Pre-operative risk factors predict post-operative respiratory failure after liver transplantation. PLoS One. 2011;6:e22689. [PMID: 21829646 PMCID: PMC3148242 DOI: 10.1371/journal.pone.0022689]

LightGBM outperforms other machine learning techniques in predicting graft failure after liver transplantation: Creation of a predictive model through large-scale analysis

BACKGROUND

The incidence of graft failure following liver transplantation (LTx) is consistent. While traditional risk scores for LTx have limited accuracy, the potential of machine learning (ML) in this area remains uncertain, despite its promise in other transplant domains. This study aims to determine ML's predictive limitations in LTx by replicating methods used in previous heart transplant research.

METHODS

This study utilized the UNOS STAR database, selecting 64,384 adult patients who underwent LTx between 2010 and 2020. Gradient boosting models (XGBoost and LightGBM) were used to predict 14, 30, and 90-day graft failure compared to conventional logistic regression model. Models were evaluated using both shuffled and rolling cross-validation (CV) methodologies. Model performance was assessed using the AUC across validation iterations.

RESULTS

In a study comparing predictive models for 14-day, 30-day and 90-day graft survival, LightGBM consistently outperformed other models, achieving the highest AUC of.740,.722, and.700 in shuffled CV methods. However, in rolling CV the accuracy of the model declined across every ML algorithm. The analysis revealed influential factors for graft survival prediction across all models, including total bilirubin, medical condition, recipient age, and donor AST, among others. Several features like donor age and recipient diabetes history were important in two out of three models.

CONCLUSIONS

LightGBM enhances short-term graft survival predictions post-LTx. However, due to changing medical practices and selection criteria, continuous model evaluation is essential. Future studies should focus on temporal variations, clinical implications, and ensure model transparency for broader medical utility.

Ventilator support in the pretransplant period predisposes early graft failure after deceased donor liver transplantation

Purpose

Deceased donor liver transplantation (DDLT) recipients in Korea are generally sicker due to an increasing organ shortage. In the present study, the risk factors for early 30-day liver graft failure after DDLT were identified.

Methods

From August 2017 to February 2021, 265 adult DDLTs were performed. The characteristics of patients with and without 30-day graft failure were compared.

Results

Liver graft failure occurred in 11 patients (17.7%) after DDLT. Baseline and perioperative characteristics of donors and recipients were not statistically significantly different between the 2 groups. The cumulative graft and overall survival rates at 6 months were 83.9% and 88.7%, respectively. Multivariate analysis showed ventilator support in the pretransplant period was a predisposing factor for 30-day graft failure after DDLT.

Conclusion

Present study indicates that cautious decision is required when allocating DDLT in critically ill patients on mechanical ventilatory support.

Construction and validation of a pulmonary complication score for patients after liver transplantation

PURPOSE

Identification of preoperative risk factors associated with pulmonary complications may benefit high-risk patients from more intense surveillance and earlier interventions in liver transplantation (LT). Our study aimed to identify risk factors for predicting pulmonary complications in LT patients.

MATERIALS AND METHODS

The discovery data set enrolled 208 patients who underwent orthotopic LT while the validation data set included 117 patients. Clinical data were collected from medical history retrospectively and risk factors were determined by logistic regression analyses. The pulmonary complication score (PCS-LT) was established and validated for predicting pulmonary complications after LT.

RESULTS

In the discovery data set, 47 (22.6%) participants experienced pulmonary complications following LT. Four independent risk factors for pulmonary complications were identified by multivariate logistic regression analysis, including preoperative abnormal pulmonary function (OR = 4.743, p < .001), elevated lymphocyte count (OR = 2.336, p = .027), hypoproteinemia (OR = 2.635, p = .030), and hypokalemia (OR = 5.257, p = .003), and PCS-LT based on these factors was established. ROC analyses showed PCS-LT could predict PC in both the discovery data set (area under curve [AUC] .752, 95% confidence interval [CI] .687-.809) and the validation data set (AUC .754, 95% CI, .666-.829). The PCS-LT demonstrated superior predictive value (AUC .735, 95% CI, .703-.799) to APACHE II score (AUC .653, 95% CI, .599-.705) in the combined data set (p = .032). Meanwhile, PCS-LT > 1 was used as the cut-off value and has prognostic significance in LT patients.

CONCLUSIONS

The PCS-LT score, consisting of abnormal pulmonary function, elevated lymphocyte count, hypoproteinemia, and hypokalemia, could predict pulmonary complications after LT.

Early postoperative mortality in liver transplant recipients involving indications other than hepatocellular carcinoma. A retrospective cohort study

AIMS

To analyze the perioperative differences in a consecutive cohort of liver transplant recipients (LTRs) classified according to the indication of transplantation, and assess their impact upon early mortality 90 days after transplantation.

