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

Role of immune checkpoint inhibitor-based therapies for metastatic renal cell carcinoma in the first-line setting: A Bayesian network analysis

BACKGROUND

Several novel immune checkpoint inhibitor (ICI)-based treatments exhibited promising survival benefits for metastatic renal cell carcinoma (mRCC), yet there is no current guidance regarding the optimum first-line regimen. We performed this network analysis to compare the efficacy and safety of all available treatments for mRCC.

METHODS

A systematic search of literature was conducted up to April 30, 2019, and the analysis was done on a Bayesian fixed-effect model.

FINDINGS

Twenty-five randomized clinical trials (RCTs) involving 13,010 patients were included in this study. The results showed that for overall survival, pembrolizumab plus axitinib (hazard ratio [HR]: 0.53; 95% credible interval [CrI]: 0.38-0.73) and nivolumab plus ipilimumab (HR: 0.63; 95% CrI: 0.50-0.79) were significantly more effective than sunitinib, and pembrolizumab plus axitinib was probably (68%) to be the best choice. For progression-free survival, cabozantinib (HR: 0.66; 95% CrI: 0.46-0.94), pembrolizumab plus axitinib (HR: 0.69; 95% CrI: 0.57-0.84), avelumab plus axitinib (HR: 0.69; 95% CrI: 0.56-0.85), nivolumab plus ipilimumab (HR: 0.82; 95% CrI: 0.68-0.99), and atezolizumab plus bevacizumab (HR: 0.86; 95% CrI: 0.74-0.99) were statistically superior to sunitinib, and cabozantinib was likely (43%) to be the preferred options. Nivolumab plus ipilimumab (OR: 0.50; 95% CrI: 0.28-0.84), and atezolizumab plus bevacizumab (OR: 0.56; 95% CrI: 0.36-0.83) were associated with significantly lower rate of high-grade adverse events than sunitinib.

INTERPRETATION

Our findings demonstrate that pembrolizumab plus axitinib might be the best treatment for mRCC, while nivolumab plus ipilimumab has the most favorable balance between efficacy and acceptability, and may provide new guidance to make treatment decisions. FUND: This research was supported by the Henan Provincial Scientific and Technological Research Project (Grant No. 192102310036).

Radiofrequency-assisted liver resection: Technique and results

BACKGROUND

Radiofrequency (RF)-assisted liver resection allows non-anatomical liver resection with reduced blood loss and offers the opportunity for a combination of resection and ablation. However, there are still concerns with regard to postoperative complications related to this technique. In the present study, we discuss the technical aspects of RF-assisted liver resections and analyse the rate of perioperative complications, focusing on post-hepatectomy liver failure (PLF), bile leak and abscess, and mortality.

METHODS

Between 2001 and 2015, 857 consecutive open and laparoscopic elective RF-assisted liver resections for benign and malignant liver tumours were reviewed retrospectively to assess perioperative outcomes.

RESULTS

Median intraoperative blood loss was 130 mL, with 9.8% of patients requiring blood transfusion. Intra-abdominal collections requiring percutaneous drainage developed in 8.7% of all patients, while bile leak at resection margin developed in 2.8% of the cases. Major liver resection was performed in 34% of patients and the incidence of PLF was 1.5% with one directly related mortality (0.1%).

CONCLUSION

RF-assisted liver resection has evolved into a feasible and safe technique of liver resection with an acceptable incidence of perioperative morbidity and a low incidence of PLF and related mortality.

Spray Diathermy Versus Harmonic Scalpel Technique for Hepatic Parenchymal Transection of Living Donor

BACKGROUND

Liver parenchymal transection is the most invasive and challenging part in the living donor operation. The study was planned to compare the safety, efficacy, and outcome of harmonic scalpel versus spray diathermy as a method of parenchymal liver transection in donor hepatectomy.

PATIENT AND METHOD

Eighty consecutive patients, who were treated by living donor liver transplantation (LDLT), were included in the study. The study population was divided into two groups according to the method of liver transection: group A by harmonic scalpel (HS) and group B by spray diathermy (SD). The primary outcome was the volume of blood loss during transection. Secondary outcomes were time of transection, number of ligatures needed during transection, pathological changes at cut surface, postoperative morbidities, cost, and hospital stay RESULTS: Blood loss during overall liver transection and in each zone was significantly less in the SD than in the HS group (P = 0.015). The number of ligatures was significantly less in the SD than in the HS group (P = 0.0001). The SD group had significantly higher level of serum bilirubin, serum glutamic pyruvic transaminase (SGPT), and international normalized ratio (INR) levels on postoperative day 3 than the HS group. Lateral tissue coagulation and hepatic necrosis are significantly less in HS group. The overall incidence of postoperative morbidities was the same in both groups. The cost was higher in HS group than SD group (US$760 vs. US$40 P = 0.0001).

