PURPOSE: Based upon the our brand new theory of “A Dynamic Model Integrates Multi-systems for Breathing Control”, lung breath generated signals of O2, CO2 and [H+] oscillations to trigger the next breath via fast sensors (carotid and aorta) and the slow central medullary censor control the “gain” of breath with longer time delay in collaboration with an integrative respiratory center. We hypotheses that left heart function effecting on the breath via the damping breathing control signals (magnitudes of arterial O2 and CO2 oscillation from alveoli) is one mechanism of heart/lung interconnection.
METHODS: The PO2, PCO2 and flow were measured at mouth using 200 Hz database; then based on the dead space volume and Functional Residual Capacity to calculate the alveolar partial pressure oscillations of O2 and CO2.( Yamamoto et al. JAP1960; Beaver, L. et al. JAP 1981) Left heart functional parameters, i.e. stoke volume (SV), left ventricle end-diastolic volume (LVEDV) and ejection fraction (EF) in normal and CHF, were used to calculate the magnitudes of arterial PO2 and PCO2 oscillation.
RESULTS: The calculated magnitudes of the oscillation PO2 and PCO2 in alveolar were ~7mmHg. Using normal SV, LVEDV and EF were 80ml/beat, 120ml and 67%; and 5:1 for ratio of heart rate to breathe, the calculated magnitudes were ~5mmHg in arterial blood. But using CHF’s SV (40ml/beat), LVEDV(200ml) and EF (20%), the calculated magnitudes were decreased to <2mmHg in arterial blood. The poorer heart function the weaker signal (magnitude).
CONCLUSIONS: Breathing lung generated O2 and CO2 (H+) oscillations magnitude is damped by left ventricle. The poor heart function has a significant decrease in arterial blood from the normal alveoli. It may be one of the mechanisms of Cheney-Stokes breathing in CHF.
CLINICAL IMPLICATIONS: Circulation and respiration are coupling regulated. They affect each other. Heart function affects on the damping range of breathing control signal from alveoli to arterial side may explain the heart-lung interconnection in the clinical medicine, i.e. “why heart failure patients have manifestation of abnormal breathing”.
DISCLOSURE: The following authors have nothing to disclose: Xing-Guo Sun, William Stringer
No Product/Research Disclosure Information