O'Toole S J, Karamanoukian H L, Sharma A, Morin F C, Holm B A, Azizkhan R G, Glick P L
Buffalo Institute of Fetal Therapy, Children's Hospital of Buffalo, NY 14222, USA.
J Pediatr Surg. 1996 Aug;31(8):1105-8; discussion 1108-9. doi: 10.1016/s0022-3468(96)90097-4.
Surfactant therapy given before the onset of ventilation (surfactant prophylaxis) has been shown to improve oxygenation, ventilation, and pulmonary hemodynamics in the lamb model of congenital diaphragmatic hernia (CDH). The aim of this study was to assess the efficacy of surfactant administered after the onset of ventilation ("surfactant rescue"). Ten lambs with surgically created CDH were instrumented, at full term, to measure pulmonary blood flow and pulmonary vascular resistance (PVR). Catheters also were positioned for monitoring of systemic blood pressure and arterial blood gases. The animals were delivered and pressure-ventilated according to a standard protocol (PIP, 30 cm; PEEP, 4 cm; respiratory rate, 60 breaths per minute). After 30 minutes of ventilation, five animals received an intratracheal dose of calf lung surfactant extract (50 mg/kg). The animals were studied for 4 hours. Surfactant rescue had no discernible effect on Pco2, Pco2, or pH. There was an increase in pulmonary blood flow, but it was not significant. The dramatic improvement in oxygenation, ventilation, and pulmonary blood flow found with prophylactic surfactant cannot be reproduced when surfactant is administered as rescue therapy. This indicates that the surfactant is not being delivered adequately, the lungs have already incurred significant barotrauma, and/or the surfactant is being inactivated by alveolar protein. Therefore, the authors suggest that when exogenous surfactant therapy is being considered for the fetus or newborn with CDH, it should be administered as early as possible, preferably before the infant's first breath. Prenatal diagnosis and delivery in a tertiary care center would facilitate this optimum management.
在先天性膈疝（CDH）羔羊模型中，通气开始前给予表面活性剂治疗（表面活性剂预防）已被证明可改善氧合、通气和肺血流动力学。本研究的目的是评估通气开始后给予表面活性剂（“表面活性剂抢救”）的疗效。十只通过手术制造CDH的羔羊在足月时进行仪器安装，以测量肺血流量和肺血管阻力（PVR）。还放置了导管以监测体循环血压和动脉血气。根据标准方案（吸气峰压30cm；呼气末正压4cm；呼吸频率60次/分钟）对动物进行通气。通气30分钟后，五只动物接受气管内注射小牛肺表面活性剂提取物（50mg/kg）。对动物进行4小时的研究。表面活性剂抢救对二氧化碳分压、氧分压或pH值没有明显影响。肺血流量有所增加，但不显著。当将表面活性剂作为抢救治疗给药时，预防性表面活性剂所带来的氧合、通气和肺血流量的显著改善无法再现。这表明表面活性剂没有得到充分输送，肺已经遭受了严重的气压伤，和/或表面活性剂被肺泡蛋白灭活。因此，作者建议，当考虑对患有CDH的胎儿或新生儿进行外源性表面活性剂治疗时，应尽早给药，最好在婴儿第一次呼吸之前。产前诊断并在三级护理中心分娩将有助于实现这种最佳管理。