DESIGN

A retrospective cohort study was carried out.

SCOPE

A single university hospital.

PATIENTS

A total of 892 consecutive adult LTRs were included from January 1995 to December 2017. Recipients with acute liver failure, retransplantation or with grafts from non-brain death donors were excluded. Two cohorts were analyzed according to transplant indication: hepatocellular carcinoma (HCC-LTR) versus non-carcinoma (non-HCC-LTR).

MAIN VARIABLES OF INTEREST

Recipient early mortality was the primary endpoint. The pretransplant recipient and donor characteristics, surgical time data and postoperative complications were analyzed as independent predictors.

RESULTS

The crude early postoperative mortality rate related to transplant indication was 13.3% in non-HCC-LTR and 6.6% in HCC-LTR (non-adjusted HR=2.12, 95%CI=1.25-3.60; p=0.005). Comparison of the perioperative features between the cohorts revealed multiple differences. Multivariate analysis showed postoperative shock (HR=2.02, 95%CI=1.26-3.24; p=0.003), early graft vascular complications (HR=4.01, 95%CI=2.45-6.56; p<0.001) and multiorgan dysfunction syndrome (HR=18.09, 95%CI=10.70-30.58; p<0.001) to be independent predictors of mortality. There were no differences in early mortality related to transplant indication (adjusted HR=1.60, 95%CI=0.93-2.76; p=0.086).

CONCLUSIONS

The crude early postoperative mortality rate in non-HCC-LTR was higher than in HCC-LTR, due to a greater incidence of postoperative complications with an impact upon mortality (shock at admission to intensive care and the development of multiorgan dysfunction syndrome).

Pleural Effusions Following Liver Transplantation: A Single-Center Experience

INTRODUCTION

This was a single-center retrospective study to evaluate incidence, prognosis, and risk factors in patients with postoperative pleural effusions, a common pulmonary complication following liver transplantation.

METHODS

A retrospective review was performed on 374 liver transplantation cases through a database within the timeframe of January 1, 2009 through December 31, 2015. Demographics, pulmonary and cardiac function testing, laboratory studies, intraoperative transfusion/infusion volumes, postoperative management, and outcomes were analyzed.

RESULTS

In the immediate postoperative period, 189 (50.5%) developed pleural effusions following liver transplantation of which 145 (76.7%) resolved within 3 months. Those who developed pleural effusions demonstrated a lower fibrinogen (149.6 ± 66.3 mg/dL vs 178.4 ± 87.3 mg/dL; P = .009), total protein (5.8 ± 1.0 mg/dL vs 6.1 ± 1.2 mg/dL; P = .04), and hemoglobin (9.8 ± 1.8 mg/dL vs 10.3 ± 1.9 mg/dL; P = .004). There was not a statistically significant difference in 1-year all-cause mortality and in-hospital mortality between liver transplant recipients with and without pleural effusions. Liver transplant recipients who developed pleural effusions had a longer hospital length of stay (16.4 ± 10.9 days vs 14.0 ± 16.5 days; P = .1), but the differences were not statistically significant. However, there was a significant difference in tracheostomy rates (11.6% vs 5.4%; P = .03) in recipients who developed pleural effusions compared to recipients who did not.

CONCLUSIONS

In summary, pleural effusions are common after liver transplantation and are associated with increased morbidity. Pre- and intraoperative risk factors can offer both predictive and prognostic value for post-transplantation pleural effusions. Further prospective studies will be needed to further evaluate the relevance of these findings to limit instances of postoperative pleural effusions.

Significant lung injury and its prognostic significance in acute liver failure: A cohort analysis

BACKGROUND AND AIMS

Respiratory failure complicating acute liver failure (ALF) may preclude liver transplantation (LT). We evaluated the association between significant lung injury (SLI) and important clinical outcomes.

METHODS

Retrospective cohort study of 947 ALF patients with chest radiograph (CXR) and arterial blood gas (ABG) data enrolled in the US Acute Liver Failure Study Group (US-ALFSG) from January 1998 to December 2016. SLI was defined by moderate hypoxaemia (Berlin classification; PaO₂ /FiO₂  < 200 mm Hg) and abnormalities on CXR. Primary outcomes were 21-day transplant-free survival (TFS) and overall survival.

