Postoperative respiratory failure in liver transplantation: Risk factors and effect on prognosis

Protocol for an international multicenter, prospective, observational, non-competitive, study to validate and optimise prediction models of 90-day and 1-year allograft failure after liver transplantation: The global IMPROVEMENT Study

More liver transplants (LT) are performed worldwide thanks to extended criteria donors (ECD). This is paralleled by a supposed increased risk of allograft failure (AF) at 90 and 365 days. This study has been designed to portray the LT practice worldwide and investigate models of AF prediction and the impact of risk mitigation strategies for further improving graft and patient outcomes. This is a multicenter, international, non-competitive, observational two segment study on consecutive LTs over two periods (2017-2019 and 2022-2024). A steering committee of LT experts defined the study protocol. The prospective segment will enroll 750 patients from 15 high-volume LT centers (50 per center), and the retrospective segment will enrol 4200 patients from 56 LT centers (75 per center). To provide a snapshot of the LT activity globally and to develop new algorithms for the timely prediction of AF at 90 and 365 days post-LT. The study also aims (1) to validate the existing predictive models and (2) to investigate the best time for re-transplantation, paying attention to the differences in AF and Ischemic cholangiopathy according to the donor types and mitigation strategies implemented in the various settings. Since the adoption of machine perfusion has increased in different proportions worldwide, models will be adjusted according to this parameter. Finally, retrospective and prospective data will be available for further stratifications and modelling according to the degree of decompensation at transplant, gender match, postoperative complications and their management. This protocol was approved by Fondazione Policlinico Universitario Agostino Gemelli IRCCS Ethics Committee (study ID: 4571) and the Institutional Review Board of the University of California, Los Angeles. The provisional study protocol was submitted to the main scientific international societies in the transplant field. Results will be published in international peer-reviewed journals and presented at congresses.

Clinical predictors of extubation failure in postoperative critically ill patients: a post-hoc analysis of a multicenter prospective observational study

BACKGROUND

Postoperative patients constitute majority of critically ill patients, although factors predicting extubation failure in this group of patients remain unidentified. Aiming to propose clinical predictors of reintubation in postoperative patients, we conducted a post-hoc analysis of a multicenter prospective observational study.

METHODS

This study included postoperative critically ill patients who underwent mechanical ventilation for > 24 h and were extubated after a successful 30-min spontaneous breathing trial. The primary outcome was reintubation within 48 h after extubation, and clinical predictors for reintubation were investigated using logistic regression analyses.

RESULTS

Among the 355 included patients, 10.7% required reintubation. Multivariable logistic regression identified that the number of endotracheal suctioning episodes during the 24 h before extubation and underlying respiratory disease or pneumonia occurrence were significantly associated with reintubation (adjusted odds ratio [OR] 1.11, 95% confidence interval [CI] 1.05-1.18, p < 0.001; adjusted OR 2.58, 95%CI 1.30-5.13, p = 0.007). The probability of reintubation was increased significantly with the higher frequency of endotracheal suctioning, as indicated by restricted cubic splines. Subgroup analysis showed that these predictors were consistently associated with reintubation regardless of the use of noninvasive respiratory support after extubation.

CONCLUSIONS

Endotracheal suctioning frequency and respiratory complications were identified as independent predictors of reintubation. These readily obtainable predictors may aid in decision-making regarding the extubation of postoperative patients.

Perioperative Considerations Regarding Sex in Solid Organ Transplantation

Sex plays a pivotal role in all stages of the organ transplant process. In the preoperative phase, sex can affect being listed or considered for a transplant, and sex/size matching of organs is necessary for some organ transplants, thereby affecting organ availability. In the postoperative period, sex has a profound impact on complications as well as graft survival. Sex-related differences in organ transplantation are likely multifactorial related to biological and social characteristics. This article provides an overview of the impact of sex on various types of solid organ transplant, including kidney, pancreas, liver, lung, and heart transplants.

