Vascular occlusion for elective liver resections

Efficacy and safety of terlipressin infusion during liver surgery: a meta-analysis

Although numerous studies have investigated terlipressin (TP) administration in liver surgery to mitigate bleeding, its efficacy remains controversial. This meta-analysis evaluates the effects of TP on estimated blood loss (EBL), blood transfusion requirements, and patient outcomes. We systematically searched PubMed, EMBASE, Cochrane Library, and Web of Science (WOS) for studies on perioperative TP use in liver surgery from their inception through February 2024. Only English-language publications were included. Primary outcomes included EBL and allogeneic blood transfusion volume. Twelve studies involving 988 eligible subjects were included. No significant differences were observed in EBL (weighted mean difference [WMD] =  - 99.09; 95% confidence interval [CI], - 318.41 to 120.24; P = 0.38), red blood cell (RBC) transfusion volume (standardized mean difference [SMD] =  - 0.10; 95% CI =  - 0.74 to 0.54; P = 0.76), or fresh frozen plasma (FFP) transfusion volume (SMD = 0.07; 95% CI =  - 0.24 to 0.37; P = 0.67). Subgroup analysis demonstrated that continuous TP infusion significantly reduced intraoperative EBL (WMD =  - 336.22; 95% CI =  - 562.13 to - 110.31; P = 0.004). TP infusion does not reduce intraoperative EBL or allogeneic blood transfusion requirements in liver surgery. However, continuous TP infusion may lower EBL.PROSPERO registration number: CRD42023450333.

Efficacy and safety of terlipressin infusion during liver surgery: a protocol for systematic review and meta-analysis

INTRODUCTION

Liver disease causes 2 million deaths annually, accounting for 4% of all deaths worldwide. Liver surgery is one of the effective therapeutic options. Bleeding is a major complication during liver surgery. Perioperative bleeding and allogeneic blood transfusion may deteriorate the prognosis. Terlipressin (TP), a synthetic analogue of the antidiuretic hormone, may reduceblood loss during abdominal surgery. Several clinical centres have attempted to use TP during liver surgery, but the evidence for its effectiveness in reducing blood loss and the need for allogeneic blood transfusion, as well as its safety during the perioperative period, remains unclear. The aim of this systematic review and meta-analysis is to evaluate the efficacy and safety of TP in reducing blood loss and allogeneic blood transfusion needs during liver surgery.

METHODS AND ANALYSIS

We will search PubMed, EMBASE, the Cochrane Library and Web of Science for studies on perioperative use of TP during liver surgery from inception to July 2023. We will limit the language to English, and two reviewers will independently screen and select articles. The primary study outcomes are estimated blood loss and the need for allogeneic blood transfusion. Secondary outcomes include operating time, intensive care unit stay, length of stay, intraoperative urine output, acute kidney injury rate, postoperative complications, hepatic and renal function during follow-up, and TP-related adverse effects. We will include studies that met the following criteria: (1) randomised controlled trials (RCTs), cohort studies or case-control studies; (2) the publication time was till July 2023; (3) adult patients (≥18 years old) undergoing elective liver surgery; (4) comparison of TP with other treatments and (5) the study includes at least one outcome. We will exclude animal studies, case reports, case series, non-original articles, reviews, paediatric articles, non-controlled trials, unpublished articles, non-English articles and other studies that are duplicates. We will use Review Manager V.5.3 software for meta-analysis and perform stratification analysis for the study quality of RCTs based on the Jadad score. For cohort or case-control studies, the study quality will be analysed based on Newcastle-Ottawa Scale scores. Grading of Recommendations, Assessment, Development and Evaluation will be used to assess confidence in the cumulative evidence. For primary outcomes, we will conduct subgroup analyses based on meta-regression. We will also perform leave-one-out sensitivity analyses to evaluate the effect of each individual study on the combined results by removing the individual studies one by one for outcomes with significant heterogeneity. The protocol follows the Cochrane Handbook for Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols guidelines.

ETHICS AND DISSEMINATION

This study is a secondary analysis of existing data; therefore, it does not require ethical approval. We will disseminate the results through peer-reviewed publications.

PROSPERO REGISTRATION NUMBER

CRD42023450333.

Fibrin-based haemostatic agents for reducing blood loss in adult liver resection

BACKGROUND

Liver resection is the optimal treatment for selected benign and malignant liver tumours, but it can be associated with significant blood loss. Numerous anaesthetic and surgical techniques have been developed to reduce blood loss and improve perioperative outcomes. One such technique is the application of topical fibrin-based haemostatic agents (FBHAs) to the resection surface. There is no standard practice for FBHA use, and a variety of commercial agents and devices are available, as well as non-FBHAs (e.g. collagen-based agents). The literature is inconclusive on the effectiveness of these methods and on the clinical benefits of their routine use.

OBJECTIVES

To evaluate the benefits and harms of fibrin-based haemostatic agents in reducing intraoperative blood loss in adults undergoing liver resection.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group (CHBG) Controlled Trials Register, CENTRAL, MEDLINE, Embase, LILACS, Science Citation Index Expanded, and Conference Proceedings Citation Index-Science up to 20 January 2023. We also searched online trial registries, checked the reference lists of all primary studies, and contacted the authors of included trials for additional published or unpublished trials.