RESULTS

Of 947 ALF patients, 370 (39%) had evidence of SLI. ALF patients with SLI (ALF-SLI) had significantly worse oxygenation than controls on admission (median PF ratio 120 vs 300 mm Hg, P < .0001) and higher lactate (6.1 vs 4.6 mmol/l, P = .0008). ALF-SLI patients had higher rates of tracheal (19% vs 14%) and bloodstream (17% vs 11%, P < .005 for both) infections and were more likely to receive transfusions (red cells 55% vs 43%; FFP 74% vs 66%; P < .009 for both). ALF-SLI patients were less likely to receive LT (18% vs 25%, P = .02) and had significantly decreased 21-day TFS (34% vs 42%) and overall survival (49% vs 64%, P < .007 for both). After adjusting for significant covariates (INR, bilirubin, acetaminophen aetiology), the development of SLI was independently associated with decreased 21-day TFS (OR 0.71, P = .03) in ALF patients (C-index 0.78). The incorporation of SLI improved discriminatory ability of the King's College Criteria (P = .0061) but not the ALFSG prognostic index (P = .34).

CONCLUSION

Significant lung injury is a common complication in ALF patients that adversely affects patient outcomes.

Perioperative Pleural Drainage in Liver Transplantation: A Retrospective Analysis from a High-Volume Liver Transplant Center

BACKGROUND Pleural effusions represent a common complication after liver transplantation (LT) and chest drain (CD) placement is frequently necessary. MATERIAL AND METHODS In this retrospective cohort study, adult LT recipients between 2009 and 2016 were analyzed for pleural effusion formation and its treatment within the first 10 postoperative days. The aim of the study was to compare different settings of CD placement with regard to intervention-related complications. RESULTS Overall, 597 patients met the inclusion criteria, of which 361 patients (60.5%) received at least 1 CD within the study period. Patients with a MELD >25 were more frequently affected (75.7% versus 56.0%, P<0.001). Typically, CDs were placed in the intensive care unit (ICU) (66.8%) or in the operating room (14.1% during LT, 11.5% in the context of reoperations). In total, 97.0% of the patients received a right-sided CD, presumably caused by local irritations. Approximately one-third (35.4%) of ICU-patients required pre-interventional optimization of coagulation. Of the 361 patients receiving a CD, 15 patients (4.2%) suffered a post-interventional hemorrhage and 6 patients (1.4%) had a pneumothorax requiring further treatment. Less complications were observed when the CD was performed in the operating room compared to the ICU: 1 out 127 patients (0.8%) versus 20 out of 332 patients (6.0%); P=0.016. CONCLUSIONS CD placement occurring in the operating room was associated with fewer complications in contrast to placement occurring in the ICU. Planned CD placement in the course of surgery might be favorable in high-risk patients.

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

Background

Postoperative respiratory failure (PRF, namely mechanical ventilation >48 hours) significantly affects morbidity and mortality in liver transplantation (LTx). Previous studies analyzed only one or two categories of PRF risk factors (preoperative, intraoperative or postoperative ones).

The aims of this study were to identify PRF predictors, to assess the length of stay (LoS) in ICU and the 90-day survival according to the PRF in LTx patients.

Methods

Two classification approaches were used: systematic classification (recipient-related preoperative factors; intraoperative factors; logistic factors; donor factors; postoperative ICU factors; postoperative surgical factors) and patient/organ classification (patient-related general factors; native-liver factors; new-liver factors; kidney factors; heart factors; brain factors; lung factors). Two hundred adult non-acute patients were included. Missing analysis was performed. The competitive role of each factor was assessed.

Results

PRF occurred in 36.0% of cases. Among 28 significant PRF predictors at univariate analysis, 6 were excluded because of collinearity, 22 were investigated by ROC curves and by logistic regression analysis. Recipient age (OR = 1.05; p = 0.010), female sex (OR = 2.75; p = 0.018), Model for End-Stage Liver Disease (MELD, OR = 1.09; p<0.001), restrictive lung pattern (OR = 2.49; p = 0.027), intraoperative veno-venous bypass (VVBP, OR = 3.03; p = 0.008), pre-extubation PaCO₂ (OR = 1.11; p = 0.003) and Model for Early Allograft Function (MEAF, OR = 1.37; p<0.001) resulted independent PRF risk factors. As compared to patients without PRF, the PRF-group had longer LoS (10 days IQR 7–18 versus 5 days IQR 4–7, respectively; p<0.001) and lower day-90 survival (86.0% versus 97.6% respectively, p<0.001).

Conclusion

In conclusion, MELD, restrictive lung pattern, surgical complexity as captured by VVBP, pre-extubation PaCO₂ and MEAF are the main predictors of PRF in non-acute LTx patients.

