Greater exercise tolerance in COPD during acute interval, compared to equivalent constant‐load, cycle exercise: physiological mechanisms

The relative importance of ventilatory, circulatory and peripheral muscle factors in determining tolerance to exercise in patients with COPD is not known. In twelve COPD patients (FEV1 :58 ± 17%pred.) we measured ventilation, cardiac output, dynamic hyperinflation, local muscle oxygenation, blood lactate and time to exhaustion during a) interval exercise (IE) consisting of 30 s at 100% peak work-rate alternated with 30 s at 50% and b) constant load exercise (CLE) at 75% WRpeak, designed to produce the same average work rate. Exercise time was substantially longer during IE than CLE (19.5 ± 4.8 versus 11.4 ± 2.1 min, p = 0.0001). Total work output was therefore greater during IE than CLE (81.3 ± 27.7 versus 48.9 ± 23.8 kJ, p = 0.0001). Dynamic hyperinflation (assessed by changes from baseline in inspiratory capacity-ΔIC) was less during IE than CLE at CLE exhaustion time (isotime, p = 0.009), but was similar at exhaustion (ΔICCLE : -0.38 ± 0.10 versus ΔICIE : -0.33 ± 0.12 l, p = 0.102). In contrast, at isotime, minute ventilation, cardiac output and systemic oxygen delivery did not differ between protocols (p>0.05). At exhaustion in both protocols, vastus lateralis and intercostal muscle oxygen saturation were higher in IE than CLE (p = 0.014 and p = 0.0002, respectively) and blood lactate concentrations were lower (4.9 ± 2.4 mmol/l versus 6.4 ± 2.2 mmol/l, p = 0.039). These results suggest that 1) exercise tolerance in COPD is limited by dynamic hyperinflation; and 2) cyclically lower (50%) effort intervals in IE help preserve muscle oxygenation and reduce metabolic acidosis compared to CLE at the same average work rate, but these factors do not appear to determine time to exhaustion

Prospective evaluation of haemoglobin oxygen saturation at rest and after exercise in paediatric sickle cell disease patients

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73511/1/j.1365-2141.2009.07854.x.pd

A randomized controlled trial of allopurinol in patients with peripheral arterial disease

AbstractBackgroundPatients with peripheral arterial disease (PAD) are limited by intermittent claudication in the distance they can walk. Allopurinol has been shown in coronary arterial disease to prolong exercise before angina occurs, likely by prevention of oxygen wastage in tissues and reduction of harmful oxidative stress.MethodsIn this study we evaluated whether allopurinol could prolong the time to development of leg pain in participants with PAD. In a double-blind, randomized controlled clinical trial participants were randomized to receive either allopurinol 300 mg twice daily or placebo for 6 months. The primary outcome was change in exercise capacity on treadmill testing at 6 months. Secondary outcomes were 6-minute walking distance, Walking Impairment Questionnaire, SF-36 questionnaire, flow-mediated dilatation, and oxidized low-density lipoprotein. Outcome measures were repeated midstudy and at the end of study. The mean age of the 50 participants was 68.4 ± 1.2 years with 39 of 50 (78%) male.ResultsFive participants withdrew during the study (2 active, 3 placebo). There was a significant reduction in uric acid levels in those who received active treatment of 52.1% (P < 0.001), but no significant change in either the pain-free or the maximum walking distance. Other measures of exercise capacity, blood vessel function, and the participants' own assessment of their health and walking ability also did not change during the course of the study.ConclusionsAlthough allopurinol has been shown to be of benefit in a number of other diseases, in this study there was no evidence of any improvement after treatment in patients with PAD

Effectiveness of home-based exercise in older patients with advanced chronic obstructive pulmonary disease: A 3-year cohort study

Aim To determine whether home‐based exercise can improve clinical outcomes in older patients with advanced chronic obstructive pulmonary disease using long‐term oxygen therapy. Methods Information was provided to improve chronic obstructive pulmonary disease self‐management before the onset of the present prospective 3‐year cohort study. Patients selected either home‐based exercise using a lower‐limb cycle machine (ergo‐bicycle; group E), or usual exercise (group U). To assess self‐management, the Lung Information Needs Questionnaire was evaluated every 6 months. Clinical outcomes included the 6‐min walk test, pulmonary function tests, the body mass index, airflow obstruction, dyspnea and exercise index, St. George's respiratory questionnaire, and the number of exacerbations and hospitalizations. Results A total of 136 patients (group E = 72; group U = 64), with a mean age of 74.2 years were enrolled. Total Lung Information Needs Questionnaire scores improved over 3 years for group E (P = 0.003). The distance of the 6‐min walk test was well maintained in group E, but significantly decreased in group U (P < 0.001). The percentage of forced expiratory volume in 1 s at baseline was lower in group E (P = 0.016), but was maintained over 3 years, whereas a significant reduction was seen in group U (P = 0.001). The body mass index, airflow obstruction, dyspnea and exercise index significantly worsened in both groups over 3 years (group E: P = 0.011; group U: P < 0.001), whereas a significant decrease in the number of exacerbations was noted in group E (P = 0.009). Conclusions Patients who undertook home‐based exercise using an ergo‐bicycle were able to maintain clinical outcomes including 6‐min walk test distance and percentage of forced expiratory volume in 1 s predicted, and recorded fewer exacerbations over 3 years

