Intraoperative fluid management of living donor versus cadaveric liver transplant recipients

Intraoperative predictors of early tracheal extubation after living-donor liver transplantation

BACKGROUND

Prolonged mechanical ventilation after liver transplantation has been associated with deleterious clinical outcomes, so early tracheal extubation posttransplant is now increasing. However, there is no universal clinical criterion for predicting early extubation in living-donor liver transplantation (LDLT). We investigated specific predictors of early extubation after LDLT.

METHODS

Perioperative data of adult patients undergoing LDLT were reviewed. "Early" extubation was defined as tracheal extubation in the operating room or intensive care unit (ICU) within 1 h posttransplant, and we divided patients into early extubation (EX) and non-EX groups. Potentially significant (P < 0.10) perioperative variables from univariate analyses were entered into multivariate logistic regression analyses. Individual cut-offs of the predictors were calculated by area under the receiver operating characteristic curve (AUC) analysis.

RESULTS

Of 107 patients, 66 (61.7%) were extubated early after LDLT. Patients in the EX group showed shorter stays in the hospital and ICU and lower incidences of reoperation, infection, and vascular thrombosis. Preoperatively, model for end-stage liver disease score, lung disease, hepatic encephalopathy, ascites, and intraoperatively, surgical time, transfusion of packed red blood cell (PRBC), urine output, vasopressors, and last measured serum lactate were associated with early extubation (P < 0.05). After multivariate analysis, only PRBC transfusion of ≤ 7.0 units and last serum lactate of ≤ 8.2 mmol/L were selected as predictors of early extubation after LDLT (AUC 0.865).

CONCLUSIONS

Intraoperative serum lactate and blood transfusion were predictors of posttransplant early extubation. Aggressive efforts to ameliorate intraoperative circulatory issues would facilitate successful early extubation after LDLT.

Acute kidney injury during liver transplantation as determined by neutrophil gelatinase-associated lipocalin

Acute kidney injury (AKI) has significant prognostic implications for long-term outcomes in patients undergoing liver transplantation. In several retrospective studies, perioperative variables have been associated with AKI. These variables have been mainly associated with changes in creatinine concentrations over several days or months post-transplantation. To better define AKI, new markers have become available that help to identify patients at risk for renal injury within hours of a triggering insult. We prospectively enrolled liver transplant patients at our institutions to evaluate neutrophil gelatinase-associated lipocalin (NGAL), a marker of early renal injury, as a surrogate for AKI in patients undergoing liver transplantation. Blood was prospectively collected at predetermined time points from 59 patients at 2 institutions. The electronic anesthesia records and the hospital computer data system were reviewed for perioperative variables. Data collection included patient demographics, intraoperative variables such as fluid management, transfusion requirements, hemodynamics, and urine output. Subsequently, patients were grouped according to the presence of risk for developing AKI as defined by the RIFLE (risk, injury, failure, loss, and end-stage kidney disease) criteria. The difference between the NGAL concentration 2 hours after reperfusion and the baseline NGAL concentration was predictive of AKI in all patients, including patients with preexisting renal dysfunction. In patients with creatinine concentrations less than 1.5 mg/dL, a single NGAL determination 2 hours after reperfusion of the liver was associated with the development of AKI. Total occlusion of the inferior vena cava was associated with AKI. In conclusion, NGAL concentrations obtained during surgery were highly associated with postoperative AKI in patients undergoing liver transplantation. These findings will allow the design of larger interventional studies. Our findings regarding the impact of surgical techniques and glucose require validation in larger studies.

Increased severity of renal ischemia-reperfusion injury with venous clamping compared to arterial clamping in a rat model

BACKGROUND

Arterial inflow occlusion is a well-known mechanism of renal injury during major vascular surgery. In contrast, renal injury from venous outflow obstruction is poorly understood. The goal of this study was to examine the injury pattern of renal venous outflow obstruction, compare this with the traditional model of arterial occlusion, and examine possible mechanisms.

METHODS

Male Fisher rats were used for the renal warm ischemia model. Twenty-five minutes of renal ischemia was induced by selectively occluding either the renal artery or vein. After 24 h of reperfusion, whole blood and kidney tissue were collected for further analysis.

