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Abstract

Background and aims: Acute kidney injury (AKI) is a frequent complication after cardiac surgery with cardiopulmonary bypass in infants. Renal near-infrared spectroscopy (NIRS) evaluates regional oximetry in a non-invasive continuous fashion and reflects tissue perfusion. Aims: The aim of this study was to evaluate the relation between renal oximetry and development of AKI in infants undergoing cardiopulmonary surgery. Methods: We prospectively enrolled 59 infants undergoing cardiopulmonary bypass surgery for uni- (n = 26) or biventricular (n = 33) repair. IRB approval was given and parents signed written informed consent. Renal NIRS was continuously measured intraoperatively and at least 24 hours postoperatively. Renal oximetry values were correlated with the pediatric Renal-Injury-Failure-Loss-End (pRIFLE) classification for AKI, renal biomarkers and the postoperative course. Results: 28 (48 %) infants developed AKI. Already in the intraoperative renal oximetry and further in the first 12, 24 and 48 hours postoperatively significantly lower renal oximetry values in AKI patients as compared to patients with normal renal function could be shown (p < 0.05). 11 % (3/28) of infants with AKI needed renal replacement therapy and 2/28 (7 %) died. In the non AKI group no fatal course occurred. Infants with decreased renal oximetry values developed significantly higher lactate levels 24 hours after surgery. NGAL values were not correlated with AKI. Conclusions: Our results suggest that prolonged lower renal oximetry values during cardiac surgery correlate with the development of AKI and are superior to conventional biomarkers. Renal NIRS is a promising tool to develop kidney-protective strategies during cardiac surgery with cardiopulmonary bypass in infants.