Critical care issues in patients after liver transplantation

Bacterial infection after liver transplantation

Infectious complications are major causes of morbidity and mortality after liver transplantation, despite recent advances in the transplant field. Bacteria, fungi, viruses and parasites can cause infection before and after transplantation. Among them, bacterial infections are predominant during the first two months post-transplantation and affect patient and graft survival. They might cause surgical site infections, including deep intra-abdominal infections, bacteremia, pneumonia, catheter-related infections and urinary tract infections. The risk factors for bacterial infections differ between the periods after transplant, and between centers. Recently, the emergence of multi-drug resistant bacteria is great concern in liver transplant (LT) patients. The instructive data about effects of infections with extended-spectrum beta lactamase producing bacteria, carbapenem-resistant gram-negative bacteria, and glycopeptide-resistant gram-positive bacteria were reported on a center-by-center basis. To prevent post-transplant bacterial infections, proper strategies need to be established based upon center-specific data and evidence from well-controlled studies. This article reviewed the recent epidemiological data, risk factors for each type of infections and important clinical issues in bacterial infection after LT.

Impact of pretransplant rifaximin therapy on early post-liver transplant infections

Bacterial and fungal infections are major causes of morbidity and mortality after liver transplantation (LT). The role of intestinal decontamination in the prevention of post-LT infections is controversial. Rifaximin is widely used for the treatment of hepatic encephalopathy. The effect of rifaximin on post-LT infections is unknown. The aim of our study was to determine the effect of rifaximin therapy in the pretransplant period on early bacterial infections (EBIs) and fungal infections within the first 30 days after LT. All adult patients who underwent LT at our institution (January 2009 to July 2011) were included in this retrospective cohort study. Patients receiving antibiotics other than pretransplant protocol antibiotics were excluded. Patients were stratified into 2 groups based on the presence or absence of rifaximin therapy for at least 2 days before LT. Infections were defined by the isolation of any bacterial or fungal organisms within 30 days of LT. Multivariate regression analysis, Student t tests, and Pearson's chi-square tests were used to compare the 2 groups. Two hundred sixty-eight patients were included, and 71 of these patients (26.5%) were on rifaximin at the time of LT. The 2 groups were comparable with respect to age, sex, race, and Model for End-Stage Liver Disease score. There were no significant differences in the rates of EBIs (30% for the non-rifaximin group and 25% for the rifaximin group, P = 0.48) or fungal infections between the 2 groups. There was no increase in antimicrobial resistance among the infecting organisms. There was no difference in survival between the rifaximin and non-rifaximin groups (98% versus 97%, P = 0.36). In conclusion, the use of rifaximin in the pre-LT period was not associated with an increased risk of bacterial or fungal infections in the early post-LT period.

Postoperative care/critical care of the transplant patient

Critical care of the general surgical patient requires synthesis of the patient's physiology, intraoperative events, and preexisting comorbidities. Evaluating an abdominal solid-organ transplant recipient after surgery adds a new dimension to clinical decisions because the transplanted allograft has undergone its own physiologic challenges and now must adapt to a new environment. This donor-recipient interaction forms the foundation for assessment of early allograft function (EAF). The intensivist must accurately assess and support EAF within the context of the recipient's current physiology and preexisting comorbidities. Optimizing EAF is essential because allograft failure is a significant predictor of recipient morbidity and mortality.

Risk factors for early bacterial infections in liver transplantation

OBJECTIVE

Our aim was to determine perioperative risk factors for early bacterial infection after liver transplantation.

METHODS

Retrospectively examining medical records using Centers for Disease Control and Prevention (CDC) definitions to identify nosocomial infections, we analyzed data on 367 adult patients.

RESULTS

The incidence of infection was 37.3% (n = 137): namely, surgical site (n = 74; 20.2%) [corrected], blood stream (n = 64; 17.4%), pulmonary (n = 49; 13.4%), urinary system (n = 26; 7.1%). Significant risk factors within the first 30 days were as follows: deceased donor, Model for End-Stage Liver Disease (MELD) >20, albumin level <2.8 g/dL, intraoperative erythrocyte transfusion >6 U, intraoperative fresh frozen plasma >12 U, bilioenteric anastomosis, postoperative intensive care unit stay >6 days, and postoperative length of stay >21 days. Significant risk factors detected within the first 90 days were as follows: MELD >20, preoperative length of stay >7 days, reoperation, postoperative length of intensive care unit stay >6 days, and postoperative length of stay >21 days. Variability was observed in risk factors according to localization of infection. As a result, except for MELD, type of donor, and biliary anastomosis, the others are preventable factors for early bacterial infection. In addition, the same risk factors showed variability according to the site of infection.

Life-threatening infection in transplant recipients

Modern post-transplant care pathways commonly encompass periods of critical care support. Infectious events account for many of these interactions making critical care physicians integral members of multidisciplinary transplant teams. Despite continuing advances in clinical care and infection prophylaxis, the morbidity and mortality attributable to infection post-transplant remains considerable. Emerging entities constantly add to the breadth of potential opportunistic pathogens. Individualized risk assessments, rapid and thorough diagnostic evaluation, and prompt initiation of appropriate antimicrobial therapies are essential. The approach to managing transplant recipients with infection in critical care is discussed and common and emerging opportunistic pathogens are reviewed.

