Measuring Effective Lung Volume (ELV) and calculating FRC
Consider a typical case:
with 180 ml/min CO2 elimination and 12 breath/min breathing rate, each breath contains 15 ml CO2
Our method is simple and results are obtained in about 60 seconds. The equipment needed is inexpensive:
A standard commercially available IR CO2 analyzer, a deadspace with precisely known volume - made up of a cylinder, a filter and a mouthpiece and a noseclip to prevent breathing through the nose. Finally, a laptop for gathering, storing and evaluating the data.
full paper:
A Gedeon, J Jansson, D Patrickson, M Wallin : A new method for bedside determination of effective lung volume and functional residual capacity Experimental Physiology 2025:1-5
https://doi.org/10.1113/EP093229
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At present the "state-of-the-art" methods to measure FRC are complicated and require sophisticated, expensive equipment that are not suitable for use at bedside or in out-of-hospital environments. For these potentially important applications, see the page "Use of new FRC method"
Examples of current "state-of-the-art" methods are shown below.
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Examples of laboratory methods :
References:
Pre-operative assessment:
Chest Volume 115, Issue 5, Supplement, May 1999, Pages 58S-63S
Preoperative Assessment of Pulmonary Risk
Ferguson M K
https://doi.org/10.1378/chest.115.suppl_2.58S
Out-of-hospital management of lung disease:
NPJ Prim Care Respir Med 7;31:23 2021
Pulmonary function testing in COPD: looking beyond the curtain of FEV1
Kakavas S et al.
https://doi.org/10.1038/s41533-021-00236-w