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Distribution of Expiratory Gas and Rebreathing in T‐piece Modifications Used in Weaning
Author(s) -
HartmannAndersen F.,
Andersen P. K.,
Olsen J. E.,
Jakubaszko J.
Publication year - 1983
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1983.tb01995.x
Subject(s) - medicine , respirator , positive end expiratory pressure , anesthesia , mechanical ventilation , materials science , composite material
The simple T‐piece is frequently used as a weaning system during respirator treatment. It is modified with an expiratory non‐compliant reservoir (EnCR), an inspiratory compliant reservoir (ICR) and/or an expiratory one‐way valve. The distribution of expiratory gases and rebreathing were studied in a model set‐up in the corresponding systems at different fresh gas flows (FGF) and tidal volumes (V T ). An EnCR produces no change, whereas an ICR causes the expiratory gas to flow into the inspiratory limb, an effect which is intensified by the presence of an expiratory valve. With a falling FGF and a rising V T , increasing amounts of expiratory gas are found in the inspiratory limb in the modifications with an ICR. However, this only gives rise to rebreathing in the valve modification with a low FGF and high V T . The modification of the T‐piece with an ICR but without a one‐way valve is advantageous, as this system combines only slight dilution via the expiratory limb and a minimal risk of rebreathing.