Holopainen R, Soukka H, Halkola L, Kääpä P
Cardiorespiratory Research Unit, University of Turku, Finland.
Pediatr Pulmonol. 1998 Feb;25(2):107-13. doi: 10.1002/(sici)1099-0496(199802)25:2<107::aid-ppul6>3.0.co;2-k.
To investigate the effects of aspirating different meconium concentrations on the pulmonary circulation in 10- to 12-day-old piglets, 30 catheterized animals were studied. The piglets received an intratracheal bolus of 3 ml/kg of a mixture of human meconium in saline with concentrations of 20 mg/ml (light, n = 7), 40 mg/ml (moderate, n = 6), or 65 mg/ml (thick, n = 10) meconium in saline. Control piglets (n = 7) received 3 ml/kg of intratracheal saline. Pulmonary and systemic pressures were measured and vascular resistances calculated at baseline and serially for 4 hours after instillation. Four of the piglets died early and were excluded from the study. In addition, 23 samples of human meconium-stained amniotic fluid were collected at delivery for determination of their meconium concentration. After an initial rise in pulmonary artery pressure and vascular resistance after meconium and saline instillation, pulmonary artery pressure and resistance increased progressively and concentration-dependently in the meconium groups, but returned to baseline in the control group. The saline and meconium-induced initial increases, and the subsequent meconium-stimulated progressive rise in vascular resistance occurred mainly in the postarterial segment. There were no significant changes in systemic hemodynamics. Mean airway pressure increased and oxygenation deteriorated after meconium instillation. The impairment of oxygenation depended on the meconium concentration in the instilled bolus and persisted throughout the study after moderate and thick meconium instillation. Similarly, the intrapulmonary shunt fraction increased initially and remained elevated in the moderate and thick meconium groups. Meconium concentrations in the human amniotic fluid samples were in the same range as concentrations used in the present experimental study. These results indicate that aspirated meconium at concentrations found in light to moderate meconium-stained human amniotic fluid has significant effects on pulmonary hemodynamic and oxygenation in newborn piglets.
为研究吸入不同胎粪浓度对10至12日龄仔猪肺循环的影响，对30只插管动物进行了研究。给仔猪气管内注入3 ml/kg含不同浓度人胎粪的生理盐水混合物，胎粪浓度分别为20 mg/ml（轻度，n = 7）、40 mg/ml（中度，n = 6）或65 mg/ml（重度，n = 10）。对照仔猪（n = 7）接受3 ml/kg气管内生理盐水。在基线时以及滴注后连续4小时测量肺和全身压力，并计算血管阻力。4只仔猪早期死亡，被排除在研究之外。此外，分娩时收集了23份人胎粪污染羊水样本，以测定其胎粪浓度。在注入胎粪和生理盐水后，肺动脉压力和血管阻力最初升高，之后在胎粪组中肺动脉压力和阻力呈浓度依赖性逐渐升高，但在对照组中恢复到基线水平。生理盐水和胎粪引起的最初升高以及随后胎粪刺激的血管阻力逐渐升高主要发生在动脉后段。全身血流动力学无显著变化。注入胎粪后平均气道压力升高，氧合恶化。氧合受损取决于注入推注中的胎粪浓度，在注入中度和重度胎粪后整个研究过程中持续存在。同样，肺内分流分数最初升高，并在中度和重度胎粪组中持续升高。人羊水样本中的胎粪浓度与本实验研究中使用的浓度范围相同。这些结果表明，吸入轻度至中度胎粪污染人羊水中发现的浓度的胎粪对新生仔猪的肺血流动力学和氧合有显著影响。