Hemostasis in patients with acute kidney injury secondary to acute liver failure

Acute kidney injury (AKI) occurs in over half of patients with acute liver failure. Despite prolonged prothrombin times and thrombocytopenia, continuous renal replacement therapy circuits frequently develop clots during patient treatment. Here we assessed factors contributing to this by measuring coagulation parameters (standard coagulation tests, pro- and anticoagulant factors, thromboelastography, and thrombin generation) in 20 consecutive patients with acute liver failure; mean age 42 years. Within 48 h, 10 had developed stage 3 AKI and 9 required continuous renal replacement therapy, of whom 2 had frequent circuit clots. The patients with stage 3 AKI were found to have significantly lower platelet counts and levels of factor V and the natural anticoagulants antithrombin, Protein C and Protein S, but increased extrinsic pathway activation and von Willebrand factor levels. Tissue factor levels were greater in those with stage 3 AKI, as was microparticle activity. Although patients with acute liver failure and advanced AKI requiring continuous renal replacement therapy have an even more marked thrombocytopenia and more prolonged extrinsic pathway activation, this was not associated with increased bleeding. Thus, more frequent circuit clots during continuous renal replacement therapy appear to be due to a combination of increased tissue factor and microparticle release, endothelial activation, and reduction in natural anticoagulants.

Nutrition support and infections associated with hepatic resection and liver transplantation in patients with chronic liver disease

Malnutrition is common in liver cirrhotic patients who will undergo liver resection or liver transplantation. A precise evaluation of their nutrition status is thus difficult because of the presence of ascites and the edema caused by their impaired protein synthesis. Both perioperative enteral and parenteral nutrition have benefits in reducing the morbidity and mortality of liver surgery, and in general, oral nutrition supplements are recommended. Branched-chain amino acids (BCAAs) promote protein and glycogen synthesis and regulate immune system function. Synbiotics, a combination of pro- and prebiotics, is reported to enhance immune responses. Oral nutrition support with BCAAs, synbiotics, and an immune-enhancing diet have a beneficial effect on preventing the perioperative infections associated with hepatic resection or liver transplantation.

Is a mandatory intensive care unit stay needed after liver transplantation? Feasibility of fast-tracking to the surgical ward after liver transplantation

The continuation of hemodynamic, respiratory, and metabolic support for a variable period after liver transplantation (LT) in the intensive care unit (ICU) is considered routine by many transplant programs. However, some LT recipients may be liberated from mechanical ventilation shortly after the discontinuation of anesthesia. These patients might be appropriately discharged from the postanesthesia care unit (PACU) to the surgical ward and bypass the ICU entirely. In 2002, our program started a fast-tracking program: select LT recipients are transferred from the operating room to the PACU for recovery and tracheal extubation with a subsequent transfer to the ward, and the ICU stay is completely eliminated. Between January 1, 2003 and December 31, 2007, 1045 patients underwent LT at our transplant program; 175 patients were excluded from the study. Five hundred twenty-three of the remaining 870 patients (60.10%) were fast-tracked to the surgical ward, and 347 (39.90%) were admitted to the ICU after LT. The failure rate after fast-tracking to the surgical ward was 1.90%. The groups were significantly different with respect to the recipient age, the raw Model for End-Stage Liver Disease (MELD) score at the time of LT, the recipient body mass index (BMI), the retransplantation status, the operative time, the warm ischemia time, and the intraoperative transfusion requirements. A multivariate logistic regression analysis revealed that the raw MELD score at the time of LT, the operative time, the intraoperative transfusion requirements, the recipient age, the recipient BMI, and the absence of hepatocellular cancer/cholangiocarcinoma were significant predictors of ICU admission. In conclusion, we are reporting the largest single-center experience demonstrating the feasibility of bypassing an ICU stay after LT.

The assessment of GFR after orthotopic liver transplantation using cystatin C and creatinine-based equations

The measurement of kidney function after orthotopic liver transplantation (OLT) is still a clinical challenge. Cystatin C (CysC) has been proposed as a more accurate marker of renal function than serum creatinine (sCr). The aim of this study was to evaluate sCr- and CysC-based equations including the Chronic kidney disease (CKD)-EPI to determine renal function in liver transplant recipients. CysC and sCr were measured in 49 patients 24 months after OLT. The glomerular filtration rate (GFR) was calculated using the MDRD 4, the Cockroft-Gault, Hoek, Larsson, and the CKD-EPI equations based on sCr and/or CysC. As reference method, inulin clearance (IC) was estimated. Bias, precision, and accuracy of each equation were assessed and compared with respect to IC. Forty-five percent had a GFR < 60 ml/min/1.73 m(2) according to the IC. The Larsson, the Hoek and the CKD-EPI-CysC formula identified the highest percentage of patients with CKD correctly (88%, 88%, and 84%, respectively). The sCr-based equations showed less bias than CysC-based formulas with a similar precision. All CysC-based equations were superior as compared with sCr-based equations in the assessment of renal function in patients with an IC < 60 ml/min/1.73 m(2).