Schrikker A C, Wesenhagen H, Luijendijk S C
Department of Medical Physiology and Sports Medicine, University of Utrecht, The Netherlands.
Pflugers Arch. 1993 Oct;425(1-2):16-21. doi: 10.1007/BF00374498.
To investigate the effect of incomplete gas mixing between tidal air and residual gas on pulmonary gas exchange, anaesthetized dogs were ventilated artificially with breathing patterns with different durations of the post-inspiratory apnoea (ta = 0, 0.5, 1.0 and 2.0 s), where tidal volume, breathing frequency, inspiratory and expiratory flow patterns were kept constant. We determined the alveolar ventilations (VA) of He and SF6 from the product of end-expiratory lung volume (VL,E') and specific ventilation (VA/VL,E'). VL,E' was determined by the dilution technique and the specific ventilations of the two gases were obtained from their multiple-breath washout. Further, tracer amounts of acetone, ether and enflurane were infused continuously into a peripheral vein and a bolus of a gas mixture of krypton, Freon12 and SF6 was introduced into the peritoneal cavity. We determined the Excretion (E) and Retention (R) of these six gases according to the multiple-inert-gas-elimination technique (MIGET). VA increased with increasing ta, where VA,He was about 14% larger than VA,SF6. For both gases, however, the increase in VA relative to control (VA for ta = 0) was virtually the same: 9, 11 and 19% (mean values) for ta = 0.5, 1.0 and 2.0 s respectively. For all dogs the E/R curve shifted to larger E values with increasing ta. E for the most soluble tracer gas (acetone) increased by 11, 21 and 25% for ta = 0.5, 1.0 and 2.0 s respectively. VA, determined with MIGET from the ventilation/perfusion distribution, increased by almost the same percentages.(ABSTRACT TRUNCATED AT 250 WORDS)
为研究潮气与残气之间气体混合不完全对肺气体交换的影响，对麻醉犬进行人工通气，采用不同吸气后暂停时间（(t_a) = 0、0.5、1.0和2.0秒）的呼吸模式，同时潮气量、呼吸频率、吸气和呼气气流模式保持恒定。我们根据呼气末肺容积（(V_{L,E}')）与比通气量（(V_A/V_{L,E}')）的乘积来测定氦气和六氟化硫的肺泡通气量（(V_A)）。(V_{L,E}')通过稀释技术测定，两种气体的比通气量通过多次呼吸冲洗法获得。此外，将微量的丙酮、乙醚和恩氟烷持续注入外周静脉，并将氪气、氟利昂12和六氟化硫的混合气体团注入腹腔。我们根据多惰性气体消除技术（MIGET）测定这六种气体的排出量（(E)）和潴留量（(R)）。(V_A)随(t_a)增加而增加，其中氦气的(V_A)比六氟化硫的(V_A)大约大14%。然而，对于两种气体，相对于对照（(t_a) = 0时的(V_A)），(V_A)的增加实际上是相同的：(t_a) = 0.5、1.0和2.0秒时分别为9%、11%和19%（平均值）。对于所有犬只，随着(t_a)增加，(E/R)曲线向更大的(E)值移动。最易溶示踪气体（丙酮）的(E)在(t_a) = 0.5、1.0和2.0秒时分别增加了11%、21%和25%。通过MIGET根据通气/灌注分布测定的(V_A)增加的百分比几乎相同。（摘要截断于250字）
