Arterial oxygen desaturation kinetics during apnea
Arterial oxygen desaturation kinetics during apnea
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DOI：
10.1249/01.mss.0000176305.51360.7e
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发表时间：
2005-11-01
期刊：
影响因子：
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通讯作者：
Ridgway, L
中科院分区：
文献类型：
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作者：
Stewart, IB;Bulmer, AC;Ridgway, L
目的：量化自由潜水员呼吸暂停期间的动脉血氧减饱和率。方法：10名自由潜水员和10名对照组在10℃的水中进行5次最大面部浸泡呼吸暂停，间隔2分钟恢复。连续记录心电图、血压和脉搏血氧饱和度。每隔30天用小腿体积描记仪测量S的外周血流量，并在安静时、呼吸暂停后1、3、5时采集静脉血，分析血液中红细胞压积(Hct)、乳酸和血红蛋白(Hb)浓度。结果：呼吸暂停持续时间随潜水次数的增加而延长，自由潜水员最大呼吸暂停时间明显延长(训练组2 46+/-44名S，非训练组12 9+/-39名S，P<；0.001)。与对照组相比，自由潜水员的心率(训练前为-27.2+/-9.5次/分，未训练为-19.7+/-9.3次/分，P=0.001)和平均动脉压(训练后为48+/-20.7 mm Hg，未经训练为37+/-10.0 mm Hg，P=0.002)有显著变化，但在外周血流量、红细胞压积、血乳酸和Hb方面无显著差异。Sao(2)曲线的最大斜率在训练组和非训练组(训练组-0.16+/-0.05%中心点S(-1)，非训练组-0.15+/-0.06%中心点S(-1)，P=0.26)之间无显著差异，但双斜率连续模型得到的Delta SaO(2)/Delta t表明，自由潜水员Delta SaO(2)/Delta t的变化85%可以用呼吸暂停诱发的心动过缓、呼吸暂停前的肺活量、和Hb浓度。结论：乙状结肠功能在氧减饱和率方面没有提供可量化的差异。然而，双斜率连续法表明，拥有较大氧气储备并产生最大心动过缓的自由潜水员能够将Delta SaO(2)/Delta t减慢至最不显著反应的两到三倍。
Purpose: To quantify the rate of arterial oxygen desaturation during apnea in freedivers. Methods: Ten freedivers and ten controls undertook five maximal face immersion apneas in 10 degrees C water separated by 2 min of recovery. Electrocardiogram (ECG), blood pressure, and pulse oximetry were recorded continuously. Peripheral blood flow was measured by calf plethysmography every 30 s, and venous blood samples were collected at rest and after apineas 1, 3, and 5. The blood was analyzed for hematocrit (Hct), lactate, and hemoglobin (Hb) concentration. The arterial oxygen saturation (SaO(2)) data were curve fitted with both a sigmoid and two-slope continuous function.Results: Apnea duration increased with successive attempts, with freedivers achieving significantly longer maximal apneas (trained 246 +/- 44 s, untrained 129 +/- 39 s, P < 0.001). Compared with controls, freedivers displayed a significant change from baseline in heart rate (trained -27.2 +/- 9.5 bpm, untrained -19.7 +/- 9.3 bpm, P < 0.001) and mean arterial pressure (MAP) (trained 48 +/- 20.7 mm Hg, untrained 37 +/- 10.0 mm Hg, P = 0.002), but no difference existed in peripheral blood flow, Hct, lactate, or Hb. The maximal slope of the SaO(2) sigmoid curve was not significantly different between the groups (trained -0.16 +/- 0.05%center dot s(-1), untrained -0.15 +/- 0.06%center dot s(-1), P = 0.26), but the Delta SaO(2)/Delta t obtained from the two-slope continuous model indicated that 85% of the variance in the freedivers Delta SaO(2)/Delta t could be explained by the apnea-induced bradycardia, preapnea vital capacity, and Hb concentration.Conclusions: The sigmoidal function provided no quantifiable difference in the rate of oxygen desaturation. The two-slope continuous method, however, indicated that freedivers who had larger oxygen stores and produced the largest bradycardia were able to slow the Delta SaO(2)/Delta t to two to three times that of the least marked response.