(1315) Altered Renal Blood Flow and Renin Correlate With Presence and Persistence of AKI in Pediatric Shock

Introduction: Up to 25% of PICU patients develop acute kidney injury (AKI), which is associated with increased morbidity and mortality. Prior studies demonstrated alterations in renal blood flow (RBF) and the renin-angiotensin-aldosterone system (RAS) in AKI. Power doppler (PDU), which quantifies blood flow (higher score = more blood flow), and renal resistive index (RRI), which reflects regional vascular resistance (normal < 0.70), can be assessed via point-of-care ultrasound (POCUS). We hypothesize that RBF and RAS alterations will correlate with presence and/or persistence of AKI in pediatric shock.

Methods: This prospective observational cohort study enrolled July 2020-Jan 2022. Patients requiring fluid resuscitation (>=1 bolus) or vasoactive support were enrolled within 48hrs of PICU admission. Renal POCUS was performed on Days 1 and 3; serum was collected on Day 1. RRI, PDU scores, clinical and lab data were recorded. Pre-admission baseline creatinine (Cr) was collected; if unavailable, a normal GFR was assumed and baseline Cr was calculated with the revised Schwartz equation. KDIGO criteria were used to define presence of AKI. T-test with Satterthwaite approximation was performed to identify differences between groups. Multivariate analysis adjusted for baseline Cr, vasoactive inotrope score (VIS), and age.

Results: Fifty patients met inclusion criteria: 20 patients had AKI on Day 1. Median Day 1 RRI was higher (0.78 vs 0.67, p=0.001) and median PDU was lower (1.6 vs 2.4, p=0.017) in patients with AKI. Patients with Day 1 AKI had higher Day 3 RRI (p=0.025). Day 1 renin (pg/mL) and aldosterone (pg/mL) were higher in the AKI group (2784 vs 1246, p=0.003 and 322 vs 152, p=0.007). No difference was found in the renin:aldosterone ratio. On multivariate analysis, Day 1 RRI correlated with higher Day 3 Cr. Day 1 renin correlated with higher Day 3 Cr and Day 3 VIS.

Conclusions: Admission RRI and PDU correlate with the presence of AKI in pediatric shock. Early abnormalities in RBF correlate with AKI on Day 3. Early increased renin correlates with higher Day 3 vasoactive needs. There was no correlation between renin:aldosterone and AKI, which is different from published adult data. POCUS-measured RBF and renin may be useful in predicting persistent AKI in pediatric shock.