Effect of neurally adjusted ventilator assist versus pressure support ventilation on asynchronies and cardiac function in pediatric liver transplantation

In pediatric liver recipients perioperative factors may affect respiratory and cardiac function, and prolong mechanical ventilation during post-operative period. The use of NAVA can improve the interaction between the patient and the ventilator from both a respiratory and cardiac perspective. The objective of this study is to evaluate the synchronization between the patient and the ventilator, as well as cardiac function, during the application of neurally adjusted ventilatory assist (NAVA) and pressure support ventilation (PSV) in pediatric liver transplant recipients. This is a single-center, prospective, randomized, physiological cross-over controlled trial conducted between 2021 and 2022. Children (1 month-10 years old) who underwent liver transplantation were admitted to the pediatric intensive care unit. Patients were randomised to one of two crossover sequences of ventilation trials of 40 min each (PSV/NAVA/PSV or NAVA/PSV/NAVA). Cardiac function was studied by echocardiogram. Twenty-four patients were enrolled and 21 completed the study. Primary outcomes were variation of asynchrony index (AI) and tricuspid annular plane systolic excursion (TAPSE) during the two ventilation modes. Secondary outcomes were patient-ventilator interaction parameters, gas exchange, left and right ventricular function, and hemodynamic parameters. NAVA compared to PSV: (1) improves patient-ventilator interaction reducing AI (coeff - 6.66 95% CI -11.5 to -1.78, p = 0.008); (2) does not improve TAPSE (coeff 0.62 95% CI -1.49 to 2.74, p < 0.557) No differences in terms of pulmonary gas exchange and hemodynamic parameters were detected. NAVA (when compared to PSV) improves patient-ventilator interaction in terms of asynchronies without affecting cardiac biventricular function.Trial registration: NCT04792788, Registration date: 2021-03-11.

Developing a nomogram for forecasting the 28-day mortality rate of individuals with bleeding esophageal varices using model for end-stage liver disease scores

BACKGROUND

This study aimed to create a nomogram using the model for end-stage liver disease (MELD) that can better predict the risk of 28-day mortality in patients with bleeding esophageal varices.

METHODS

Data on patients with bleeding esophageal varices were retrospectively collected from the Medical Information Mart for Intensive Care database. Variables were selected using the least absolute shrinkage and selection operator logistic regression model and were used to construct a prognostic nomogram. The nomogram was evaluated against the MELD model using various methods, including receiver operating characteristic (ROC) curve analysis, calibration plotting, net reclassification improvement (NRI), integrated discrimination improvement (IDI), and decision curve analysis (DCA).

RESULTS

A total of 280 patients were included in the study. The patient's use of vasopressin and norepinephrine, respiratory rate, temperature, mean corpuscular volume, and MELD score were included in the nomogram. The area under the ROC curve, NRI, IDI, and DCA of the nomogram indicated that it performs better than the MELD alone.

CONCLUSION

A nomogram was created that outperformed the MELD score in forecasting the risk of 28-day mortality in individuals with bleeding esophageal varices.

The effects of venovenous bypass use in liver transplantation with piggyback technique: a propensity score-weighted analysis

Venovenous bypass (VVB) use during liver transplantation (LT) is notably variable among the centres and it is actually restricted to surgically complex cases, severely unstable recipients or grafts from high-risk donors. Historically, VVB was associated with the classical LT with caval cross clamping, while not much is known about the safety of this technique applied to piggyback LT. This retrospective observational study evaluated the effects of VVB applied to piggyback LT on mortality, hospital outcomes, postoperative graft and other organ dysfunction. We retrospectively collected data about recipient status, surgical complexity and graft quality of all the piggyback LTs performed at the Transplant Unit of IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy, from January 2012 to December 2022. A propensity score (PS) was built taking into account the variables possibly associated with either VVB choice and the investigated outcomes with the average treatment overlap method. PS-weighted general linear models (GLMs) were developed to investigate the adjusted effect of VVB use on the selected outcomes. The final analysis included 874 LT cases, of whom 74 (8.5%) underwent VVB. The effective sample sizes after PS-weighting were 280.2 and 64.3 patients in the no-VVB and VVB groups, respectively. PS-weighted GLMs did not show any differences regarding hospital and graft-related outcomes. However, significantly higher odds ratios for serum creatinine > 2 mg/dL and AKIN stage 2 or 3 during the first 24 h after ICU admission together with a higher renal replacement therapy need during ICU stay were reported for VVB exposure in the weighted analyses. This study suggests similar mortality and length of stay but a higher risk for postoperative acute kidney injury in patients undergoing piggyback LT with VVB.

