术后早期仍存在一定的高动力循环状态，同时全身氧供和氧耗明显增加，组织摄取氧的能力存在一定障碍；死亡者术前疾病的严重程度明显高于存活者，心脏储备能力差，术后早期存在心功能不全。     

Does adult liver transplantation without venovenous bypass result in renal failure?

Thirty-eight adult orthotopic liver transplant recipients were studied to compare renal hemodynamics and renal function with (17 patients) and without (21 patients) venovenous bypass. Bypass was used when mean arterial blood pressure decreased by greater than 30% or cardiac index decreased by greater than 50%, or both, during a 5-min trial of clamping of the suprahepatic and infrahepatic vena cava and portal vein. Intraoperative measurements were performed 2 h after induction of anesthesia, 10 min before the end of the anhepatic phase, and 2 h after cava unclamping. During the anhepatic stage, renal perfusion pressure decreased significantly in the group with no bypass (79 +/- 20 vs 60 +/- 17 mm Hg, P less than 0.05) (mean +/- SD), whereas it remained unchanged in the group with bypass (77 +/- 14 vs 74 +/- 16 mm Hg, NS); urinary output was not modified in the bypass group, whereas it decreased significantly in the group with no bypass compared with the dissection phase (0.7 +/- 0.6 vs 1.7 +/- 2.0 mL.kg-1.h-1, P less than 0.05). However, during the postreperfusion phase, urinary output was similar in both groups and was more when compared with the dissection phase (P less than 0.05). Serum creatinine level was increased in both groups on the third postoperative day, but no difference occurred between the groups (bypass group 107 +/- 49 mmol/L; nonbypass group 126 +/- 95 mmol/L). No patient required dialysis in either group in the postoperative period. This study suggests that in patients without preoperative renal failure and who tolerate the trial of clamping well, venovenous bypass is not required to maintain postoperative renal function after liver transplantation.     

经典式原位肝移植术弃用静脉转流的经验总结

目的：观察经典式原位肝移植术不作静脉转流的效果,分析不转流对术后胃肠道及肾脏功能的影响。方法：总结自１９９９年来我所４５例经典式原位肝移植术弃用静脉转流的经验。结果：４５例术中无肝期时间平均为５４．５ｍｉｎ,术后与不转流相关的胃肠道和肾功能明显损害的并发症有４例：３例术后近期发生急性肾功能衰竭,２例经血透后恢复,１例死亡;另１例于术后１．５月发生急性坏死性胰腺炎。结论：若无肝期控制在１ｈ内,经典式原位肝移植不作转流,并不显著增加胃肠道和肾脏功能损害等并发症,且有缩短手术时间和节省费用等优点。     

Novel magnetic rings for rapid vascular reconstruction in canine liver transplantation model

OBJECTIVE: Magnetic rings were used for rapid vascular reconstruction in a canine liver transplantation model. MATERIALS AND METHODS: Thirty-two adult mongrel dogs weighing 13 to 16 kg were randomly selected as donors or recipients of transplantations. The recipients were randomly divided into two groups: group A (n = 10) had magnetic rings used for vascular reconstruction without venovenous bypass; group B (n = 6) had vascular reconstruction performed by continuous suturing with splenojugular venovenous bypass. RESULTS: In group A, the entire operative period was 3.24 +/- 0.49 hours, the durations of clamping the portal vein and the infrahepatic vena cava of the recipient were 5.89 +/- 2.27 minutes and 3.89 +/- 0.73 minutes, respectively. In group B, the entire operative period was 4.12 +/- 0.51 hours with the duration of clamping portal vein and infrahepatic vena cava, 28.33 +/- 6.04 minutes and 12.16 +/- 3.72 minutes (P < .01 vs group A). In group A, mean arterial pressure dropped during the anhepatic phase but recovered quickly after reperfusion. The fluid infusion was about 730.56 +/- 50.56 mL in the group A and a pressor agent was unnecessary. In group B, blood pressure dropped during the anhepatic phase and slowly recovered. The fluid infusion was about 2241.67 +/- 390.78 mL and a pressor agent was used to maintain the blood pressure of the recipient. No twist or thrombus was discovered in the anastomoses group A and the endothelium at the site of anastomosis was entire. In group B, errhysis was common in the anastomotic stomas. Nine of 10 dogs in group A survived more than 3 days, the longest being 8 days, whereas four of the six dogs in group B survived less than 3 days. CONCLUSION: The results showed that the anhepatic time was significantly shortened (about 5.89 +/- 2.27 minutes) in group A compared with group B and venovenous bypass was unnecessary. Magnetic rings could be used for rapid vascular reconstruction in canine liver transplantation model. The long-term results of this procedure should be clarified before it is applied in clinical practice in the future.     

Liver transplantation without venovenous bypass: morbidity and mortality in patients with greater than 50% reduction in cardiac output after vena cava clamping

OBJECTIVE: To investigate whether a decrease in cardiac output of >or=50% after vena cava clamping is associated with an increase in perioperative morbidity or mortality in patients undergoing orthotopic liver transplantation without venovenous bypass. DESIGN: Retrospective, clinical study. PARTICIPANTS: Patients undergoing elective orthotopic liver transplantation without venovenous bypass (n = 172). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In 82 patients (group 1), the decrease in cardiac output after vena cava clamping was >or=50%; in 90 patients (group 2), the decrease was <50%. Hemodynamics during surgery and perioperative morbidity and mortality were compared between group 1 and group 2 patients. Mean arterial pressure during the anhepatic phase was not significantly different between groups, but cardiac output and mixed venous oxygen saturation were significantly lower in group 1 patients. Perioperative mortality, need for postoperative renal replacement therapy, postoperative serum creatinine levels, and graft function were not different between groups. CONCLUSION: A >50% reduction in cardiac output after vena cava clamping is not associated with an increase in perioperative morbidity and mortality when compared with patients with a less pronounced reduction in cardiac output. These results question the common practice of basing the indication for venovenous bypass during the anhepatic phase on a reduction in cardiac output of >50% after a trial of vena cava clamping.     

