Validity of pediatric index of mortality 2 (PIM2) score in pediatric acute liver failure

Prevalence, Associated Factors, and Outcomes of Severe Acute Kidney Injury in Pediatric Acute Liver Failure: Single-Center Retrospective Study, 2003-2017

OBJECTIVES

Our aim was to determine the prevalence and explanatory factors associated with outcomes in children with acute liver failure (ALF) admitted to the PICU, who also develop severe acute kidney injury (AKI).

DESIGN

Retrospective cohort, 2003 to 2017.

SETTING

Sixteen-bed PICU in a university-affiliated tertiary care hospital.

PATIENTS

Admissions to the PICU with ALF underwent data review of the first week and at least 90-day follow-up. Patients with stages 2-3 AKI using the British Association of pediatric Nephrology definitions, or receiving continuous renal replacement therapy (CRRT) for renal indications, were defined as severe AKI. We excluded ALF cases on CRRT for hepatic-only indications.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Baseline characteristics, proportion with severe AKI, illness severity and interventions, and outcomes (i.e., transplant, survival with native liver, overall survival, duration of PICU stay, and mechanical ventilation). Ninety-four children with ALF admitted to the PICU were included. Over the first week, 29 had severe AKI, and another eight received CRRT for renal/mixed reno-hepatic indications; hence, the total severe AKI cohort was 37 of 94 (39.4%). In a multivariable logistic regression model, peak aspartate aminotransferase (AST) and requirement for inotropes on arrival were associated with severe AKI. Severe AKI was associated with longer PICU stay and duration of ventilation, and lower spontaneous survival with native liver. In another model, severe AKI was associated with greater odds of mortality (odds ratio 7.34 [95% CI, 1.90-28.28], p = 0.004). After 90 days, 3 of 17 survivors of severe AKI had serum creatinine greater than the upper limit of normal for age.

CONCLUSIONS

Many children with ALF in the PICU develop severe AKI. Severe AKI is associated with the timecourse of PICU admission and outcome, including survival with native liver. Future work should look at ALF goal directed renoprotective strategies at the time of presentation.

Prognostic Markers in Pediatric Acute Liver Failure

Introduction

Acute liver failure (ALF), although rare in children, is a complex progressive pathology, with multisystem involvement and high mortality. Isolated variables or those included in prognostic scores have been studied, to optimize organ allocation. However, its validation is challenging. This study aimed to assess the accuracy of several biomarkers and scores as predictors of prognosis in pediatric ALF (PALF).

Methods

An observational study with retrospective data collection, including all cases of ALF, was defined according to the criteria of the Pediatric Acute Liver Failure Study Group, admitted to a pediatric intensive care unit (PICU) for 28 years. Two groups were defined: spontaneous recovery (SR) and non-SR (NSR) - submitted to liver transplantation (LT) or death at PICU discharge.

Results

Fifty-nine patients were included, with a median age of 24 months, and 54% were female. The most frequent etiologies were metabolic (25.4%) and infectious (18.6%); 32.2% were undetermined. SR occurred in 21 patients (35.6%). In NSR group (N = 38, 64.4%), 25 required LT (42.4%) and 19 died (32.2%), 6 (15.7%) of whom after LT. The accuracy to predict NSR was acceptable for lactate at admission (AUC 0.72; 95% CI: 0.57-0.86; p = 0.006), ammonia peak (AUC 0.72; 95% CI: 0.58-0.86; p = 0.006), and INR peak (AUC 0.70; 95% CI: 0.56-0.85; p = 0.01). The cut-off value for lactate at admission was 1.95 mmol/L (sensitivity 78.4% and specificity 61.9%), ammonia peak was 64 μmol/L (sensitivity 100% and specificity 38.1%), and INR peak was 4.8 (sensitivity 61.1% and specificity 76.2%). Lactate on admission was shown to be an independent predictor of NSR on logistic regression model. Two prognostic scores had acceptable discrimination for NSR, LIU (AUC 0.73; 95% CI: 0.59-0.87; p = 0.004) and PRISM (AUC 0.71; 95% CI: 0.56-0.86; p = 0.03). In our study, the PALF delta score (PALF-ds) had lower discrimination capacity (AUC 0.63; 95% CI: 0.47-0.78; p = 0.11).

Conclusions

The lactate at admission, an easily obtained parameter, had a similar capacity than the more complex scores, LIU and PRISM, to predict NSR. The prognostic value in our population of the promising dynamic score, PALF-ds, was lower than expected.

The Role of Predictive Models in the Assessment of the Poor Outcomes in Pediatric Acute Liver Failure

OBJECTIVES

In children, acute liver failure (ALF) is a severe condition with high mortality. As some patients need liver transplantation (LT), it is essential to predict the fatal evolution and to refer them early for LT if needed. Our study aimed to evaluate the prognostic criteria and scores for assessing the outcome in children with ALF.

