Article of the Month - Feb 2020

There are no treatment options or therapies for acute kidney injury once it has occurred. Thus, the focus of our current AKI mitigation strategies has been early recognition, improved surveillance, and prevention of AKI where feasible. Nephrotoxic medication stewardship and targeted AKI surveillance in the highest risk populations represent key strategies for improving the care and outcomes of patients at risk for acute kidney injury. Electronic medical record surveillance systems are one way to do this. Such a system (Goldstein et al. Pediatrics 2013) demonstrated success in increasing surveillance of and reducing AKI episodes in a pediatric cohort. The current article evaluates this system in the neonatal intensive care unit.

Baby NINJA (Nephrotoxic Injury Negated by Just-IN Time Action): Reduction of Nephrotoxic Medication-Associated Acute Kidney Injury in the Neonatal Intensive Care Unit

The Journal of Pediatrics 2019 Dec; 215:223-228.e6. doi: 10.1016/j.jpeds.2019.08.046

Stoops C, Stone S, Evans E, Dill L, Henderson T, Griffin R, Goldstein SL, Coghill C, Askenazi DJ.

Reviewed by Amanda Dyson

What was the purpose of the study?

The authors examined whether nephrotoxin induced acute kidney injury (AKI) is avoidable in a neonatal intensive care unit (NICU) through the introduction of a nephrotoxic medication surveillance program. A similar program has previously been shown to be successful in a pediatric non intensive care population.

What was the study design?

This is a prospective quality improvement project (Baby NINJA protocol) in a single-center level IV NICU. They looked prospectively at 3 epochs; pre-NINJA initiation, during NINJA initiation and during a post- NINJA sustainability epoch.

Population: This NICU is not in a delivery center and has a high proportion of patients requiring surgery and ECMO. All newborns in the NICU without AKI requiring dialysis were included. Those who met nephrotoxin exposure criteria received >/= three nephrotoxic medications within 24 hours or >/= 4 consecutive days of an aminoglycoside antibiotic.

Intervention: For those who met exposure criteria a rounding pharmacist recommended daily serum creatinine whilst on a nephrotoxic medication and for 2 days post-exposure/post resolution of AKI (whichever was later). Although no recommendations were made to cease the medication early, alternatives medications were discussed, and patients’ hydration status, dosing and monitoring were reviewed.

Outcome measures: Outcome measures included serum creatinine compliance, number of patients with a high nephrotoxin exposure, AKI prevalence per 1000 patient days, number of patients in the high nephrotoxin exposure group who develop AKI per 1000 patient days and the AKI intensity rate (the number of days a patient experiences AKI). A serum creatinine >0.5mg/dL was defined as meeting AKI criteria.

What were the characteristics of the sample?

The mean gestation age of participants in the three epochs was 31-32 weeks. They met exposure criteria at a mean gestation age of 39-40 weeks and at around 2 months of chronological age. There were no significant differences between the three groups.

What are the results/main learning points?

476 high nephrotoxin exposures occurred over the 30-month study period of which 44 were repeated exposures. There was a 19.7% incidence of AKI in the high exposure group; 52.9% occurring in those <28 days of age. Adherence to the NINJA protocol was good with 90.7% performing the recommended creatinine measures during implementation and 86.1% in the sustainability era.

Outcome measures:

Nephrotoxin exposure: Both the high nephrotoxin exposure rate and the nephrotoxin exposure rate increased during NINJA initiation and then decreased during the sustainability era relative to the pre-intervention epoch. The high exposure rate decreased from 16.4 to 9.6/1000 patient days between eras. More newborns in the sustainability era met the criterion of receiving >/=3 nephrotoxic medications in a 24-hour period than in other epochs (i.e. fewer received a prolonged course of an aminoglycoside).

Rate of AKI: The AKI rate increased during the NINJA initiation epoch (from 23.6 to 30.9 per 100 nephrotoxin exposures) and then decreased during the sustainability epoch (to 11.7 per 100 nephrotoxin exposures). There was no statistically significant difference in the proportion of patients in the high exposure group who developed AKI between the pre intervention (25.2 %) and initiation (30.9%) epochs, however this dropped to 11% during the sustainability epoch.

AKI intensity: The AKI intensity rate also increased during the initiation epoch and then decreased during the sustainability epoch (from 9.1 -2.9/100 susceptible patient days).

What are the implications?

The Baby NINJA protocol led to an important reduction in nephrotoxin exposure, AKI incidence and AKI intensity in a high-risk population. Preventing AKI has many short- and long-term health benefits and centers with a similar patient group should consider implementing this intervention. Preterm newborn kidneys continue to grow glomeruli until 36 weeks of gestation; it is important to avoid AKI where able in order to maximize their nephron mass and consequent long-term renal health. It would be interesting to apply this intervention in a delivery center with a predominantly extremely or very preterm population (this population were mostly term at the time they experienced a high nephrotoxin exposure) and see whether these results can be replicated.