Howard L S, Robbins P A
University Laboratory of Physiology, Oxford, UK.
Respir Physiol. 1994 Nov-Dec;98(3):241-9. doi: 10.1016/0034-5687(94)90074-4.
This study examined whether the form of the acute ventilatory response to different levels of end-tidal PO2 (PETO2) could be determined from a progressive series of steps in PETO2 at constant end-tidal PCO2. Seven levels of PETO2 were employed each lasting 2 min. The steps were performed in both ascending and descending order to test whether the ventilatory responses were affected by the order of the hypoxic exposures. These exposures were carried out both with and without a prior 20 min period of isocapnic hypoxia (PETO2 = 50 mmHg). Each protocol was undertaken 6 times in each of 6 subjects. With prior exposure to hypoxia, the order in which the steps were performed affected the ventilatory response (P < 0.005, ANOVA). Without prior exposure to hypoxia, this finding did not quite reach significance (P < 0.056), unless one particular abnormal subject was excluded (P < 0.001). It is concluded that the order of the hypoxic exposures in this particular test affects the form of the hypoxic response.
本研究探讨了在呼气末二氧化碳分压（PETCO2）恒定的情况下，能否通过一系列逐步递增的呼气末氧分压（PETO2）水平来确定急性通气反应的形式。采用了七个水平的PETO2，每个水平持续2分钟。这些步骤按升序和降序进行，以测试通气反应是否受低氧暴露顺序的影响。这些暴露在有和没有预先20分钟等碳酸血症低氧（PETO2 = 50 mmHg）的情况下进行。每个方案在6名受试者中的每一名中进行6次。预先暴露于低氧时，进行步骤的顺序影响通气反应（P < 0.005，方差分析）。没有预先暴露于低氧时，这一发现不太显著（P < 0.056），除非排除一名特定的异常受试者（P < 0.001）。得出的结论是，在这个特定测试中低氧暴露的顺序会影响低氧反应的形式。