RESULTS

Serum creatinine (SCr) concentrations taken 24 h after reperfusion were significantly greater in the venous occlusion group (V) when compared to the arterial group (A). While histology did not demonstrate significant differences in extent of necrosis between both groups, a stronger inflammatory response resulted from venous occlusion. Specifically, significantly greater MCP-1 mRNA and significantly greater MCP-1, TNF-alpha, and HO-1 protein levels were found in the venous group, while no differences in MIP-2, ICAM-1, and VCAM-1 mRNA expression existed between A and V. Further analysis demonstrated presence of increased cleaved caspase-3 protein in the artery group than in the venous group.

CONCLUSIONS

Venous renal outflow obstruction results in more severe functional renal injury when compared to arterial inflow occlusion. Macrophage activation and neutrophilic infiltration appear to be exaggerated during venous occlusion.

Recombinant factor VIIa reduces transfusion requirements in liver transplant patients with high MELD scores

Patients undergoing orthotopic liver transplantation (OLT) often experience significant coagulopathy and remain at risk for excessive blood loss and massive transfusion. The ability of recombinant factor VIIa (rFVIIa) to reduce transfusion requirements during OLT has not been well established. This retrospective study investigates whether rFVIIa reduces transfusion requirements in liver transplant patients with a significantly prolonged prothrombin time (PT) and a model of end-stage liver disease (MELD) score of > 20. Eleven patients received a single dose of rFVIIa (58 +/- 18 microg kg(-1)) at the time of incision. This group was matched with a selected control group that fulfilled all of the inclusion/exclusion criteria. Patient characteristics, pre-operative PT, HCT, PLT and MELD were identical between groups. Prophylactic application of rFVIIA reduced packed red blood cells (3.9 +/- 2.6 versus 6.9 +/- 2.3 U, P = 0.01) and fresh-frozen plasma (FFP) (12.6 +/- 6 versus 19.8 +/- 7 U, P = 0.018) transfusion requirements when compared with the control group. FFP administration in the first 24 h after surgery was also significantly less in the rVIIa group when compared with the control group (388 +/- 385 versus 1225 +/- 701 mL, P = 0.003). Hospital stay following transplantation tended to be shorter in the rFVIIa group, albeit statistical significance was not achieved (11 +/- 7.3 versus 7.9 +/- 2.7, P = 0.2). All but one patient in the control group survived for 30 days after transplantation. In a selected group of patients with prolonged PT and high MELD score, the prophylactic application of rFVIIa at the start of the OLT may reduce perioperative transfusion requirements.

Elective Transjugular Intrahepatic Portosystemic Shunt Creation for Portal Decompression in the Immediate Pretransplantation Period in Adult Living Related Liver Transplant Recipient Candidates: Preliminary Results

PURPOSE

To evaluate (i) the efficacy of purposeful creation of transjugular intrahepatic portosystemic shunts (TIPS) before transplantation to optimize potential living related liver transplantation (LRLTx) and (ii) the efficacy of TIPS creation in this setting in reducing perioperative resource utilization.

MATERIALS AND METHODS

Retrospective review was performed of the records of patients who underwent adult LRLTx with or without preoperative TIPS creation from October 2003 through April 2005. Patients were evaluated for preoperative parameters (Child-Pugh class, Model for End-stage Liver Disease score, Acute Physiology and Chronic Health Evaluation [APACHE] II score, and coagulation parameters), intraoperative parameters (blood transfusion requirements and operative time), and postoperative parameters (intensive care unit stay, hospital stay, and 30-day repeat operation and mortality rates). Comparison between the two treatment groups was made with the Mann-Whitney U test. Within the TIPS group, comparison of blood transfusion requirements was performed by one-way analysis of variance based on the degree of portosystemic gradient reduction after TIPS creation.

RESULTS

Sixteen patients were included in the TIPS group, and 12 patients were included in the group without TIPS. Median time between TIPS and transplantation was 2 days. There was no statistical difference in the preoperative, intraoperative, and postoperative parameters between groups except for the APACHE II score (P<.002), which was higher in the TIPS group. Despite this, the outcome and postoperative hospital resource utilization were similar between groups. Intraoperative blood transfusion based on the degree of portosystemic gradient reduction after TIPS creation was not significantly different between groups.

CONCLUSIONS

Newly created TIPS do not interfere with the intraoperative technical and perioperative clinical aspects of adult LRLTx. Preoperative TIPS creation before transplantation may reduce the postoperative morbidity and mortality seen in liver transplant recipients who have a greater APACHE II score at the outset of treatment.