Vol. 278, Issue 6, R1446-R1452, June 2000
Correlation structure of end-expiratory lung volume in
anesthetized rats with intact upper airway
Xiaobin
Zhang and
Eugene N.
Bruce
Center for Biomedical Engineering, University of Kentucky,
Lexington, Kentucky 40506
The correlation structure of
breath-to-breath fluctuations of end-expiratory lung volume (EEV) was
studied in anesthetized rats with intact airways subjected to positive
and negative transrespiratory pressure (i.e., PTRP and NTRP,
correspondingly). The Hurst exponent, H, was estimated from EEV
fluctuations using modified dispersional analysis. We
found that H for EEV was 0.5362 ± 0.0763 and 0.6403 ± 0.0561 with
PTRP and NTRP, respectively (mean ± SD). Both H were significantly
different from those obtained after random shuffling of the original
time series. Also, H with NTRP was significantly greater than that with
PTRP (P = 0.029). We conclude that in rats breathing through
the upper airway, a positive long-term correlation is present in EEV
that is different between PTRP and NTRP.
intact airways; dispersional analysis; Hurst exponent
