Manipulation of central blood volume and implications for respiratory control function

作者：Miyamoto Tadayoshi^*; Bailey Damian Miles; Nakahara Hidehiro; Ueda Shinya; Inagaki Masashi; Ogoh Shigehiko

来源：American Journal of Physiology - Heart and Circulatory Physiology, 2014, 306(12): H1669-H1678.

DOI：10.1152/ajpheart.00987.2013

• system analysis
• respiratory control
• central blood volume
• head-out water immersion
• lower body negative pressure

The respiratory operating point (ventilatory or arterial PCO2 response) is determined by the intersection point between the controller and plant subsystem elements within the respiratory control system. However, to what extent changes in central blood volume (CBV) influence these two elements and the corresponding implications for the respiratory operating point remain unclear. To examine this, 17 apparently healthy male participants were exposed to water immersion (WI) or lower body negative pressure (LBNP) challenges to manipulate CBV and determine the corresponding changes. The respiratory controller was characterized by determining the linear relationship between end-tidal PCO2 (PETCO2) and minute ventilation ((V) over dot(E)) [(V) over dot(E) = S x (PETCO2 - B)], whereas the plant was determined by the hyperbolic relationship between (V) over dot(E) and PETCO2 ( PETCO2 = A/(V) over dot(E) + C). Changes in (V) over dot(E) at the operating point were not observed under either WI or LBNP conditions despite altered PETCO2 (P < 0.01), indicating a moving respiratory operating point. An increase (WI) and a decrease (LBNP) in CBV were shown to reset the controller element (PETCO2 intercept B) rightward and leftward, respectively (P < 0.05), without any change in S, whereas the plant curve remained unaltered at the operating point. Collectively, these findings indicate that modification of the controller element rather than the plant element is the major factor that contributes toward an alteration of the respiratory operating point during CBV shifts.

• 出版日期2014-6-15