Orr J A, Fraser D B, Shirer H W, Wagerle L C, DeSoignie R C
Can J Physiol Pharmacol. 1984 Jul;62(7):793-7. doi: 10.1139/y84-130.
Carbon dioxide concentrations were increased during expiration in the upper one-half of the trachea, pharynx, and nasal sinuses to determine if elevation of upper airway CO2 would alter breathing or arterial blood gases in the awake pony. Carbon dioxide (100%) was injected into the midcervical trachea via a chronically implanted transcutaneous cannula during the first part of the animal's expiration. This maneuver elevated upper airway expiratory CO2 concentrations but prevented any exogenous CO2 from entering the lung and being absorbed into the arterial blood. Twelve experiments were performed on six ponies in which upper airway CO2 was elevated 2, 4, and 6% above the normal expired CO2 concentrations. Tidal volume increased in a dose dependent manner during upper airway CO2 exposure, but total ventilation was unchanged from base-line measurements made while the animal breathed room air. Arterial Po2 also increased during upper airway CO2 administration, reaching a mean value 6 Torr (1 Torr = 133.322 Pa) greater than the base-line values at the +6% CO2 exposure. We conclude that upper airway CO2 exposure alters breathing pattern slightly (increases tidal volume) and increases arterial PO2 in the awake pony.
在气管上半段、咽部和鼻窦呼气过程中增加二氧化碳浓度，以确定上呼吸道二氧化碳升高是否会改变清醒小马的呼吸或动脉血气。在动物呼气的第一阶段，通过长期植入的经皮套管将二氧化碳（100%）注入颈中气管。这一操作提高了上呼吸道呼气二氧化碳浓度，但阻止了任何外源性二氧化碳进入肺部并被吸收到动脉血中。对6匹小马进行了12次实验，其中上呼吸道二氧化碳浓度比正常呼出二氧化碳浓度高出2%、4%和6%。在上呼吸道二氧化碳暴露期间，潮气量以剂量依赖的方式增加，但总通气量与动物呼吸室内空气时的基线测量值相比没有变化。在上呼吸道给予二氧化碳期间，动脉血氧分压也升高，在二氧化碳暴露增加6%时，平均值比基线值高6托（1托 = 133.322帕）。我们得出结论，上呼吸道二氧化碳暴露会轻微改变清醒小马的呼吸模式（增加潮气量）并提高动脉血氧分压。