METHODS

Data of 161 children with ALF (54.66% female, mean age 7.66 ± 6.18 years) were analyzed based on final evolution (32.91% with fatal evolution or LT) and etiology. We calculated on the first day of hospitalization the PELD score (109 children), MELD, and MELD-Na score (52 children), and King's College Criteria (KCC) for all patients. The Nazer prognostic index and Wilson index for predicting mortality were calculated for nine patients with ALF in Wilson's disease (WD).

RESULTS

PELD, MELD, and MELD-Na scores were significantly higher in patients with fatal evolution (21.04 ± 13.28 vs. 13.99 ± 10.07, p = 0.0023; 36.20 ± 19.51 vs. 20.08 ± 8.57, p < 0.0001; and 33.07 ± 8.29 vs. 20.08 ± 8.47, p < 0.0001, respectively). Moreover, age, bilirubin, albumin, INR, and hemoglobin significantly differed in children with fatal evolution. Function to etiology, PELD, MELD, MELD-Na, and KCC accurately predicted fatal evolution in toxic ALF (25.33 vs. 9.90, p = 0.0032; 37.29 vs. 18.79, p < 0.0001; 34.29 vs. 19.24, p = 0.0002, respectively; with positive predicting value 100%, negative predicting value 88.52%, and accuracy 89.23% for King's College criteria). The Wilson index for predicting mortality had an excellent predictive strength (100% sensibility and specificity), better than the Nazer prognostic index.

CONCLUSIONS

Prognostic scores may be used to predict the fatal evolution of ALF in children in correlation with other parameters or criteria. Early estimation of the outcome of ALF is essential, mainly in countries where emergency LT is problematic, as the transfer to a specialized center could be delayed, affecting survival chances.

Validity of Pediatric Index of Mortality 2 score as an Outcome Predictor in Pediatric ICU of a Public Sector Tertiary Care Hospital in Pakistan

Pediatric Index of Mortality 2 (PIM-2) is one of the leading mortality scores used in intensive care units all around the world. We assessed its validity as an outcome predictor in a pediatric intensive care unit (PICU) of Mayo Hospital/King Edward Medical University Lahore, Pakistan. We enrolled 154 consecutive admissions, aged 1 month to 13 years, requiring intensive care from January to June of 2019. Patient demographics along with PIM-2 data were collected; PIM-2 score and mortality risk was calculated; and the outcome recorded as death or survival. The median age at admission was 0.50 years (interquartile range [IQR]: 0.24–1.78) and the median weight was 5.0 kg (IQR: 3.08–10.0) with females constituting 54%; malnutrition was also common (66%). Observed mortality was 29.9% (46 out of 154) and expected mortality (cut-off ≥ 99.8%) was 27.9% with a standardized mortality ratio of 1.07 (95% confidence interval [CI]: 0.79–1.41). Sepsis was the most common diagnosis at admission (27.9%) with the highest mortality (52.2%). Chi-square analysis revealed a sensitivity of 54.3% and a specificity of 83.3% (p-value 0.00). PIM-2 score showed acceptable discrimination between survivors and nonsurvivors with an area under the receiver operating characteristic curve of 0.75 (95% CI: 0.67–0.84) (p-value = 0.00); however, poor calibration according to Hosmer–Lemeshow goodness of fit test (Chi-square = 15.80, df = 7, and p-value of 0.027 [< 0.1]), thus requiring recalibration according to local population characteristics.

A novel, bedside, etiology specific prognostic model (Peds-HAV) in hepatitis A induced pediatric acute liver failure

BACKGROUND

Hepatitis A virus (HAV) is the commonest cause of pediatric acute liver failure (PALF) in developing countries. Our objective was to develop and validate a HAV-etiology specific prognostic model in PALF.

METHODS

All children with HAV induced PALF (IgM HAV reactive) were included. Outcome was defined at day 28. Only those with death or native liver survival were included. The model (Peds-HAV) was derived using the independent predictors of outcome and validated in a prospective independent cohort.

RESULTS

Hepatitis A accounted for 131 (45.9%) of total 285 PALF. After excluding 11 children who underwent liver transplant, 120 children (74 survivors and 46 death) were included. The first 75 patients formed the derivation cohort and the next 45 patients formed the prospective validation cohort. In the derivation cohort, INR: OR 2.208, (95% CI 1.321-3.690), p = 0.003, grade of hepatic encephalopathy (HE): OR 3.078, (95% CI 1.017-9.312), p = 0.047 and jaundice-to-HE interval: OR 1.171, (95% CI 1.044-1.314), p = 0.007 were independent predictors of death. The final model comprised three criteria: (1) presence of grade 3-4 HE, (2) INR greater than 3.1, and (3) jaundice to HE interval more than 10 days. Presence of 2 or more of these criteria predicted death with 90% sensitivity, 81.4% specificity and 84.9% accuracy. Peds-HAV model was superior to existing prognostic models. In the validation cohort, Peds-HAV model predicted death with 83.3% sensitivity and 92.6% specificity.