Fluid Responsiveness Is Associated with Successful Weaning after Liver Transplant Surgery

A positive fluid balance may evolve to fluid overload and associate with organ dysfunctions, weaning difficulties, and increased mortality in ICU patients. We explored whether individualized fluid management, assessing fluid responsiveness via a passive leg-raising maneuver (PLR) before a spontaneous breathing trial (SBT), is associated with less extubation failure in ventilated patients with a high fluid balance admitted to the ICU after liver transplantation (LT). We recruited 15 LT patients in 2023. Their postoperative fluid balance was +4476 {3697, 5722} mL. PLR maneuvers were conducted upon ICU admission (T1) and pre SBT (T2). Cardiac index (CI) changes were recorded before and after each SBT (T3). Seven patients were fluid-responsive at T1, and twelve were responsive at T2. No significant differences occurred in hemodynamic, respiratory, and perfusion parameters between the fluid-responsive and fluid-unresponsive patients at any time. Fluid-responsive patients at T1 and T2 increased their CI during SBT from 3.1 {2.8, 3.7} to 3.7 {3.4, 4.1} mL/min/m2 (p = 0.045). All fluid-responsive patients at T2 were extubated after the SBTs and consolidated extubation. Two out of three of the fluid-unresponsive patients experienced weaning difficulties. We concluded that fluid-responsive patients post LT may start weaning earlier and achieve successful extubation despite a high postoperative fluid balance. This highlights the profound impact of personalized assessments of cardiovascular state on critical surgical patients.

Estimating risk of prolonged mechanical ventilation after liver transplantation in children: PROVE-ALT score

BACKGROUND

Children at high risk for prolonged mechanical ventilation (PMV) after liver transplantation (LT) need to be identified early to optimize pulmonary support, allocate resources, and improve surgical outcomes. We aimed to develop and validate a metric that can estimate risk for Prolonged Ventilation After LT (PROVE-ALT).

METHODS

We identified preoperative risk factors for PMV by univariable analysis in a retrospective cohort of pediatric LT recipients between 2011 and 2017 (n = 205; derivation cohort). We created the PROVE-ALT score by mapping multivariable logistic regression coefficients as integers, with cutoff values using the Youden Index. We validated the score by C-statistic in a retrospectively collected separate cohort of pediatric LT recipients between 2018 and 2021 (n = 133, validation cohort).

RESULTS

Among total 338 patients, 21% (n = 72) were infants; 49% (n = 167) had cirrhosis; 8% (n = 27) required continuous renal replacement therapy (CRRT); and 32% (n = 111) required management in hospital (MIH) before LT. Incidence of PMV post-LT was 20% (n = 69) and 3% (n = 12) required tracheostomy. Independent risk factors (OR [95% CI]) for PMV were cirrhosis (3.8 [1-14], p = .04); age <1-year (8.2 [2-30], p = .001); need for preoperative CRRT (6.3 [1.2-32], p = .02); and MIH before LT (12.4 [2.1-71], p = .004). PROVE-ALT score ≥8 [Range = 0-21] accurately predicted PMV in the validation cohort with 73% sensitivity and 80% specificity (AUC: 0.81; 95% CI: 0.71-0.91).

CONCLUSION

PROVE-ALT can predict PMV after pediatric LT with a high degree of sensitivity and specificity. Once externally validated in other centers, PROVE-ALT will empower clinicians to plan patient-specific ventilation strategies, provide parental anticipatory guidance, and optimize hospital resources.

Intensive Care Unit-Acquired Weakness after Liver Transplantation: Analysis of Seven Cases and a Literature Review

Intensive Care Unit (ICU)-Acquired Weakness (ICU-AW) is a generalized muscle weakness that is clinically detected in critical patients and has no plausible etiology other than critical illness. ICU-AW is uncommon in patients undergoing orthotopic liver transplantation (OLT). Our report sheds light on the highest number of ICU-AW cases observed in a single center on OLT patients with early allograft dysfunction. Out of 282 patients who underwent OLT from January 2015 to June 2023, 7 (2.5%) developed generalized muscle weakness in the ICU and underwent neurophysiological investigations. The neurologic examination showed preserved extraocular, flaccid quadriplegia with the absence of deep tendon reflexes in all patients. Neurophysiological studies, including electromyography and nerve conduction studies, showed abnormalities with fibrillation potentials and the rapid recruitment of small polyphasic motor units in the examined muscles, as well as a reduced amplitude of the compound muscle action potential and sensory nerve action potential, with an absence of demyelinating features. Pre-transplant clinical status was critical in all patients. During ICU stay, early allograft dysfunction, acute kidney injury, prolonged mechanical ventilation, sepsis, hyperglycemia, and high blood transfusions were observed in all patients. Two patients were retransplanted. Five patients were alive at 90 days; two patients died. In non-cooperative OLT patients, neurophysiological investigations are essential for the diagnosis of ICU-AW. In this setting, the high number of red blood cell transfusions is a potential risk factor for ICU-AW.

