Correlation properties of tidal volume and end-tidal O2 and CO2 concentrations in healthy infants.
We investigated whether breath-to-breath fluctuations in tidal volume (VT) and end-tidal O2 and CO2 exhibit long-range correlations and whether parameters describing the correlations can be used as noninvasive descriptors of control of breathing. We measured VT and end-tidal O2 and CO2 over n = 352 +/- 104 breaths in 26 term, healthy, unsedated infants (mean age +/- SD: 36 +/- 6 days) and calculated the detrended fluctuation function [F(n)]. The F(n) of the breath-to-breath time series of VT, O2, and CO2 revealed a linear increase with a breath number on log-log plots with a slope that was significantly different from 0.5 (random) and thus consistent with scale-invariant behavior. Long-range correlations were stronger for O2 than for VT and CO2. The F(n) of many individual signals exhibited a crossover behavior indicating that control mechanisms regulating fluctuations of VT, O2, and CO2 may be different on different time scales. Thus breathing has a memory up to at least 400 breaths that can be characterized by the simple indicator alpha.
Cernelc
Mateja
M
Department of Pediatrics, University Hospital of Berne, CH-3010 Switzerland.
Suki
Béla
B
Reinmann
Benjamin
B
Hall
Graham L
GL
Frey
Urs
U
D002245:Carbon Dioxide / Q000032:analysis / Q000502:physiology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008954:Models, Biological; D010100:Oxygen / Q000032:analysis / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012016:Reference Values; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D013990:Tidal Volume / Q000502:physiology*; D013997:Time Factors
D002245:Carbon Dioxide; D010100:Oxygen