代谢、血液碱化和纯氧影响呼吸调控的人体实验研究III： 血液碱化后纯氧运动试验*

目的: 在急性血液碱化前、后空气吸入下完成症状限制性最大极限心肺运动试验(CPET)的基础上,本文探讨在血液碱化后吸入纯氧对呼吸调控的影响。方法: 正常志愿者5名在碱化血液后呼吸纯氧CPET,在静息、热身、运动及恢复期,连续测定肺通换气指标及每分钟动脉取样的血气指标,对CPET期间的呼吸气体交换和血气指标的动态变化进行分析,同时与急性碱化血液前、后空气CPET数据比较。结果: 碱化血液后吸入纯氧运动呼吸反应与急性碱化血液前、后空气CPET呼吸反应基本一致。CPET期间,各运动状态下的每分通气量均与对照组相似(P>0.05);仅静息每分通气量较血液碱化空气CPET略高(P<0.05),而其它状态和恢复2min时均相近(P>0.05)。潮气量仅峰值运动时较对照和血液碱化空气CPET略低(P<0.05);而运动过程和恢复2min时的潮气量均相近(P>0.05)。呼吸频率在各个时间与血液碱化前后CPET均无差异(P>0.05)。在碱化血液后吸入纯氧运动各个时期的PaO₂和SaO₂较碱化血液前后空气CPET时明显提高(P<0.001,P<0.05)。血红蛋白浓度虽然较急性血液碱化前后均低,但仅较血液碱化前显著降低(P<0.05),比血液碱化后差异不显著(P>0.05) ; 开始时的PaCO₂较碱化血液前后空气CPET时降低(P<0.05),无氧阈时相近(P>0.05),但到峰值及恢复2 min时明显增高(P<0.05);pH仅较对照增高(P<0.05),但与碱化血液空气试验时无差异;乳酸水平较对照略高,但仅在热身和恢复期有差异(P<0.05)。纯氧提高了两人无氧阈和三人峰值运动的功率和时间。结论: 虽然血液碱化给予纯氧, CPET呼吸反应与碱化血液前、后空气CPET呼吸反应模式相似,表明运动中呼吸反应主要取决于代谢变化,而非动脉血气平均值高低。

Human experiments of metabolism,blood alkalization and oxygen effect on control and regulation of breathing III: pure oxygen exercise test after blood alkalization

Objective: After performed symptom-limited maximum cardiopulmonary exercise testing (CPET) before and after acute alkalized blood, we repeated CPET with pure oxygen. Methods: Five volunteers, 3hr after alkalizing blood room air CPET, re-performed CPET inhaling from Douglas bag connected with pure oxygen tank. We compared with those of room air CPETs before and after alkalized blood. Results: After alkalized blood oxygen CPET had a similar response pattern as those of CPETs before and after blood alkalization. During the CPET, all breath frequency, minute ventilation and tidal volume at each stage weresimilar to those of CPETs before and after alkalized blood (P>0.05),except there was a lower peak tidal volume than those of both CPETs and a slightly higher resting minute ventilation only than CPET after alkalized blood (P>0.05). After alkalized blood, oxygen CPET, all PaO₂ and SaO₂ and most Hb were lower than those of both CPETs (P<0.05). The pHa and HCO₃^-]a were higher than those of CPET before alkalized blood (P<0.05); but were not CPET after alkalized blood (P>0.05). PaCO₂ was similar to that of CPET before alkalized blood (P>0.05), but was lower than that of CPET after alkalized blood at resting and warm-up (P<0.05); then was similar to both CPETs at anaerobic threshold (P>0.05); but was higher at peak exercise higher than those of both CPETs (P<0.01). Oxygen increased 2,3 volunteers' workload and time at AT and peak exercises. Conclusion: Respiratory response pattern to oxygen CPET after alkalized blood is similar to those of both CPETs before and after alkalized blood. The CPET response is dominantly depended upon metabolic rate, but not levels of pHa, PaCO₂ and PaO₂.