Factors associated with mechanical ventilation longer than 24 h after liver transplantation in patients at risk for bleeding

BACKGROUND

This risk analysis aimed to explore all modifiable factors associated with prolonged mechanical ventilation (lasting > 24 h) after liver transplantation, based on prospectively collected data from a clinical trial.

METHODS

We evaluated 306 candidates. Ninety-three patients were excluded for low risk for transfusion (preoperative haemoglobin > 130 g.l-1), and 31 patients were excluded for anticoagulation therapy, bleeding disorders, familial polyneuropathy, or emergency status. Risk factors were initially identified with a log-binomial regression model. Relative risk was then calculated and adjusted for age, sex, and disease severity (Model for End-Stage Liver Disease [MELD] score).

RESULTS

Early tracheal extubation was performed in 149 patients (84.7%), and 27 patients (15.3%) required prolonged mechanical ventilation. Reoperations were required for 6.04% of the early extubated patients and 44% of patients who underwent prolonged ventilation (p = 0.001). A MELD score > 23 was the main risk factor for prolonged ventilation. Once modifiable risk factors were adjusted for MELD score, sex, and age, three factors were significantly associated with prolonged ventilation: tranexamic acid (p = 0.007) and red blood cell (p = 0.001) infusion and the occurrence of postreperfusion syndrome (p = 0.004). The median (IQR) ICU stay was 3 (2-4) days in the early extubation group vs. 5 (3-10) days in the prolonged ventilation group (p = 0.001). The median hospital stay was also significantly shorter after early extubation, at 14 (10-24) days, vs. 25 (14-55) days in the prolonged ventilation group (p = 0.001). Eight patients in the early-extubation group (5.52%) were readmitted to the ICU, nearly all for reoperations, with no between-group differences in ICU readmissions (prolonged ventilation group, 3.7%).

CONCLUSION

We conclude that bleeding and postreperfusion syndrome are the main modifiable factors associated with prolonged mechanical ventilation and length of ICU stay, suggesting that trials should explore vasopressor support strategies and other interventions prior to graft reperfusion that might prevent potential fibrinolysis.

TRIAL REGISTRATION

European Clinical Trials Database (EudraCT 2018-002510-13,) and on ClinicalTrials.gov (NCT01539057).

Challenges in Diagnosis and Therapeutic Approach of Acute on Chronic Liver Failure-A Review of Current Evidence

Acute-on-chronic liver failure (ACLF) is a syndrome characterized by acute and severe decompensation of chronic liver disease (CLD) correlated with multiple organ failure, poor prognosis, and increased mortality. In 40-50% of ACLF cases, the trigger is not recognized; for many of these patients, bacterial translocation associated with systemic inflammation is thought to be the determining factor; in the other 50% of patients, sepsis, alcohol consumption, and reactivation of chronic viral hepatitis are the most frequently described trigger factors. Other conditions considered precipitating factors are less common, including acute alcoholic hepatitis, major surgery, TIPS insertion, or inadequate paracentesis without albumin substitution. Host response is likely the primary factor predicting ACLF severity and prognosis, the host immune response having a particular significance in this syndrome, together with the inflammatory cascade. The management of ACLF includes both the prevention of the precipitating factors that lead to acute liver decompensation and the support of vital functions, the prevention and management of complications, the estimation of prognosis, and the opportunity for liver transplantation.

Viscoelastic versus conventional coagulation tests to reduce blood product transfusion in patients undergoing liver transplantation: A systematic review and meta-analysis

BACKGROUND

Recent literature suggests viscoelastic test (VET)-guided transfusion management could be associated with reduced blood product administration in patients undergoing liver transplantation.

OBJECTIVES

To assess the effectiveness of coagulation management guided by VETs compared with conventional coagulation tests (CCTs) in reducing blood product transfusion in patients undergoing liver transplantation.

DESIGN

Systematic review and meta-analysis of randomised (RCTs) and nonrandomised clinical trials performed according to PRISMA guidelines. The protocol was previously published (PROSPERO: CRD42021230213).

DATA SOURCES

The Cochrane Central Library, PubMed/MEDLINE, Embase and the Transfusion Evidence Library were searched up to 30 th January 2022.

ELIGIBILITY CRITERIA

Setting: operating room. Patients: liver transplantation recipients. Intervention: use of VETs versus CCTs. Main outcome measures: the primary outcome was the mean number of transfused units for each blood product including red blood cells (RBCs), fresh frozen plasma (FFP), platelets (PLTs) and cryoprecipitate. Secondary outcomes included mortality rate, intensive care unit (ICU) and hospital length of stay (LOS).