CONCLUSION

Peds-HAV model is a simple, bedside, dynamic, etiology (HAV) specific prognostic model based on 3 objective parameters with optimum sensitivity and specificity, hence should be used as liver transplant listing criteria in HAV induced PALF.

Effect of Continuous Renal Replacement Therapy on Outcome in Pediatric Acute Liver Failure

OBJECTIVES

To establish the effect of continuous renal replacement therapy on outcome in pediatric acute liver failure.

DESIGN

Retrospective cohort study.

SETTING

Sixteen-bed PICU in a university-affiliated tertiary care hospital and specialist liver centre.

PATIENTS

All children (0-18 yr) admitted to PICU with pediatric acute liver failure between January 2003 and December 2013.

INTERVENTIONS

Children with pediatric acute liver failure were managed according to a set protocol. The guidelines for continuous renal replacement therapy in pediatric acute liver failure were changed in 2011 following preliminary results to indicate the earlier use of continuous renal replacement therapy for both renal dysfunction and detoxification.

MEASUREMENTS AND MAIN RESULTS

Of 165 children admitted with pediatric acute liver failure, 136 met the inclusion criteria and 45 of these received continuous renal replacement therapy prior to transplantation or recovery. Of the children managed with continuous renal replacement therapy, 26 (58%) survived: 19 were successfully bridged to liver transplantation and 7 spontaneously recovered. Cox proportional hazards regression model clearly showed reducing hyperammonemia by 48 hours after initiating continuous renal replacement therapy significantly improved survival (HR, 1.04; 95% CI, 1.013-1.073; p = 0.004). On average, for every 10% decrease in ammonia from baseline at 48 hours, the likelihood of survival increased by 50%. Time to initiate continuous renal replacement therapy from PICU admission was lower in survivors compared to nonsurvivors (HR, 0.96; 95% CI, 0.916-1.007; p = 0.095). Change in practice to initiate early and high-dose continuous renal replacement therapy led to increased survival with maximum effect being visible in the first 14 days (HR, 3; 95% CI, 1.0-10.3; p = 0.063). Among children with pediatric acute liver failure who did not receive a liver transplant, use of continuous renal replacement therapy significantly improved survival (HR, 4; 95% CI, 1.5-11.6; p = 0.006).

CONCLUSION

Continuous renal replacement therapy can be used successfully in critically ill children with pediatric acute liver failure to provide stability and bridge to transplantation. Inability to reduce ammonia by 48 hours confers poor prognosis. Continuous renal replacement therapy should be considered at an early stage to help prevent further deterioration and buy time for potential spontaneous recovery or bridge to liver transplantation.

EASL Clinical Practical Guidelines on the management of acute (fulminant) liver failure

The term acute liver failure (ALF) is frequently applied as a generic expression to describe patients presenting with or developing an acute episode of liver dysfunction. In the context of hepatological practice, however, ALF refers to a highly specific and rare syndrome, characterised by an acute abnormality of liver blood tests in an individual without underlying chronic liver disease. The disease process is associated with development of a coagulopathy of liver aetiology, and clinically apparent altered level of consciousness due to hepatic encephalopathy. Several important measures are immediately necessary when the patient presents for medical attention. These, as well as additional clinical procedures will be the subject of these clinical practice guidelines.

Prognostic modeling in pediatric acute liver failure

Liver transplantation (LT) is the only proven treatment for pediatric acute liver failure (PALF). However, over a period of time, spontaneous native liver survival is increasingly reported, making us wonder if we are overtransplanting children with acute liver failure (ALF). An effective prognostic model for PALF would help direct appropriate organ allocation. Only patients who would die would undergo LT, and those who would spontaneously recover would avoid unnecessary LT. Deriving and validating such a model for PALF, however, encompasses numerous challenges. In particular, the heterogeneity of age and etiology in PALF, as well as a lack of understanding of the natural history of the disease, contributed by the availability of LT has led to difficulties in prognostic model development. Several prognostic laboratory variables have been identified, and the incorporation of these variables into scoring systems has been attempted. A reliable targeted prognostic model for ALF in Wilson's disease has been established and externally validated. The roles of physiological, immunological, and metabolomic parameters in prognosis are being investigated. This review discusses the challenges with prognostic modeling in PALF and describes predictive methods that are currently available and in development for the future. Liver Transplantation 22 1418-1430 2016 AASLD.