The Effects of Hyper and Hypocapnia on Phonatory Laryngeal Resistance

描述（由申请人提供）：喉部具有挑战性的双重作用，同时调节呼吸，维持血液和气体的平衡，并产生声音进行交流。当需要喉部改变上呼吸道阻力以满足呼吸需求时，就会出现特殊的挑战，这种方式与发声的要求相冲突。这一挑战尤其适用于估计有25%的美国人，他们经历过呼吸异常，也使用喉部进行口头交流[1-16]。不幸的是，绝大多数呼吸生理学研究未能认识到喉部功能在发声中的作用，就像大多数发声生理学研究未能考虑到下气道对血气交换的作用一样。事实上，喉部具有独特的作用，通过调节气体进出肺部的流动来维持血气稳态，并在发声交流中建立声带振动所需的阻力。对这些功能之间的相互关系知之甚少，特别是在影响大部分人口的呼吸异常情况下。当前建议的主要目的是通过评估不同浓度的动脉二氧化碳对发声过程中喉功能的影响来解决这一差距。第二个目标是评估反功能，即在发音和休息期间喉部调整对动脉二氧化碳水平的影响。拟议的工作利用跨学科的方法来解决单个受试者实验中的两个具体目标：（SA1）与对照条件相比，评估(a)诱导低碳酸血症（低动脉二氧化碳）和(b)诱导高碳酸血症（高动脉二氧化碳）状态下发音喉部阻力的自发波动；（SA2）研究喉阻力调节对呼吸稳态的相互作用。最重要的假设是，在呼吸需求和发音需求冲突的情况下，呼吸需求将占上风。具体假设有：（SA1[a]和[b]）：低碳酸血症时喉部发声阻力增加，高碳酸血症时喉部发声阻力减少，有利于呼吸稳态的恢复；（SA2）：发声喉部阻力的大小反过来会调节相对的内稳态状态。这方面的数据将为呼吸功能和喉部功能在呼吸异常情况下如何相互作用发声提供重要证据。本基础科学研究的结果将为未来的临床研究提供一个平台，以探索呼吸系统疾病的假说

DESCRIPTION (provided by applicant): The larynx has a challenging dual role in the simultaneous regulation of breathing for blood-gas homeostasis and voice production for communication. Particular challenges arise when the larynx is required to alter upper airway resistance to meet respiratory demands in a way that conflicts with requirements for voice production. This challenge is particularly for relevant the estimated 25% of the US population who experience respiratory abnormalities and also use the larynx for oral communication [1-16] Unfortunately, the vast majority of studies in respiratory physiology fail to appreciate the overla of laryngeal function in voice production, just as most studies in phonatory physiology fail to consider the lower airway's responsibility for blood-gas exchange. In fact, the larynx has the unique role of sustaining blood-gas homeostasis via regulation of the flow of gases into and out of the lungs as well as establishing resistance required for vocal fold vibration in voiced communication. Little if anything is known about reciprocal relations between these functions, particularly under conditions of respiratory abnormality that affect large sectors of the population. The primary objective of the current proposal is to address this gap by assessing the effects of varying concentrations of arterial carbon dioxide on laryngeal function during phonation. The secondary objective is to assess the inverse function, and that is the effects of laryngeal adjustments during phonation and rest on arterial carbon dioxide levels. The proposed work utilizes an interdisciplinary approach to address two specific aims in a single within-subjects experiment: (SA1) assess spontaneous fluctuations in phonatory laryngeal resistance during states of (a) induced hypocapnia (low arterial carbon dioxide) and (b) induced hypercapnia (high arterial carbon dioxide), in comparison to a control condition and (SA2) investigate reciprocal effects of laryngeal resistance modulations on respiratory homeostasis. The overarching hypothesis is that under conditions in which respiratory and phonatory demands conflict, respiratory requirements will prevail. Specific hypotheses are: (SA1[a] and [b]): phonatory laryngeal resistance will increase during hypocapnia and decrease during hypercapnia, favoring a return towards respiratory homeostasis; (SA2): amount of phonatory laryngeal resistance will in turn modulate relative homeostatic condition. Data to this effect would provide critical evidence on how respiratory and laryngeal functions may interact in phonation under conditions of respiratory abnormality. Results from this basic science study will provide a platform for future clinical research, which will explore the hypothesis that respiratory induced changes in laryngeal function may increase the risk of phonatory malfunction, will identify bio-behavioral markers for at-risk individuals, and will develop targeted evaluation and treatment protocols for them. PUBLIC HEALTH RELEVANCE: The proposed research will measure the effects of hypercapnia and hypocapnia on laryngeal airway resistance during phonation, and in turn the effects of laryngeal airway resistance changes on resulting blood gas levels. Results from the present study will guide future clinical research investigating the potential pathogenic influence of blood gas changes in affected individuals, potentially putting them at risk for laryngeal malfunction and pathology. Future research will also aim to identify bio-behavior markers for individuals at risk for respiratory-induced laryngeal pathology, and to establish targeted evaluation and treatment of at-risk individuals.