Nucleated red blood cells as a biomarker for mortality in neonates following cardiac surgery.

INTRODUCTION: Nucleated red blood cells (NRBCs) are immature red cells that under normal conditions are not present in the peripheral circulation. Several studies have suggested an association between elevated NRBC and poor outcome in critically ill adults and neonates. We sought to determine if elevations in NRBC value following cardiac surgery and following clinical events during the hospital stay can be used as a biomarker to monitor for mortality risk in neonates post-cardiac surgery. MATERIALS AND METHODS: We constructed a retrospective study of 264 neonates who underwent cardiac surgery at Children's Hospital, New Orleans between 2011 and 2020. Variables included mortality and NRBC value were recorded following cardiac surgery and following peri-operative clinical events. The study was approved by LSU Health IRB. Sensitivity, specificity, receiver operating characteristic (ROC) curves with area under the curve (AUC) and logistic regression analysis were performed. RESULTS: Thirty-six patients (13.6%) died, of which 32 had an NRBC value ≥10/100 white blood cell (WBC) during hospitalisation. Multi-variable analysis found extracorporeal membrane oxygenation use (OR 10, 95% CI 2.9-33, p=<0.001), NRBC ≥10/100 WBC (OR 16.1, CI 4.1-62.5, p ≤ 0.001) and peak NRBC in the 14-day period post-cardiac surgery (continuous variable, OR 1.05, 95% CI 1.0-1.09, p = 0.03), to be independently associated with mortality. Using a cut-off NRBC value of 10/100 WBC, there was an 88.9% sensitivity and a 90.8% specificity, with ROC curve showing an AUC of 0.9 and 0.914 for peak NRBC value in 14 days post-surgery and entire hospitalisation, respectively. CONCLUSIONS: NRBC ≥10/100 WBC post-cardiac surgery is strongly associated with mortality. Additionally, NRBC trend appears to show promise as an accurate biomarker for mortality.

Comparison of different definitions of acute kidney injury in extremely low birth weight infants.

BACKGROUND: The definition of acute kidney injury (AKI) has evolved over the years, and three definitions have been adapted including pediatric risk injury failure, loss of kidney function (pRIFLE), Acute Kidney Injury Network (AKIN), and Neonatal Modified Kidney Disease Improving Global Outcomes (KDIGO). We sought to report the prevalence and outcome of (AKI) according to the three existing definitions in extremely low birth weight (ELBW) infants. METHODS: In a retrospective cohort study, medical records of all ELBW infants (<1000 g) admitted to our neonatal intensive care unit (NICU) between Jan 2002 and Dec 2011 were reviewed. Infants' demographics, anthropometric measurements, and clinical characteristics were collected at the time of birth and at discharge from the NICU. Infants were staged according to the three different definitions. RESULTS: During the study period, 483 ELBW infants met our inclusion criteria. The incidence of AKI was 56, 59, and 60% according to pRIFLE, AKIN, and KDIGO, respectively. Mortality, NICU length of stay, and serum creatinine (SCr) at NICU discharge were higher in infants with advanced AKI stages regardless of the definition. In addition, discharge NICU weight and length z scores were lower in infants with advanced AKI stages. SCr at 72 h of life and SCr peak were predictable of NICU mortality [AUC 0.667 (95% CI 0.604-0.731), p < 0.001 and AUC 0.747 (95% CI 0.693-0.801), p < 0.001, respectively]. CONCLUSION: Regardless of the definition, advanced AKI is associated with increased mortality, prolonged NICU length of stay, and poor growth in ELBW infants. SCr at 72 h of life and SCr peak may be predictable of NICU mortality.

Outcome of extremely low birth weight infants with a history of neonatal acute kidney injury.

OBJECTIVE: To study the outcome of extremely low birth weight (ELBW) infants with a history of acute kidney injury (AKI). METHOD: In a retrospective, case control study, medical records of all ELBW infants admitted to the neonatal intensive care unit (NICU) between Jan 2002 and Dec 2011 were reviewed. Medical records were reviewed for infants' demographics, blood pressure (BP) at NICU discharge and at ≥3 years, and estimated glomerular filtration rate (eGFR) at ≥2 years. RESULTS: During the study period, 222 patients met the inclusion criteria, of whom 10% (23 out of 222) had AKI stage 2 and 3, 39% (87 out of 222) had AKI stage 1, and the rest did not have AKI. At NICU discharge, there was a difference in diastolic BP (DBP) among infants who had AKI stages 2 and 3, those who had stage 1, and those who did not have AKI (53 ± 12 vs 46 ± 9 vs 46 ± 11 mmHg respectively; p = 0.007), and 11% (23 out of 209) had hypertension (HTN). Although there was a significant correlation between the rise in SCr and DBP at NICU discharge in infants with AKI (R = 0.304; p = 0.004), there was no difference in HTN between infants with and those without AKI. At ≥2 years of age, 4% (5 out of 120) across all groups had an eGFR < 90 ml/min/1.73m2 or chronic kidney disease (CKD). At ≥3 years of age, 5% (11 out of 222) had HTN. CONCLUSION: At NICU discharge, infants with AKI stages 2 and 3 have a higher DBP than infants with stage 1 AKI and those who did not have AKI. However, there is no difference in the rate of HTN between the two groups. At ≥2 years ELBW infants are at risk for CKD independently of whether or not they develop neonatal AKI.