Rescaled range analysis of resting respiration.
Fluctuations in resting depth of breathing (tidal volume) at constant breathing rate in the anesthetized adult rat exhibit fractal properties when analyzed by a rescaled range method characterized by a mean (+/-SD) exponent H=0.83+/-0.02 and 0.92+/-0.03 with and without sighs, respectively, for up to 400 breaths. Values of H determined from shuffled tidal volumes and simulated tidal volumes taken randomly from a Gaussian distribution of mean and variance approximating that of the actual data are consistent with the expected value of H=0.5 for an independent random process with finite variances. An empirical description is proposed to predict the change in H with length of time record.
Hoop
Bernard
B
Medical Services (Pulmonary and Critical Care Unit), Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114Department of Ophthalmology, College of Physicians & Surgeons, Columbia University, New York, New York 10032.
Kazemi
Homayoun
H
Liebovitch
Larry
L