Objective To explore the relationship between renal volume and function in the preterm and term newborns at different gestational ages.Methods This study was conducted at the First Affiliated Hospital of Zhengzhou University from October 2016 to March 2018.A total of 626 newborns with different gestational ages were included and the renal volume was determined by ultrasonography.Blood samples were taken for laboratory tests to detect renal function including urea,creatinine,uric acid and estimated glomerular filtration rate.Results A total of 352 preterm and 274 full term newborns were enrolled at birth.The mean gestational age of the neonates was (36.0 ± 3.5) weeks and the mean birth weight was (2.59 ±0.77) kg.The mean renal volume of the preterm infants was (19.57 ±4.30) cm3 and estimated glomerular filtration was (21.68 ± 5.99) mL/(min · 1.73 m2);the mean renal volume of the term infants was(23.03 ± 3.80) cm3 and estimated glomerular filtration was(46.60 ± 10.21) mL/(min · 1.73 m2).The renal volume and estimated glomerular filtration of term infants was significantly greater compared to the preterm infants (t =12.96,33.10,all P ＜ 0.001).The renal volume was highly linear positively correlated with gestational age,birth weight and birth length (r =0.546,0.605,0.592,all P ＜ 0.001).The renal volume was highly linear positively correlated with estimated glomerular filtration(r =0.396,P ＜ 0.001).The renal volume was negatively correlated with urea,creatinine and uric acid(r =-0.210,-0.280,-0.176,all P ＜ 0.001).Conclusions The renal volume increases with gestational age and birth weight in neonates.Estimated glomerular filtration increases with renal volume in neonates.The preterm infants have immaturity kidney size and poor development so that they need special medical care.

Objective To explore the value of plasma N-terminal pro-brain natriuretic peptide(NT-proBNP) level combined with the Neonatal critical illness scores(NCIS) on mortality risk evaluation in very low birth weight infants(VLBWI).Methods Between Jun.2011 and Dec.2012,preterm infants admitted to the Neonatal Intensive Care Unit of the First Affiliated Hospital of Zhengzhou University within 6 hours after birth,with birth weight ＜ 1500 g were eligible.All the infants were scored with the use of NCIS,and plasma NT-proBNP levels were measured simultaneously.A Logistic regression analysis(Method =Enter) was performed to determine the independent risk factors.The value of relevant factors on mortality risk evaluation were determined and compared with the use of receiver operator characteristic (ROC) curve.The extent to which NT-proBNP reassigned individuals to risk categories that better predicted the mortality risk was assessed by use of the net reclassification index(NRI) measure.Results One hundred and twenty-two cases of VLBWI (male/female =64/58 cases) were included in the study.The total mortality rate was 17.21％ (21 / 122 cases).The NT-proBNP,NCIS score,pH,pa (O2),blood urea nitrogen (BUN),hematocrit (HCT),systolic blood pressure,occurrence of gastrointestinal injury and occurrence of intubation among those neonates who died was significantly different with those who didn't(all P ＜ 0.001).The Logistic regression analysis indicated that NT-proBNP was the only independent factor which was closely related with mortality risk (OR =1.174,P ＜ 0.05).The area under the ROC curve for NT-proBNP was 0.935,with the cut-off ＞ 19580 ng/L,the sensitivity was 95.21％,the specificity was 87.13％.The area under the ROC curve for NCIS was 0.816,with the cut-off ≤ 76,the sensitivity was 95.19％,the specificity was 56.41％.The area under the ROC curve for NT-proBNP along with NCIS was 0.947,the sensitivity was 100.00％,the specificity was 84.18％.The addition of NT-proBNP to NCIS in prediction of mortality risk significantly improved the net reclassification improvement(NRI=0.385,Z=2.714,P =0.034).Conclusions The addition of NT-proBNP to NCIS significantly improve the predictive value on mortality risk,predicting the mortality risk early and accurately.

