Moawad A H, Ismail M A, River L P
Department of Obstetrics and Gynecology, University of Chicago, Illinois.
J Reprod Med. 1991 Jun;36(6):425-8.
Respiratory distress syndrome (RDS), resulting from inadequate amounts of alveolar surfactant, is a leading cause of neonatal mortality. This study analyzed the drop volume for predicting the risk of neonatal RDS by evaluating the surface tension of amniotic fluid. The drop-volume method quantifies the surface tension of amniotic fluid using the fact that the volume of a falling drop of liquid is proportional to the quantity of surface-active substances (surfactant) in the solution. Distilled water is used as a reference solution. The test is simple to perform and requires only two minutes and 2 mL of amniotic fluid. Amniotic fluid was obtained by amniocentesis from 120 pregnancies, ranging from 24 to 42 weeks of gestation, within four days of delivery. Specimens contaminated with meconium or hemolyzed blood or from patients with clinical chorioamnionitis were not used. The lecithin:sphingomyelin ratio and phosphatidylglycerol tests were also determined for 54 of the study cases. A mature drop-volume test result was associated with a healthy infant with no RDS 95% of the time (negative predictive value). Fifty-two percent of the healthy infants in the study were predicted by an arbitrary unit of time (S) value of less than or equal to 85.0 (specificity). Thirteen of the 16 infants who developed RDS (81%) were predicted by an S value of greater than or equal to 85.1 (sensitivity). Of those infants with an S value of greater than or equal to 85.1, 21% developed RDS (positive predictive value).
呼吸窘迫综合征（RDS）是新生儿死亡的主要原因，由肺泡表面活性物质不足所致。本研究通过评估羊水表面张力分析滴体积以预测新生儿RDS风险。滴体积法利用液体下落滴的体积与溶液中表面活性物质（表面活性剂）的量成正比这一事实来量化羊水表面张力。蒸馏水用作参比溶液。该测试操作简单，仅需两分钟和2毫升羊水。在分娩前四天内，通过羊膜穿刺术从120例妊娠（妊娠24至42周）中获取羊水。不使用被胎粪、溶血血液污染的标本或来自临床绒毛膜羊膜炎患者的标本。对54例研究病例还进行了卵磷脂：鞘磷脂比值和磷脂酰甘油检测。成熟的滴体积测试结果95%的情况下与无RDS的健康婴儿相关（阴性预测值）。研究中52%的健康婴儿通过小于或等于85.0的任意时间单位（S）值预测（特异性）。16例发生RDS的婴儿中有13例（81%）通过大于或等于85.1的S值预测（敏感性）。在S值大于或等于85.1的婴儿中，21%发生RDS（阳性预测值）。