Pulmonary complications after liver transplantation in children: risk factors and impact on early post-operative morbidity

Liver transplantation (LT) is associated with high post-operative morbidity, despite excellent survival rates. With this retrospective study, we report the incidence of early and late pulmonary complications (PC) after LT, identify modifiable risk factors for PC and analyzed the role of PC in post-operative ventilation duration and hospital length of stay. In a series of 79 children (0-16 years) with LT over a 12 years period, early (<3 months post-LT) and/or late (>3 months post-LT) PC occurred in 68 patients (86%). Sixty-four percent (64%) developed early major complications such as pulmonary edema, atelectasis, or pleural effusion. Atelectasis requiring an intervention (P ≤ .02), pulmonary edema (P ≤ .02), or elevated PELD/MELD scores (P = .05) were associated with an increase in total ventilation duration and length of stay in the ICU. Risk factors for early PC included preoperative hypoxemia (P = .005), low serum albumin at LT admission (P = .003), or early rejection (P = .002). About 20% of patients experienced late PC of which 81% were infections. Risk factor assessment prior to LT may ultimately help reduce early PC thereby possibly minimizing post-operative morbidity and ICU length of stay.

Intensive Care of Pulmonary Complications Following Liver Transplantation

Chronic liver disease has been associated with pulmonary dysfunction both before and after liver transplantation. Post-liver transplantation pulmonary complications can affect both morbidity and mortality often necessitating intensive care during the immediate postoperative period. The major pulmonary complications include pneumonia, pleural effusions, pulmonary edema, and atelectasis. Poor clinical outcomes have been known to be associated with age, severity of liver dysfunction, and preexisting lung disease as well as perioperative events related to fluid balance, particularly transfusion and fluid volumes. Delineating each and every one of these pulmonary complications and their associated risk factors becomes paramount in guiding specific therapeutic strategies.

Cost Analysis and Determinants of Living Donor Liver Transplantation in Taiwan

BACKGROUND

Liver transplantation (LT) has become established therapy for end-stage liver disease and small-cell hepatocellular carcinoma (HCC), relying mainly on living donor LT (LDLT) in Taiwan. The cost of LDLT varies in different countries depending on the insurance system, the costs of the facility, and staff. In this study we aimed to investigate cost outcomes and determinants of LDLT in Taiwan.

METHODS

From January 2014 to December 2015, 184 LDLT patients were enrolled in a study performed at the Kaohsiung Chang Gung Memorial Hospital. Patients' transplantation costs were defined as expense from immediately after surgery to discharge during hospitalization for LDLT. Antiviral therapy and hepatitis B immunoglobulin (HBIG) for prevention of hepatitis B virus (HBV) were included, but direct-acting antiviral (DAA) therapy for hepatitis C (HCV) was excluded.

RESULTS

The median total, intensive care unit (ICU), and ward costs of LT were US$64,250, $43,357, and $16,138 (currency ratio 1:30), respectively. HBV significantly increased the total cost of LT, followed by postoperative reintubation and bile duct complications.

CONCLUSION

The charges associated with anti-HBV viral therapy and HBIG increase the cost of LDLT. Disease severity of liver cirrhosis showed less importance in predicting cost. Postoperative complications such as reintubation or bile duct complications should be avoided to reduce the cost of LT.

Noninfectious Pulmonary Complications of Liver, Heart, and Kidney Transplantation: An Update

Despite significant advances in surgical techniques, perioperative care, and immunosuppressive therapy, solid organ transplantation still carries considerable risk of complications. Pulmonary complications, in particular, are a major cause of morbidity and mortality. Although infectious complications prevail, the lungs are also vulnerable to a variety of noninfectious complications related to the transplant surgery and adverse effects of the immunosuppressive regimen. This article focuses on noninfectious pulmonary complications associated with the 3 most commonly performed solid organ transplant procedures: liver, kidney, and heart.

Pretransplant Factors and Associations with Postoperative Respiratory Failure, ICU Length of Stay, and Short-Term Survival after Liver Transplantation in a High MELD Population

Changes in distribution policies have increased median MELD at transplant with recipients requiring increasing intensive care perioperatively. We aimed to evaluate association of preoperative variables with postoperative respiratory failure (PRF)/increased intensive care unit length of stay (ICU LOS)/short-term survival in a high MELD cohort undergoing liver transplant (LT). Retrospective analysis identified cases of PRF and increased ICU LOS with recipient, donor, and surgical variables examined. Variables were entered into regression with end points of PRF and ICU LOS > 3 days. 164 recipients were examined: 41 (25.0%) experienced PRF and 74 (45.1%) prolonged ICU LOS. Significant predictors of PRF with univariate analysis: BMI > 30, pretransplant MELD, preoperative respiratory failure, LVEF < 50%, FVC < 80%, intraoperative transfusion > 6 units, warm ischemic time > 4 minutes, and cold ischemic time > 240 minutes. On multivariate analysis, only pretransplant MELD predicted PRF (OR 1.14, p = 0.01). Significant predictors of prolonged ICU LOS with univariate analysis are as follows: pretransplant MELD, FVC < 80%, FEV1 < 80%, deceased donor, and cold ischemic time > 240 minutes. On multivariate analysis, only pretransplant MELD predicted prolonged ICU LOS (OR 1.28, p < 0.001). One-year survival among cohorts with PRF and increased ICU LOS was similar to subjects without. Pretransplant MELD is a robust predictor of PRF and ICU LOS. Higher MELDs at LT are expected to increase need for ICU utilization and modify expectations for recovery in the immediate postoperative period.

