1. Kalra, Sanjay MD
  2. Roitman, Jeffrey L. EdD

Article Content

Neuromuscular Electrical Stimulation Prevents Muscle Function Deterioration In Exacerbated Copd: A Pilot Study

Giavedoni S, Deans A, McCaughey P, Drost E, MacNee W, Rabinovich RA - Respir Med. Published online first June 20, 2012, doi:10.1016/j.rmed.2012.05.005


Purpose: COPD is a condition with systemic effects of which peripheral muscle dysfunction is a prominent contributor to exercise limitation, health related quality of life (HRQoL) impairment, and is an independent predictor of morbidity and mortality. Pulmonary rehabilitation (PR) is a successful strategy to improve exercise tolerance and HRQoL through the improvement of muscle function in patients with stable COPD or early after severe exacerbations of COPD (SECOPD). However, muscle function further deteriorates during SECOPD before early PR programmes commence. We aimed to investigate the feasibility and efficacy of quadriceps neuromuscular electrical stimulation (NMES) applied during a SECOPD to prevent muscle function deterioration.


Methods: We have conducted a pilot study in eleven COPD patients (FEV1 41.3 +/- 5.6 % pred) admitted to hospital with a SECOPD. We randomly allocated one leg to receive NMES (once a day for 14 days) with the other leg as a control (non-stimulated leg). We measured the change in quadriceps maximal voluntary contraction (DQMVC) as the main outcome.


Results: Mean quadriceps muscle strength decreased in control legs ([DELTA]QMVC -2.9 +/- 5.3 N, p = ns) but increased in the stimulated legs ([DELTA]QMVC 19.2 +/- 6.1 N, p < 0.01). The difference in [DELTA]QMVC between groups was statistically significant (p < 0.05). The effect of NMES was directly related to the stimulation intensity ([n-ary summation]mA) applied throughout the 14 sessions (r = 0.76, p < 0.01). All patients tolerated NMES without any side effects.


Conclusions: NMES is a feasible and effective treatment to prevent quadriceps muscle strength derangement during severe exacerbations of COPD and may be used to compliment early post-exacerbation pulmonary rehabilitation.


Editor's Comment: Muscle function, and the preservation thereof, in patients with chronic obstructive pulmonary disease (COPD) continues to be a component of pulmonary rehabilitation intervention that is intermittently recognized as being potentially important. In the last decade there have been attempts at using neuromuscular electrical stimulation (NMES) as an alternative to exercise training, especially in patients admitted to intensive care units or in other situations that make conventional exercise impractical. This pilot study looks at a small group of patients (n = 11) who were subjected to NMES within 48 hours of being hospitalized with severe exacerbations of COPD (SECOPD). The study design randomly allocated the quadriceps muscle of 1 leg to receive 14 daily 30 minute sessions of NMES while the other leg served as the control. Results were clearly in favor of the intervention, with not only no loss of strength, as seen in the control leg, but an actual strengthening effect in the stimulated muscle.


This study further extends available data on NMES as a possible method of preserving/augmenting muscle strength in situations where conventional exercise may be impractical or at least difficult to implement. This includes the early phases of SECOPD, and NMES may be a useful adjunctive treatment even before the patient enrolls in a pulmonary rehabilitation program, a practice that now tends to often occur soon after the acute exacerbation starts to resolve but, despite this early start, not necessarily soon enough to prevent early loss of muscle strength. It is, however, premature to consider this a clinically established treatment as the present study is preliminary and only shows that quadriceps strength can be preserved/augmented with NMES; meaningful clinical outcomes were not explored, and until this is done, NMES will remain a theoretically useful intervention in SECOPD.




Optimizing the Six Minute Walk Test as a Measure of Exercise Capacity in Copd

Chandra D, Wise RA, Kulkarni HS, Benzo RP, Criner G, Make B, Slivka WA, Ries AL, Reilly JJ, Martinez FJ, Sciurba FC; NETT Research Group - Chest. Published online first June 14, 2012, doi:10.1378/chest.11-2702


Background: It is uncertain whether the effort and expense of performing a second walk for the six-minute-walk test improves test performance. Hence, we attempted to quantify the improvement in six-minute-walk distance if an additional walk were to be performed.


Methods: We studied patients consecutively enrolled into the National Emphysema Treatment Trial who, prior to randomization and after 6-10 weeks of pulmonary rehabilitation, performed two six-minute-walks on consecutive days (n = 396). Patients also performed two six-minute-walks at 6-month follow up after randomization to lung volume reduction surgery (n = 74) or optimal medical therapy (n = 64). We compared change in the first-walk distance to change in the second-, average-of-two, and best-of-two walk distances.


Results: Compared to change in first-walk distance, change in average-of-two and best-of-two walk distances had better validity and precision. Specifically, six months after randomization to LVRS, changes in average-of-two (r = 0.66 vs. 0.58, P = 0.01) and best-of-two walk distances (r = 0.67, vs. 0.58, P = 0.04) better correlated with the change in maximal exercise capacity (i.e. better validity). Also, the variance of change in the average-of-two walk distances was 14-25% less and best-of-two was 14-33% less than the variance of change in the single-walk distance, indicating better precision.


