早期血清蛋白生化指標對不同胎齡早產兒的營養評估價值

楊琳　姜紅

[摘要] 目的 通過測定不同胎齡、不同相對體質量早產兒早期血清白蛋白、前白蛋白及總蛋白水平，探討早產兒早期蛋白生化指標對評價早產兒成熟度、宮內營養狀況以指導營養支持治療的臨床意義。 方法 選取2010年1月～2013年8月同期住院的新生兒189例，分為≤28周組16例、28～32周組53例、32～37周組72例、足月兒組48例。于出生后24h內采集靜脈血2mL，測定白蛋白、前白蛋白、總蛋白水平。 結果 四個胎齡組間，胎齡越小，白蛋白、前白蛋白、總蛋白水平越低，差異具有統計學意義（P<0.05）。28～32周、32～37周及足月兒組三組中相對體質量越低，前白蛋白水平越低，差異具有統計學意義（P<0.05），≤28周組中不同相對體質量間前白蛋白水平差異無統計學意義（P>0.05）。各胎齡組內不同相對體質量間白蛋白、總蛋白水平差異無統計學意義（P>0.05）。 結論 早產兒胎齡越小，白蛋白、前白蛋白、總蛋白水平越低，前白蛋白是目前評價早產兒成熟度及營養狀況最敏感的指標。監測早產兒血清蛋白水平變化，對臨床合理營養支持治療及預防疾病具有指導意義。

[關鍵詞] 早產兒；前白蛋白；白蛋白；營養評估

[中圖分類號] R722.6 [文獻標識碼] A [文章編號] 2095-0616（2014）03-22-05

complications after birth such as feeding difficulty， which is prone to protein deficiency.The early nutrition condition is not only to decide whether the premature babies can survive but also has a lasting impact on their long-term quality of life [1].In this paper，the assessment value of early serum biochemical indexes to the maturity and intrauterine nutrition statue of the premature infant and its guiding significance for nutrition support therapy in clinical are discussed by detecting the levels of early serum albumin （ALB），prealbumin （PA） and total proteins （TP） of the premature infants at different gestational ages with different relative body weight （RBW）.

1 Materials and Methods

1.1 General Information

（1） Research object：189 newborns admitted in NICU of the affiliated hospital of Qingdao university between 2010-01 and 2013-08；（2） Inclusion criteria： neither infection was observed in the research objects and their pregnant mothers，nor the congenital malformations，genetic metabolic disease and severe liver and kidney dysfunction.

1.2 Methods

Collection of clinical data.Infants were divided into groups according to the gestational age：there were 16 cases in≤28 weeks group，where 7 cases were male and 9 cases were female；53 cases in the 28+1-32 weeks group （namely>28 weeks and ≤32 weeks），29 cases were male and 24 cases were female； 72 cases in 32+1-36+6 weeks （namely > 32 weeks and <37 weeks），where 29 cases were male and 43 cases were female；48 cases in the full-term group （namely ≥37 weeks and <42weeks），with half male and half female.In each group，the infants were divided into small for gestational age（SGA），appropriate for gestational age （AGA） and large for gestational age （LGA），where SGA refers to the infants whose birth weight was lower than that of the 10 percentiles new born with the same gestational age；AGA refers to the infants whose birth weight was between that of the 10 and 90 percentiles new born with the same gestational age，while LGA refers to the infants whose birth weight was bigger than that of the 90 percentiles new born with the same gestational age[2].ALB， PA and TP levels of AGA in each group were analyzed.And various biochemical indexes between SGA，AGA and LGA in each group were also analyzed at the same time.For all the infants， after the birth，2mL venous blood was collected within 24 hours and centrifuged for plasma.Hitachi 7600 biochemical analyzer was used for measurement，where ALB was tested by bromocresol green colorimetry，PA was by transmission turbidimetry and TP by biuret method.endprint

1.3 Statistical methods

Results in each group are expressed in mean±standard error（）.SPSS17.0 software was used for analysis， with t-test and variance analysis as statistical methods.In all cases，a p value of less than 0.05 was considered statistically significant.