RESULTS

Seventeen studies ( n  = 5345 patients), 15 observational and two RCTs, were included in this review. There was a mean difference reduction in RBCs [mean difference: -1.40, 95% confidence interval (95% CI), -1.87 to -0.92; P  < 0.001, I2  = 61%) and FFP units (mean difference: -2.98, 95% CI, -4.61 to -1.35; P  =  < 0.001; I2  = 98%) transfused in the VETs group compared with the CCTs one. A greater amount of cryoprecipitate was administered in the VETs group (mean difference: 2.71, 95% CI, 0.84 to 4.58; P  = 0.005; I2  = 91%). There was no significant difference in the mean number of PLT units, mortality, hospital and ICU-LOS.

CONCLUSION

Our meta-analysis demonstrated that VETs implementation was associated with reduced RBC and FFP consumption in liver transplantation patients without effects on mortality and hospital and ICU-LOS. The certainty of evidence ranged from moderate to very low. Further well conducted RCTs are needed to improve the certainty of evidence.

Expert consensus on liver transplantation perioperative evaluation and rehabilitation for acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) can be cured by liver transplantation; however, perioperative complications still affect posttransplant outcomes. In recent years, early rehabilitation for critical illness, liver disease, and surgery have significantly improved organ reserve function, surgery tolerance, and postoperative quality of life. They could also be applied in the perioperative period of liver transplantation in patients with ACLF. Therefore, the Transplantation Immunology Committee of Branch of Organ Transplantation Physician of Chinese Medical Doctor Association, the Organ Transplant Committee of China Association Rehabilitation Medicine, and the Guangdong Medical Doctor Association of Organ Transplantation conducted a comprehensive review of rehabilitation in end-stage liver disease, critical illness and surgical patients by summarizing current evidence and best clinical practices and proposed a practice consensus on evaluation of cardiopulmonary and physical function, rehabilitation or physiotherapies, as well as the safety concerns in perioperative liver transplant recipients. It will be a valuable resource for hepatologists, transplant surgeons, and intensivists as they care for ACLF patients during transplantation.

Rescue venovenous extracorporeal membrane oxygenation for the deterioration of acute respiratory distress syndrome in pediatric liver transplantation

BACKGROUND

Twenty percent of pediatric patients with BA develop ACLF with increased mortality while awaiting LT. Respiratory complications are common in pediatric ACLF and are associated with increased morbidity and mortality. ARDS is the most severe manifestation of acute respiratory failure with considerable risk of mortality.

METHODS

A 5-month-old girl with post-Kasai BA preoperatively experienced ARDS from RSV infection while awaiting LT. She developed decompensated liver failure with shock, acute kidney injury, coagulopathy, and pulmonary hemorrhage after several episodes of sepsis over the course of 1 month in the PICU. At this stage, RSV was not detected in the patient's tracheal aspirate by real-time polymerase chain reaction. She underwent living donor LT to manage her pre-existing critical state. Following reperfusion during LT, her pre-existing ARDS rapidly deteriorated, which was alleviated by intraoperative VV ECMO.

RESULTS

Severe respiratory acidosis improved rapidly following ECMO, and LT was completed uneventfully. The patient was successfully weaned off ECMO on POD 3.

CONCLUSIONS

This is the first pediatric case rescued by the intraoperative application of ECMO during LT. Our case and cumulative evidence suggest that VV ECMO can serve as rescue therapy for perioperative refractory respiratory failure in pediatric LT.

Malnutrition as a risk factor of adverse postoperative outcomes in patients undergoing hepatic resection: analysis of US hospitals