Hemodynamic changes during reperfusion of the graft in an animal model of liver xenotransplantation

Our goal was to determine the hemodynamic changes that are witnessed during the initial minutes of reperfusion of the graft in liver xenotransplantation from pig to baboon. METHOD: We studied a group of 12 baboons undergoing transplantation of a pig liver via the classic technique with arterial anastomosis to the aorta. The anesthesia technique was similar to that used in humans. Hemodynamic monitoring, due to the size of the recipient, consisted of heart rate (HR), mean arterial pressure (MAP), and central venous pressure (CVP) recorded at the beginning and end of each of the three phases: preanhepatic (A1, A2), anhepatic (B1, B2), and neohepatic (C1 and C2). We aimed to maintain the following values by means of crystalloids, colloids, and blood derivates: HR >50 beats/minute; MAP >60 mm Hg; and CVP >10 mm Hg. RESULTS: Both HR and CVP remained unchanged throughout the procedure. MAP droped briefly after vascular clamping (B1) but not on reperfusion (C1). CONCLUSION: In cirrhotic patients there is an autonomic dysfunction, demonstrated as cardiovascular instability at times like the clamping of major vessels and reperfusion of the graft. On the other hand, the intact baboon has an intact nervous system. After vascular clamping, the sharp decrease in venous return lead to an adequate vasopressor response. Likewise, the extreme vasodilatation involved with reperfusion managed to maintain MAP above 70 mm Hg.     

无肝期液体管理对小型猪原位肝移植短期存活率影响的实验研究

目的探讨猪原位肝移植中无肝期液体管理对移植后短期存活率的影响。方法西藏小型猪随机分为供体组和受体组，共行非体外转流原位肝移植术10次。按无肝期补液量分为A组：常规补液组（n=5）；B组：限制性补液组（n=5），比较其无肝期补液量、术中血流动力学变化、移植肝脏功能恢复情况及短期存活时间。结果A组无肝期平均补液量为950±57．7ml，B组平均补液量425±64．5ml，A组无肝期血流动力学改变较B组平稳（MAP：115．5±2．3／63．75±4．0mmHg，P〈0．01；CVP：6．3±0．45／3．5±0．41cmH2O，P〈0．05）A组术后平均存活时间明显短于B组（平均存活时间26±4．6／80．3±10．7h，P〈0．01）；移植肝脏功能恢复比较提示B组恢复较好。结论无肝期液体管理影响猪原位肝移植术后短期存活情况，非限制性输液不利于猪术后存活。控制无肝期输液量能延长猪原位肝移植术后存活时间。     

Luxury lung perfusion in end-stage liver disease during liver transplantation

BACKGROUND: End-stage liver disease is accompanied by a hyperkinetic circulation sometimes combined with hypoxaemia. Nitric oxide overproduction has been described as a possible cause by dilating the vasculature and decreasing cardiac afterload. The aim of this study was to evaluate haemodynamics, ventilation/perfusion matching, alveolar and alveolar dead space ventilation and resistance of systemic and pulmonary vasculature during liver transplantation. METHODS: Ten liver transplantation patients were studied. Cardiac output, CO, was measured with thermodilution technique. Pulmonary shuntflow was calculated from standard formulas. Effective cardiac output, COeff, was defined as the CO in contact with alveolar ventilation, VA. Effective alveolar ventilation, VAeff, was defined as VA in contact with pulmonary circulation. Measurements were performed during dissection, anhepatic and reperfusion phases. RESULTS: During the dissection phase the shunt was 23 +/- 3%, COeff was 7.9 +/- 0.6 l/min, SVR was 620 +/- 67 dyn.s/cm5, VAeff was 3.4 +/- 0.5 l/min, SaO2 was 98 +/- 1% and SvO2 was 86 +/- 2%. Corresponding values during the anhepatic phase were 16 +/- 2%, 5.6 +/- 0.4 l/min, 931 +/- 78 dyn.s/cm5, 3.1 +/- 0.2 l/min, 99 +/- 1% and 88 +/- 1%. During the reperfusion phase the values returned to levels close to that of the dissection phase. The reduction of COeff between the dissection and the anhepatic phase was significant (P < 0.01). CONCLUSIONS: The low vascular resistance is accompanied by a high cardiac output. In spite of the high shunt fraction, these patients were not hypoxaemic. This is explained by the fact that the increased cardiac output leads to a decrease in arterio-mixed venous oxygen content difference and an increase in mixed venous oxygenation level, SvO2 86-88%, normal value approximately 70%. The VAeff/COeff in this study was approximately 0.5, i.e. the effective cardiac output, COeff is 235, 180 and 197% of the effective alveolar ventilation, VAeff during the three phases. Thus, about twice the amount blood is oxygenated as compared to a normodynamic situation, which compensates for the effect of the shunt flow on oxygenation.