Modelling mixing within the dead space of the lung improves predictions of functional residual capacity
Journal
Respiratory Physiology and Neurobiology
Journal Volume
242
Pages
12-18
Date Issued
2017
Author(s)
Abstract
Routine estimation of functional residual capacity (FRC) in ventilated patients has been a long held goal, with many methods previously proposed, but none have been used in routine clinical practice. This paper proposes three models for determining FRC using the nitrous oxide concentration from the entire expired breath in order to improve the precision of the estimate. Of the three models proposed, a dead space with two mixing compartments provided the best results, reducing the mean limits of agreement with the FRC measured by whole body plethysmography by up to 41%. This moves away from traditional lung models, which do not account for mixing within the dead space. Compared to literature values for FRC, the results are similar to those obtained using helium dilution and better than the LUFU device (Dr?ger Medical, Lubeck, Germany), with significantly better limits of agreement compared to plethysmography. ? 2017 Elsevier B.V.
Subjects
helium
nitrous oxide
accuracy
Article
body plethysmography
breathing
functional residual capacity
human
lung blood flow
lung dead space
lung model
prediction
priority journal
anatomy and histology
biological model
breath analysis
computer simulation
devices
female
least square analysis
lung
male
physiology
procedures
regression analysis
young adult
Breath Tests
Computer Simulation
Female
Functional Residual Capacity
Helium
Humans
Least-Squares Analysis
Lung
Male
Models, Biological
Nitrous Oxide
Plethysmography, Whole Body
Regression Analysis
Respiration
Respiratory Dead Space
Young Adult
Type
journal article