CONCLUSION

Spray diathermy is an effective method of parenchymal transection with significantly lower blood loss and lower cost compared to HS with no increase in morbidity. HS is associated with earlier recovery of liver functions.

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.

Mechanical ventilation strategies for intensive care unit patients without acute lung injury or acute respiratory distress syndrome: a systematic review and network meta-analysis

Background

It has been shown that the application of a lung-protective mechanical ventilation strategy can improve the prognosis of patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). However, the optimal mechanical ventilation strategy for intensive care unit (ICU) patients without ALI or ARDS is uncertain. Therefore, we performed a network meta-analysis to identify the optimal mechanical ventilation strategy for these patients.

Methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, EMBASE, MEDLINE, CINAHL, and Web of Science for studies published up to July 2015 in which pulmonary compliance or the partial pressure of arterial oxygen/fraction of inspired oxygen (PaO₂/FIO₂) ratio was assessed in ICU patients without ALI or ARDS, who received mechanical ventilation via different strategies. The data for study characteristics, methods, and outcomes were extracted. We assessed the studies for eligibility, extracted the data, pooled the data, and used a Bayesian fixed-effects model to combine direct comparisons with indirect evidence.

Results

Seventeen randomized controlled trials including a total of 575 patients who received one of six ventilation strategies were included for network meta-analysis. Among ICU patients without ALI or ARDS, strategy C (lower tidal volume (VT) + higher positive end-expiratory pressure (PEEP)) resulted in the highest PaO₂/FIO₂ ratio; strategy B (higher VT + lower PEEP) was associated with the highest pulmonary compliance; strategy A (lower VT + lower PEEP) was associated with a shorter length of ICU stay; and strategy D (lower VT + zero end-expiratory pressure (ZEEP)) was associated with the lowest PaO₂/FiO₂ ratio and pulmonary compliance.

Conclusions

For ICU patients without ALI or ARDS, strategy C (lower VT + higher PEEP) was associated with the highest PaO₂/FiO₂ ratio. Strategy B (higher VT + lower PEEP) was superior to the other strategies in improving pulmonary compliance. Strategy A (lower VT + lower PEEP) was associated with a shorter length of ICU stay, whereas strategy D (lower VT + ZEEP) was associated with the lowest PaO₂/FiO₂ ratio and pulmonary compliance.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1396-0) contains supplementary material, which is available to authorized users.

Comparative safety and efficacy of vasopressors for mortality in septic shock: A network meta-analysis

INTRODUCTION

Septic shock is a life-threatening condition requiring vasopressor agents to support the circulatory system. Several agents exist with choice typically guided by the specific clinical scenario. We used a network meta-analysis approach to rate the comparative efficacy and safety of vasopressors for mortality and arrhythmia incidence in septic shock patients.

METHODS

We performed a comprehensive electronic database search including Medline, Embase, Science Citation Index Expanded and the Cochrane database. Randomised trials investigating vasopressor agents in septic shock patients and specifically assessing 28-day mortality or arrhythmia incidence were included. A Bayesian network meta-analysis was performed using Markov chain Monte Carlo methods.

RESULTS

Thirteen trials of low to moderate risk of bias in which 3146 patients were randomised were included. There was no pairwise evidence to suggest one agent was superior over another for mortality. In the network meta-analysis, vasopressin was significantly superior to dopamine (OR 0.68 (95% CI 0.5 to 0.94)) for mortality. For arrhythmia incidence, standard pairwise meta-analyses confirmed that dopamine led to a higher incidence of arrhythmias than norepinephrine (OR 2.69 (95% CI 2.08 to 3.47)). In the network meta-analysis, there was no evidence of superiority of one agent over another.

CONCLUSIONS

In this network meta-analysis, vasopressin was superior to dopamine for 28-day mortality in septic shock. Existing pairwise information supports the use of norepinephrine over dopamine. Our findings suggest that dopamine should be avoided in patients with septic shock and that other vasopressor agents should continue to be based on existing guidelines and clinical judgement of the specific presentation of the patient.

[Vascular management in anatomical liver resection]

The vascular management in anatomical liver resection plays a pivotal role in maintaining an adequately functional residual liver volume. In this respect it is essential to guarantee an adequate portal and arterial inflow as well venous outflow for the whole residual liver (lobe or segments). To achieve this, the liver surgeon should have excellent perioperative imaging, surgical expertise based on knowledge of vascular anatomy, physiology and hemodynamics of the liver and a well-designed and cautious operative strategy. The use of intraoperative ultrasonography (with or without contrast enhancement) and modern parenchymal dissectors (e.g. ultrasound or water jet dissectors) are strongly recommended.