Long-term effect of respiratory training for chronic obstructive pulmonary disease patients at an outpatient clinic: a randomised controlled trial

Objective: To assess the effect of respiratory training (RT ) on lung function, activity tolerance and acute exacerbation frequency with chronic obstructive pulmonary disease (COPD). Design: A randomised controlled trial. Setting: Outpatient clinic and home of the COPD patients, Zhengzhou City, China. Subjects: Sixty participants with COPD were randomised into two groups: an intervention group ( n = 30) which received the RT in self-management and a control group ( n = 30) that received an education program during the study. Intervention: Pulmonary function, activity tolerance and frequency of acute exacerbation of these COPD patients were evaluated before and after the program. The intervention and control programs were delivered at monthly out - patient clinic visits over a period of 12 months. The pulmonary rehabilitation (PR) program was conducted by a physiotherapist (who delivered RT to the participant over a minimum of 1 h per visit) for the intervention group, whereas the control group received routine health education provided by physiotherapists. The intervention group patients were then instructed to perform exercises at home as taught in the RT at least 5 days per week at home. Results: After 12 months of RT, the lung function and the activity tolerance of the COPD patients in the intervention group were significantly improved and the exacerbation frequency was also decreased. Conclusion: Long-term RT can improve lung function and activity tolerance while decreasing the frequency of acute exacerbation for COPD patient

Absence of influence of gender and BMPR2 mutation type on clinical phenotypes of pulmonary arterial hypertension

<p>Abstract</p> <p>Background</p> <p>Previous studies indicate that patients with pulmonary arterial hypertension (PAH) carrying a mutation in the bone morphogenetic protein receptor type 2 (<it>BMPR2</it>) gene, develop the disease 10 years earlier than non-carriers, and have a more severe hemodynamic compromise at diagnosis. A recent report has suggested that this may only be the case for females and that patients with missense mutations in <it>BMPR2 </it>gene have more severe disease than patients with truncating mutations.</p> <p>Methods</p> <p>We reviewed data from all patients with PAH considered as idiopathic and patients with a family history of PAH, who underwent genetic counselling in the French PAH network between January, 1^st2004 and April, 1^st2010. We compared clinical, functional, and hemodynamic characteristics between carriers and non-carriers of a <it>BMPR2 </it>mutation, according to gender or <it>BMPR2 </it>mutation type.</p> <p>Results</p> <p>PAH patients carrying a <it>BMPR2 </it>mutation (n = 115) were significantly younger at diagnosis than non-carriers (n = 267) (35.8 ± 15.4 and 47.5 ± 16.2 respectively, p < 0.0001). The presence of a <it>BMPR2 </it>mutation was associated with a younger age at diagnosis in females (36.4 ± 14.9 in <it>BMPR2 </it>mutation carriers and 47.4 ± 15.8 in non-carriers, p < 0.0001), and males (34.6 ± 16.8 in <it>BMPR2 </it>mutation carriers and 47.8 ± 17.1 in non-carriers, p < 0.0001). <it>BMPR2 </it>mutation carriers had a more severe hemodynamic compromise at diagnosis, but this was not influenced by gender. No differences in survival and time to death or lung transplantation were found in male and female PAH patients carrying a <it>BMPR2 </it>mutation. No differences were observed in clinical outcomes according to the type of <it>BMPR2 </it>mutations (missense, truncating, large rearrangement or splice defect).</p> <p>Conclusion</p> <p>When compared to non-carriers, <it>BMPR2 </it>mutation carriers from the French PAH network are younger at diagnosis and present with a more severe hemodynamic compromise, irrespective of gender. Moreover, <it>BMPR2 </it>mutation type had no influence on clinical phenotypes in our patient population.</p

Evaluation of Activity Limitation in Patients With Idiopathic Pulmonary Fibrosis Grouped According to Medical Research Council Dyspnea Grade

Objective To investigate the relations between Medical Research Council (MRC) dyspnea grade and peripheral muscle force, activities of daily living (ADL) performance, health status, lung function, and exercise capacity in subjects with idiopathic pulmonary fibrosis (IPF). Design Prospective cross-sectional observational study. Setting University hospital. Participants Subjects with IPF (N=65, 46 men) in a stable clinical state with a mean age of 68±7 years. Interventions Not applicable. Main Outcome Measures Right ventricular systolic pressure (RVSP) via transthoracic echocardiography, pulmonary function, isometric quadriceps force (QF) and handgrip force (HF), 6-minute walk distance (6MWD), ADL score, and health status (Medical Outcomes Study 36-Item Short-Form Health Survey [SF-36]) were assessed and compared between subjects grouped according to MRC grade. Results Of the participants, 16 were in MRC grade 2, 17 were in MRC grade 3, 17 were in MRC grade 4, and 15 were in MRC grade 5. RVSP, pulmonary function, QF, HF, 6MWD, ADL, and SF-36 scores decreased with increasing MRC grade (all P.56, P=.001). Conclusions The MRC dyspnea scale provides a simple and useful method of categorizing individuals with IPF with respect to their activity limitation and may assist in understanding the impact of IPF on an individual