Pulmonary rehabilitation does not improve efficiency slopes in patients with COPD

Background: Pulmonary rehabilitation (PR) is known to improve the peak exercise capacity during incremental cardiopulmonary exercise test (CPET) in patients with chronic obstructive pulmonary disease (COPD). However, its effects on variables reflective of effort-independent exercise response, such as efficiency slopes, are not well studied. Objectives: To investigate the effects of PR on efficiency slopes in patients with COPD. Methods: Patients with COPD were assessed for exercise capacity (CPET), before and 3 months after PR. The ventilatory efficiency (∆VE/∆VCO2), the oxygen uptake efficiency (OUES), and the mechanical efficiency (∆VO2/∆Wr) slopes and oxygen pulse (PuO2) were calculated from the CPET. PuO2 was defined as the ratio of oxygen uptake (VO2) and heart rate (HR). Isotime was identified as the highest workload achieved either at baseline or 3 months after PR. Results: Twenty-five patients were included [16 men; 64 (9) years-old; FEV1: 48.9 (14.5)%pred; 6MWD 72 (11.3)%pred]. The PR outcomes are shown in Table 1. Conclusions: Although peak exercise capacity and iso-work response improved, the efficiency slopes reflective effort-independent exercise response did not change significantly after PR.