Effects of asphyxia as a"Second Hit"on renal function in small for gestational age infants

Abstract

Objective To investigate the effects of the asphyxia as aSecond Hiton renal function during early stage after birth in small for gestational age (SGA) infants. Methods The infants who were hospitalized within 24 hours after birth in Peking University Third Hospital between January 2013 and March 2015 were retrospectively enrolled, and divided into different groups depending on gestational age and asphyxia history. There were 40 preterm non-asphyxia SGA infants and 80 controls who were preterm non-asphyxia appropriate for gestational age (AGA) infants; 11 preterm asphyxia SGA infants and an equal number of preterm asphyxia AGA infants as controls; 33 term non-asphyxia SGA infants and 33 term non-asphyxia AGA infants as controls; and four term asphyxia SGA infants and 13 term asphyxia AGA infants as controls. Blood urea nitrogen (BUN), serum creatinine (SCr), and estimate glomerular filtration rate (eGFR) were tested within 48 h after admission and the incidence of abnormal indexes was compared between groups by t-test and Fisher exact test. Results (1) Compared with preterm non-asphyxia AGA group, BUN level significantly decreased in preterm non-asphyxia SGA group [(3.99±1.69) vs (5.11±2.08) mmol/L, t=2.948, P=0.004]. Compared with term non-asphyxia AGA group, term non-asphyxia SGA group had higher SCr level [(72.03±10.29) vs (62.58±12.27) μmol/L, t=3.390, P=0.001] and lower eGFR level [(25.19±4.07) vs (33.99±8.75) ml/(min·1.73 m2), t=5.238, P=0.000]. (2) Compared with preterm non-asphyxia AGA infants, preterm asphyxia AGA infants had higher BUN [(6.96±3.09) vs (5.11±2.08) mmol/L, t=2.602, P=0.011] and SCr [(76.45±10.11) vs (66.70±13.18) μmol/L, t=2.357, P=0.021] and lower eGFR level [(15.86±2.31) vs (19.54±5.08) ml/(min·1.73 m2), t=2.361, P=0.020]. Compared with preterm non-asphyxia SGA group, there was a significant increase in BUN level [(6.70±3.37) vs (3.99±1.69) mmol/L, t=2.581, P=0.025] and decrease in eGFR level [(14.80±4.67) vs (18.66±5.03) ml/(min·1.73 m2), t=2.285, P=0.027] in preterm asphyxia SGA group. Changes in term infants were similar to preterm infants. (3) Compared with asphyxia AGA group, asphyxia SGA group showed a higher frequency of abnormal eGFR in term infants (4/4 vs 4/13, Fisher exact test, P=0.029). Conclusions Asphyxia as a probableSecond Hitcan influence the renal function during early stage in both preterm and term infants, especially in SGA infants. Key words: Asphyxia neonatorum; Infant, small for gestational age; Glomerular filtration rate; Blood urea nitrogen; Creatinine