McNamara S G, Issa F G, Szeto E, Sullivan C E
Respir Physiol. 1986 Sep;65(3):315-29. doi: 10.1016/0034-5687(86)90016-2.
We examined the influence of changes in upper airway pressure on the breathing pattern in 5 unanesthetized awake dogs. The dogs breathed through an endotracheal tube or through a comfortably fitting fiberglass snout mask. With matched resistances and volume of the dead space, the inspiratory duration, tidal volume, and minute ventilation were higher during nasal breathing compared to tracheal breathing. Nasal and tracheal occlusion produced prolongation of inspiration in the first occluded breathing attempt, but the prolongation was more marked in nasal occlusion tests. Augmentation of genioglossus muscle activity occurred on the first occluded breath in nasal but not tracheal occlusion. In another series of experiments, negative pressure was applied to the isolated upper airway while the dog breathed through a tracheostomy tube. Negative pressure caused a prolongation of inspiratory duration which was proportional to the level of the applied pressure. However, the prolongation of inspiratory duration was significantly more marked when application of negative pressure was timed simultaneously with tracheal occlusion. Our results demonstrate that the upper airway has a powerful effect on the control of breathing, which becomes more evident during tracheal occlusion.
我们研究了上呼吸道压力变化对5只未麻醉清醒犬呼吸模式的影响。这些犬通过气管插管或佩戴舒适的玻璃纤维口鼻面罩进行呼吸。在死腔阻力和容积匹配的情况下，与经气管呼吸相比，经鼻呼吸时吸气持续时间、潮气量和分钟通气量更高。鼻阻塞和气管阻塞在首次阻塞呼吸尝试时均会导致吸气延长，但在鼻阻塞试验中这种延长更为明显。在鼻阻塞而非气管阻塞的首次阻塞呼吸时，颏舌肌活动增强。在另一系列实验中，当犬通过气管造口管呼吸时，对分离的上呼吸道施加负压。负压导致吸气持续时间延长，且与施加的压力水平成正比。然而，当负压施加与气管阻塞同时进行时，吸气持续时间的延长明显更显著。我们的结果表明，上呼吸道对呼吸控制有强大作用，在气管阻塞时这种作用变得更加明显。
