窒息作为“二次打击”因素对小于胎龄儿肾脏功能的影响

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

目的探讨窒息作为“二次打击”因素对小于胎龄儿（small forg estationalage，SGA）生后早期。肾脏功能的影响。方法选取2013年1月至2015年3月在北京大学第三医院新生儿病房住院患儿（生后24h内人院），根据胎龄和窒息情况进行分组，共纳入非窒息早产SGA40例，非窒息早产适于胎龄儿（appropriate for gestationalage，AGA）为相应对照组（n=80）；窒息早产SGA11例，窒息早产AGA共11例作为相应对照组；非窒息足月SGA33例，非窒息足月AGA33例作为相应对照组；窒息足月SGA4例，窒息足月AGA13例作为相应对照组。比较各组入院48h内血清尿素氮（blood urea nitrogen，BUN）、血清肌酐（serumcreatinine，SCr）、估算的肾小球滤过率（estimate glomerular filtration rate，eGFR）及各组窒息病例中肾脏指标异常发生率。采用两均数比较的t检验及Fisher精确概率法进行统计分析。结果（1）早产非窒息SGA组较早产非窒息AGA组BUN降低[（3．99±1．69）与（5．11±2．08）mmol／L，t=2．948，P=0．004]；足月非窒息SGA组SCr高于足月非窒息AGA组[（72．03±10．29）与（62．58±12．27）μmol／L，t=3．390，P=0．001]，eGFR低于足月非窒息AGA组[（25．19α4．07）与（33．99±8．75）ml／（min·1．73m^2），t=5．238，P=0．000]。（2）在早产儿中，与非窒息AGA比较，窒息AGABUN升高[（6．96±3．09）与（5．11±2．08）mmol／L，t=2．602，P=0．011]，SCr升高[（76．45±10．11）与（66．70±13．18）μmol／L，t=2．357，P=0．021]，eGFR降低[（15．86±2．31）与（19．54±5．08）ml／（min·1．73m^2），t=2．361，P=0．020]；与非窒息SGA比较，窒息SGABUN升高[（6．70±3．37）与（3．99±1．69）mmol／L，t=2．581，P=0．025]，eGFR降低[（14．80±4．67）与（18．66±5．03）ml／（min·1．73m。），t=2．285，P=0．027]。在足月儿组，非窒息AGA与窒息AGA组比较，非窒息SGA与窒息SGA比较结果与早产儿基本一致。（3）窒息病例中仅足月儿eGFR的异常发生率在SGA组高于AGA组，差异有统计学意义（4／4与4／13，Fisher精确概率法，P=0．029）。结论窒息影响新生儿的肾脏功能，且不论早产儿或足月儿，窒息对SGA早期肾功能的影响均较AGA更为显著。

Objective To investigate the effects of the asphyxia as a ＂Second Hit＂ on 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 m^2）, 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） μ mol/L, t=2.357, P=0.021 ] and lower eGFR level [（ 15.86±2.31 ） vs （19.54±5.08） ml/（min· 1.73 m^2）, 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 m^2）, 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 probable ＂Second Hit＂ can influence the renal function during early stage in both preterm and term infants, especially in SGA infants.