The utility of pulmonary function testing in predicting outcomes following liver transplantation

Although pulmonary function tests (PFTs) are routinely performed in patients during the evaluation period before liver transplantation (LT), their utility in predicting post-LT mortality and morbidity outcomes is not known. The aim of this study was to determine the impact of obstructive and/or restrictive lung disease on post-LT outcomes. We conducted a retrospective analysis of patients who had pre-LT PFTs and underwent a subsequent LT (2007-2013). We used statistical analyses to determine independent associations between PFT parameters and outcomes (graft/patient survival, time on ventilator, and hospital/intensive care unit [ICU] length of stay [LOS]). A total of 415 LT recipients with available PFT data were included: 65% of patients had normal PFTs; 8% had obstructive lung disease; and 27% had restrictive lung disease. There was no difference in patient and graft survival between patients with normal, obstructive, and restrictive lung disease. However, restrictive lung disease was associated with longer post-LT time on ventilator and both ICU and hospital LOS (P < 0.05). More specific PFT parameters (diffusing capacity of the lungs for carbon monoxide, total lung capacity, and residual volume) were all significant predictors of ventilator time and both ICU and hospital LOS (P < 0.05). Although pre-LT PFT parameters may not predict post-LT mortality, restrictive abnormalities correlate with prolonged post-LT ventilation and LOS. Efforts to identify and minimize the impact of restrictive abnormalities on PFTs might improve such outcomes. Liver Transplantation 22 805-811 2016 AASLD.

Awareness of Respiratory Failure Can Predict Early Postoperative Pulmonary Complications in Liver Transplant Recipients

OBJECTIVES

Cardiovascular and respiratory system complications are the most common causes of early mortality after liver transplant. We evaluated the causes of respiratory failure as an early postoperative pulmonary complication in liver transplant recipients.

MATERIALS AND METHODS

Patients who underwent orthotropic liver transplant between 2001 and 2014 were retrospectively evaluated. Clinical and demographic variables and pulmonary complications at the first and second visit after transplant were noted. The first visit was within the first week and the second was between 1 and 4 weeks after transplant. An arterial oxygen saturation value below 90% in room air for at least 1 day was considered a medically significant respiratory failure.

RESULTS

Our study included 204 (148 men and 56 women; mean age 43.0.4 ± 13.06 y) adult liver transplant recipients (46 from deceased and 158 from living donors). At the first visit after transplant, 161 patients (79%) had postoperative pulmonary complications, including pleural effusion accompanied by atelectasis (47.1%), only atelectasis (17.2%), and only pleural effusion (10.3%). At the second visit, complications included atelectasis associated with pleural effusion (12.3%) and pneumonia (12.3%). All patients had documented respiratory failure at the first visit, and 92 patients (45.1%) had respiratory failure at the second visit. Causes of respiratory failure at the first visit included atelectasis in 35 patients (17.2%) and atelectasis accompanied by pleural effusion in 96 patients (47.1%). At the second visit, 25 of 161 patients (25.3%) had respiratory failure due to pneumonia. Other causes included atelectasis accompanied by pleural effusion (24.2%) and pleural effusion (23.2%). Ninety-seven patients had no pulmonary complications. The mortality rate was 6.4% within the first visit and 8.7% within the second visit.

CONCLUSIONS

Pneumonia, atelectasis, and pleural effusion can cause respiratory failure within the first month after liver transplant. Early pulmonary examination, diagnosis, and treatment can improve patient survival.

Predicting postoperative acute respiratory failure in critical care using nursing notes and physiological signals

Postoperative Acute Respiratory Failure (ARF) is a serious complication in critical care affecting patient morbidity and mortality. In this paper we investigate a novel approach to predicting ARF in critically ill patients. We study the use of two disparate sources of information – semi-structured text contained in nursing notes and investigative reports that are regularly recorded and the respiration rate, a physiological signal that is continuously monitored during a patient's ICU stay. Unlike previous works that retrospectively analyze complications, we exclude discharge summaries from our analysis envisaging a real time system that predicts ARF during the ICU stay. Our experiments, on more than 800 patient records from the MIMIC II database, demonstrate that text sources within the ICU contain strong signals for distinguishing between patients who are at risk for ARF from those who are not at risk. These results suggest that large scale systems using both structured and unstructured data recorded in critical care can be effectively used to predict complications, which in turn can lead to preemptive care with potentially improved outcomes, mortality rates and decreased length of stay and cost.