Objective To explore the value of plasma N-terminal pro-brain natriuretic peptide(NT-proBNP) in diagnosing or excluding concurrent heart failure (HF) in neonates with respiratory distress syndrome (RDS).Methods One hundred and fifteen preterm infants with RDS,admitted to Neonatal Intensive Care Unit of the First Affiliated Hospital of Zhengzhou University from Jan.2011 to Oct.2012,were classified into 2 groups:HF group (56 cases) and non-HF group (59 cases).Differences in cardiac biomarkers and parameters of ultrasonic cardiogram for cardiac function between the 2 groups were analyzed within 24 hours after birth through univariate factors.To evaluate independent factors for HF,logistic regression analysis was performed including significant univariate factors.Receiver operator characteristic curve (ROC) was used to determine the best cutoff for diagnosis of HF with sensitivity and specificity of more than 90％.Results The level of plasma troponin and CK-MB showed no significant difference between the 2 groups (all P ＞ 0.05).Compared with the non-HF group,the incidence of patent ductus arteriosus,patent foramen ovale and pulmonary hypertension,as well as plasma NT-proBNP level and pulmonary artery pressure were significantly higher in the HF group (all P ＜0.05).In contrast,left ventricular ejection fraction and E/A ratio were significantly lower in the HF group (all P ＜0.05).Logistic regression analysis,which was performed using the 7 significant univariate factors,showed that only plasma NT-proBNP was the independent factor for evaluating HF(OR =1.359,P =0.000).The area under ROC for NT-proBNP levels for diagnosis of HF in RDS neonates was 0.997 (95％ CI 0.962-1.000,P =0.000).A cutoff value of at least 16 379 ng/L had a sensitivity of 91.1％ and specificity of 98.3％.All the 8 neonates who died had a plasma NT-proBNP level of 35 000 ng/L in 24 hours after birth,significantly higher than that in survival neonates(P =0.000).Conclusions Plasma NT-proBNP level proved to have the value for independently determining or excluding HF in RDS neonates,and dynamic observation for NT-proBNP level may be used for early prediction of mortality risk in neonates with HF.

Objective To establish the reference range of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in early preterm infants.Methods 1.Inclusion criteria of the subjects:(1) preterm infants admitted to Neonatal Ward of First Affiliated Hospital of Zhengzhou University between Oct.2009 and Aug.2012 within 24 hours after birth;(2) maternal health during pregnancy; (3) written informed consent obtained from parents;(4) normal laboratory examination results such as blood gas analysis,electrolyte,hepatorenal function,myocardial enzyme,routine blood count and infectious disease screening (hepatitis B,hepatitis C,syphilis and acquired immune deficiency syndrome) within 24 hours after birth.Plasma NT-proBNP levels were measured on day 1,day 3 and day 7 of life.Variable data was analyzed using the Shapiro-Wilk test for normality test.Difference in plasma NT-proBNP levels on different days of life was analyzed using repeated measure analysis of variance.A multiple regression analysis was performed to determine the influencing factors for plasma NT-proBNP level,reference value interval:reference range containing 95 ％ of the reference population,namely(x-1.96 s)-(x-+ 1.96 s),with inspection level α =0.05.Results 1.A total of 204 preterm infants (104 cases were male and 100 cases were female) were included in the present study,with gestational age ranging from 27 + 1 to 36 +6 weeks(median 33 weeks) and birth weight ranging from 700 to 3050 g (median 1590 g).Of these preterm infants,vaginal delivery were 78 cases,cesarean delivery in 126 cases,serum bilirubin level was (56.6 ± 23.1) μmol/L,maternal age was (30.6 ± 5.3) years.There was no difference of these parameters between male and female(P ＞ 0.05).2.A multiple regression analysis was performed including following factors:gender,delivery mode,gestational age,birth weight,alimentation mode,serum bilirubin,and maternal age,and none of the evaluated factors was independent influencing factor for plasma NT-proBNP level,with α =0.05 for inspection level.3.Plasma NT-proBNP levels of the 204 preterm infants on day 1,day 3 and day 7 of life followed normal distribution by Shapiro-Wilk test.By repeated measure analysis of variance,the NT-proBNP levels were significantly different on different days (F =443.824,P =0.000).NT-proBNP levels were highest on day 1 of life,and negatively correlated with age in days(r =-0.476,P =0.000).There was significant difference among groups according to different days after birth (t1 d-3d =4.358,t1 d-7 d =14.743,t3 d-7 d =11.105,respectively;all P =0.000).The levels on day 1,day 3 and day 7 of life were (1875 ±686) ng/L,(1615 ±574) ng/L and (1118 ± 380) ng/L,respectively,with 95％ confidence interval 530-3220 ng/L,490-2740 ng/L and 373-1863 ng/L.Conclusions Plasma NT-proBNP levels of early preterm infants are highest on day 1 of life,and negatively correlated with age in days;but not affected by gestational age,gender,birth weight,vaginal delivery or alimentation mode.