2 Results

2.1 Plasma ALB，PA and TP levels in different age for AGA

The level of the ALB， PA and TP was related to getiotational age.The smaller the gestational age was， the lower the ALB，PA and TP levels were，and the difference was statistically significant（P<0.05）.Table 1.

2.2 Plasma ALB，PA and TP levels in different groups

In 28+1-32 weeks group，32+1-36+6 weeks group and full-term infant group， the lower the RBM was， the lower the PA level was， and the difference was statistically significant （P<0.05）；while in the≤28 weeks group， no statistically significant difference was observed in the PA level of infants with different RBM （P>0.05）. Albumin and total protein levels were not statistically different between infants with different RBM in each group（P>0.05）.Table 1-Table 5.

3 Discussion

3.1 The evaluation of serum albumin and prealbumin on maturity of premature infants and their nutrition at the early stage

Albumin，prealbumin and total protein can manifest the albumen nutrition of the body. Protein， macromolecular substance，can not pass through placental barrier.The fetus gains the synthetic protein of amino acid from the mothers' body.According to the researches of Gerogieff and Sasanow[4]，the serum albumin of pregnant woman was apparently higher than the cord blood prealbumin of newborns in each gestational week， but there was no relevancy between the mother and baby. Serum albumin and prealbumin refer to the protein generated by liver. Prealbumin，whose half-life period is short （1.9d），refers to a kind of plasma translocator locating before albumin in case of plasma protein electrophoresis.It contains low content of blood. In case of albumen-energy deficiency，it will fall abruptly. When albumen energy intake is increased，it can be increased evidently after 3d. Contrarily，the half-life period of albumin is longer （20-25d）. The blood can not be changed until about 14d passes by.The sensitiveness is so low，which only can manifest the nutritional state of engine body two weeks ago and even longer.Sensitiveness of nutrition assessment index is mainly based on physiological half-life period of albumen.The shorter its half-life period， the higher the sensitiveness.Prealbumin can well assess the nutrition of the fetus. Some researches have proved[5-7] that the level of prealbumin was related to gestational age and body mass.The smaller the gestational age，the lighter the body mass. This research showed that the smaller the gestational age，the smaller the level of prealbumin，albumin and total protein，which was in line with the documentary report[8].It is relevant to the imperfect liver development and protein synthesis of newborns and under-reserve. According to the research by Chi Meizhu[9]，it indicated that prealbumin can be used as the index differentiating those larger， appropriate and smaller for gestational age. In the research， there was no statistical significance in difference in prealbumin between SGA and AGA in gestational age≤28，considering it is related to the few sample quantity.There was obvious difference in prealbumin which is among the smaller，appropriate and larger for gestational age in the remaining groups.The relatively smaller the body mass，the lower the level of prealbumin，which was in conformity with the relevant document reports. There is no known obvious difference in comparison of albumin and total protein among newborns of different body masses at the same gestational age， which is associated with the rise in consumption of neonatal hyperbilirubinemia of newborns and also in line with the relevant researches.It is thus stated that prealbumin can be used as nutritive index to assess the maturity and nutrition of premature infants and compare it to albumin.It has high sensitiveness and further can precisely manifest the nutrition of newborn and especially the premature infants at different phases.endprint