SELECTION CRITERIA

We considered for inclusion all randomised clinical trials evaluating FBHAs versus no topical intervention or non-FBHAs, irrespective of publication type, publication status, language of publication, and outcomes reported. Eligible participants could have any liver pathology and be undergoing major or minor liver resections through open or laparoscopic surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the results of the literature search and used data extraction forms to collate the results. We expressed dichotomous outcome results as risk ratios (RRs) and continuous outcome results as mean differences (MDs), each with their corresponding 95% confidence interval (CI). We used a random-effects model for the main analyses. Our primary outcomes were perioperative mortality, serious adverse events, haemostatic efficacy, and health-related quality of life. Our secondary outcomes were efficacy as sealant, adverse events considered non-serious, operating time, and length of hospital stay. We assessed the certainty of the evidence with GRADE and presented results in two summary of findings tables.

MAIN RESULTS

We included 22 trials (2945 participants) evaluating FBHAs versus no intervention or non-FBHAs; 19 trials with 2642 participants provided data for the meta-analyses. Twelve trials reported commercial funding, one trial reported no financial support, and nine trials provided no information on funding. Below we present the most clinically relevant outcome results, also displayed in our summary of findings table. Fibrin-based haemostatic agents versus no intervention Six trials (1001 participants) compared FBHAs with no intervention. One trial was at low risk of bias in all five domains, and all other trials were at high or unclear risk of bias in at least one domain. Two trials were at high risk of bias related to blinding. It is unclear if FBHAs compared with no intervention have an effect on perioperative mortality (RR 2.58, 95% CI 0.89 to 7.44; 4 trials, 782 participants), serious adverse events (RR 0.96, 95% CI 0.88 to 1.05; 4 trials, 782 participants), postoperative transfusion (RR 1.04, 95% CI 0.77 to 1.40; 5 trials, 864 participants), reoperation (RR 2.92, 95% CI 0.58 to 14.61; 2 trials, 612 participants), or postoperative bile leak (RR 1.00, 95% CI 0.67 to 1.48; 4 trials, 782 participants), as the certainty of evidence was very low for all these outcomes. Fibrin-based haemostatic agents versus non-fibrin-based haemostatic agents Sixteen trials (1944 participants) compared FBHAs with non-FBHAs. All trials had at least one domain at high or unclear risk of bias. Twelve trials were at high risk of bias related to blinding. It is unclear if FBHAs compared with non-FBHAs have an effect on perioperative mortality (RR 1.03, 95% CI 0.62 to 1.72; 11 trials, 1436 participants), postoperative transfusion (RR 0.92, 95% CI 0.68 to 1.25; 7 trials, 599 participants), reoperation (RR 0.48, 95% CI 0.25 to 0.90; 3 trials, 358 participants), or postoperative bile leak (RR 1.15, 95% CI 0.60 to 2.21; 9 trials, 1115 participants), as the certainty of evidence was very low for all these outcomes. FBHAs compared with non-FBHAs may have little or no effect on the risk of serious adverse events (RR 0.99, 95% CI 0.95 to 1.03; 9 trials, 1176 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

The evidence for the outcomes in both comparisons (FBHAs versus no intervention and FBHAs versus non-FBHAs) was of very low certainty (or low certainty in one instance) and cannot justify the routine use of FBHAs to reduce blood loss in adult liver resection. While the meta-analysis showed a reduced risk of reoperation with FBHAs compared with non-FBHAs, the analysis was confounded by the small number of trials reporting the event and the risk of bias in all these trials. Future trials should focus on the use of FBHAs in people undergoing liver resection who are at particularly high risk of bleeding. Investigators should evaluate clinically meaningful and patient-important outcomes and follow the SPIRIT and CONSORT statements.

Hepatocyte SGK1 activated by hepatic ischemia-reperfusion promotes the recurrence of liver metastasis via IL-6/STAT3

BACKGROUND

Liver metastasis is the leading cause of death in patients with colorectal cancer (CRC). Surgical resection of the liver metastases increases the incidence of long-term survival in patients with colorectal liver metastasis (CRLM). However, many patients experience CRLM recurrence after the initial liver resection. As an unavoidable pathophysiological process in liver surgery, liver ischemia-reperfusion (IR) injury increases the risk of tumor recurrence and metastasis.

METHODS

Colorectal liver metastasis (CRLM) mouse models and mouse liver partial warm ischemia models were constructed. The levels of lipid peroxidation were detected in cells or tissues. Western Blot, qPCR, elisa, immunofluorescence, immunohistochemistry, scanning electron microscope, flow cytometry analysis were conducted to evaluate the changes of multiple signaling pathways during CRLM recurrence under liver ischemia-reperfusion (IR) background, including SGK1/IL-6/STAT3, neutrophil extracellular traps (NETs) formation, polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) infiltration.

RESULTS

Hepatocyte serum/glucocorticoid regulated kinase 1 (SGK1) was activated in response to hepatic ischemia-reperfusion injury to pass hepatocyte STAT3 phosphorylation and serum amyloid A (SAA) hyperactivation signals in CRLM-IR mice, such regulation is dependent on SGK-activated IL-6 autocrine. Administration of the SGK1 inhibitor GSK-650394 further reduced ERK-related neutrophil extracellular traps (NETs) formation and polymorphonucler myeloid-derived suppressor cells (PMN-MDSC) infiltration compared with targeting hepatocyte SGK1 alone, thereby alleviating CRLM in the context of IR.

