Findlay R D, Taeusch H W, Walther F J
Department of Pediatrics, Martin Luther King, Jr Hospital/Charles R. Drew University of Medicine and Science, Los Angeles, CA 90059, USA.
Pediatrics. 1996 Jan;97(1):48-52.
The pathophysiology of meconium aspiration syndrome (MAS) is related not only to mechanical obstruction of the airways and chemical injury to the respiratory epithelium but also to surfactant inactivation by meconium. A randomized, controlled study was performed to determine whether high-dose surfactant therapy improves the pulmonary morbidity of term infants ventilated for MAS.
Forty term infants receiving mechanical ventilation for MAS were enrolled in this trial, in which the infants in the study group (n = 20) received up to four doses of 150 mg (6 mL)/kg beractant (Survanta), instilled every 6 hours by continuous infusion for 20 minutes via a side hole endotracheal tube adapter, and the infants in the control group (n = 20) received 6 mL/kg air placebo.
Mean arterial-to-alveolar PO2 ratio values increased from 0.09 to 0.11 at 1 and 6 hours with a concomitant slight decrease in oxygenation index values from 23.7 to 19.7 at 1 hour and 20.7 at 6 hours after the first dose of surfactant. Oxygenation improved cumulatively after the second and third dose of surfactant, with mean arterial-to-alveolar PO2 ratios and oxygenation indices of 0.18 and 12.1 at 6 hours after the second dose of surfactant and 0.31 and 5.9 at 6 hours after the third dose of surfactant, eliminating the need for a fourth dose in any infant in the study group. After three doses of surfactant, persistent pulmonary hypertension had resolved in all but one of the infants in the study group versus none of the infants in the control group. No air leaks developed in any of the 20 infants in the study group after surfactant therapy, and only 1 infant required extracorporeal membrane oxygenation. Air leaks developed in 5 of the 20 infants in the control group, and 6 underwent extracorporeal membrane oxygenation. The duration of mechanical ventilation, oxygen therapy, and admission was significantly shorter in the surfactant group than in the control group.
Surfactant replacement therapy, if started within 6 hours after birth, improves oxygenation and reduces the incidence of air leaks, severity of pulmonary morbidity, and hospitalization time of term infants with MAS.
胎粪吸入综合征（MAS）的病理生理学不仅与气道机械性阻塞及呼吸上皮化学性损伤有关，还与胎粪导致的表面活性物质失活有关。进行了一项随机对照研究，以确定高剂量表面活性物质治疗是否能改善因MAS接受机械通气的足月儿的肺部疾病发生率。
40例因MAS接受机械通气的足月儿纳入本试验，研究组（n = 20）的婴儿接受高达4剂150 mg（6 mL）/kg的贝拉克坦（固尔苏），通过侧孔气管内导管适配器每6小时持续输注20分钟，对照组（n = 20）的婴儿接受6 mL/kg空气安慰剂。
在首剂表面活性物质给药后1小时和6小时，平均动脉血氧分压与肺泡血氧分压比值从0.09升至0.11，同时氧合指数值在1小时时从23.7略有降至19.7，6小时时降至20.7。在第二剂和第三剂表面活性物质给药后氧合累积改善，在第二剂表面活性物质给药后6小时，平均动脉血氧分压与肺泡血氧分压比值及氧合指数分别为0.18和12.1，在第三剂表面活性物质给药后6小时分别为0.31和5.9，研究组中无婴儿需要第四剂表面活性物质。在给予三剂表面活性物质后，研究组除1例婴儿外，其余所有婴儿的持续性肺动脉高压均已缓解，而对照组无婴儿缓解。研究组20例婴儿在表面活性物质治疗后均未发生气胸，仅1例婴儿需要体外膜肺氧合。对照组20例婴儿中有5例发生气胸，6例接受体外膜肺氧合。表面活性物质组的机械通气、氧疗及住院时间显著短于对照组。
表面活性物质替代治疗若在出生后6小时内开始，可改善氧合，降低气胸发生率、肺部疾病严重程度及患有MAS的足月儿的住院时间。
