Davis G M, Bureau M A, Gaultier C
McGill University, Montreal Children's Hospital Research Foundation, Quebec, Canada.
Respir Physiol. 1988 Mar;71(3):307-14. doi: 10.1016/0034-5687(88)90024-2.
The diphasic ventilatory response to steady-state hypoxia has been reported in anesthetised, intubated newborn piglets. We questioned whether this diphasic response persisted in the awake, spontaneously breathing piglet. Nine piglets, at one day of age, breathing spontaneously through a fitted mask and pneumotachograph were examined, monitoring the minute ventilation. (VE) tidal volume (VT), respiratory frequency (f), mean inspiratory flow (VT/TI), inspiratory time (TI). The piglets were studied in room air, followed by a step change to an FIO2 of 0.12, and a subsequent step-change to an FIO2 of 0.08. For each step-change in the FIO2 there was a decline in VT during hypoxia, but the VE increased significantly throughout the hypoxia through a progressive increase in both f and VT/VI. Thus, the awake newborn piglets were able to sustain the increase in VE during hypoxia. These results differ from previous observations of the diphasic VE response to hypoxia in lightly anesthetised piglets suggesting that the ventilatory response to steady state hypoxia is dependent upon experimental conditions. Further, the finding of a sustained ventilatory response in awake piglets breathing through an intact upper airway differs from previous studies in lambs and kittens suggesting a difference in the level of maturity at birth between the species.
在麻醉、插管的新生仔猪中，已有关于对稳态低氧的双相通气反应的报道。我们质疑这种双相反应在清醒、自主呼吸的仔猪中是否持续存在。对9只1日龄的仔猪进行了检查，它们通过适配面罩和呼吸流速仪自主呼吸，监测分钟通气量（VE）、潮气量（VT）、呼吸频率（f）、平均吸气流量（VT/TI）、吸气时间（TI）。仔猪先在室内空气中进行研究，然后将吸入氧分数（FIO2）逐步改变为0.12，随后再逐步改变为0.08。对于FIO2的每一次逐步改变，低氧期间VT均下降，但在整个低氧过程中，VE通过f和VT/VI的逐渐增加而显著增加。因此，清醒的新生仔猪能够在低氧期间维持VE的增加。这些结果与之前对轻度麻醉仔猪低氧双相VE反应的观察结果不同，表明对稳态低氧的通气反应取决于实验条件。此外，通过完整上呼吸道自主呼吸的清醒仔猪中持续通气反应的发现，与之前对羔羊和小猫的研究不同，这表明不同物种出生时的成熟水平存在差异。
