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The rebreathing characteristics of the Hudson oxygen mask
Author(s) -
CAMPKIN N.T.A.,
OOI R.G.,
SONI N.C.
Publication year - 1993
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1111/j.1365-2044.1993.tb06911.x
Subject(s) - medicine , ventilation (architecture) , anesthesia , oxygen , respiratory minute volume , inflow , tidal volume , respiratory system , mechanics , meteorology , chemistry , physics , organic chemistry
Summary A lung model was used to study the effect of varying minute ventilation, oxygen flow and inspiratory: expiratory ratio on the rebreathing chracteristics of the Hudson oxygen mask. The onset of rebreathing was detected using two different sets of criteria; those defined by Kain et al. and Humphrey. The onset of rebreathing was also quantified in terms of the inspired volume of carbon dioxide and increases in deadspace. The magnitude of rebreathing was increased by reducing oxygen inflow and increasing minute ventilation. Variation in I:E ratio between 1:1 and 1:4 had little effect on rebreathing. Using the clinical criteria of Kain et al, the onset of rebreathing was detected when oxygen inflow/minute ventilation ratio was reduced below 0.78 on average. With the other criterion, rebreathing occurred when the ratio was 0.46.