Kelsen S G, Shustack A, Hough W
Respir Physiol. 1982 Sep;49(3):339-53. doi: 10.1016/0034-5687(82)90121-9.
The present study examined the variability of breathing in five (5) awake tracheostomized dogs with the vagi intact and during complete vagal blockade produced by cooling exteriorized cervical vagal loops (VC). Breath by breath variations in both respiratory timing (assessed from the airflow signal) and the drive to the respiratory muscles (as assessed from the rate of inspiratory airflow (VI/TI) and occlusive pressure (P100) were examined. The degree of variability in the parameters characterizing breathing was evaluated from frequency distribution histograms and by calculation of the standard deviation. VC increased the mean values of VT, TI, TE, TI/TTOT, and decreased VT/TI and occlusion pressure, but had no consistent effect on the mean value of VE. The variability of VE, PACO2, VT, TI, TE, TI/TTOT was greater during VC in 4 of the 5 dogs. The increased variability of VE and PACO2 during VC appeared to be due to a poorer correlation between TI and TE. The present study suggests that vagal mechanoreceptors, presumably pulmonary stretch receptors, minimize breath by breath fluctuations in both the level and pattern of ventilation by controlling respiratory timing. An explanation, based on the model of inspiratory off-switching proposed by Beadley et al. (1975) is invoked.
本研究检测了5只清醒的气管切开犬在迷走神经完整时以及通过冷却外置的颈迷走神经袢（VC）产生完全迷走神经阻滞期间的呼吸变异性。研究考察了呼吸时间（根据气流信号评估）和呼吸肌驱动力（根据吸气气流速率（VI/TI）和闭塞压（P100）评估）的逐次呼吸变化。通过频率分布直方图和计算标准差来评估表征呼吸的参数的变异性程度。VC增加了VT、TI、TE、TI/TTOT的平均值，降低了VT/TI和闭塞压，但对VE的平均值没有一致的影响。5只犬中有4只在VC期间VE、PACO2、VT、TI、TE、TI/TTOT的变异性更大。VC期间VE和PACO2变异性增加似乎是由于TI和TE之间的相关性较差。本研究表明，迷走神经机械感受器，可能是肺牵张感受器，通过控制呼吸时间来最小化通气水平和模式的逐次呼吸波动。基于Beadley等人（1975年）提出的吸气切断模型进行了解释。
