CARDIOVASCULAR DETERMINANTS OF GAS EXCHANGE DYNAMICS

这项建议的重点是心血管因素， 负责呼吸气体交换（氧气）的动态变化 吸收和二氧化碳排放）， 代谢率增加。 我们计划确定 负责正常的气体交换和心率反应， 运动，这些反应的幅度和范围，以及 由肺循环异常引起的反应。 很好地理解，在稳定状态下，氧的测量 肺中的摄取（VO2）反映氧消耗水平，或 代谢率，在细胞水平上。 很多日常生活都不稳定 然而，国家，但一系列不同的和不同的活动水平， 不同的能源需求。 在过渡后的非稳态中 从一个活动水平到另一个，心血管和呼吸系统 系统必须适当调整，以满足变化的代谢 组织的要求。 因此，对非稳态的分析可以 提供有关心脏和呼吸功能的信息 系统及其控制机制。 这种分析的基础是 Fick关系，即VO2等于 肺血流量和动静脉氧含量的差异， 肺循环 VO2的动态变化同样 取决于这些因素的变化率、模式和幅度。 因为VO2动力学的直接决定因素是 肺循环，这种分析具有特别的潜力， 提供有关功能状态的重要信息， 肺血管 拟议的工作是重要的，因为 获得关于正常心血管功能的见解， 因为它提供了一种独特的、非侵入性的手段， 评估肺血管疾病患者。 原则 研究者接受过呼吸医学和运动生理学培训 并对运动后的气体交换反应进行了初步研究 紫绀型先天性心脏病患者。 拟议工作 利用赞助商在运动和呼吸方面的广泛专业知识， 生理学，以及实验室独特的技术能力， 肺泡气体交换的逐呼吸测定。

The focus of this proposal is on the cardiovascular factors which are responsible for the dynamic changes in respiratory gas exchange (oxygen uptake and carbon dioxide output) occurring in response to a sudden increase in metabolic rate. We plan to determine the mechanisms responsible for the normal gas exchange and heart rate responses induced by exercise, the magnitude and range of these responses, and the alterations in responses brought about by abnormalities in the pulmonary circulation. It is well appreciated that in the steady state, measurements of oxygen uptake in the lungs (VO2) reflect the level of oxygen consumption, or metabolic rate, at the cellular level. Much of daily living is not steady state, however, but a series of different and varied activity levels with different energy requirements. In the unsteady state following transition from one activity level to another, the cardiovascular and respiratory systems must adjust appropriately to satisfy the changed metabolic requirements of the tissues. Analysis of the unsteady state can therefore provide information about the function of the cardiac and respiratory systems and their control mechanisms. The basis for such analysis is the Fick relationship which states that VO2 is equal to the product of pulmonary blood flow and the arteriovenous difference in O2 content across the pulmonary circulation. The dynamic changes in VO2 are likewise dependent on the rate, pattern, and magnitude of change of these factors. Because the immediate determinants of VO2 kinetics are changes occurring in the pulmonary circulation, this analysis has particular potential for providing important information regarding the functional state of the pulmonary vasculature. The proposed work is significant both because of the insights to be gained regarding normal cardiovascular function and because of the potential of providing a unique, noninvasive means of evaluating patients with pulmonary vascular disease. The principle investigator has training in respiratory medicine and exercise physiology and has done preliminary studies of the gas exchange response to exercise in patients with cyanotic congenital heart disease. The proposed work makes use of the sponsor's extensive expertise in exercise and respiratory physiology, and the laboratory's unique technical capabilities for breath-by-breath determination of alveolar gas exchange.