Intraoperative mechanical ventilation strategies for obese patients: a systematic review and network meta-analysis

Several intraoperative ventilation strategies are available for obese patients. However, the same ventilation interventions have exhibited different effects on PaO2 /FIO2 concerning obese patients in different trials, and the issue remains controversial. Therefore, we conducted a network meta-analysis to identify the optimal mechanical ventilation strategy. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, Embase, MEDLINE, CINAHL and Web of Science for studies published up to June 2014, and the PaO2 /FIO2 in obese patients given different mechanical ventilation strategies was assessed. We assessed the studies for eligibility and extracted data and then pooled the data and used a Bayesian fixed-effect model to combine direct comparisons with indirect evidence. Eligible studies evaluated different ventilation strategies for obese patients and reported the intraoperative PaO2 /FIO2 ratio, atelectasis and pulmonary compliance. Thirteen randomized controlled trials were included for network meta-analysis, including 476 patients who received 1 of 12 ventilation strategies. Volume-controlled ventilation with higher PEEP plus single recruitment manoeuvres (VCV + higher PEEP + single RM) was associated with the highest PaO2 /FiO2 ratio, improving intraoperative pulmonary compliance and reducing the incidence of intraoperative atelectasis.

Mechanical ventilation modes for respiratory distress syndrome in infants: a systematic review and network meta-analysis

Introduction

The effects of different mechanical ventilation (MV) modes on mortality outcome in infants with respiratory distress syndrome (RDS) are not well known.

Methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, EMBASE, MEDLINE, CINAHL, and Web of Science for studies published through April 2014 that assessed mortality in infants with RDS given different MV modes. We assessed studies for eligibility, extracted data, and subsequently pooled the data. A Bayesian fixed-effects model was used to combine direct comparisons with indirect evidence. We also performed sensitivity analyses and rankings of the competing treatment modes.

Results

In total, 20 randomized controlled trials were included for the network meta-analysis, which consisted of 2,832 patients who received one of 16 ventilation modes. Compared with synchronized intermittent mandatory ventilation (SIMV) + pressure support ventilation (PSV), time-cycled pressure-limited ventilation (TCPL) (hazard ratio (HR) 0.290; 95% confidence interval (CI) 0.071 to 0.972), high-frequency oscillatory ventilation (HFOV) (HR 0.294; 95% CI 0.080 to 0.852), SIMV + volume-guarantee (VG) (HR 0.122; 95% CI 0.014 to 0.858), and volume-controlled (V-C) (HR 0.139; 95% CI 0.024 to 0.677) ventilation modes are associated with lower mortality. The combined results of available ventilation modes were not significantly different in regard to the incidences of patent ductus arteriosus and intraventricular hemorrhage.

Conclusion

Compared with the SIMV + PSV ventilation mode, the TCPL, HFOV, SIMV + VG, and V-C ventilation modes are associated with lower mortality.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0843-7) contains supplementary material, which is available to authorized users.

Modern technical approaches in resectional hepatic surgery

Techniques in liver surgery have improved considerably during the last decades, allowing for liver resections with low morbidity and mortality. Preoperative patient selection, perioperative management, and intraoperative blood-sparing techniques are the cornerstones of modern liver surgery. Multimodal treatment of colorectal liver metastases has expanded the group of patients who are potential candidates for liver resection. Adjunctive techniques, including preoperative portal vein embolization and staged hepatectomy, have facilitated the safe performance of extensive liver resection. This article provides an overview of indications for liver resection and a systematic description of the technical approach to the most commonly performed resections.

Overview and recent trends of systematic reviews and meta-analyses in hepatology

A systematic review (SR) is a research methodology that involves a comprehensive search for and analysis of relevant studies on a specific topic. A strict and objective research process is conducted that comprises a systematic and comprehensive literature search in accordance with predetermined inclusion/exclusion criteria, and an assessment of the risk of bias of the selected literature. SRs require a multidisciplinary approach that necessitates cooperation with clinical experts, methodologists, other experts, and statisticians. A meta-analysis (MA) is a statistical method of quantitatively synthesizing data, where possible, from the primary literature selected for the SR. Review articles differ from SRs in that they lack a systematic methodology such as a literature search, selection of studies according to strict criteria, assessment of risk bias, and synthesis of the study results. The importance of evidence-based medicine (EBM) in the decision-making for public policy has recently been increasing thanks to the realization that it should be based on scientific research data. SRs and MAs are essential for EBM strategy and evidence-based clinical practice guidelines. This review addresses the current trends in SRs and MAs in the field of hepatology via a search of recently published articles in the Cochrane Library and Ovid-MEDLINE.