Zubieta-Calleja G R, Zubieta-Castillo G, Paulev P-E, Zubieta-Calleja L
High Altitude Pathology Institute (IPPA), La Paz, Bolivia.
J Physiol Pharmacol. 2005 Sep;56 Suppl 4:251-6.
Pulse oximetry during breath-holding (BH) in normal residents at high altitude (3510 m) shows a typical graph pattern. Following a deep inspiration to total lung capacity (TLC) and subsequent breath-holding, a fall in oxyhemoglobin saturation (SaO(2) is observed after 16 s. The down-pointed peak in SaO(2) corresponds to the blood circulation time from the alveoli to the finger where the pulse oximeter probe is placed. This simple maneuver corroborates the measurement of circulation time by other methods. This phenomenon is even observed when the subject breathes 88% oxygen (PIO(2) = 403 mmHg for a barometric pressure of 495 mmHg). BH time is, as expected, prolonged under these circumstances. Thus the time delay of blood circulation from pulmonary alveoli to a finger is measured non-invasively. In the present study we used this method to compare the circulation time in 20 healthy male high altitude residents (Group N with a mean hematocrit of 50%) and 17 chronic mountain sickness patients (Group CMS with a mean hematocrit of 69%). In the two study groups, the mean circulation time amounted to 15.94 +/-2.57 s (SD) and to 15.66 +/-2.74 s, respectively. The minimal difference was not significant. We conclude that the CMS patients adapted their oxygen transport rate to the rise in hematocrit and blood viscosity.
对海拔3510米的正常居民进行屏气（BH）期间的脉搏血氧饱和度测定显示出典型的图形模式。在深吸气至肺总量（TLC）并随后屏气后，16秒后观察到氧合血红蛋白饱和度（SaO₂）下降。SaO₂的向下尖峰对应于从肺泡到放置脉搏血氧仪探头的手指的血液循环时间。这种简单的操作证实了通过其他方法对循环时间的测量。即使受试者吸入88%的氧气（在气压为495 mmHg时，PIO₂ = 403 mmHg），也能观察到这种现象。在这些情况下，屏气时间如预期的那样延长。因此，从肺泡到手指的血液循环时间延迟是通过无创方式测量的。在本研究中，我们使用这种方法比较了20名健康男性高原居民（N组，平均血细胞比容为50%）和17名慢性高山病患者（CMS组，平均血细胞比容为69%）的循环时间。在两个研究组中，平均循环时间分别为15.94±2.57秒（标准差）和15.66±2.74秒。最小差异不显著。我们得出结论，CMS患者使他们的氧运输速率适应血细胞比容和血液粘度的升高。