CONCLUSIONS

Our study demonstrates that hepatocyte and immune cell SGK1 synergistically promote postoperative CRLM recurrence in response to hepatic IR stress, and identifies SGK1 as a translational target that may improve postoperative CRLM recurrence.

Effect of intraoperative hypovolemic phlebotomy on transfusion and clinical outcomes in patients undergoing hepatectomy: a retrospective cohort study

BACKGROUND

There is no consensus on how to best achieve a low central venous pressure during hepatectomy for the purpose of reducing blood loss and red blood cell (RBC) transfusions. We analyzed the associations between intraoperative hypovolemic phlebotomy (IOHP), transfusions, and postoperative outcomes in cancer patients undergoing hepatectomy.

METHODS

Using surgical and transfusion databases of patients who underwent hepatectomy for cancer at one institution (11 January 2011 to 22 June 2017), we retrospectively analyzed associations between IOHP and RBC transfusion on the day of surgery (primary outcome), and with total perioperative transfusions, intraoperative blood loss, and postoperative complications (secondary outcomes). We fitted logistic regression models by inverse probability of treatment weighting to adjust for confounders and reported adjusted odds ratio (aOR).

RESULTS

There were 522 instances of IOHP performed during 683 hepatectomies, with a mean (standard deviation) volume of 396 (119) mL. The IOHP patients had a 6.9% transfusion risk on the day of surgery compared with 12.4% in non-IOHP patients (aOR, 0.53; 95% confidence interval [CI], 0.29 to 0.98; P = 0.04). Total perioperative RBC transfusion tended to be lower in IOHP patients compared with non-IOHP patients (14.9% vs 22.4%, respectively; aOR, 0.72; 95% CI, 0.44 to 1.16; P = 0.18). In patients with a predicted risk of ≥ 47.5% perioperative RBC transfusion, 24.6% were transfused when IOHP was used compared with 56.5% without IOHP. The incidence of severe postoperative complications (Clavien-Dindo scores ≥ 3) was similar in patients whether or not IOHP was performed (15% vs 16% respectively; aOR, 0.97; 95% CI, 0.53 to 1.54; P = 0.71).

CONCLUSIONS

The use of IOHP during hepatectomy was associated with less RBCs transfused on the same day of surgery. Trials comparing IOHP with other techniques to reduce blood loss and transfusion are needed in liver surgery.

Shorter Survival after Liver Pedicle Clamping in Patients Undergoing Liver Resection for Hepatocellular Carcinoma Revealed by a Systematic Review and Meta-Analysis

Simple Summary

Hepatocellular carcinoma (HCC) is the most prevalent tumor of the liver and represents the second most common cause of oncological-related deaths worldwide. Despite all progress made in the field, surgical resection or liver transplantation are, at the moment, the only curative therapies available. Liver resection, especially for large, central tumors, are at risk of important bleeding. Significative hemorrhage during HCC resections have been linked to an increased rate of post-operative complications and tumor recurrence. Therefore, hepatic pedicle clamping during surgery has been used in order to reduce the bleeding risks. However, this method induces ischemia/reperfusion injuries, which has also been associated with tumor recurrence. For this reason, we aimed to evaluate if pedicle clamping is indeed associated with tumor recurrence and shorter survival, by performing a systematic review of the literature and meta-analysis.

Abstract

Liver pedicle clamping minimizes surgical bleeding during hepatectomy. However, by inducing ischemia-reperfusion injury to the remnant liver, pedicle clamping may be associated with tumor recurrence in the regenerating liver. Hepatocellular carcinoma (HCC) having a high rate of recurrence, evidences demonstrating an eventual association with pedicle clamping is strongly needed. We did a systematic review of the literature until April 2020, looking at studies reporting the impact of liver pedicle clamping on long-term outcomes in patients undergoing liver resection for HCC. Primary and secondary outcomes were overall survival (OS) and disease-free survival, respectively. Results were obtained by random-effect meta-analysis and expressed as standardized mean difference (SMD). Eleven studies were included, accounting for 8087 patients. Results of seven studies were pooled in a meta-analysis. Findings indicated that, as compared to control patients who did not receive liver pedicle clamping, those who did had a significantly shorter OS (SMD = −0.172, 95%CI: −0.298 to −0.047, p = 0.007, I² = 76.8%) and higher tumor recurrence rates (odds ratio 1.36 1.01 to 1.83. p = 0.044, I² = 50.7%). This meta-analysis suggests that liver pedicle clamping may have a deleterious impact on long-term outcomes. An individual patient-data meta-analysis of randomized trials evaluating liver pedicle clamping is urgently needed.

Red blood cell transfusion in liver resection

BACKGROUND

Several modalities exist for the management of hepatic neoplasms. Resection, the most effective approach, carries significant risk of hemorrhage. Blood loss may be corrected with red blood cell transfusion (RBCT) in the short term, but may ultimately contribute to negative outcomes.

PURPOSE

Using available literature, we seek to define the frequency and risk factors of blood loss and transfusion following hepatectomy. The impact of blood loss and RBCT on short- and long-term outcomes is explored with an emphasis on peri-operative methods to reduce hemorrhage and transfusion.

