Influence of cardiac action on gas mixing in closed-chest dogs.
Influence of cardiac action on gas mixing in closed-chest dogs.
复制标题
心脏活动对闭胸犬气体混合的影响。
DOI：
10.1152/jappl.1995.79.1.113
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Klocke,RA
中科院分区：
文献类型：
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作者：
Zhang,S;Saltzman,AR;Klocke,RA
我们对闭胸、瘫痪和麻醉的狗（6只双侧迷走神经切断术和6只迷走神经完整）在心脏跳动和心脏骤停期间进行了单次呼吸测试。通过心室颤动和随后的除颤实现反复心脏骤停。每只狗进行 24 次单次呼吸测试，结合三种吸气量（VI；0.2、0.5 和 0.8 升）和四种吸气后暂停（0、5、10 和 30 秒），有或没有心脏骤停。测试气体包含四种相对不溶的惰性气体（He、Ne、Ar 和 SF6），其扩散率范围为六倍。系列死腔 (VD) 随着吸气后暂停的增加、气体扩散率的增加或 VI 的降低而减少。在迷走神经切断的动物中，心脏跳动时的 VD 比心脏骤停时要小，但这种关系在迷走神经完整的动物中却相反。心源性混合引起的 VD 减少仅占吸气后暂停 30 秒期间发生的 VD 总减少的 10.8%。除 VI 为 0.2 升外，III 相的斜率随着吸气后停顿的增加而减小。在心脏跳动或停止时进行的实验之间，第三阶段的斜率没有显着差异。呼气后残留在残余体积中的示踪气体随着吸气暂停的增加而增加。 He 的气体滞留大于 SF6，但不受心脏活动的影响。这些发现表明，心脏活动主要影响吸入气体和肺泡气体之间的界面，而对肺泡室中的混合影响很小。
We performed single-breath tests in closed-chest, paralyzed, and anesthetized dogs (6 with bilateral vagotomy and 6 with intact vagi) with the heart beating and during cardiac arrest. Repeated cardiac arrest was achieved by ventricular fibrillation and subsequent defibrillation. Twenty-four single-breath tests per dog were performed in combinations of three inspiratory volumes (VI; 0.2, 0.5, and 0.8 liter) and four postinspiratory pauses (0, 5, 10, and 30 s), either with or without cardiac arrest. The test gas contained four inert relatively insoluble gases (He, Ne, Ar, and SF6) with a sixfold range in diffusivity. Series dead space (VD) decreased with increasing postinspiratory pause, increasing gas diffusivity, or decreasing VI. In vagotomized animals, VD was smaller with the heart beating than during cardiac arrest, but this relationship was reversed in animals with intact vagi. The decrease in VD due to cardiogenic mixing accounted for only 10.8% of the total decrease in VD occurring during a 30-s postinspiratory pause. The slope of phase III decreased with increasing postinspiratory pause except at VI of 0.2 liter. No significant differences were noted in the slope of phase III between experiments performed with the heart beating or arrested. Tracer gas retained in the residual volume after expiration increased with increasing inspiratory pause. Gas retention was greater for He than for SF6 but was not affected by cardiac action. These findings indicate that cardiac action mainly affects the interface between inspired and alveolar gas and has little effect on mixing in the alveolar compartment.