Laryngeal chemosensitivity: a possible mechanism for sudden infant death.
Laryngeal chemosensitivity: a possible mechanism for sudden infant death.
复制标题
喉化学敏感性：婴儿猝死的可能机制。
作者：
S. Downing;John C. Lee
在32只1 ~ 42日龄的麻醉仔猪中，远端气管插管并记录压力变化。对近端气管插管，以将试验液体引入喉部区域。连续记录动脉压、心率和中心静脉压。每隔一段时间采集动脉血样本，并分析PO 2、PCO 2、pH和红细胞压积。生理盐水不产生呼吸模式和动脉压的变化，或产生短暂的呼吸模式和动脉压的变化。相比之下，滴注蒸馏水在30头仔猪中的29头中产生呼吸暂停。20例患者持续呼吸暂停。11人在窒息后约50分钟内死亡。另有9人预计将死于持续呼吸暂停（PO 2，10至15 mm Hg; PCO 2大于100 mm Hg; pH小于6.8），但通过用盐水替代水中断了该顺序。29头仔猪中有23头表现出对牛奶的呼吸暂停反应，与蒸馏水相似。7人死于窒息，另外3人表现出持续的呼吸抑制，直到用盐水代替牛奶。上级喉神经（SLN）切断完全消除的反应。SLN的电刺激产生持续的呼吸暂停在七个八仔猪测试。在两个3天大的羔羊的研究表明，类似的歧视，但只有短暂的呼吸暂停与水或牛奶。两者均在SLN刺激期间死亡。两只母羊表现出不显著的反应。这些发现表明了一种致命的反射机制，对小岛屿发展中国家问题有影响。
In 32 anaesthetized piglets 1 to 42 days of age the distal trachea was cannulated and pressure changes were recorded. The proximal trachea was cannulated for introduction of test fluids into the laryngeal area. Arterial pressure, heart rate, and central venous pressure were continuously recorded. Arterial blood samples were obtained at intervals and analyzed for PO2, PCO2, pH, and hematocrit. Normal saline produced no, or brief, transitory alterations of the respiratory pattern and arterial pressure. In contrast, instillation of distilled water produced apnea in 29 of 30 piglets. In 20 the apnea was sustained. Eleven died within approximately 50 minutes of asphyxia. An additional nine were expected to die with continuing apnea (PO2, 10 to 15 mm Hg; PCO2 greater than 100 mm Hg; pH smaller than 6.8) but the sequence was interrupted by replacement of water with saline. Twenty-three of 29 piglets showed an apneic response to cow's milk similar to that seen with distilled water. Seven died of asphyxia and an additional three showed sustained respiratory inhibition until milk was replaced with saline. The responses were completely abolished by superior laryngeal nerve (SLN) sectioning. Electrical stimulation of the SLN produced sustained apnea in seven of eight piglets tested. Studies in two 3-day-old lambs showed similar discrimination but only transitory apnea with water or cow's milk. Both died during SLN stimulation. Two ewes showed insignificant responses. These findings suggest a lethal reflex mechanism with implications for the SIDS problem.