ORIGINAL ARTICLES   

The Journal of Sports Medicine and Physical Fitness 1999 June;39(2):93-100

Copyright © 1999 EDIZIONI MINERVA MEDICA

lingua: Inglese

Transcutaneous carbon dioxide threshold during exercise

Abraham P., Carter D., Bickert S., Desvaux B., Saumet J. L.

Laboratoire de Physiologie et d’Exploration Fonctionnelle, Centre Hospitalier Universitaire, Angers, France

Background. To ­study the pos­sible use of trans­cu­ta­ne­ous car­bon diox­ide pres­sure meas­ure­ments to esti­mate ven­til­a­to­ry thresh­old dur­ing exer­cise.
Methods. Experimental ­design: comparative ­study. Settings: Institutional prac­tice, ambu­la­to­ry ­care. Patients and meas­ures: seventy-nine sub­jects. Intervention: incremental exer­cise ­tests ­with simul­ta­ne­ous record­ings of ­breath by ­breath gas ­exchange and trans­cu­ta­ne­ous car­bon diox­ide pres­sure. Measures: six review­ers deter­mined the ven­til­a­to­ry thresh­old ­using ­both the ­graphs for the car­bon diox­ide excre­tion to oxy­gen con­sump­tion rela­tion­ship: V ­slope tech­nique (VTa), and the ven­til­a­to­ry equiv­a­lent for oxy­gen ­uptake chang­es ­over ­time: (VTb), the res­pir­a­to­ry com­pen­sa­tion ­point (RCP) on ven­til­a­to­ry equiv­a­lent for car­bon diox­ide, and the trans­cu­ta­ne­ous thresh­old (Ttc) on the trans­cu­ta­ne­ous car­bon diox­ide pres­sure chang­es ­over ­time respec­tive­ly.
Results. A Ttc ­could be ­defined by all observ­ers in 85% of the sub­jects. Correlation ­between Ttc and VT ­expressed as oxy­gen con­sump­tion abso­lute val­ues ­ranged ­from 0.971 to 0.975 on the ­mean val­ues of six observ­ers. Using the Bland-Altmann ­approach, dif­fer­enc­es (­mean±SD) ­were 13±215, -40±204, 231±221 ml·min-1 ­between Ttc and VTa, VTb, RCP respec­tive­ly. A dif­fer­ence of 38±173 ml·min-1 was ­found ­between VTa and VTb. This sug­gests ­that Ttc ­shows lit­tle dif­fer­ence ­with VT but not ­with RCP.
Conclusions. We sug­gest ­that a car­bon diox­ide trans­cu­ta­ne­ous thresh­old can be ­found ­close to the ven­til­a­to­ry thresh­old. Potential clin­i­cal use of trans­cu­ta­ne­ous ­device are ­vast.