Fernandes M S, Giusti H, Glass M L
Department of Physiology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Avenida Bandeirantes 3900, 14.049-900 Ribeirão Preto, SP, Brazil.
Comp Biochem Physiol A Mol Integr Physiol. 2005 Dec;142(4):446-50. doi: 10.1016/j.cbpa.2005.09.011. Epub 2005 Oct 28.
The respiratory cycles of Rana and Bufo has been disputed in relation to flow patterns and to the respiratory dead-space of the buccal volume. A small tidal volume combined with a much larger buccal space motivated the "jet steam" model that predicts a coherent expired flow within the dorsal part of the buccal space. Some other studies indicate an extensive mixing of lung gas within the buccal volume. In Bufo schneideri, we measured arterial, end-tidal and intrapulmonary PCO(2) to evaluate dead-space by the Bohr equation. Dead-space was also estimated as: V(D)=(total ventilation-effective ventilation)/f(R), where total ventilation and f(R) were measured by pneumotachography, while effective ventilation was derived from the alveolar ventilation equation. These approaches were consistent with a dead space of 30-40% of tidal volume, which indicates a specific pathway for the expired lung gas.
关于林蛙和蟾蜍的呼吸周期，在气流模式以及口腔容积的呼吸无效腔方面一直存在争议。小潮气量与大得多的口腔空间促使人们提出了“喷射气流”模型，该模型预测口腔空间背侧部分内有连贯的呼出气流。其他一些研究表明，肺内气体在口腔容积内广泛混合。在施耐德蟾蜍中，我们测量了动脉血、呼气末和肺内的PCO₂，以通过玻尔方程评估无效腔。无效腔也可按以下公式估算：V(D)=(总通气量-有效通气量)/呼吸频率(f(R))，其中总通气量和f(R)通过呼吸流速仪测量，而有效通气量则根据肺泡通气方程得出。这些方法得出的无效腔占潮气量的30%-40%，这表明呼出的肺内气体存在特定路径。
