GAS EXCHANGE EVALUATION   Free access

Minerva Anestesiologica 1999 June;65(6):377-82

Copyright © 2000 EDIZIONI MINERVA MEDICA

language: English

Gas exchange: large surface and thin barrier determine pulmonary diffusing capacity

Weibel E. R.

Department of Anatomy and Fondation “M. E. Müller”, University of Berne

The ­lung is char­ac­ter­ized by its dif­fus­ing capac­ity for oxy­gen, DLO2, ­which is esti­mat­ed ­from mor­pho­met­ric infor­ma­tion as a theo­ret­i­cal capac­ity. It is deter­mined by the ­large gas ­exchange sur­face, the ­thin tis­sue bar­ri­er, and the ­amount of cap­il­lary ­blood. The ques­tion is ­asked wheth­er DLO2 ­could be a lim­it­ing fac­tor for O2 ­uptake in ­heavy exer­cise, par­tic­u­lar­ly in ath­letes ­with ­their 50% high­er O2 ­demand. This is ­answered by stud­y­ing the rela­tion ­between DLO2 and max­i­mal O2 con­sump­tion in dif­fer­ent sed­en­tary and ath­let­ic mam­mals, com­par­ing ­horse and cow, dog and ­goat, and, final­ly, the ­most ath­let­ic mam­mal, the prong­horn ante­lope of the Rocky Mountains. It is con­clud­ed ­that in ath­let­ic spe­cies the ­lung is ­just suf­fi­cient to sat­is­fy the O2 ­needs and can there­fore be a lim­it­ing fac­tor for aero­bic ­work.