RESULTS

Following hepatic surgery, 25.2-56.8% of patients receive RBCT. Patients who receive RBCT are at increased risk of surgical morbidity in a dose-dependent manner. The relationship between blood transfusion and surgical mortality is less apparent. RBCT might also impact long-term oncologic outcomes including disease recurrence and overall survival. Risk factors for bleeding and blood transfusion include hemoglobin concentration < 12.5 g/dL, thrombocytopenia, pre-operative biliary drainage, presence of background liver disease (such as cirrhosis), coronary artery disease, male gender, tumor characteristics (type, size, location, presence of vascular involvement), extent of hepatectomy, concomitant extrahepatic organ resection, and operative time. Strategies to mitigate blood loss or transfusion include pre-operative (iron, erythropoietin), intra-operative (vascular occlusion, parenchymal transection techniques, hemostatic agents, antifibrinolytics, low central pressure, hemodilution, autologous blood recycling), and post-operative (normothermia, correction of coagulopathy, optimization of nutrition, restrictive transfusion strategy) methods.

CONCLUSION

Blood loss during hepatectomy is common and several risk factors can be identified pre-operatively. Blood loss and RBCT during hepatectomy is associated with post-operative morbidity and mortality. Disease-free recurrence, disease-specific survival, and overall survival may be associated with blood loss and RBCT during hepatectomy. Attention to pre-operative, intra-operative, and post-operative strategies to reduce blood loss and RBCT is necessary.

Influence of Hydrogen-rich Saline on Hepatocyte Autophagy During Laparoscopic Liver Ischaemia-reperfusion Combined Resection Injury in Miniature Pigs

Introduction

The purpose of this study was to investigate the protective effect of hydrogen-rich saline (HRS) against liver ischaemia-reperfusion combined resection injury.

Material and Methods

Eighteen miniature pigs were randomly divided into three groups: a sham operated group (sham group, laparoscopic liver ischaemia-reperfusion combined resection injury group (IRI group), and a hydrogen-rich saline intervention group (IRI + HRS group). Samples of hepatic tissue and serum were collected at the time of reperfusion and then 3 h, 1 d, and 3 d post reperfusion. Liver function, oxidative stress, autophagy-related mRNA genes, and protein expression were evaluated. Changes in cell and tissue ultrastructure were examined by transmission electron microscopy.

Results

Compared with the sham group, the level of autophagy of hepatocytes increased in the IRI and IRI + HRS groups, corresponding to high oxidative stress and severe liver function injury. Liver function, antioxidant content, autophagy levels, and liver injury were improved after intervention with HRS in the IRI + HRS group compared with the IRI group.

Conclusion

Intervention with hydrogen-rich saline could exert a protective effect against liver ischaemia-reperfusion combined resection injury through the reduction of oxidative stress and hepatocyte autophagy.

Preserving hepatic artery flow during portal triad blood occlusion improves regeneration of the remnant liver in rats with obstructive jaundice following partial hepatectomy

In certain cases, major hepatectomy is essential and inevitable in patients with hilar cholangiocarcinoma and obstructive jaundice (OJ). The current study was designed to evaluate effects of a novel method of portal blood occlusion, where the portal vein was occluded (OPV) and the hepatic artery flow was preserved in rats with OJ that underwent partial hepatectomy. OJ was induced in rats by ligation of the common bile duct for 7 days. Subsequently, OJ rats underwent hepatectomy removing 76% of the liver following occlusion of the portal triad (OPT), OPV or without portal blood occlusion. Liver blood flow (LBF), liver damage and regeneration were assessed. The safety limit for the duration of liver ischemia was 20 min for OPT and 40 min for OPV in rats with OJ. OPT and OPV methods resulted in significantly decreased microvascular LBF in rats with OJ from 529.53±91.55 laser speckle perfusion units (LSPU) in the control to 136.89±32.32 and 183.99±49.25 LSPU, respectively. Liver damage was assessed analyzing levels of serum alanine transaminase and direct bilirubin, determining interleukin-1β and tumor necrosis factor-α expression and histological examination. It was demonstrated that liver damage and caspase-3 and −9 expression in the liver were substantially reduced in the OPV group compared with the OPT group. In addition, the OPV method significantly improved liver regeneration in OJ rats, as indicated by increased rates of liver regeneration and expression of proliferating cell nuclear antigen and Ki-67 compared with the OPT group. Therefore, the OPV method may prolong the duration of portal blood occlusion, reduce liver injury and improve liver regeneration by preserving hepatic arterial flow during portal blood control in rats with OJ undergoing partial hepatectomy. The current study describes a novel technique, which may be applied in liver surgery in patients with complex jaundice.

Methods to decrease blood loss during liver resection: a network meta-analysis

BACKGROUND

Liver resection is a major surgery with significant mortality and morbidity. Specialists have tested various methods in attempts to limit blood loss, transfusion requirements, and morbidity during elective liver resection. These methods include different approaches (anterior versus conventional approach), use of autologous blood donation, cardiopulmonary interventions such as hypoventilation, low central venous pressure, different methods of parenchymal transection, different methods of management of the raw surface of the liver, different methods of vascular occlusion, and different pharmacological interventions. A surgeon typically uses only one of the methods from each of these seven categories. The optimal method to decrease blood loss and transfusion requirements in people undergoing liver resection is unknown.

