Do maximum flow-volume loops collected during maximum exercise test alter the main cardiopulmonary parameters?
BACKGROUND
Traditionally, ventilatory limitation to exercise is assessed by measuring the breathing reserve (BRR) [ie, the difference between minute ventilation at peak exercise and maximum voluntary ventilation measured at rest]. Recent studies have however, documented important abnormalities in ventilatory adaptation with a remarkable potential to limit exercise even in the presence of a normal BRR. Among these abnormalities is lung hyperinflation and expiratory flow limitation. This was documented by comparing tidal to maximum flow-volume loops (FVLs) collected throughout the test. In the present study, we wondered whether the advantages of using such a technique within the classic cardiopulmonary exercise test (CPET) might be obscured by the maneuvers interfering with the main functional parameters of the test, and eventually with interpretation of the CPET.


METHODS
We studied 18 healthy subjects, 19 patients affected by COPD, and 19 patients with chronic heart failure during a maximum exercise test on three different study days in a random order. On one occasion, the CPET was conducted with no FVLs (control test [CTRL]), whereas on the other occasions FVLs were incorporated every 1 min during exercise (FVL(1)-min) or every 2 min during exercise (FVL(2)-min).


RESULTS
None of the classic cardiovascular parameters recorded at ventilatory anaerobic threshold or at peak exercise differed between the study days (by analysis of variance). Furthermore, the coefficients of variation of the main parameters between FVL(1)-min and FVL(2)-min days vs CTRL day were well within the natural variability thresholds reported in the literature.


CONCLUSIONS
The FVLs appear to not interfere with the main functional parameters used for the interpretation of CPET.
Bussotti
Maurizio
M
Istituto di Cardiologia dell'Università degli Studi di Milano, Centro Cardiologico, Istituto di Ricovero e Cura a Carattere Scientifico, Centro di Studio per le Ricerche Cardiovascolari del Centro Di Studio per le Ricerche, Milan, Italy. Electronic address: maurizio.bussotti@ccfm.it.
Agostoni
PierGiuseppe
P
Istituto di Cardiologia dell'Università degli Studi di Milano, Centro Cardiologico, Istituto di Ricovero e Cura a Carattere Scientifico, Centro di Studio per le Ricerche Cardiovascolari del Centro Di Studio per le Ricerche, Milan, Italy.
Durigato
Alberto
A
SC Pneumologia, Ospedale Cà Foncello, Treviso, Italy.
Santoriello
Carlo
C
OUC Fisiopatologia Respiratoria, Ospedale Cava De'Tirreni (SA), Tirreni, Italy.
Farina
Stefania
S
Istituto di Cardiologia dell'Università degli Studi di Milano, Centro Cardiologico, Istituto di Ricovero e Cura a Carattere Scientifico, Centro di Studio per le Ricerche Cardiovascolari del Centro Di Studio per le Ricerche, Milan, Italy.
Brusasco
Vito
V
Cattedra di Fisiopatologia Respiratoria, DISM, Università di Genova, Genoa, Italy.
Pellegrino
Riccardo
R
Centro di Fisiopatologia Respiratoria, Azienda Sanitaria Ospedaliera S Croce e Carle, Cuneo, Italy.
D000328:Adult; D000368:Aged; D015308:Anaerobic Threshold; D000704:Analysis of Variance; D016022:Case-Control Studies; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000175:diagnosis*; D006801:Humans; D008176:Lung Volume Measurements; D008297:Male; D008451:Maximal Voluntary Ventilation; D008875:Middle Aged; D005082:Physical Exertion / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis*; D012016:Reference Values; D012680:Sensitivity and Specificity; D014797:Vital Capacity