Hypoxia augments apnea-induced increase in hemoglobin concentration and hematocrit
Hypoxia augments apnea-induced increase in hemoglobin concentration and hematocrit
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DOI：
10.1007/s00421-008-0873-9
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发表时间：
2009-01-01
影响因子：
3
通讯作者：
Schagatay, Erika
中科院分区：
文献类型：
--
作者：
Richardson, Matt X.;de Bruijn, Robert;Schagatay, Erika
由于脾脏收缩，血红蛋白浓度（Hb）和红细胞压积（Hct）增加，会增加呼吸暂停期间的血气储存能力，但触发这种反应的机制尚未阐明。我们重点关注缺氧在触发这些Hb和Hct升高中的作用。水平休息20分钟后，10名志愿者进行3次最大呼吸暂停，间隔2分钟，每次深吸气。使用相同的呼吸暂停持续时间重复该系列，但在每次呼吸暂停前进行100%氧（O（2））呼吸和O（2）吸入1分钟后。呼吸暂停1、2和3的平均呼吸暂停持续时间分别为150、171和214 s。相对于呼吸暂停前的数值，空气试验后平均呼吸暂停后动脉血氧饱和度最低值为84.7%，氧饱和度试验后为98%。在空气试验中，Hb和Hct的升高更为明显：在第一次空气呼吸暂停后，平均Hb增加了1.5%（P <0.01），但在第一次O（2）呼吸暂停后没有发现明显的增加。第3次呼吸暂停后，空气组Hb增加3.0%（P <0.01），O2组Hb增加2.0%（P <0.01）。第一次呼吸暂停后Hct增加了1.9%（P <0.01），第三次呼吸暂停后增加了3.0%（P <0.01），但在O（2）试验中Hct无显著变化。在两项试验中，Hb和Hct在呼吸暂停后10分钟处于呼吸暂停前水平。在两项试验中，呼吸暂停期间的潜水心动过缓相同。我们的结论是，缺氧有助于脾收缩呼吸暂停，可能通过化学传感器相关的交感神经输出。然而，即使在没有缺氧的情况下，也有其他因素参与触发脾脏收缩。
Increased hemoglobin concentration (Hb) and hematocrit (Hct), attributable to spleen contraction, raise blood gas storage capacity during apnea, but the mechanisms that trigger this response have not been clarified. We focused on the role of hypoxia in triggering these Hb and Hct elevations. After horizontal rest for 20 min, 10 volunteers performed 3 maximal apneas spaced by 2 min, each preceded by a deep inspiration of air. The series was repeated using the same apneic durations but after 1 min of 100% oxygen (O(2)) breathing and O(2) inspiration prior to each apnea. Mean apneic durations were 150, 171, and 214 s for apneas 1, 2, and 3, respectively. Relative to pre-apnea values, the mean post-apneic arterial O(2) saturation nadir was 84.7% after the air trial and 98% after the O(2) trial. A more pronounced elevation of both Hb and Hct occurred during the air trial: after apnea 1 with air, mean Hb had increased by 1.5% (P < 0.01), but no clear increase was found after the first apnea with O(2). After the third apnea with air Hb had increased by 3.0% (P < 0.01), and with O(2) by 2.0% (P < 0.01). After the first apnea with air Hct had increased by 1.9% (P < 0.01) and after 3 apneas by 3.0% (P < 0.01), but Hct did not change significantly in the O(2) trial. In both trials, Hb and Hct were at pre-apneic levels 10 min after apneas. Diving bradycardia during apnea was the same in both trials. We conclude that hypoxia contributes to spleen contraction during apnea, likely through chemosensor-related sympathetic output. There are, however other factors involved that trigger spleen contraction even in the absence of hypoxia.