A multicenter study of 30 days complications after deceased donor liver transplantation in the model for end-stage liver disease score era

Knowledge of risk factors for posttransplant complications is likely to improve patient outcomes. Few large studies of all early postoperative complications after deceased donor liver transplantation (DDLT) exist. Therefore, we conducted a retrospective, cohort study of 30-day complications, their risk factors, and the impact on outcomes after DDLT. Three centers contributed data for 450 DDLTs performed from January 2005 through December 2009. Data included donor, recipient, transplant, and outcome variables. All 30-day postoperative complications were graded by the Clavien-Dindo system. Complications per patient and severe (≥ grade III) complications were primary outcomes. Death within 30 days, complication occurrence, length of stay (LOS), and graft and patient survival were secondary outcomes. Multivariate associations of risk factors with complications and complications with LOS, graft survival, and patient survival were examined. Mean number of complications/patient was 3.3 ± 3.9. At least 1 complication occurred in 79.3%, and severe complications occurred in 62.8% of recipients. Mean LOS was 16.2 ± 22.9 days. Graft and patient survival rates were 84% and 86%, respectively, at 1 year and 74% and 76%, respectively, at 3 years. Hospitalization, critical care, ventilatory support, and renal replacement therapy before transplant and transfusions during transplant were the significant predictors of complications (not the Model for End-Stage Liver Disease score). Both number and severity of complications had a significant impact on LOS and graft and patient survival. Structured reporting of risk-adjusted complications rates after DDLT is likely to improve patient care and transplant center benchmarking. Despite the accomplished reductions in transfusions during DDLT, opportunities exist for further reductions. With increasing transplantation of sicker patients, reduction in complications would require multidisciplinary efforts and institutional commitment. Pretransplant risk characteristics for complications must factor in during payer contracting.

Hydrothorax with alveolar-pleural fistula mimicking re-expansion pulmonary edema during liver transplantation: a case report

We present a case of an alveolar-pleural fistula with hepatic hydrothorax in a patient undergoing orthotropic liver transplantation, which was detected by drainage of transudate through an endotracheal tube during operation. A standard endotracheal tube was changed to a double-lumen tube to provide differential lung ventilation. The patient was diagnosed with an alveolar-pleural fistula by direct vision of an air leak during positive-pressure ventilation through a diaphragmatic incision. There was still a concern about worsening his ventilation due to persistent aspiration of pleural effusion towards the ipsilateral lung during the remaining operation period. Surgeon repaired the defect on the exposed lung surface via diaphragmatic opening. Anesthesiologists should consider an alveolar-pleural fistula as a possible differential diagnosis with re-expansion pulmonary edema when transudate emanating from the endotracheal tube is obtained in patients with massive hydrothorax.

Prognostic impact of mechanical ventilation after liver transplantation: a national database study

BACKGROUND

The impact of mechanical ventilatory support (MCVS) on mortality and graft loss after liver transplantation (LT) is not well described.

METHODS

Multivariate analysis of a novel database linking national transplant registry and Medicare claims data was used to assess the impact of early MCVS on mortality and graft survival following LTs performed between 2002 and 2008.

RESULTS

Among 10,517 LT recipients, 6.9% (n = 726) required postoperative MCVS, 25.6% of whom required less than 96 hours, 24.2% required 96 hours or longer, and 50.1% received an unspecified duration. Significant predictors of prolonged MCVS included older age, female sex, pretransplant dialysis requirement, and ascites. After multivariate adjustment, MCVS of 96 hours or longer was associated with nearly 3 times the adjusted hazard ratio of mortality (2.95, P < .001), while MCVS less than 96 hours was not significantly associated with mortality (adjusted hazard ratio .88, P = .55).

CONCLUSIONS

Recognition of LT patients at risk for prolonged MCVS may help to reduce the incidence and consequences of this complication.

Early respiratory complications after liver transplantation

The poor clinical conditions associated with end-stage cirrhosis, pre-existing pulmonary abnormalities, and high comorbidity rates in patients with high Model for End-Stage Liver Disease scores are all well-recognized factors that increase the risk of pulmonary complications after orthotopic liver transplantation (OLT) surgery. Many intraoperative and postoperative events, such as fluid overload, massive transfusion of blood products, hemodynamic instability, unexpected coagulation abnormalities, renal dysfunction, and serious adverse effects of reperfusion syndrome, are other factors that predispose an individual to postoperative respiratory disorders. Despite advances in surgical techniques and anesthesiological management, the lung may still suffer throughout the perioperative period from various types of injury and ventilatory impairment, with different clinical outcomes. Pulmonary complications after OLT can be classified as infectious or non-infectious. Pleural effusion, atelectasis, pulmonary edema, respiratory distress syndrome, and pneumonia may contribute considerably to early morbidity and mortality in liver transplant patients. It is of paramount importance to accurately identify lung disorders because infectious pulmonary complications warrant speedy and aggressive treatment to prevent diffuse lung injury and the risk of evolution into multisystem organ failure. This review discusses the most common perioperative factors that predispose an individual to postoperative pulmonary complications and these complications’ early clinical manifestations after OLT and influence on patient outcome.