3.2 The significance of monitoring the changes in serum albumin on clinical and rational nutrition support therapy

Low birth weight （LBW）infant faced growth retardation， development delay and increased risks in infectious diseases and death at infancy stage and childhood，which was closely associated with the nutrition after its birth[10].Extrauterine growth retardation of premature infants is a relatively universal phenomenon of NICU[11-13].It is greatly influential to the survival rate of premature infants and physical development and nervous system of them at infancy stage and childhood[14].The malnutrition of newborns at the early stage is more due to the deficiency in protein and energy.In case of supplementing nutrition promptly，the survival rate and disease resistance can be enhanced[15].For LBW infants，due to the food reserve deficiency in utero ，the development of each organ system is not mature so as to the premature infant can not tolerate the nutrition in intestinal tact，thus it is imperative to give partial total parenteral nutrition for complete parental nutrition support therapy[16].Amino acid is an important part of parental nutrient solution. It is not only important to the growth of physique but also necessary for connecting metabolism signal pathway，protein synthesis and albumen.The sufficient amino acid should be replenished to maintain the fast protein synthesis and growth[17].The deficiency in amino acid intake might give rise to or aggravate extrauterine growth retardation of premature infants. When giving excessive amino acid to the premature infants，the rise in blood ammonia might be triggered[18]. For the protein and energy malnutrition of LBWIs at different gestational stages，it is necessary to conduct meaningful assessment on nutrition of biochemical criterion and evaluate the curative effect of its nutrition support[19].The half-life period of prealbumin is short but can rapidly manifest the positive and negative balance of nutrition intake and sensitively manifest the level of protein synthesis in vivo and the nutrition state of the organism[20].Therefore，according to the prealbumin level， the nutrition state of premature infants can be assessed to guide clinical and rational nutrition support therapy[21].

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（收稿日期：2013-11-20）endprint

[16] Wang Jing，Zhang Wei，Ma Jian-rong，et al. Role of sertnm prealbun in nutritional treatment of low birth weight premaUh-e infants in parenteral alirnentafion[J].International Journal of Pediatrics，2009，36（4）：337-339.

[17] Feng Zhi chun，Wang Rui-juan，Li Qiu-ping. To improve the level of clinical management of premature infant nutrition[J].Chinese Journal of Child Health Care，2011，19（9）：777-778.

[18] Zhang Bo. Effect of different administrations of intravenous anljno acid Oil the nutrlflonal status of preterm infants[J].Hainan Medical Journal，2012，23（7）：58-59.

[19] Kuang Wen-ying，Liao Yan，Wang Wei-shan，et al.Nutritional Status of Low Birth Weight Newborns with Different Gestational Age in Neonatal Intensive Care Unit[J].Journal of Applied Clinical Pediatrics，2012，27（24）：1886-1897.

[20] Chen Chao，Wei Ke-lun，Yao Yu-jia，et al.Management guidelines of premature infants[J].Chinese Journal of Pediatrics， 2006，44（3）：188-191.

[21] Su PH，Wang SL，Chen JY，et al.Transthyretin levels are not related to Apgar score in low birth weight and very low birth weight infants[J].Early Hum Dev，2008，84（8）：533-538.

（收稿日期：2013-11-20）endprint

[16] Wang Jing，Zhang Wei，Ma Jian-rong，et al. Role of sertnm prealbun in nutritional treatment of low birth weight premaUh-e infants in parenteral alirnentafion[J].International Journal of Pediatrics，2009，36（4）：337-339.

[17] Feng Zhi chun，Wang Rui-juan，Li Qiu-ping. To improve the level of clinical management of premature infant nutrition[J].Chinese Journal of Child Health Care，2011，19（9）：777-778.

[18] Zhang Bo. Effect of different administrations of intravenous anljno acid Oil the nutrlflonal status of preterm infants[J].Hainan Medical Journal，2012，23（7）：58-59.

[19] Kuang Wen-ying，Liao Yan，Wang Wei-shan，et al.Nutritional Status of Low Birth Weight Newborns with Different Gestational Age in Neonatal Intensive Care Unit[J].Journal of Applied Clinical Pediatrics，2012，27（24）：1886-1897.

[20] Chen Chao，Wei Ke-lun，Yao Yu-jia，et al.Management guidelines of premature infants[J].Chinese Journal of Pediatrics， 2006，44（3）：188-191.

[21] Su PH，Wang SL，Chen JY，et al.Transthyretin levels are not related to Apgar score in low birth weight and very low birth weight infants[J].Early Hum Dev，2008，84（8）：533-538.

（收稿日期：2013-11-20）endprint