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Calculation of end–tidal carbon dioxide fractions in the Bain system
Author(s) -
JONSSON L. O.,
ZETTERSTRÖM H.
Publication year - 1989
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.1399-6576.1989.tb02863.x
Subject(s) - medicine , carbon dioxide , anesthesia , respiration , breathing , respiratory system , coaxial , ventilation (architecture) , volunteer , halothane , thermodynamics , anatomy , physics , ecology , agronomy , biology , electrical engineering , engineering
The validity of the Stenqvist–Sonander formula for calculating the end–expiratory fraction of carbon dioxide (F A CO 2 ) in the coaxial Mapleson D (Bain) systems was evaluated using a lung model for simulated spontaneous breathing with an optional respiratory wave form. Two different respiratory flow patterns were used, one representing relaxed breathing in a volunteer and one resembling the respiration found in halothane anaesthesia. Each pattern was used with five different fresh gas flows and three different respiratory rates. The formula was found to be quite accurate when the flow pattern of an awake volunteer was simulated, but it underestimated the observed F ET CO 2 value by about 10% in halothane breathing. It is concluded that the formula can be recommended for use in theoretical and educational situations but that it is too complicated for application in clinical practice.