Patients with liver cancer or space-occupying cysts suffer from malnutrition due to compression of gastric and digestive structures, liver and cancer-mediated dysmetabolism, and impaired nutrient absorption. As proportion of these patients requires removal of lesions through hepatic resection, it is important to evaluate the effects of malnutrition on post-hepatectomy outcomes. In our study approach, 2011-2017 National Inpatient Sample was used to isolate in-hospital hepatectomy cases, which were stratified using malnutrition (composite of malnutrition, sarcopenia and weight loss/cachexia). The malnutrition-absent controls were matched to cases using nearest neighbour propensity score matching method and compared with the following endpoints: mortality, length of stay, hospitalisation costs and postoperative complications. There were 2531 patients in total who underwent hepatectomy with matched number of controls from the database; following the match, malnutrition cohort (compared with controls) was more likely to experience in-hospital death (6·60 % v. 5·25 % P < 0·049, OR 1·27, 95 % CI 1·01, 1·61) and was more likely to have higher length of stay (18·10 d v. 9·32 d, P < 0·001) and hospitalisation costs ($278 780 v. $150 812, P < 0·001). In terms of postoperative complications, malnutrition cohort was more likely to experience bleeding (6·52 % v. 3·87 %, P < 0·001, OR 1·73, 95 % CI 1·34, 2·24), infection (6·64 % v. 2·49 %, P < 0·001, OR 2·79, 95 % CI 2·07, 3·74), wound complications (4·5 % v. 1·38 %, P < 0·001, OR 3·36, 95 % CI 2·29, 4·93) and respiratory failure (9·40 % v. 4·11 %, P < 0·001, OR 2·42, 95 % CI 1·91, 3·07). In multivariate analysis, malnutrition was associated with higher mortality (P < 0·028, adjusted OR 1·3, 95 % CI 1·03, 1·65). Thus, we conclude that malnutrition is a risk factor of postoperative mortality in patients undergoing hepatectomy.

Preoperative evaluation of geriatric patients undergoing liver transplantation

PURPOSE OF REVIEW

As the population of the world is aging the number of geriatric patients undergoing liver transplantation (LT) is also increasing. They pose a unique challenge for the caregivers, as they have age-related physiological changes, multiple comorbidities and cirrhosis-related pathologies.

RECENT FINDINGS

Twenty-two percent of patients who undergo LT are older than 65 years. Many patients suffer from nonalcoholic steatohepatitis (NASH), hepatocellular carcinoma and hepatitis-C virus. Incidence of NASH tends to increase with age, obesity, diabetes and metabolic syndrome. Elderly patients require comprehensive cognitive, cardiac and pulmonary evaluation prior to LT. Cirrhotic cardiomyopathy, hepatopulmonary syndrome, portopulmonary hypertension and frailty are of specific concern.

SUMMARY

Proportion of elderly patients who are undergoing LT continues to increase. These patients require comprehensive cardiopulmonary and frailty evaluation. Consensus-based practice advisories need to be developed to standardize preoperative evaluation of geriatric patients awaiting LT.

Association between surgical volumes and hospital mortality in patients: a living donor liver transplantation single center experience

Background

Many factors cause hospital mortality (HM) after liver transplantation (LT).

Methods

We performed a retrospective research in a single center from October 2005 to June 2019. The study included 463 living donor LT patients. They were divided into a no-HM group (n = 433, 93.52%) and an HM group (n = 30, 6.48%). We used logistic regression analysis to determine how clinical features and surgical volume affected HM. We regrouped patients based on periods of surgical volume and analyzed the clinical features.

Results

Multivariate analysis revealed that donor age (OR = 1.050, 95% CI 1.011–1.091, p = 0.012), blood loss (OR = 1.000, 95% CI 1.000–1.000, p = 0.004), and annual surgical volumes being < 30 LTs (OR = 2.540, 95% CI 1.011–6.381, p = 0.047) were significant risk factors. A comparison of years based on surgical volume found that when the annual surgical volumes were at least 30 the recipient age (p = 0.023), donor age (p = 0.026), and ABO-incompatible operations (p < 0.001) were significantly higher and blood loss (p < 0.001), operative time (p < 0.001), intensive care unit days (p < 0.001), length of stay (p = 0.011), rate of re-operation (p < 0.001), and HM (p = 0.030) were significantly lower compared to when the annual surgical volumes were less than 30.

Conclusions

Donor age, blood loss and an annual surgical volume < 30 LTs were significant pre- and peri-operative risk factors. Hospital mortality and annual surgical volume were associated with statistically significant differences; surgical volume may impact quality of care and transplant outcomes.

The problem of postoperative respiratory depression

WHAT IS KNOWN AND OBJECTIVE

Postsurgical recovery is influenced by multiple pre-, intra- and perioperative pharmacotherapeutic interventions, including the administration of medications that can induce respiratory depression postoperatively. We present a succinct overview of the topic, including the nature and magnitude of the problem, contributing factors, current limited options, and potential novel therapeutic approach.

COMMENT

Pre-, intra- and perioperative medications are commonly administered for anxiety, anaesthesia, muscle relaxation and pain relief among other reasons. Several of the medications alone or in joint-action can be additive or synergistic producing respiratory depression. Given the large number of surgical procedures that are performed each year, even a small percentage of postoperative respiratory complications translates into a large number of affected patients.

