Exercise induced skeletal muscle metabolic stress is reduced after pulmonary rehabilitation in COPD

SummaryIn COPD, skeletal muscle ATP resynthesis may be insufficient to meet demand during exercise due to excessive anaerobic and reduced oxidative (mitochondrial) energy production, leading to metabolic stress. We investigated the effect of outpatient pulmonary rehabilitation (PR) on the metabolic response (measured by exercise-induced accumulation of plasma ammonia) and determined whether this response predicted functional improvement following PR.25 subjects with stable COPD [mean (SD) age 67 (8)years and FEV1 47 (18)% predicted] performed maximal cycling ergometry before and after PR. Plasma ammonia was measured at rest, during exercise and 2 min post-exercise.Following PR, there were significant increases in peak cycle WR and ISWT performance (Mean (SEM) changes 13.1 (2.0) W and 93 (15) m respectively, p < 0.001). Mean (SEM) rise in plasma ammonia was reduced at peak (Pre vs Post-PR: 29.0 (4.5) vs 20.2 (2.5) μmol/l, p < 0.05) and isotime (Pre vs Post-PR: 29.0 (4.5) vs 10.6 (1.7) μmol/l, p < 0.001) exercise. Improvements in exercise performance after PR were similar among subgroups who did versus those who did not show a rise in ammonia at baseline.The results suggest that muscle cellular energy production was better matched to the demands of exercise following PR. We conclude that a pragmatic outpatient PR programme involving high intensity walking exercise results in significant adaptation of the skeletal muscle metabolic response with a reduction in exercise-related metabolic stress. However, the outcome of PR could not be predicted from baseline metabolic response

Communicating uncertainty: contrasting the communication experiences of patients with advanced COPD and incurable lung cancer.

BACKGROUND: Due to the uncertain disease trajectory and variable rate of progression in chronic obstructive pulmonary disease (COPD), health care professionals (HCPs) are challenged in explaining what the future may hold for patients compared to those with lung cancer (LC). Support and communication of timely information can significantly improve health outcomes. OBJECTIVE: This study sought to identify factors that impact communication and support and recommend ways to improve patients' understanding of living with life-threatening illness. METHODS: Semi-structured interviews with patients with LC (n = 22) and advanced COPD (n = 18), their informal carers (21 LC and 18 COPD) and HCPs (n = 51). Patients were recruited from primary and secondary care in the East of England, UK, during 2010-12. RESULTS: Directness and clarity characterized communication in LC, whereas uncertainty and limited explanations predominated in COPD. Discussions on how the disease might impact on decisions and preferences to be made in the future were less common in COPD. Information for LC patients was mainly from hospital clinicians and any information for COPD patients mainly from primary care clinicians. CONCLUSIONS: The experience of COPD patients could be improved by professionals soon after diagnosis explaining to them the typical pattern of decline in COPD, highlighting the inherent uncertainties about when exacerbations and death may occur. This conversation should lead to planning for the different challenges that the patient and informal carer recognize as most important to them. This contrasts with the 'breaking bad news' conversation that oncologists are highly trained to deliver