Conclusions: Adding a second walk to the six-minute-walk test significantly improves its performance in determining response to a therapeutic intervention, improves the validity of COPD clinical trials and would result in a 14-33% reduction in sample size requirements. Hence, it should be strongly considered by clinicians and researchers as an outcome measure for therapeutic interventions in COPD patients.


Editor's Comment: The 6-minute walk test distance (6MWD) has become the most frequently used outcome measure in assessing exercise performance in many clinical situations and is also a critical assessment tool in many cardiopulmonary disease study protocols. Its reproducibility and susceptibility to training and learning effects remain somewhat contentious, and there has been some tension between the time and effort involved in performing 2 walk tests and concerns regarding the validity and precision of just 1 measurement.


This analysis of data from the large National Emphysema Treatment Trial (NETT) cohort by Chandra et al helps clarify this issue significantly. Whether an average of 2 or the best of 2 walk distances is used, both validity (correlation with maximal exercise capacity) and precision (reflected by the variance) are significantly better than from a single 6-minute walk test. The better validity has the clinically important implication that this test can serve as an easier alternative to maximal exercise testing. Perhaps even more significantly, the higher precision may allow a more confident assessment of small changes in 6MWD and permit smaller sample sizes without compromising the power of the study. Carefully applied, this could more than offset the added time, effort, and cost of performing 2 tests instead of 1. Based on the presented data, two 6MWD measurements should be considered the testing standard in study protocols and the desired standard in clinical practice. What are not completely established yet are the ideal and maximum/minimum intervals between tests; these cannot be answered by NETT, which used a pragmatic (but still scientifically arbitrary) 2 consecutive days protocol.




European Guidelines on Cardiovascular Disease Prevention in Clinical Practice (Version 2012). The Fifth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice. Developed With the Special Contribution of the European Association for Cardiovascular Prevention & Rehabilitation (eacpr)

Authors/Task Force Members: Perk J, De Backer G, Gohlk H, et al. - Eur Heart J. 2012;33:1635-1701.


Editor's Comment: The European Society has just published their fifth set of preventive guidelines for clinical practitioners. This updated version of the European Guidelines has been significantly updated and contains several new sections, including more attention to behavior change, the physician's role in assisting patients with behavior change, psychosocial risk factors, and, interestingly, an entirely new (though relatively short) section titled, "Why do patients not adhere to prescribed medication?" Although the literature, particularly the nursing literature, has a long history of medication adherence articles, the addition of such a section to a set of prestigious guidelines is significant. Finally, there is also a significant discussion in a section titled "Where should programs be offered?" that concerns the interplay of hospital-based and community-based preventative services. This section speaks to the need to integrate and network these kinds of healthcare services among and between hospitals, communities, and other health care organizations. This newly revised set of guidelines merits reading by cardiac rehabilitation and other preventive specialists.




Community-Based Partnerships for Improving Chronic Disease Management

Plumb J, Weinstein LC, Brawer R, Scott K - Prim Care. 2012;39(2):433-447.


Abstract: With the growing burden of chronic disease, the medical and public health communities are re-examining their roles and opportunities for more effective prevention and clinical interventions. The potential to significantly improve chronic disease prevention and have an impact on morbidity and mortality from chronic conditions is enhanced by adopting strategies that incorporate a social ecology perspective, realigning the patient-physician relationship, integrating population health perspectives into the Chronic Care Model, and effectively engaging communities using established principles of community engagement.


Editor's Comment: This article was selected as another example of the increasing call for integration of chronic disease management and preventive efforts in medicine and healthcare (see above comment on the newly revised European Guidelines document). This article, published in a journal aimed at primary care physicians, is significant in that it calls for a wide array of constituencies to provide these preventive, chronic disease management services. It is incumbent on cardiac rehabilitation professionals and programs to reach out and connect with other health care providers in the community (not just physicians' offices and hospitals) to expand the reach of preventive services. The days of operating in a vacuum, of being the sole providers of secondary (or primary) prevention are long over. It has become clear that our ability to provide effective prevention is, practically speaking, restricted to those patients and clients with whom we have frequent contact. Once patients leave the confines of our programs, the new health behaviors that are so appropriately and effectively implemented and supported, usually become quickly extinguished. Behavior change, as we now know, takes months (perhaps years) of practice, along with lots of support, especially during times of lapse. Ongoing positive feedback and patient success at repeating the behavior are critical to permanent change. When a behavior as complex as dietary pattern is the target for change, the difficulties of maintaining the change are immense. The pathway to success is expanding the community of preventive caregivers that patients and their families can encounter and from whom they can garner the ongoing support necessary to make these lifestyle changes permanent. This article is well worth reading for those purposes alone.