VENTILATORY VARIABILITY INDUCED BY SPONTANEOUS VARIATIONS OF PA-CO2 IN HUMANS
VENTILATORY VARIABILITY INDUCED BY SPONTANEOUS VARIATIONS OF PA-CO2 IN HUMANS
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DOI：
10.1152/jappl.1994.76.6.2765
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发表时间：
1994-06-01
影响因子：
3.3
通讯作者：
BRUCE, EN
中科院分区：
文献类型：
--
作者：
MODARRESZADEH, M;BRUCE, EN
我们测试了这一假设，呼吸到呼吸的动脉CO2分压（Pa-CO2）的变化，在清醒的人的自主呼吸引起的自发性呼吸变异性（包括周期性振荡）的显着部分。这一假设在两个方面得到了检验。首先，使用最近开发的自适应Pa-CO2缓冲技术，我们减少了自发变异性Pa-CO2的六个清醒的正常年轻人受试者在高氧，并观察到相应的减少，他们的呼吸的呼吸变异。第二，我们预测的净化响应CO2干扰使用的化学控制通气模型，既检查高氧条件（类似于实验研究）和预测的响应正常受试者呼吸室内空气的CO2变化。在所有的实验和理论研究中，我们发现对Pa-CO2的小的随机干扰对通气有显著的影响，包括这种Pa-CO2干扰引起通气振荡波动的可能性，即使净化化学控制系统是稳定的（即，对Pa-CO2的短暂干扰不会引起持续的呼吸振荡）。在这些结果的基础上，我们提出，化学反射的解释性控制回路的稳定性取决于“回路增益”的因素和随机干扰的特点，以Pa-CO2。
We tested the hypothesis that breath-to-breath variations in arterial CO2 partial pressure (Pa-CO2) during spontaneous breathing of awake humans cause a significant portion of spontaneous ventilatory variability (including periodic oscillations). This hypothesis was tested in two ways. First, using a recently developed adaptive Pa-CO2 buffering technique we reduced the spontaneous variability in Pa-CO2 of six awake normal young human subjects during hyperoxia and observed a corresponding decrease in their breath-to-breath ventilatory variations. Second, we predicted the ventilatory responses to CO2 disturbances by using a model of chemical control of ventilation, both examining the hyperoxic condition (similar to experimental studies) and predicting the responses to CO2 variations of a normal subject breathing room air. In all experimental and theoretical studies, we found that small random disturbances to Pa-CO2 have significant effects on ventilation, including the potential for such Pa-CO2 disturbances to elicit oscillatory fluctuations in ventilation even though the ventilatory chemical control system was stable (i.e., a brief disturbance to Pa-CO2 did not elicit sustained ventilatory oscillations). On the basis of these results we propose that the stability of chemoreflex ventilatory control loops depends on both ''loop gain'' factors and the characteristics of random disturbances to Pa-CO2.