Dijk P H, Heikamp A, Bambang Oetomo S
Department of Pediatrics, Beatrix Children's Hospital, University Hospital Groningen, The Netherlands.
Intensive Care Med. 1997 Oct;23(10):1070-6. doi: 10.1007/s001340050458.
Surfactant nebulisation is a promising alternative to surfactant instillation in newborns with the respiratory distress syndrome. Although less surfactant is deposited in the lung, it improves gas exchange, probably due to a superior distribution. We hypothesize that a more uniform distribution of nebulised surfactant results in a more uniform pulmonary blood flow and consequently a more efficient gas exchange. We asked whether the pulmonary blood flow changes after surfactant replacement, and to what extent pulmonary blood flow is influenced by the amount of surfactant deposition. Furthermore, we investigated whether sufficient nebulised surfactant is deposited in the lungs to achieve a sustained improvement in lung function.
Surfactant was nebulised or instilled, or saline was nebulised, in 18 lung-lavaged rabbits. After 2 h the rabbits were weaned from mechanical ventilation to continuous positive airway pressure, 40% oxygen. We measured blood gasses, dynamic lung compliance, surfactant distribution using 99m technetium nanocoll label, and the pulmonary blood flow distribution, using microspheres.
Partial pressure of oxygen in arterial blood and lung compliance were significantly higher after surfactant nebulisation than after saline nebulisation. Surfactant instillation gave a superior effect with respect to these variables. Nebulised surfactant was distributed more uniformly over the lungs than instilled surfactant. Although pulmonary blood flow changed over time, it remained uniformly distributed following both modes of surfactant treatment. Surfactant deposition was neither strongly related to pulmonary blood flow nor strongly related to the change in blood flow.
Although nebulised surfactant is uniformly distributed, we can provide no evidence that this results in a more uniform pulmonary blood flow distribution. Therefore, other than a superior surfactant distribution, no additional reason was found for the efficient gas exchange after nebulisation.
对于患有呼吸窘迫综合征的新生儿，表面活性剂雾化是一种很有前景的替代表面活性剂滴注的方法。尽管雾化时进入肺内的表面活性剂较少，但它能改善气体交换，这可能是由于其分布更优。我们推测雾化表面活性剂更均匀的分布会导致肺血流更均匀，从而实现更有效的气体交换。我们研究了表面活性剂替代治疗后肺血流是否发生变化，以及肺血流受表面活性剂沉积量影响的程度。此外，我们还研究了肺内是否沉积了足够的雾化表面活性剂以实现肺功能的持续改善。
对18只经肺灌洗的兔子进行表面活性剂雾化或滴注，或生理盐水雾化。2小时后，将兔子从机械通气撤机，改为持续气道正压通气，吸入40%的氧气。我们测量了血气、动态肺顺应性、使用锝99m纳米胶体标记物测定表面活性剂分布，以及使用微球测定肺血流分布。
雾化表面活性剂后动脉血氧分压和肺顺应性显著高于雾化生理盐水后。在这些变量方面，表面活性剂滴注效果更佳。雾化表面活性剂在肺内的分布比滴注表面活性剂更均匀。尽管肺血流随时间变化，但在两种表面活性剂治疗方式下其分布仍保持均匀。表面活性剂沉积与肺血流既无强相关性，也与血流变化无强相关性。
尽管雾化表面活性剂分布均匀，但我们没有证据表明这会导致肺血流分布更均匀。因此，除了表面活性剂分布更优外，未发现雾化后有效气体交换的其他原因。