WHAT IS NEW AND CONCLUSION

Due to the large number of surgeries performed each year, and the variety of medications used before, during, and after surgery, the occurrence of postoperative respiratory depression is surprisingly common. It is a significant medical problem and burden on hospital resources. There is a need for new strategies to prevent and treat the acute and collateral problems associated with postoperative respiratory depression.

Solid Organ Transplantation During COVID-19 Pandemic: An International Web-based Survey on Resources' Allocation

Supplemental Digital Content is available in the text.

Solid organ transplants (SOTs) are life-saving interventions, recently challenged by coronavirus disease 2019 (COVID-19). SOTs require a multistep process, which can be affected by COVID-19 at several phases.

Thromboelastography does not reduce transfusion requirements in liver transplantation: A propensity score-matched study

STUDY OBJECTIVE

To compare total blood product requirements in liver transplantation (LT) assisted by thromboelastography (TEG) or conventional coagulation tests (CCTs).

DESIGN

Retrospective observational study.

SETTING

A tertiary care referral center for LT.

PATIENTS

Adult patients undergoing LT from deceased donor.

INTERVENTION

Hemostasis was monitored by TEG or CCTs and corresponding transfusion algorithms were adopted.

MEASUREMENTS

Number and types of blood products (red blood cells, RBC; fresh-frozen plasma, FFP; platelets, PLT) transfused from the beginning of surgery until the admission to the intensive care unit.

METHODS

We compared data retrospectively collected in 226 LTs, grouped according to the type of hemostasis monitoring (90 with TEG and 136 with CCTs, respectively). Confounding variables affecting transfusion needs (recipient age, sex, previous hepatocellular carcinoma surgery, Model for End Stage Liver Disease - MELD, baseline hemoglobin, fibrinogen, creatinine, veno-venous by pass, and trans-jugular intrahepatic portosystemic shunt) were managed by propensity score match (PSM).

MAIN RESULTS

The preliminary analysis showed that patients in the TEG group received fewer total blood products (RBC + FFP + PLT; p = 0.001, FFP (p = 0.001), and RBC (p = 0.001). After PSM, 89 CCT patients were selected and matched to the 90 TEG patients. CCT and TEG matched patients received similar amount of total blood products. In a subgroup of 39 patients in the top MELD quartile (MELD ≥25), the TEG use resulted in lower consumption of FFP units and total blood products. Nevertheless, due to the low number of patients, any meaningful conclusion could be achieved in this subgroup.

CONCLUSIONS

In our experience, TEG-guided transfusion in LT does not reduce the intraoperative blood product consumption. Further studies are warranted to assess an advantage for TEG in either the entire LT population or the high-MELD subgroup of patients.

Development and Validation of a Comprehensive Model to Estimate Early Allograft Failure Among Patients Requiring Early Liver Retransplant

IMPORTANCE

Expansion of donor acceptance criteria for liver transplant increased the risk for early allograft failure (EAF), and although EAF prediction is pivotal to optimize transplant outcomes, there is no consensus on specific EAF indicators or timing to evaluate EAF. Recently, the Liver Graft Assessment Following Transplantation (L-GrAFT) algorithm, based on aspartate transaminase, bilirubin, platelet, and international normalized ratio kinetics, was developed from a single-center database gathered from 2002 to 2015.

OBJECTIVE

To develop and validate a simplified comprehensive model estimating at day 10 after liver transplant the EAF risk at day 90 (the Early Allograft Failure Simplified Estimation [EASE] score) and, secondarily, to identify early those patients with unsustainable EAF risk who are suitable for retransplant.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter cohort study was designed to develop a score capturing a continuum from normal graft function to nonfunction after transplant. Both parenchymal and vascular factors, which provide an indication to list for retransplant, were included among the EAF determinants. The L-GrAFT kinetic approach was adopted and modified with fewer data entries and novel variables. The population included 1609 patients in Italy for the derivation set and 538 patients in the UK for the validation set; all were patients who underwent transplant in 2016 and 2017.

MAIN OUTCOMES AND MEASURES

Early allograft failure was defined as graft failure (codified by retransplant or death) for any reason within 90 days after transplant.

