Cao K Y, Zwillich C W, Berthon-Jones M, Sullivan C E
David Read Laboratory, Department of Medicine, University of Sydney, New South Wales, Australia.
J Appl Physiol (1985). 1992 Nov;73(5):2083-8. doi: 10.1152/jappl.1992.73.5.2083.
To determine if a long-lasting increase in normoxic ventilatory drive is induced in conscious animals by repetitive hypoxia, we examined the normoxic [arterial O2 saturation (SaO2) > 93%] ventilatory response following successive episodes of 2-min eucapnic hypoxic challenges (SaO2 = 80%) in awake tracheotomized dogs. End-tidal CO2 was maintained at the resting level during and after repetitive hypoxia. The experimental protocol was performed twice in each of five dogs on separate days. To determine if changes in normoxic ventilation occurred between episodes of repetitive hypoxia, data were compared from six periods (epochs) for all experiments. The mean minute ventilation (VI) during three normoxic periods between episodes of intermittent hypoxia was 135, 154, and 169% of control (P < 0.05). VI during a 30-min recovery period was still higher at 183 and 172% of control (P < 0.05). Normoxic VI between hypoxic and recovery periods was significantly higher than the corresponding values in sham experiments. Our results indicate that a long-lasting increase in normoxic ventilation can be evoked in an awake unanesthetized dog by a short exposure to repetitive hypoxia.
为了确定反复低氧是否会在清醒动物中诱发常氧通气驱动的长期增加，我们在清醒的气管切开犬中，检查了在连续进行2分钟等碳酸血症性低氧刺激（动脉血氧饱和度（SaO2）=80%）后常氧（动脉血氧饱和度（SaO2）>93%）通气反应。在反复低氧期间及之后，呼气末二氧化碳维持在静息水平。实验方案在5只犬中的每只犬身上分别进行了两次。为了确定反复低氧发作之间常氧通气是否发生变化，对所有实验的六个时间段（时期）的数据进行了比较。间歇性低氧发作之间三个常氧期的平均分钟通气量（VI）分别为对照值的135%、154%和169%（P<0.05）。在30分钟恢复期的VI仍较高，为对照值的183%和172%（P<0.05）。低氧期和恢复期之间的常氧VI显著高于假手术实验中的相应值。我们的结果表明，短时间暴露于反复低氧可在清醒未麻醉的犬中诱发常氧通气的长期增加。