Predictive Factors for Reintubation following Noninvasive Ventilation in Patients with Respiratory Complications after Living Donor Liver Transplantation

Background

Postoperative respiratory complications are a major cause of mortality following liver transplantation (LT). Noninvasive ventilation (NIV) appears to be effective for respiratory complications in patients undergoing solid organ transplantation; however, mortality has been high in patients who experienced reintubation in spite of NIV therapy. The predictors of reintubation following NIV therapy after LT are not exactly known.

Methods

Of 511 adult patients who received living-donor LT, data on the 179 who were treated by NIV were retrospectively examined.

Results

Forty-three (24%) of the 179 patients who received NIV treatment required reintubation. Independent factors associated with reintubation by multivariate logistic regression analysis were controlled preoperative infections (odds ratio [OR] 8.88; 95% confidence interval (CI) 1.64 to 48.11; p = 0.01), ABO-incompatibility (OR 4.49; 95% CI, 1.50 to 13.38; p = 0.007), and presence of postoperative pneumonia at the time of starting NIV (OR 3.28; 95% CI, 1.02 to 11.01; p = 0.04). The reintubated patients had a significant higher rate of postoperative infectious complications and a significantly longer intensive care unit stay than those in whom NIV was successful (p<0.0001). Of the 43 reintubated patients, 22 (51.2%) died during hospitalization following LT vs. 8 (5.9%) of the 136 patients in whom NIV was successful (p<0.0001).

Conclusions

Because controlled preoperative infection, ABO-incompatibility or pneumonia prior to the start of NIV were independent risk factors for reintubation following NIV, caution should be used in applying NIV in patients with these conditions considering the high rate of mortality in patients requiring reintubation following NIV.

Anesthetic management including extracorporeal membrane oxygenation therapy of liver transplant recipient with life-threatening hypoxemia -a case report-

We present a rare case of successful anesthetic management for a patient who had refractory hypoxia during liver transplantation (LT) with intraoperative veno-venous (VV) extracorporeal membrane oxygenation (ECMO) support. A 49 year-old female patient underwent living donor LT. After reperfusion of the grafted liver, graft congestion and massive oozing developed. Thus it was decided to reoperate with a temporary gauze packing. However, the patient's condition deteriorated with azotemia and severe hypoxemia. VV ECMO with continuous renal replacement therapy was started 24 hours before secondary LT and maintained during secondary LT. VV ECMO was weaned 32 hours after secondary LT. This case indicates that not only after the LT but also before and during LT, VV ECMO can be a treatment option for the patient with end-stage liver disease combined with respiratory failure when there is the possibility of lung recovery.

Respiratory risk score for the prediction of 3-month mortality and prolonged ventilation after liver transplantation

Survival of critically ill patients is significantly affected by prolonged ventilation. The goal of this study was the development of a respiratory risk score (RRS) for the prediction of 3-month mortality and prolonged ventilation after liver transplantation (LT). Two hundred fifty-four consecutive LT patients from a single center were retrospectively randomized into a training group for model design and a validation group. A receiver operating characteristic (ROC) curve analysis was used to test sensitivity and specificity. The accuracy of the predictions was assessed with the Brier score, and the model calibration was assessed with the Hosmer-Lemeshow test. Cutoff values were determined with the best Youden index. The RRS was calculated in the first 24 hours as follows: (laboratory Model for End-Stage Liver Disease score > 30 = 2.36 points) + (fresh frozen plasma > 13.5 U = 2.70 points) + (partial pressure of arterial oxygen/fraction of inspired oxygen ratio < 200 mm Hg = 2.23 points) + (packed red blood cells > 10.5 U = 3.50 points) + (preoperative mechanical ventilation = 3.87 points) +  (preoperative dialysis = 2.83 points) + (donor steatosis hepatis > 40% = 2.95 points). The RSS demonstrated high predictive accuracy, good model calibration, and c statistics > 0.7 in the training and validation groups. The RSS was able to predict 3-month mortality [cutoff = 6.64, area under the (ROC) curve (AUROC) = 0.794] and prolonged ventilation (cutoff = 3.69, AUROC = 0.798) with sensitivities of 69% and 81%, specificities of 83% and 73%, and overall model correctness of 76% and 77%, respectively. In conclusion, this study provides the first prognostic model for the prediction of 3-month mortality and prolonged ventilation after LT with high sensitivity and specificity and good model accuracy. The application of the RRS to an external cohort would be desirable for its further validation and introduction as a clinical tool for intensive care resource planning and prognostic decision making.

