Evaluation of Renal Artery Resistive Index as a Predictor of Acute Kidney Injury in Perinatal Asphyxia: A Prospective Observational Study

Introduction: Acute Kidney Injury (AKI) is a serious but challenging complication of perinatal asphyxia. Doppler flowmetric studies have demonstrated the potential for its prediction. Renal artery resistive index, a non-invasive modality and prompt intervention can help in early detection of AKI. Aim: To evaluate the utility of renal artery resistive index as a predictor of acute kidney injury in perinatal asphyxia. Materials and Methods: The present prospective observational study was conducted at Department of Paediatrics, VPIMS , Lucknow, Uttar Pradesh, India from December 2019 to February 2021. Sixty newborns with perinatal asphyxia were enrolled in the study. At enrollment, sex, gestational age at birth, mode of delivery, birth weight, and Apgar scores at 1 and 5-min were recorded. Renal artery Resistive Indices (RRI) were measured using color doppler at 2-24 hr and 48-72 hr intervals. Maternal Serum Creatinine (S.Cr) levels were assessed at enrollment. Neonatal S.Cr. levels were assessed at enrollment and every 24-hr interval till day 7. The chi-square test was used for proportions, whereas the independent samples t-test was used to compare the mean values. Comparative differences were considered significant at ‘p’ value <0.05. Results: The majority of newborns were males 38 (63.3%), born at term 37 (61.7%), through caesarean delivery 40 (66.7%), and had a birth weight of >2500 g, 34 (56.7%). The incidence of AKI was found in 17 neonates (28.3%). No significant association between AKI and the demographic, baseline characteristics of the newborns was observed. RRI at 2-24 hr as well as 48-72 hr too did not significantly associated with AKI (p-value 0.460 and 0.423, respectively). Conclusion: RRI failed to predict AKI in newborns with perinatal asphyxia. Additional studies with large sample sizes and incorporation of other non-invasive measures such as Near Infrared Spectroscopy (NIRS) may provide more insight into this relationship.