TINKER-ing with neonatal acute kidney injury

The newborn’s kidneys are immature and vulnerable to multiple perinatal insults. Acute kidney injury (AKI) occurs in 30–70% of critically ill neonates and is an important contributor to neonatal mortality and morbidity. With significant contributions made by the Assessment of Worldwide Acute Kidney Injury Epidemiology in Neonates (AWAKEN) database to neonatal nephrology, the past decade has witnessed a growing body of literature on the incidence, risk factors and outcomes of neonatal AKI. Neonates are particularly at risk for perinatal hypoperfusion injury; with redistribution of cardiac output secondary to a hypoxic–ischaemic insult, perfusion to the kidneys can be compromised, causing AKI. Fundamentally, making a prompt diagnosis of AKI in neonates is challenging as the baby’s results reflect the maternal creatinine in the first 72 h of birth and several perinatal insults that are unique to neonates can trigger AKI. Differences in the physiological parameters of kidney function across the spectrum of gestational age and birth weight add to the diagnostic complexity. Interestingly, there are considerable differences in the perception and practice of diagnosing and managing neonatal AKI among care providers such as neonatologists, paediatricians and paediatric nephrologists. The Acute Disease Quality Initiative highlights the need for strategies designed to improve AKI care processes for neonates. In contrast to paediatric AKI, kidney replacement therapy (KRT) is used sparingly in neonatal AKI. There is limited data on the utility of KRT in high-risk neonates. KRTs for neonates can be in the form of acute peritoneal dialysis (PD), extracorporeal therapy with or without extracorporeal membrane oxygenation or a combination of the above. Globally, PD is the most common modality offered to neonates. However, newer continuous KRT systems like the Cardio-Renal Pediatric Emergency Dialysis Machine, Newcastle infant dialysis and ultrafiltration system and the Aquadex system for ultrafiltration are routinely being used in resource-rich countries. Recently, PD has gained considerable interest in special groups of neonates (very low birth weight (VLBW) and extremely low birth weight (ELBW)). In this issue of Peritoneal Dialysis International, Sethi et al. report their findings of a multicentre prospective study of neonates with AKI from the ‘The Indian Iconic Neonatal Kidney Educational Registry – TINKER’. Across 11 Indian centres consisting of level 2 or level 3 neonatal intensive care units (NICUs), 1600 neonates <28 days of life were included through a web-database system. Neonates needing congenital heart surgery within the first week of life were excluded. The objective was to study potentially modifiable risk factors that predicted the need for acute PD in neonates with AKI and correlate these with clinical outcomes. AKI was defined based on the modified Kidney Disease Improving Global Outcomes (KDIGO) criteria. Neonates with AKI were managed as per each individual centre’s treatment protocols. Among 1600 neonates, 491 (30.7%) had AKI (18.9% in stage 2 and 46.8% in stage 3), 6.9% were <28 weeks of gestation and 9% had a birth weight of <1000 g. Neonates with AKI had evidence of fluid overload (4.1%), cardiac disease (44%), required respiratory support (84.5%) or inotropes (59.7%) and were exposed to nephrotoxic medications (95.7%). Although nearly 47% of neonates were classified as stage 3 AKI, only 9% underwent acute PD. Indications for PD were not predefined and presumably decided by the treating physician in each centre. The commonest reasons for starting dialysis were fluid overload, oliguria and metabolic acidosis. While a large number of risk factors such as significant cardiac disease, inotrope usage, severe peripartum events, need for respiratory support, necrotising enterocolitis, intraventricular haemorrhage, fluid overload and need for resuscitation showed significant associations with the requirement for PD on