Adenine nucleotide loss in the skeletal muscles during exercise in chronic obstructive pulmonary disease.

BACKGROUND: Skeletal muscle adenine nucleotide loss has been associated with fatigue during high intensity exercise in healthy subjects but has not been studied in patients with chronic obstructive pulmonary disease (COPD). Changes in adenine nucleotides and other metabolites in the skeletal muscles were measured in patients with COPD and age matched healthy volunteers by obtaining biopsy samples from the quadriceps muscle at rest and following a standardised exercise challenge. METHODS: Eighteen patients with COPD (mean (SD) forced expiratory volume in 1 second 38.1 (16.8)%) and eight age matched healthy controls were studied. Biopsy samples were taken from the vastus lateralis muscle at rest and immediately after a 5 minute constant workload cycle test performed at 80% peak work achieved during a maximal incremental cycle test performed previously. RESULTS: The absolute workload at which exercise was performed was substantially lower in the COPD group than in the controls (56.7 (15.9) W v 143.2 (26.3) W, p<0.01). Despite this, there was a significant loss of adenosine triphosphate (mean change 4.3 (95% CI -7.0 to -1.6), p<0.01) and accumulation of inosine monophosphate (2.03 (95% CI 0.64 to 3.42), p<0.01) during exercise in the COPD group that was similar to the control group (-4.8 (95% CI -9.7 to 0.08), p = 0.053 and 1.6 (95% CI 0.42 to 2.79), p<0.01, respectively). CONCLUSIONS: These findings indicate that the ATP demands of exercise were not met by resynthesis from oxidative and non-oxidative sources. This suggests that significant metabolic stress occurs in the skeletal muscles of COPD patients during whole body exercise at low absolute workloads similar to those required for activities of daily living.

Postoperative pain detracts from early health status improvement seen after video-assisted thoracoscopic lung volume reduction surgery.

OBJECTIVES: To assess the impact of lung volume reduction surgery (LVRS) on postoperative pain. METHODS: Fifty-two patients, 34 male/18 female, median age 59 (46-70) years, underwent unilateral video-assisted thoracoscopic (VAT) LVRS. FEV(1), TLC, RV and RV/TLC ratio were assessed preoperatively and at 3, 6, 12 and 24 months post surgery. At the same time interval health status was assessed by Euroquol and SF 36 questionnaires. RESULTS: Significant improvements in health status, as assessed by SF 36, persisted from 3 months to 1 year. However, in the pain domain there was a worsening of the mean score from 74 preoperatively to 64 at 3 months, 68 at 6 months, 73 at 12 months and 65 at 24 months. The improvements in Euroquol score were not statistically significant. However, they became significant for at least 2 years postoperatively, when those patients who had a worsening pain score postoperatively were excluded. While the percentage of patients with a worsening of pain scores measured with SF 36 remained between 40 and 45% even 2 years after LVRS, when using Euroquol this percentage did decrease from 30% at 3 months to 14% at 2 years. There was no significant correlation between the change of scores and length of operation, hospital stay or air leak. It was also not statistically significant whether these patients had an extra procedure (redo thoracotomy or insertion of extra drain postoperatively). There were some significant correlations between changes in hyperinflation and changes in pain scores but this was not consistent for Euroquol and SF 36. CONCLUSION: Postoperative pain detracts from global improvement in health status after LVRS even after unilateral VATS. There may be an influence of alterations in chest mechanics after surgery on the development of pain.

Chronic obstructive pulmonary disease 8: non-pharmacological management of COPD.

The role of smoking cessation and the use of measures to reduce the disability associated with COPD are reviewed. The political profile of patients with COPD is increasing as patient support groups develop the confidence to campaign for better services.

Lung volume reduction surgery--a comparison of the long term outcome of unilateral vs. bilateral approaches.

OBJECTIVE: Bilateral lung volume reduction surgery (LVRS) is thought to be preferable to unilateral surgery due to greater initial benefit but the subsequent rate of decline may also be greater. We compared the long term physiological and health status outcome of LVRS performed on one or simultaneously on both lungs. METHODS: Prospective data were collected on a consecutive series of 65 patients undergoing LVRS who were all suitable for bilateral surgery. Twenty-six patients: age 59 (8) years underwent bilateral LVRS by video-assisted thoracoscopy (VAT) or sternotomy and 39 patients: age 60 (6) years underwent unilateral VAT. The perioperative effects of LVRS on spirometry were prospectively recorded at 3, 6, 12 and 24 months. RESULTS: The unilateral group had similar preoperative lung volumes to the bilateral patients: forced expiratory volume in 1s (FEV(1)) 26 vs. 30% predicted, RV 275 vs. 246% predicted and total lung capacity (TLC) 148 vs. 142% predicted. Unilateral LVRS was associated with significantly lower weight of lung resected: 80 (31) vs. 118 (46) g; hospital stay: 16 (10) days vs. 28 (22) days. Thirty-day mortality was 3% in the unilateral and 8% in the bilateral group (P=0.34). Postoperative ventilation occurred in 5% in the unilateral and in 42% in the bilateral group (P=0.0002). The decline of FEV(1) during the first postoperative year was significant in the bilateral group (-313 ml/y, P=0.04) but not significant in the unilateral group (-50 ml/y, P=0.18). SF 36 scores in all eight domains were similar in both groups preoperatively and at any postoperative interval. CONCLUSION: We have found no benefit from bilateral simultaneous LVRS and prefer unilateral LVRS because of the lower morbidity, resulting in earlier discharge, and slower decline in physiological benefit.