Bangyozova Maya, Jordanova Albena, Tsanova Asya, Jekova Neli, Chakarov Decho, Doumanov Jordan, Christova Emilia, Lalchev Zdravko
Faculty of Biology, University of Sofia, Sofia, Bulgaria.
Acta Med Port. 2013 Jan-Feb;26(1):33-8. Epub 2013 Apr 24.
The optimal approach to detection of surfactant deficiency in the prematurely born infants at birth remains unclear and the decision to apply exogenous surfactant is based mainly on the development of clinical and radiological signs of neonatal respiratory distress syndrome (NRDS).
We studied the biochemical and biophysical properties of gastric aspirates (GA) from prematurely born infants with NRDS and healthy full term infants with an aim to find an approachable method for assessment of surfactant maturity at birth.
Forty-seven newborn infants divided into two groups were enrolled in the study. The first group comprised 34 healthy infants born at term (after 37 weeks of gestation). The second group included 13 premature infants (aged from 26 to 32 weeks of gestation) developing clinical signs of NRDS for which they were treated by assisted ventilation and exogenous surfactant. A biochemical analysis of the protein and lipid content of GA collected at birth was performed. The fatty acid composition of the GA samples was determined by Gas Chromatography-Mass Selective Detector (GS-MSD) analysis. The surface characteristics (equilibrium, maximal and minimal surface tension values) of the GA samples were measured by using the pending drop method. Data were compared between the groups by using Student's t test or Mann-Whitney analysis. Values were considered significantly different if the p value was = 0.05.
The mean phospholipids' concentration in GA of the premature infants was lower (295.7 µg / ml vs. 374.5 µg / ml) than in the term infants and the mean protein content was less in GA of the premature babies than the term newborns (574.5 µg / ml vs. 641.5 µg / ml). The measurement of dynamic surface characteristics of GA showed significantly higher mean values of the minimal surface tension (γmin) in the premature infants - 20.5 m / Nm compared to the term babies - 12.3 mN/m (p < 0,01). There was no difference between the equilibrium surface tensions (38 mN/m vs. 38 mN/m) of both groups; The mean values of maximal surface tension (?max) in GA did not differ significantly between the groups (50.1 mN/m vs. 48.5 mN/m).
Our findings revealed lower phospholipids' and protein concentrations in the GA at birth from premature infants as compared to the healthy term infants. The dynamic surface characteristics of GA had significant differences between the two groups, the minimal surface tension being the most important parameter for evaluation of surfactant maturity. It could be used in the clinical practice for fast surfactant's assessment in the premature infants in regard to administration of exogenous surfactant.
出生时检测早产婴儿表面活性剂缺乏的最佳方法仍不明确，应用外源性表面活性剂的决定主要基于新生儿呼吸窘迫综合征（NRDS）临床和放射学征象的发展情况。
我们研究了患有NRDS的早产婴儿和健康足月儿胃吸出物（GA）的生化和生物物理特性，旨在找到一种可用于评估出生时表面活性剂成熟度的可行方法。
47例新生儿被分为两组纳入研究。第一组包括34例足月（妊娠37周后）出生的健康婴儿。第二组包括13例早产婴儿（妊娠26至32周），他们出现了NRDS的临床征象，并接受了辅助通气和外源性表面活性剂治疗。对出生时采集的GA的蛋白质和脂质含量进行了生化分析。通过气相色谱 - 质量选择检测器（GS - MSD）分析测定GA样本的脂肪酸组成。使用悬滴法测量GA样本的表面特性（平衡、最大和最小表面张力值）。使用学生t检验或曼 - 惠特尼分析对两组数据进行比较。如果p值≤0.05，则认为差异具有统计学意义。
早产婴儿GA中磷脂的平均浓度低于足月儿（295.7μg/ml对374.5μg/ml），早产婴儿GA中的平均蛋白质含量也低于足月新生儿（574.5μg/ml对641.5μg/ml）。GA动态表面特性的测量显示，早产婴儿的最小表面张力（γmin）平均值显著高于足月儿 - 20.5mN/m对12.3mN/m（p < 0.01）。两组的平衡表面张力无差异（38mN/m对38mN/m）；GA中最大表面张力（γmax）的平均值在两组之间无显著差异（50.1mN/m对48.5mN/m）。
我们的研究结果显示，与健康足月儿相比，早产婴儿出生时GA中的磷脂和蛋白质浓度较低。GA的动态表面特性在两组之间存在显著差异，最小表面张力是评估表面活性剂成熟度的最重要参数。它可用于临床实践中，以便在考虑给予外源性表面活性剂时快速评估早产婴儿的表面活性剂情况。
