These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Effect of hyperoxic hypercapnia on variational activity of breathing.
    Author: Jubran A, Grant BJ, Tobin MJ.
    Journal: Am J Respir Crit Care Med; 1997 Oct; 156(4 Pt 1):1129-39. PubMed ID: 9351612.
    Abstract:
    Dysrhythmias of breathing occur in several clinical disorders, but their mechanistic basis is obscure. To understand their pathophysiology, factors responsible for the variability of breathing need to be defined. We studied the effect of hyperoxic hypercapnia (CO2) on the variational activity of breathing in 14 volunteers before and after delivering CO2 nonobstrusively via a plastic hood. Compared with air, CO2 increased the gross variability of minute ventilation (VI) and tidal volume (VT), and decreased that of inspiratory time (TI) and expiratory time (TE) (all p < 0.03). CO2 increased the autocorrelation coefficient at a lag of one breath for VI (p < 0.05), the number of consecutive breath lags having significant autocorrelation coefficients for VI and VT (both p < 0.01), and the cycle time of oscillations in VI (p = 0.03) and VT (p = 0.04). Uncorrelated random behavior constituted > or = 80% of the variance of each breath component, correlated behavior represented 9 to 20%, and oscillatory behavior represented < 1% during both air and CO2. CO2 increased the correlated behavior of volume components, which was accompanied by development of low-frequency oscillations with a cycle time consistent with central chemoreceptor activation.
    [Abstract] [Full Text] [Related] [New Search]