OBJECTIVES

To assess the effects of different interventions for decreasing blood loss and blood transfusion requirements during elective liver resection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and Science Citation Index Expanded to September 2015 to identify randomised clinical trials. We also searched trial registers and handsearched the references lists of identified trials.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or publication status) comparing different methods of decreasing blood loss and blood transfusion requirements in people undergoing liver resection.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified trials and collected data. We assessed the risk of bias using Cochrane domains. We conducted a Bayesian network meta-analysis using the Markov chain Monte Carlo method in WinBUGS 1.4, following the guidelines of the National Institute for Health and Care Excellence Decision Support Unit guidance documents. We calculated the odds ratios (OR) with 95% credible intervals (CrI) for the binary outcomes, mean differences (MD) with 95% CrI for continuous outcomes, and rate ratios with 95% CrI for count outcomes, using a fixed-effect model or random-effects model according to model-fit. We assessed the evidence with GRADE.

MAIN RESULTS

We identified 67 randomised clinical trials involving a total of 6197 participants. All the trials were at high risk of bias. A total of 5771 participants from 64 trials provided data for one or more outcomes included in this review. There was no evidence of differences in most of the comparisons, and where there was, these differences were in single trials, mostly of small sample size. We summarise only the evidence that was available in more than one trial below. Of the primary outcomes, the only one with evidence of a difference from more than one trial under the pair-wise comparison was in the number of adverse events (complications), which was higher with radiofrequency dissecting sealer than with the clamp-crush method (rate ratio 1.85, 95% CrI 1.07 to 3.26; 250 participants; 3 studies; very low-quality evidence). Among the secondary outcomes, the only differences we found from more than one trial under the pair-wise comparison were the following: blood transfusion (proportion) was higher in the low central venous pressure group than in the acute normovolemic haemodilution plus low central venous pressure group (OR 3.19, 95% CrI 1.56 to 6.95; 208 participants; 2 studies; low-quality evidence); blood transfusion quantity (red blood cells) was lower in the fibrin sealant group than in the control (MD -0.53 units, 95% CrI -1.00 to -0.07; 122 participants; 2; very low-quality evidence); blood transfusion quantity (fresh frozen plasma) was higher in the oxidised cellulose group than in the fibrin sealant group (MD 0.53 units, 95% CrI 0.36 to 0.71; 80 participants; 2 studies; very low-quality evidence); blood loss (MD -0.34 L, 95% CrI -0.46 to -0.22; 237 participants; 4 studies; very low-quality evidence), total hospital stay (MD -2.42 days, 95% CrI -3.91 to -0.94; 197 participants; 3 studies; very low-quality evidence), and operating time (MD -15.32 minutes, 95% CrI -29.03 to -1.69; 192 participants; 4 studies; very low-quality evidence) were lower with low central venous pressure than with control. For the other comparisons, the evidence for difference was either based on single small trials or there was no evidence of differences. None of the trials reported health-related quality of life or time needed to return to work.

AUTHORS' CONCLUSIONS

Paucity of data meant that we could not assess transitivity assumptions and inconsistency for most analyses. When direct and indirect comparisons were available, network meta-analysis provided additional effect estimates for comparisons where there were no direct comparisons. However, the paucity of data decreases the confidence in the results of the network meta-analysis. Low-quality evidence suggests that liver resection using a radiofrequency dissecting sealer may be associated with more adverse events than with the clamp-crush method. Low-quality evidence also suggests that the proportion of people requiring a blood transfusion is higher with low central venous pressure than with acute normovolemic haemodilution plus low central venous pressure; very low-quality evidence suggests that blood transfusion quantity (red blood cells) was lower with fibrin sealant than control; blood transfusion quantity (fresh frozen plasma) was higher with oxidised cellulose than with fibrin sealant; and blood loss, total hospital stay, and operating time were lower with low central venous pressure than with control. There is no evidence to suggest that using special equipment for liver resection is of any benefit in decreasing the mortality, morbidity, or blood transfusion requirements (very low-quality evidence). Radiofrequency dissecting sealer should not be used outside the clinical trial setting since there is low-quality evidence for increased harm without any evidence of benefits. In addition, it should be noted that the sample size was small and the credible intervals were wide, and we cannot rule out considerable benefit or harm with a specific method of liver resection.

How much ischemia can the liver tolerate during resection?

The use of vascular inflow occlusion (VIO, also known as the Pringle maneuver) during liver surgery prevents severe blood loss and the need for blood transfusion. The most commonly used technique for VIO entails clamping of the portal triad, which simultaneously occludes the proper hepatic artery and portal vein. Although VIO is an effective technique to reduce intraoperative blood loss, it also inevitably inflicts hepatic ischemia/reperfusion (I/R) injury as a side effect. I/R injury induces formation of reactive oxygen species that cause oxidative stress and cell death, ultimately leading to a sterile inflammatory response that causes hepatocellular damage and liver dysfunction that can result in acute liver failure in most severe cases. Since the duration of ischemia correlates positively with the severity of liver injury, there is a need to find the balance between preventing severe blood loss and inducing liver damage through the use of VIO. Although research on the maximum duration of hepatic ischemia has intensified since the beginning of the 1980s, there still is no consensus on the tolerable upper limit. Based on the available literature, it is concluded that intermittent and continuous VIO can both be used safely when ischemia times do not exceed 120 min. However, intermittent VIO should be the preferred technique in cases that require >120 min duration of ischemia.

