The influence of gas exchange on lung gas concentrations during air breathing

✍ Scribed by M.R. Davidson

• Publisher: Springer
• Year: 1977
• Tongue: English
• Weight: 764 KB
• Volume: 39
• Category: Article
• ISSN: 1522-9602
• DOI: 10.1016/s0092-8240(77)80036-0

✦ Synopsis

A model study is made of the contribution that continuing respiratory gas exchange make~ to the alveolar plateau slope for 02 during air breathing. Calculations m the model of the 02 concentration appearing at the mouth during expiration, are performed for single breaths of air at constant flow rates 18 litres/min and 120 litres/min. At 18 litres/min the breathing period is 5 see, the initial lung volume is 2300 ml, and the 02 uptake rate is 300 m] STPD/min; whereas at 120 litres/min these parameters are 4 sec, 1200 ml, and 1800 ml STPD/min respectively. In each case the initial lung O2 tension is taken to be 98 mm ttg. It is found that at 18 litres/min, the O8 concentration difference on the alveolar plateau over the last second of expiration is 0.4 mm I-Ig when gas exchange is omitted and 1.2 mm Hg when gas exchange is included in the model. At 120 litrcs/min, this difference is zero and 5.0 mm I-Ig respectively. The gas exchange component predicted from a corresponding well-mixed compartment model is the same at 18 litres/min (0.8 mm Hg) but is 6.0 mm Hg at 120 litres/min.