The role of early extubation on short-term outcomes after liver transplantation - A systematic review, meta-analysis and expert recommendations.

BACKGROUND: Early extubation in liver transplantation (LT) and its potential benefits such as reduction in pulmonary complications and enhanced postoperative recovery have been described. The extent of the effect of early extubation on short-term outcomes after LT across the published literature is to the best of our knowledge unknown. OBJECTIVES: The objective of this systematic review and meta-analysis was to determine whether early extubation improves immediate and short-term outcomes after LT and to provide expert recommendations. DATA SOURCES: Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central. METHODS: A systematic review and meta-analysis on short-term outcomes after early extubation in LT was performed (CRD42021241402), following PRISMA guidelines and quality of evidence (QOE) and recommendations grading using the GRADE approach, derived from an international experts panel. Endpoints were reintubation rates, pulmonary and other complications/organ dysfunction, intensive care unit (ICU) and hospital length of stay (LOS). RESULTS: Of 831 screened articles, 20 observational studies with a total of 3573 patients addressing early extubation protocols were included, of which 12 studies compared results after early versus deferred extubation. Reintubation and pulmonary complication rates were lower in the early versus deferred extubation groups (OR 0.29, CI 0.22-0.39; OR 0.17, CI 0.09-0.33, respectively). ICU and hospital LOS were shorter in eight out of eight and seven out of eight comparative studies, respectively. CONCLUSIONS: Early extubation after LT is associated with improved short-term outcomes after LT and should be performed in the majority of patients (QOE; Moderate to low | Grade of Recommendation; Strong). Randomized controlled trials using standardized definitions of early extubation and short-term outcomes are needed to demonstrate causality, validate and allow comparability of the results.

Not All Piggybacks Are Equal: A Retrospective Cohort Analysis of Variation in Anhepatic Transcaval Pressure Gradient and Acute Kidney Injury During Liver Transplant.

OBJECTIVES: Complete inferior vena cava clamping in cavalreplacement during livertransplantis associated with substantial physiological derangement and postoperative morbidity. Partial clamping in the piggyback technique may be relatively protective, but evidence is lacking. Having observed substantial variation in transhepatic inferior vena cava pressure gradient with piggyback, we hypothesized that the causative mechanism is the extent of caval clamping rather than the surgical approach. MATERIALS AND METHODS: We used internal jugular and femoral catheters to estimate suprahepatic and infrahepatic inferior vena cava pressures during clamping. Pressure gradients were calculated, and distributions were compared by surgical technique. We estimated adjusted odds ratios for pressure gradient on acute kidney injury at 72 hours. RESULTS: In 115 case records, we observed substantial variation in maximum pressure gradient; median values were 18.0 mm Hg(interquartile range, 8.0-25.0 mm Hg) with the piggyback technique and 24.0 mm Hg (interquartile range, 19.5-27.0 mm Hg) with caval replacement. Incidence of acute kidney injury was 25% (29 patients). Pressure gradient was linearly associated with probability of acute kidney injury (odds ratio, 1.06; 95% CI, 1.01-1.13). CONCLUSIONS: We report 2 novel findings. (1) Anhepatic inferior vena cavapressuregradient variedsubstantially in individuals undergoing piggyback, and (2) gradient was positively associatedwith early acute kidney injury. We hypothesize that this (unmeasured) variation explains the conflictingfindings ofprevious studies that compared surgical techniques. Also, we propose that caval pressure gradient could be routinely assessed to optimize real-time piggyback clamp position during livertransplant surgery.

Intraoperative hypercoagulability during liver transplantation as demonstrated by thromboelastography.

Thrombotic complications are more common in liver disease than might be expected because of the coagulopathy described by conventional coagulation tests. Some of these complications may be life-threatening. The phenomenon of hypercoagulation is associated with complications in many populations, but the incidence in liver transplant recipients is unclear. We performed a retrospective database review of intraoperative thromboelastography (TEG) for 124 liver transplant recipients. We assessed the prevalence of hypercoagulation in this group and investigated the relative frequency of both shortened TEG reaction times (R times) and increased net clot strength (G) values. These findings were correlated with thrombotic complications. At the baseline, the prevalence of high G values was 15.53% on native TEG, and the prevalence of shortened R times was 6.80% on native-heparinase TEG. Patients with cholestatic pathologies had particularly high rates of hypercoagulation (42.9% with primary biliary cirrhosis and 85.7% with primary sclerosing cholangitis), but hypercoagulation was also common in patients with fulminant hepatic failure (50%) and nonalcoholic steatohepatitis (37.5%). There was a poor correlation between the TEG R time and the international normalized (INR), with 37.7% of TEG analyses demonstrating a short R time with an INR > 2. Six of the patients developed early hepatic artery thrombosis (5%); 3 of these patients had TEG evidence of high G values (P = 0.25), and 4 had short R times (not significant). In conclusion, intraoperative TEG evidence of high G values and short R times is relatively common in liver transplantation. It is unclear what bearing this condition has on thrombotic complications. Conventional coagulation tests have no ability to diagnose this condition. It is conceivable that such patients may come to harm if hypercoagulability is unrecognized and, therefore, inappropriately managed.