RESULTS

At day 90 after transplant, the incidence of EAF was 110 of 1609 patients (6.8%) in the derivation set and 41 of 538 patients (7.6%) in the external validation set. Median (interquartile range) ages were 57 (51-62) years in the derivation data set and 56 (49-62) years in the validation data set. The EASE score was developed through 17 entries derived from 8 variables, including the Model for End-stage Liver Disease score, blood transfusion, early thrombosis of hepatic vessels, and kinetic parameters of transaminases, platelet count, and bilirubin. Donor parameters (age, donation after cardiac death, and machine perfusion) were not associated with EAF risk. Results were adjusted for transplant center volume. In receiver operating characteristic curve analyses, the EASE score outperformed L-GrAFT, Model for Early Allograft Function, Early Allograft Dysfunction, Eurotransplant Donor Risk Index, donor age × Model for End-stage Liver Disease, and Donor Risk Index scores, estimating day 90 EAF in 87% (95% CI, 83%-91%) of cases in both the derivation data set and the internal validation data set. Patients could be stratified in 5 classes, with those in the highest class exhibiting unsustainable EAF risk.

CONCLUSIONS AND RELEVANCE

This study found that the developed EASE score reliably estimated EAF risk. Knowledge of contributing factors may help clinicians to mitigate risk factors and guide them through the challenging clinical decision to allocate patients to early liver retransplant. The EASE score may be used in translational research across transplant centers.

Model for End-Stage Liver Disease (MELD) Score Among Patients Qualified For Lung Transplantation With End-Stage Lung Diseases With Particular Consideration of Median Pulmonary Artery Pressure

BACKGROUND

Model for End-Stage Liver Disease (MELD) score is used to assess the severity of chronic liver disease. It is implemented in transplantology in the process of qualification for urgent liver transplant. The aim of our study was to assess the liver function of patients qualified for lung transplant using MELD score, taking under consideration mean pulmonary artery pressure as an important risk factor of death.

METHODS

The study group consisted of 123 patients qualified for lung transplant in Silesian Center for Heart Diseases between 2004 and 2017. Data relevant for MELD score calculations and medial pulmonary artery pressure were acquired from medical records.

RESULTS

The average MELD score among patients qualified for lung transplant was 8.24 points, and mean pulmonary pressure (mPAP) was 35.02 mm Hg. Patients with idiopathic pulmonary artery hypertension acquired the highest MELD and highest mPAP results (13.1 points and 57.7 mm Hg, respectively). Patients with idiopathic pulmonary fibrosis presented higher mean MELD-Na score among those with pulmonary arterial hypertension than those without pulmonary arterial hypertension (36.59 mm Hg; 7.74 points vs 18 mm Hg; 6.5 points). There is strong positive correlation between MELD-Na and mPAP among patients who underwent lung transplant because of idiopathic pulmonary fibrosis.

CONCLUSIONS

This is the first study in the worldwide literature assessing MELD-Na as a predictor of survival among patients qualified for lung transplant and those who already are recipients. Further studies regarding this issue are required as authors will explore this issue in the future.

Perioperative Considerations Regarding Sex in Solid Organ Transplantation

Sex plays a role in all stages of the organ transplant process, including listing, sex/size matching of organs, complications, graft survival, and mortality. Sex-related differences in organ transplantation are likely multifactorial related to biological and social characteristics. More information is needed to determine how sex-related differences can lead to improved outcomes for future donors and recipients of solid organs. This article provides an overview on the impact of sex on various types of solid organ transplant, including kidney, pancreas, liver, lung, and heart transplants.

Preoperative risk factors for massive transfusion, prolonged ventilation requirements, and mortality in patients undergoing liver transplantation

Background

Despite improvements in techniques and management of liver transplant patients, numerous perioperative complications that contribute to perioperative mortality remain. Models to predict intraoperative massive blood transfusion, prolonged mechanical ventilation, or in-hospital mortality in liver transplant recipients have not been identified. In this study we aim to identify preoperative factors associated with the above mentioned complications.

Methods

A retrospective observational analysis was conducted on data collected from 124 orthotopic liver transplants performed at a single institution between 2014 and 2017. A multivariable logistic regression using backwards elimination was performed for three defined outcomes (massive transfusion ≥ 10 units packed red blood cells (PRBC), prolonged mechanical ventilation > 24 h, and in-hospital mortality) to identify associations with preoperative characteristics.

Results

Statistically significant (P < 0.05) associations with massive transfusion ≥ 10 units PRBC were hepatocellular carcinoma and preoperative transfusion of PRBC. Significant associations with prolonged mechanical ventilation > 24 h were hepatitis C, alcoholic hepatitis, elevated preoperative alanine aminotransferase, and hepatorenal syndrome. Male gender was protective for requiring prolonged mechanical ventilation. End-stage renal disease and hepatitis B were significantly associated with increased in-hospital mortality.

Conclusions

This study identified risk factors associated with common perioperative complications of liver transplantation. These factors may assist practitioners in risk stratification and may form the basis for further investigations of potential interventions to mitigate these risks.