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How much of the carbon dioxide produced at rest is seen in the expired breath?
Author(s) -
Avalo Luis Antonio Rueda,
Caucha Luis Jhony,
Torres Santiago Rigoberto
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a556-a
Subject(s) - carbon dioxide , expired air , tidal volume , functional residual capacity , exhalation , rest (music) , respiratory rate , respiratory system , chemistry , ventilation (architecture) , residual volume , zoology , lung volumes , cardiology , anesthesia , medicine , lung , heart rate , thermodynamics , physics , biology , organic chemistry , blood pressure
Diluted alveolar gas by the inspired air (VT) was collected during 5 minutes to calculate the CO 2 production (VCO 2 ) and oxygen uptake (VO 2 ). To answer the question posted in the title, VCO 2 and VO 2 was measured at rest in eight healthy subjects (24–44 years old). Expired CO 2 fraction was simultaneously recorded. The average end‐tidal CO 2 fraction was assumed to be equal to FACO 2 at functional residual capacity (FRC), which was obtained separately by the N 2 washout test. The rate of breathing was obtained from the CO 2 expirograms. Results are shown in the Table. It was shown in the previous abstract that the exhaled CO 2 at rest comes from the expiratory reserved volume (ERV). In this study, we show the variability of the amount of CO 2 exhaled due to VCO 2 , respiratory rate, size of VT, and the lung anatomy of each subject. The CO 2 eliminated per breath constitutes 6.9 ± 1.66 % of CO 2 output and 8.9 ± 2.81 of CO 2 present at FRC, both of which are strongly related (R 2 =0.68). In conclusion, the CO 2 eliminated by blood to RV is further diffused to ERV where it is diluted by VT and then exhaled. Supported in part by ONG‐Centro de Enseñanza, Investigación y Servicios.