探讨脐血心钠素(atrial natriuretic peptide，ANP)测定在监测早产儿水钠平衡中的作用和临床意义。

将80例早产儿分为三组，即单纯早产儿组、早产+窒息组、早产+感染组。另设30例正常新生儿为对照组。各组均在新生儿娩出后立即抽取脐血，应用放射免疫法测定ANP水平，同时抽取静脉血测定患儿的血清钠含量，并分别与对照组比较。

三组的脐血ANP水平都明显高于正常新生儿，分别为(1. 06±0. 35)ng/ml(单纯早产儿组)、(1. 64±0. 37)ng/ml(早产 + 窒息组)、(1. 25±0. 29)ng/ ml(早产+感染组)，而正常新生儿组为(0.78±0.42)ng/ml。其中，尤以早产+窒息组ANP增高最为明显(t= 8.49，P<0. 01)，各组与对照组比较，差异均有显著意义。而与其相对应的则是血清钠水平的下降，两者呈显著负相关(r=-0.97)。

ANP是新生儿生后早期水钠平衡的主要调节因子，早产儿脐血ANP增高明显，若合并有窒息或感染，则表现更为突出，易致低钠血症，早期测定可对早产儿的抢救与治疗起到指导作用。

To explore the measurement of atrial natriuretic peptide(ANP)in umbilical cord blood of premature neonates in monitor the balance between water and sodium and its clinical significance.

80 premature neonates were divided into three groups, the simple premature group, the premature plus asphyxia group and the premature plus infection group. Another 30 normal neonates are as control group. The samples of umbilical cord blood of premature neonates were collected at the time of delivery and the ANP levels in them were measured by radioimmunoassay. The sodium levels in their peripheral vein were measured simultaneously. Then compared with the control group.

The ANP levels of the simple premature group(ANP 1. 36 ng/ml ± 0. 35 ng/ml), the premature plus asphyxia group(ANP 1. 64 ng/ml ± 0. 37 ng/ml)and the premature plus infection group(ANP 0. 78 ng/ml ±0. 29ng/ml)are significantly higher than those in the normal neonates(ANP 0. 78 ng/ml ± 0. 24ng/ml), especially in those premature plus asphyxia groups(t=8. 49, P<0. 01). And the sodium levels decreased correspondingly. There is a negative correlation between ANP and sodium levels(r=-0. 97).

ANP is the main mediator of the balance between water and sodium in the premature neonates. ANP increased significantly in the umbilical cord blood of premature neonates, especially incorporate asphyxia and infection factor, and can lead hyponatremia. So early measurement of ANP has a guidance effect on the salvage and treatment of premature neonates.