By: Andrew Huszczuk and John Hoppe
There is no advantage to true BBB measurements, and in fact there are distinct disadvantages!
Early publications about measurement of VO2 and VCO2 date back to the early 1900's, with collection of exhaled gases in bags.
Then in the 1930's Douglas used gas collection bags during his expedition to the Andes; the resulting publicity credited him with the term "Douglas Bag". The collected gases were subsequently analyzed and their volume measured.
Douglas bag and mixing chambers measurements using discrete gas analyzers were the standard until computers made on-line measurements with mixing chambers relatively easy.
In the late 1960's, Beaver and Wasserman of Harbor-UCLA developed the first Breath-by-breath (BBB) measurement system and later with Brian Whipp became the gurus and advocates of BBB measurements. It was hoped that the intra-breath information of BBB measurements would yield information about the dynamics of muscle O2 uptake.
With the strong influence of the Harbor-UCLA team on purchasing decisions of new customers, many instrument manufacturers were eager to follow what was thought to be the future trend in VO2 measurements. However, the promise of measurement of muscle dynamics using BBB measurements failed totally.
Today, there is almost total consensus among experts in the field of VO2 measurements that there is not a single advantage to BBB measurements, and in fact definite disadvantages due to much more noisy data and unavoidable measurement errors at both very low and high ventilation rates*.
Copyright (C) 2008 Vacumetrics Inc
* See also "Breath-by-Breath (BBB) vs. "True Breath by Breath"
on VacuMed.com (Dr. Andrew's Corner)
5 June 2008