Reliability of the Determination of the Ventilatory Threshold in Patients with COPD

Abstract

In patients with COPD, the reliability of human estimation of VO 2VT is less than that in controls and not interchangeable with a computerized analysis. This should be taken into account when using VT for exercise prescription, as a tool to monitor responses to an intervention, as a surrogate measure of overall aerobic fitness, or as a prognostic marker in patients with COPD.

Interobserver variability of ventilatory anaerobic threshold in asymptomatic volunteers

“…A comparably high ICC of 0.98 (95% CI: 0.97–0.99) was shown in a study of 23 healthy volunteers undergoing cycle ergometer testing [23]. By contrast, analysis of 92 patients with COPD in the same study resulted in an ICC of 0.72 (95% CI: 0.60–0.81) [23]. Studies of AT in patient populations undergoing exercise testing with a treadmill ergometer revealed a range of ICCs, from 0.64 in 16 patients with chronic heart failure [20] to 0.85 in 445 tests of patients before vascular operation [25] and 0.88–0.97 (with three readers) in 13 children with congenital heart failure [21].…”

“…In phase 1 (the first 522 data sets), the consensus discussion increased the ICC to 0.99 and lowered the difference within the 95% LOA to ±90 mL/min (SD d ± 4%). A comparably high ICC of 0.98 (95% CI: 0.97–0.99) was shown in a study of 23 healthy volunteers undergoing cycle ergometer testing [23]. By contrast, analysis of 92 patients with COPD in the same study resulted in an ICC of 0.72 (95% CI: 0.60–0.81) [23].…”

“…However, comparison with previously published studies is difficult, because the software-based AT determination was performed using different algorithms. Dubé et al [23] used the LAB Manager version 5.3.0.4 (Cardinal Health, Höchberg, Germany) and Vainshelboim et al [25] used the COSMED system (Rome, Italy) and special analytic software, whereas our study used VIASYS software (JLab Labmanager V5.32.0).…”

“…However, studies of interobserver variability of AT are limited. They refer to different populations, including healthy volunteers [17] and patients with heart failure [16, 18–20], congenital heart failure [21], pulmonary arterial hypertension [22], chronic obstructive pulmonary disease (COPD) [23] and mixed etiologies [24, 25]. Furthermore, the published studies vary substantially in terms of sample size (from n = 6 to n = 428) and statistical interpretation.…”

“…Furthermore, the published studies vary substantially in terms of sample size (from n = 6 to n = 428) and statistical interpretation. Studies comparing software-based AT determination with visual determination of AT by clinically experienced readers have produced heterogeneous results [23, 25].…”