Influence of nonlinearities on estimates of respiratory mechanics using multilinear regression analysis

Kano, S. H., Lanteri, C. J., Duncan, A. W. and Sly, P. D. (1994) Influence of nonlinearities on estimates of respiratory mechanics using multilinear regression analysis. Journal of Applied Physiology, 77 3: 1185-1197.

Author Kano, S. H.
Lanteri, C. J.
Duncan, A. W.
Sly, P. D.
Title Influence of nonlinearities on estimates of respiratory mechanics using multilinear regression analysis
Journal name Journal of Applied Physiology   Check publisher's open access policy
ISSN 8750-7587
1522-1601
Publication date 1994-09-01
Year available 1994
Sub-type Article (original research)
Open Access Status Not yet assessed
Volume 77
Issue 3
Start page 1185
End page 1197
Total pages 13
Place of publication Bethesda, MD, United States
Publisher American Physiological Society
Language eng
Abstract To investigate the influence of nonlinearities on estimates of respiratory mechanics, differing patterns of mechanical ventilation patterns were analyzed from 8 puppies and 14 children. Respiratory mechanics were calculated using multiple linear regression to fit a linear single-compartment model, a volume-dependent single-compartment model (VDSCM), and a flow-dependent single-compartment model. The ratio of the compliance of the last 20% of the dynamic volume-pressure (V-P) curve to the total compliance (C20/C) and the contribution of a volume-dependent elastance to total elastance {%E2 = E2(VT)/[(E1 + E2)VT], where E1 + E2 is total elastance, E2 is the volume-dependent component, and VT is tidal volume} were used as the indexes of overdistension. By positioning the dynamic loops on the static V-P curves, ventilation patterns were classified as overdistended or nonoverdistended. In the overdistended group, the C20/C was significantly lower (0.71 +/- 0.10 vs. 0.92 +/- 0.16; P < 0.0001) and %E2 was significantly higher (43.4 +/- 15.0 vs. 0.51 + 18.02%, P < 0.0001) than in the nonoverdistended group. The mode of ventilation (pressure controlled vs. volume controlled) and the resistive pressures that resulted in widening of the dynamic V-P loop were found to alter C20/C but not %E2. When the respiratory system was overdistended, i.e., ventilated up to the flattened portion of the V-P curve, the VDSCM gave more accurate estimates of respiratory mechanics. Furthermore, %E2 calculated from VDSCM is a useful. parameter for estimating respiratory system overdistension that is not affected by resistive pressures.
Formatted abstract
To investigate the influence of nonlinearities on estimates of respiratory mechanics, differing patterns of mechanical ventilation patterns were analyzed from 8 puppies and 14 children. Respiratory mechanics were calculated using multiple linear regression to fit a linear single- compartment model, a volume-dependent single-compartment model (VDSCM), and a flow-dependent single-compartment model. The ratio of the compliance of the last 20% of the dynamic volume-pressure (V-P) curve to the total compliance (C20/C) and the contribution of a volume-dependent elastance to total elastance {%E2 = E2(VT)/[E1 + E2)VT], where E1 + E2 is total elastance, E2 is the volume-dependent component, and VT is tidal volume} were used as the indexes of overdistension. By positioning the dynamic loops on the static V- P curves, ventilation patterns were classified as overdistended or nonoverdistended. In the overdistended group, the C20/C was significantly lower (0.71 ± 0.10 vs. 0.92 ± 0.16; P < 0.0001) and %E2 was significantly higher (43.4 ± 15.0 vs. 0.51 ± 18.02%, P < 0.0001) than in the nonoverdistended group. The mode of ventilation (pressure controlled vs. volume controlled) and the resistive pressures that resulted in widening of the dynamic V-P loop were found to alter C20/C but not %E2. When the respiratory system was overdistended, i.e., ventilated up to the flattened portion of the V-P curve, the VDSCM gave more accurate estimates of respiratory mechanics. Furthermore, %E2 calculated from VDSCM is a useful parameter for estimating respiratory system overdistension that is not affected by resistive pressures.
Keyword Modeling
Overdistention
Volume-dependent
Single-compartment model
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Faculty of Health and Behavioural Sciences -- Publications
 
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