Tolerance and Physiological Correlates of Neuromuscular Electrical Stimulation in COPD: A Pilot Study

Abstract

RationaleNeuromuscular electrical stimulation (NMES) of the lower limbs is an emerging training strategy in patients with COPD. The efficacy of this technique is related to the intensity of the stimulation that is applied during the training sessions. However, little is known about tolerance to stimulation current intensity and physiological factors that could determine it. Our goal was to find potential physiological predictors of the tolerance to increasing NMES stimulation intensity in patients with mild to severe COPD.Methods20 patients with COPD (FEV1 = 54±14% pred.) completed 2 supervised NMES sessions followed by 5 self-directed sessions at home and one final supervised session. NMES was applied simultaneously to both quadriceps for 45 minutes, at a stimulation frequency of 50 Hz. Spirometry, body composition, muscle function and aerobic capacity were assessed at baseline. Cardiorespiratory responses, leg discomfort, muscle fatigue and markers of systemic inflammation were assessed during or after the last NMES session. Tolerance to NMES was quantified as the increase in current intensity from the initial to the final NMES session (ΔInt).ResultsMean ΔInt was 12±10 mA. FEV1, fat-free-mass, quadriceps strength, aerobic capacity and leg discomfort during the last NMES session positively correlated with ΔInt (r = 0.42 to 0.64, all p≤0.06) while post/pre NMES IL-6 ratio negatively correlated with ΔInt (r = −0.57, p = 0.001). FEV1, leg discomfort during last NMES session and post/pre IL-6 ratio to NMES were independent factors of variance in ΔInt (r2 = 0.72, p = 0.001).ConclusionLower tolerance to NMES was associated with increasing airflow obstruction, low tolerance to leg discomfort during NMES and the magnitude of the IL-6 response after NMES.Trial RegistrationClinicalTrials.gov NCT00809120

Acute Feasibility of Neuromuscular Electrical Stimulation in Severely Obese Patients with Obstructive Sleep Apnea Syndrome: A Pilot Study

“…The levels of force evoked by NMES were notably lower than those observed in healthy subjects at first NMES use [ 22 ], but actually close to those reported in other chronic diseases. In fact, with a mean of 6.2 ± 9.0% MVC for multipath NMES (but up to 16.4% and 30.6% of MVC in two patients), the force levels obtained in this pilot study and particularly with the multipath system were similar to those observed at first NMES application in patients with COPD [ 17 , 28 ]. It is worth noting that an increase in current intensity is largely expected in the days following the very first NMES session, which could reach >+10 mA for the first week [ 28 ].…”

“…In fact, with a mean of 6.2 ± 9.0% MVC for multipath NMES (but up to 16.4% and 30.6% of MVC in two patients), the force levels obtained in this pilot study and particularly with the multipath system were similar to those observed at first NMES application in patients with COPD [ 17 , 28 ]. It is worth noting that an increase in current intensity is largely expected in the days following the very first NMES session, which could reach >+10 mA for the first week [ 28 ]. Our current results are thus of importance since we demonstrated that it was possible to evoke visible muscle contractions in about half of the patients when initially exposed to NMES.…”

Personalised and progressive neuromuscular electrical stimulation (NMES) in patients with cancer—a clinical case series

“…Only one patient withdrew due to muscle discomfort which was reported in her second week of use. Tolerance to NMES exercise is individual-specific with around 10% of older adults and those with chronic diseases being unable to tolerate NMES exercise [29,30]. In cancer patients, this estimate may be higher particularly amongst those undergoing treatment, which may exacerbate tolerance.…”

The efficacy and prescription of neuromuscular electrical stimulation (NMES) in adult cancer survivors: a systematic review and meta-analysis

“…In addition, a habituation period of 1-2 may be required to achieve these strengthening thresholds and to identify nonresponders [19]. Indeed, 10% of patient groups and elderly cohorts do not tolerate NMES [19,39] and an extended intervention period may be required to realise the true magnitude of adaptation to NMES stimulus in the elderly [40]. Therefore, habituation to NMES should be considered in future studies.…”