Profile of respiratory evaluation through surface electromyography, manovacuometry, and espirometry in candidates on the liver transplant waiting list

INTRODUCTION

Electromyography (EMG) is the examination of skeletal muscle membrane electrical activity in response to physiologic activation. In healthy muscles, the square root (root mean square [RMS] is related to the amplitude of the obtained signal. Respiratory muscles are studied, especially those important for compliance, the diaphragm and the rectus abdominis. An evaluation to detect respiratory muscle deficits among liver disease patients on the waiting list for transplantation may serve as an alternative to providing specific treatments reducing the possibility of respiratory complications after transplantation.

OBJECTIVE

To study muscle activity by evaluating respiratory and surface EMG of the right diaphragm and right rectus abdominis muscles in patients on the liver transplant waiting list.

METHOD

Respiratory evaluation of muscle strength (maximum inspiratory pressure [MIP] and maximum expiratory pressure [MEP]) with a manometer -300, +300 from Gen-air; spirometry with Easyware Spirometer version 2.20; pulse oximetry with Nonim oximeter; Model for End-Stage Liver Disease (MELD) score as well as surface EMG of the diaphragm and rectus abdominis muscles from EMG/Brazil were applied in healthy and liver diseased subjects.

RESULTS

The 87 liver disease patients showed a mean age of 53.9 ± 7.3 years, mean body mass index of 28.21 ± 5.04 kg/m2 with 24.14% smokers (n = 21) and 43.68% physically active (n = 38 p) showing Diaphragm RMS of 61.05 ± 68.48 μV; rectus abdominis RMS of 45.28 ± 53.82 μV; MEP of 100.28 ± 27.85 cm H(2)O; and MIP of 92.41 ± 29.77 cm H2O. The average MELD of studied patients was 16.5 ± 0.71.

CONCLUSION

The respiratory profiles of patients on the liver transplant waiting list concerning muscle support were precarious owing to ascites and motor adynamia.

Outcomes following liver transplantation in intensive care unit patients

AIM

To determine feasibility of liver transplantation in patients from the intensive care unit (ICU) by estimating graft and patient survival.

METHODS

This single center retrospective study included 39 patients who had their first liver transplant directly from the intensive care unit and 927 non-ICU patients who were transplanted from hospital ward or home between January 2005 and December 2010.

RESULTS

In comparison to non-ICU patients, ICU patients had a higher model for end-stage liver disease (MELD) at transplant (median: 37 vs 20, P < 0.001). Fourteen out of 39 patients (36%) required vasopressor support immediately prior to liver transplantation (LT) with 6 patients (15%) requiring both vasopressin and norepinephrine. Sixteen ICU patients (41%) were ventilator dependent immediately prior to LT with 9 patients undergoing percutaneous tracheostomy prior to transplantation. Twenty-five ICU patients (64%) required dialysis preoperatively. At 1, 3 and 5 years after LT, graft survival was 76%, 68% and 62% in ICU patients vs 90%, 81% and 75% in non-ICU patients. Patient survival at 1, 3 and 5 years after LT was 78%, 70% and 65% in ICU patients vs 94%, 85% and 79% in non-ICU patients. When formally comparing graft survival and patient survival between ICU and non-ICU patients using Cox proportional hazards regression models, both graft survival [relative risk (RR): 1.94, 95%CI: 1.09-3.48, P = 0.026] and patient survival (RR: 2.32, 95%CI: 1.26-4.27, P = 0.007) were lower in ICU patients vs non-ICU patients in single variable analysis. These findings were consistent in multivariable analysis. Although not statistically significant, graft survival was worse in both patients with cryptogenic cirrhosis (RR: 3.29, P = 0.056) and patients who received donor after cardiac death (DCD) grafts (RR: 3.38, P = 0.060). These findings reached statistical significance when considering patient survival, which was worse for patients with cryptogenic cirrhosis (RR: 3.97, P = 0.031) and patients who were transplanted with DCD livers (RR: 4.19, P = 0.033). Graft survival and patient survival were not significantly worse for patients on mechanical ventilation (RR: 0.91, P = 0.88 in graft loss; RR: 0.69, P = 0.56 in death) or patients on vasopressors (RR: 1.06, P = 0.93 in graft loss; RR: 1.24, P = 0.74 in death) immediately prior to LT. Trends toward lower graft survival and patient survival were observed for patients on dialysis immediately before LT, however these findings did not approach statistical significance (RR: 1.70, P = 0.43 in graft loss; RR: 1.46, P = 0.58 in death).

CONCLUSION

Although ICU patients when compared to non-ICU patients have lower survivals, outcomes are still acceptable. Pre-transplant ventilation, hemodialysis, and vasopressors were not associated with adverse outcomes.