Effect of Therapeutic Hypothermia on the Incidence of Acute Kidney Injury in Neonates With Perinatal Asphyxia

Nivedita Kamath, Saudamini Nesargi, Arpana Iyengar

Abstract

Aims: To compare the incidence of acute kidney injury (AKI) in neonates with perinatal asphyxia (PA) who received therapeutic hypothermia (TH+ group) with those who did not (TH- group), to study the role of urinary biomarkers in the early diagnosis of AKI, and to assess the risk factors of AKI and short-term outcomes of the cohort

Materials and Methods: This prospective observational study was conducted in the NICU of a tertiary hospital from April 2018 to April 2020. Inborn and outborn neonates born at > 35 weeks of gestation with perinatal asphyxia and moderate hypoxic–ischemic encephalopathy (HIE) at the time of initiation of TH were included. Neonates who were not eligible for TH were enrolled into the comparator group (TH-). Serum creatinine was serially measured starting at 48 hours of life. AKI was defined and staged using only the serum creatinine criteria of the neonatal modified Kidney Disease: Improving Global Outcomes classification. The urinary biomarkers neutrophil gelatinase-associated lipocalin, cystatin C, and β2 microglobulin were estimated within 24 hours of life.

The demographic characteristics, urinary biomarkers, risk factors of AKI, and short-term neonatal outcomes were compared and analyzed statistically.

Results: Of the 39 neonates included, 29 neonates received TH. The baseline characteristics between the TH+ and TH- groups were comparable. The overall incidence of AKI was 25.6%; it was significantly lower in the TH+ group (17.2%) compared with that in the TH- group (50%) (P = .04). The incidence of mild AKI was higher in the TH+ group (80% stage 1 AKI) compared with that in the TH- group (20% stage 1 AKI) (P = .05).

The requirement of ventilation and inotropes, incidence of sepsis, and use of nephrotoxic drugs were comparable between the neonates with and without AKI. After adjusting for the stage of AKI and risk factors, TH was found to significantly reduce the risk of AKI (RR: 0.2 [0.14–0.8], P = .03).

There was no statistical difference in the levels of urinary biomarkers between the neonates with and without AKI.

Two neonates died (one each in the groups with and without AKI) and 1 neonate in the TH- group was discharged against medical advice. The median duration of NICU stay in the groups with and without AKI was comparable. Fifty percent of neonates with AKI continued to have an abnormal serum creatinine level at discharge (0.7 [0.6, 0.8] mg/dL).

Conclusion: TH reduced the incidence of AKI in neonates with PA. Urinary biomarker levels were comparable between the neonates with and without AKI. Neonates with AKI had an abnormal creatinine level at discharge and required follow-up.