Methods of haemostasis during liver resection--a UK national survey

BACKGROUND

Although haemorrhage is a major cause of morbidity and mortality in liver surgery, there is very little available guidance on its management.

METHODS

The aim of this study was to identify current practice in the UK in this regard. An online survey was created and hepatobiliary (HPB) specialists who were members of a specialist society and others who were known practitioners were invited by e-mail to complete the survey anonymously.

RESULTS

Fifty-one percent responded (n = 36/70), and most of these respondents worked at large HPB centres (>100 liver resections/year; n = 24, 66%). Not all questionnaires were fully completed by the individual surgeons. Thirty-eight percent of the surgeons routinely used Pringle's manoeuvre. Most surgeons used ligation of the inflow vessels (n = 16, 44%) and stapled the outflow vessels (n = 15, 42%). The Cavitron ultrasonic surgical aspirator (CUSA; 54%, 13/24) was preferred for parenchymal transection. The majority routinely used haemostatic adjuncts (n = 22, 62%), whilst 33% (n = 12) used them occasionally. Twenty-three (64%) felt manufactured haemostatic adjuncts played a major role in maintaining haemostasis and 19 preferred fibrin-based products.

CONCLUSION

The Pringle manoeuvre is a popular technique amongst specialist UK liver surgeons and the CUSA is used by nearly half of the surgeons. Despite the absence of definitive evidence for their benefit, manufactured haemostatic adjuncts are still widely used, especially the fibrin-based adjuncts.

Perioperative ischaemia-induced liver injury and protection strategies: An expanding horizon for anaesthesiologists

Liver resection is an effective modality of treatment in patients with primary liver tumour, metastases from colorectal cancers and selected benign hepatic diseases. Its aim is to resect the grossly visible tumour with clear margins and to ensure that the remnant liver mass has sufficient function which is adequate for survival. With the advent of better preoperative imaging, surgical techniques and perioperative management, there is an improvement in the outcome with decreased mortality. This decline in postoperative mortality after hepatic resection has encouraged surgeons for more radical liver resections, leaving behind smaller liver remnants in a bid to achieve curative surgeries. But despite advances in diagnostic, imaging and surgical techniques, postoperative liver dysfunction of varied severity including death due to liver failure is still a serious problem in such patients. Different surgical and non-surgical techniques like reducing perioperative blood loss and consequent decreased transfusions, vascular occlusion techniques (intermittent portal triad clamping and ischaemic preconditioning), administration of pharmacological agents (dextrose, intraoperative use of methylprednisolone, trimetazidine, ulinastatin and lignocaine) and inhaled anaesthetic agents (sevoflurane) and opioids (remifentanil) have demonstrated the potential benefit and minimised the adverse effects of surgery. In this article, the authors reviewed the surgical and non-surgical measures that could be adopted to minimise the risk of postoperative liver failure following liver surgeries with special emphasis on ischaemic and pharmacological preconditioning which can be easily adapted clinically.

Cardiopulmonary interventions to decrease blood loss and blood transfusion requirements for liver resection

BACKGROUND

Blood loss during liver resection is considered one of the most important factors affecting the peri-operative outcomes of patients undergoing liver resection.

OBJECTIVES

To determine the benefits and harms of cardiopulmonary interventions to decrease blood loss and to decrease allogeneic blood transfusion requirements in patients undergoing liver resections.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until January 2012 to identify randomised trials.

SELECTION CRITERIA

We included all randomised clinical trials comparing various cardiopulmonary interventions aimed at decreasing blood loss and allogeneic blood transfusion requirements in patients undergoing liver resection. Trials were included irrespective of whether they included major or minor liver resections of normal or cirrhotic livers, vascular occlusion was used or not, and irrespective of the reason for liver resection.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion and independently extracted data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For each outcome we calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) based on intention-to-treat analysis or available case analysis. For dichotomous outcomes with only one trial included under the outcome, we performed the Fisher's exact test.

MAIN RESULTS

Ten trials involving 617 patients satisfied the inclusion criteria. The interventions included low central venous pressure (CVP), autologous blood donation, haemodilution, haemodilution with controlled hypotension, and hypoventilation. Only one or two trials were included under most comparisons. All trials had a high risk of bias. There was no significant difference in the peri-operative mortality in any of the comparisons: low CVP versus no intervention (3 trials, 0/88 (0%) patients in the low CVP group versus 1/89 (1.1%) patients in the no intervention group); autologous blood donation versus no intervention (1 trial, 0/40 (0%) versus 0/39 (0%)); haemodilution versus no intervention (2 trials, 1/73 (1.4%) versus 3/77 (3.9%) in one of these trials); haemodilution with controlled hypotension versus no intervention (1 trial, 0/10 (0%) versus 0/10 (0%)); haemodilution with bovine haemoglobin (HBOC-201) versus haemodilution with hydroxy ethyl starch (HES) (1 trial, 1/6 (16.7%) versus 0/6 (0%)); hypoventilation versus no intervention (1 trial, 0/40 (0%) versus 0/39 (0%)). None of the trials reported long-term survival or quality of life. The risk ratio of requiring allogeneic blood transfusion was significantly lower in the haemodilution versus no intervention groups (3 trials, 16/115 (weighted proportion = 14.2%) versus 41/118 (34.7%), RR 0.41 (95% CI 0.25 to 0.66), P = 0.0003); and for haemodilution with controlled hypotension versus no intervention (1 trial, 0/10 (0%) versus 10/10 (100%), P < 0.0001). There were no significant differences in the allogeneic transfusion requirements in the other comparisons which reported this outcome, such as low CVP versus no intervention, autologous blood donation versus control, and hypoventilation versus no intervention.

