107 - Intra-operative renal NIRS monitoring of neonates undergoing cardiac surgery and the association with acute kidney injury

Poster Number: 107
Publication Number: 107.125

Daniel Gorski, University of Wisconsin School of Medicine and Public Health, Middleton, WI, United States; Awni Al-Subu, university of wisconsin school of medicine and public health, Madison, WI, United States; Michael R. Lasarev, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States; Matthew W. Harer, University of Wisconsin, Middleton, WI, United States

Background: Neonates with congenital heart disease (CHD) are at high risk for cardiac surgery associated acute kidney injury (csAKI) which is independently associated with mortality. Near infrared spectroscopy (NIRS) is frequently used in the cardiac ICU to monitor regional tissue oxygen saturation (rSO2), which has been associated with csAKI. However, rSO2 values during the intra-operative period have not been evaluated and may provide an early indication of the risk for developing csAKI post-operatively.

Objective: Evaluate the relationship of cerebral and renal rSO2 prior to, during, and after cardiopulmonary bypass (CPB) with csAKI in the first 72 hours post-op in neonates < 30 days of age.

Design/Methods: An IRB approved prospective cohort study at a tertiary care children’s hospital between Jan 2020 and Oct 2021 was performed. Neonates < 30 days of age who underwent CPB for correction of congenital heart disease were included without exclusions. AKI was defined by the modified neonatal KDIGO definition including urine output. Every 6 second cerebral and renal rSO2 values were recorded with Invos NIRS 5100C and neonatal sensors. The geometric mean (GM) was used to summarize intra-operative rSO2 for each neonate for the total OR time and after coming off the last CPB cycle.

Results: NIRS data were recorded during 35 CPB cases from 32 neonates; 3 had repeat CPB cases. Six deaths were recorded. AKI was diagnosed in 60% of cases (stage 1, n=11; stage 2/3, n=14; Table 1). Of the 21 AKI cases, 29% were diagnosed with creatinine, 33% with urine output, and 38% met both criteria. Time spent on CPB ranged from 0.97–6.23 hours with no difference among the 3 AKI groups (p = 0.605). Intra-operative rSO2, both on- and off-bypass did not differ among the three AKI groups (p >0.19, Table 2). Renal rSO2 (median [IQR]) after coming off the last CPB cycle steadily decreased with increasing level of AKI (Stage 0 = 83.5 (77.0,89.1); Stage 1=81.2 (71.1,86.7); Stage 2/3=75.4 (69.5,81.9); one-sided p=0.024; Jonckheere’s test; Figure 1). Conclusion(s): In this prospective NIRS monitoring study of neonates undergoing CPB, renal rSO2 decreased in proportion to AKI severity after coming off CPB. However, there were no differences in rSO2 during complete intraoperative monitoring among AKI groups. Further analysis of the rSO2 data after the last CPB cycle is needed to correct for single ventricle versus two ventricle repair and baseline oxygen saturations. Future studies could combine urinary biomarkers of AKI and renal rSO2 values after the last CPB cycle to determine risk of csAKI and guide post-operative management.
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Table 2 - Intra-operative NIRS (%rSO2)Data presented as Geometric Mean (estimated 95% Confidence Interval)