AUTHORS' CONCLUSIONS

None of the interventions seemed to decrease peri-operative morbidity or offer any long-term survival benefit. Haemodilution shows promise in the reduction of blood transfusion requirements in liver resection surgery. However, there is a high risk of type I (erroneously concluding that an intervention is beneficial when it is actually not beneficial) and type II errors (erroneously concluding that an intervention is not beneficial when it is actually beneficial) because of the few trials included, the small sample size in each trial, and the high risk of bias in the trials. Further randomised clinical trials with low risk of bias and random errors that assess clinically important outcomes such as peri-operative mortality are necessary to assess any cardiopulmonary interventions aimed at decreasing blood loss and blood transfusion requirements in patients undergoing liver resections. Trials need to be designed to assess the effect of a combination of different interventions in liver resections.

Non-cirrhotic liver tolerance to intermittent inflow occlusion during laparoscopic liver resection

While inflow occlusion techniques are accepted methods to reduce bleeding during open liver surgery, their use in laparoscopic liver resections are limited by possible effects of pneumoperitoneum on ischemia-reperfusion liver damage. This retrospective study was designed to investigate the impact of intermittent pedicle clamping (IPC) on patients with normal liver undergoing minor laparoscopic liver resections. Three matched groups of patients were retrospectively selected from our in-house database: 11 patients who underwent robot-assisted liver resection with IPC, and 16 and 11 patients who underwent robot-assisted liver resection without IPC and open liver resection with IPC, respectively. The primary end point was to assess differences in postoperative serum alanine, aspartate aminotransferase (ALT and AST) and bilirubin levels. The curves of serum AST, ALT and bilirubin levels in a span of time of five postoperative days were not significantly different between the three groups. IPC has no relevant effects on ischemia-reperfusion liver damage even in the presence of pneumoperitoneum.

Robot-assisted parenchymal-sparing liver surgery including lesions located in the posterosuperior segments

OBJECTIVE

The aim of the study is to describe techniques of robot-assisted parenchymal-sparing liver surgery.

BACKGROUND

Laparoscopy provides the same oncologic outcomes as open liver resection and better early outcome. Limitations of laparoscopy remain resections in posterior and superior liver segments, frequently approached with laparoscopic right hepatectomy, bleeding from the section line, and prolonged operative times when a combined procedure is needed.

METHODS

We retrospectively analyzed our series of robot-assisted liver resections between 2008 and September 2010 to evaluate whether robot assistance can overcome the limitations of laparoscopy.

RESULTS

A total of 23 patients underwent robot-assisted liver resection for a total of 21 subsegmentectomies, 6 segmentectomies, 2 segmentectomies S6 + subsegmentectomies S7, 1 bisegmentectomy S2-3, and 2 pericystectomies. In ten cases (47.8%) liver nodules were located in the posterior and superior liver segments. In three cases the tumor was in contact with a main portal branch and in two cases with a hepatic vein. In one case the tumor had contact with both hepatic vein and portal branch. In the latter cases a no-margin resection was carried out. In 16 cases (65.5%) liver resection was associated with a concomitant procedure (10 laparoscopic colectomies, 1 robotic rectal resection, 3 laparoscopic radiofrequency ablations, and 2 extensive adhesiolyses). Mean operative time was 280 ± 101 min, blood loss was 245 ± 254 ml, and mean hospital stay was 8.9 ± 9.4 days. Mortality was nil. One case of biliary leakage and two of intraoperative hemorrhage requiring transfusion were the main complications encountered.

CONCLUSIONS

Robot assistance allows optimal access to all liver segments and facilitates parenchymal-sparing surgery also for lesions located in the posterosuperior segments or in contact with main liver vessels.

Pharmacological interventions versus no pharmacological intervention for ischaemia reperfusion injury in liver resection surgery performed under vascular control

BACKGROUND

Vascular occlusion to reduce blood loss is used during elective liver resection but results in significant ischaemia reperfusion injury. This, in turn, might lead to significant postoperative liver dysfunction and morbidity. Various pharmacological drugs have been used with an intention to ameliorate the ischaemia reperfusion injury in liver resections.

OBJECTIVES

To assess the benefits and harms of different pharmacological agents versus no pharmacological interventions to decrease ischaemia reperfusion injury during liver resections where vascular occlusion was performed during the surgery.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until January 2009.

SELECTION CRITERIA

We included randomised clinical trials, irrespective of language or publication status, comparing any pharmacological agent versus placebo or no pharmacological agent during elective liver resections with vascular occlusion.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion and independently extracted the data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. We calculated the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis or available case analysis.

MAIN RESULTS

We identified a total of 15 randomised trials evaluating 11 different pharmacological interventions (methylprednisolone, multivitamin antioxidant infusion, vitamin E infusion, amrinone, prostaglandin E1, pentoxifylline, mannitol, trimetazidine, dextrose, allopurinol, and OKY 046 (a thromboxane A2 synthetase inhibitor)). All trials had high risk of bias. There were no significant differences between the groups in mortality, liver failure, or perioperative morbidity. The trimetazidine group had a significantly shorter hospital stay than control (MD -3.00 days; 95% CI -3.57 to -2.43). There were no significant differences in any of the clinically relevant outcomes in the remaining comparisons. Methylprednisolone improved the enzyme markers of liver function and trimetazidine, methylprednisolone, and dextrose reduced the enzyme markers of liver injury compared with controls. However, there is a high risk of type I and type II errors because of the few trials included, the small sample size in each trial, and the risk of bias.

AUTHORS' CONCLUSIONS

Trimetazidine, methylprednisolone, and dextrose may protect against ischaemia reperfusion injury in elective liver resections performed under vascular occlusion, but this is shown in trials with small sample sizes and high risk of bias. The use of these drugs should be restricted to well-designed randomised clinical trials before implementing them in clinical practice.

Pharmacological interventions for ischaemia reperfusion injury in liver resection surgery performed under vascular control

BACKGROUND

Vascular occlusion used during elective liver resection to reduce blood loss results in significant ischaemia reperfusion (IR) injury. This in turn leads to significant postoperative liver dysfunction and morbidity. Various pharmacological drugs have been used in experimental settings to ameliorate the ischaemia reperfusion injury in liver resections.

OBJECTIVES

To assess the relative benefits and harms of using one pharmacological intervention versus another pharmacological intervention to decrease ischaemia reperfusion injury during liver resections where vascular occlusion was performed during the surgery.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until January 2009.

SELECTION CRITERIA

We included randomised clinical trials, irrespective of language or publication status, comparing one pharmacological agent versus another pharmacological agent during elective liver resections with vascular occlusion.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion and independently extracted data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. We planned to calculate the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis or available case analysis. However, all outcomes were only reported on by single trials, and meta-analysis could not be performed. Therefore, we performed Fisher's exact test on dichotomous outcomes.

MAIN RESULTS

We identified a total of five randomised trials evaluating nine different pharmacological interventions (amrinone, prostaglandin E1, pentoxifylline, dopexamine, dopamine, ulinastatin, gantaile, sevoflurane, and propofol). All trials had high risk of bias. There was no significant difference between the groups in mortality, liver failure, or perioperative morbidity. The ulinastatin group had significantly lower postoperative enzyme markers of liver injury compared with the gantaile group. None of the other comparisons showed any difference in any of the other outcomes. However, there is a high risk of type I and type II errors because of the few trials included, the small sample size in each trial, and the risk of bias.

AUTHORS' CONCLUSIONS

Ulinastatin may have a protective effect against ischaemia reperfusion injury relative to gantaile in elective liver resections performed under vascular occlusion. The absolute benefit of this drug agent remains unknown. None of the drugs can be recommended for routine clinical practice. Considering that none of the drugs have proven to be useful to decrease ischaemia reperfusion injury, such trials should include a group of patients who do not receive any active intervention whenever possible to determine the pharmacological drug's absolute effects on ischaemia reperfusion injury in liver resections.

Methods of vascular occlusion for elective liver resections

BACKGROUND

Vascular occlusion is used to reduce blood loss during liver resection surgery. Various methods of vascular occlusion have been suggested.

OBJECTIVES

To compare the benefits and harms of different methods of vascular occlusion during elective liver resection.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until August 2008.

SELECTION CRITERIA

We included randomised clinical trials comparing different methods of vascular occlusion during elective liver resections (irrespective of language or publication status).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for inclusion and independently extracted the data. We calculated the risk ratio or mean difference with 95% confidence intervals using fixed-effect and random-effects models based on intention-to-treat or available data analysis.

MAIN RESULTS

Ten trials including 657 patients compared different methods of vascular occlusion. All trials were of high risk of bias. Only one or two trials were included under each comparison. There was no statistically significant differences in mortality, liver failure, or other morbidity between any of the comparisons.Hepatic vascular occlusion does not decrease the blood transfusion requirements. It decreases the cardiac output and increases the systemic vascular resistance. In the comparison between continuous portal triad clamping and intermittent portal triad clamping, four of the five liver failures occurred in patients with chronic liver diseases undergoing the liver resections using continuous portal triad clamping. In the comparison between selective inflow occlusion and portal triad clamping, all four patients with liver failure occurred in the selective inflow occlusion group. There was no difference in any of the other important outcomes in any of the comparisons.

AUTHORS' CONCLUSIONS

In elective liver resection, hepatic vascular occlusion cannot be recommended over portal triad clamping. Intermittent portal triad clamping seems to be better than continuous portal triad clamping at least in patients with chronic liver disease. There is no evidence to support selective inflow occlusion over portal triad clamping. The optimal method of intermittent portal triad clamping is not clear. There is no evidence for any difference between the ischaemic preconditioning followed by vascular occlusion and intermittent vascular occlusion for liver resection in patients with non-cirrhotic livers. Further randomised trials of low risk of bias are needed to determine the optimal technique of vascular occlusion.