Serafim Nanas

Electrical muscle stimulation preserves the muscle mass of critically ill patients: a randomized study

IntroductionCritically ill patients are characterized by increased loss of muscle mass, partially attributed to sepsis and multiple organ failure, as well as immobilization. Recent studies have shown that electrical muscle stimulation (EMS) may be an alternative to active exercise in chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) patients with myopathy. The aim of our study was to investigate the EMS effects on muscle mass preservation of critically ill patients with the use of ultrasonography (US).MethodsForty-nine critically ill patients (age: 59 ± 21 years) with an APACHE II admission score ≥13 were randomly assigned after stratification upon admission to receive daily EMS sessions of both lower extremities (EMS-group) or to the control group (control group). Muscle mass was evaluated with US, by measuring the cross sectional diameter (CSD) of the vastus intermedius and the rectus femoris of the quadriceps muscle.ResultsTwenty-six patients were finally evaluated. Right rectus femoris and right vastus intermedius CSD decreased in both groups (EMS group: from 1.42 ± 0.48 to 1.31 ± 0.45 cm, P = 0.001 control group: from 1.59 ± 0.53 to 1.37 ± 0.5 cm, P = 0.002; EMS group: from 0.91 ± 0.39 to 0.81 ± 0.38 cm, P = 0.001 control group: from 1.40 ± 0.64 to 1.11 ± 0.56 cm, P = 0.004, respectively). However, the CSD of the right rectus femoris decreased significantly less in the EMS group (-0.11 ± 0.06 cm, -8 ± 3.9%) as compared to the control group (-0.21 ± 0.10 cm, -13.9 ± 6.4%; P < 0.05) and the CSD of the right vastus intermedius decreased significantly less in the EMS group (-0.10 ± 0.05 cm, -12.5 ± 7.4%) as compared to the control group (-0.29 ± 0.28 cm, -21.5 ± 15.3%; P < 0.05).ConclusionsEMS is well tolerated and seems to preserve the muscle mass of critically ill patients. The potential use of EMS as a preventive and rehabilitation tool in ICU patients with polyneuromyopathy needs to be further investigated.Trial Registrationclinicaltrials.gov: NCT00882830

Interval training as an alternative modality to continuous exercise in patients with COPD

Understanding of what constitutes a training load adequate to induce training effects in patients with chronic obstructive pulmonary disease (COPD) is still evolving. The present study investigated whether interval training (IT) is effective in terms of inducing measurable improvements in physiological response and compared its effects on exercise tolerance (ET) and quality of life to those of continuous training (CT). Thirty-six COPD patients, with a forced expiratory volume in one second of 45±4% of the predicted value (mean±sem), were randomly assigned to CT (exercise at 50% of baseline peak work-rate) or IT (work for 30 s at 100% of peak work-rate alternating with 30‐s rest intervals) groups that cycled 40 min·day−1 and 2 days·week−1 for 12 weeks. After training, both groups showed significantly improved ET (IT, 57±6 to 71±8 W; CT, 57±5 to 70±6 W) and total quality-of-life score of the Chronic Respiratory Disease Questionnaire (IT, 77±3 to 88±2; CT, 78±3 to 93±2). At identical levels of exercise, minute ventilation was significantly reduced (IT, 35.8±2.5 to 31.7±2.5 L·min−1; CT, 36.4±2.7 to 32.5±2.7 L·min−1). The magnitude of improvement in these variables was not significantly different among groups. The present data expand on the principles of exercise prescription for chronic obstructive pulmonary disease patients by demonstrating that interval training elicits substantial training effects, which are similar in magnitude to those produced by continuous training at half the exercise intensity but double the exercise time.

Electrical muscle stimulation prevents critical illness polyneuromyopathy: a randomized parallel intervention trial

IntroductionCritical illness polyneuromyopathy (CIPNM) is a common complication of critical illness presenting with muscle weakness and is associated with increased duration of mechanical ventilation and weaning period. No preventive tool and no specific treatment have been proposed so far for CIPNM. Electrical muscle stimulation (EMS) has been shown to be beneficial in patients with severe chronic heart failure and chronic obstructive pulmonary disease. Aim of our study was to assess the efficacy of EMS in preventing CIPNM in critically ill patients.MethodsOne hundred and forty consecutive critically ill patients with an APACHE II score ≥ 13 were randomly assigned after stratification to the EMS group (n = 68) (age:61 ± 19 years) (APACHE II:18 ± 4, SOFA:9 ± 3) or to the control group (n = 72) (age:58 ± 18 years) (APACHE II:18 ± 5, SOFA:9 ± 3). Patients of the EMS group received daily EMS sessions. CIPNM was diagnosed clinically with the medical research council (MRC) scale for muscle strength (maximum score 60, <48/60 cut off for diagnosis) by two unblinded independent investigators. Duration of weaning from mechanical ventilation and intensive care unit (ICU) stay were recorded.ResultsFifty two patients could be finally evaluated with MRC; 24 in the EMS group and 28 in the control group. CIPNM was diagnosed in 3 patients in the EMS group as compared to 11 patients in the control group (OR = 0.22; CI: 0.05 to 0.92, P = 0.04). The MRC score was significantly higher in patients of the EMS group as compared to the control group [58 (33 to 60) vs. 52 (2 to 60) respectively, median (range), P = 0.04). The weaning period was statistically significantly shorter in patients of the EMS group vs. the control group [1 (0 to 10) days vs. 3 (0 to 44) days, respectively, median (range), P = 0.003].ConclusionsThis study suggests that daily EMS sessions prevent the development of CIPNM in critically ill patients and also result in shorter duration of weaning. Further studies should evaluate which patients benefit more from EMS and explore the EMS characteristics most appropriate for preventing CIPNM.Trial Registration NumberClinicalTrials.gov NCT00882830

Effects of exercise rehabilitation program on heart rate recovery in patients with chronic heart failure

Background Heart rate recovery (HRR1) immediately after exercise reflects parasympathetic activity, which is markedly attenuated in chronic heart failure (CHF) patients. The aim of our study was to examine both continuous and interval exercise training effects on HRR1 in these patients. Design The population study consisted of 29 stable CHF patients that participated at a rehabilitation program of 36 sessions, three times per week. Of the 29 patients, 24 completed the program. Patients were randomly assigned to interval {n = 10 [100% peak work rate (WRp) for 30 s, alternating with rest for 30 s]} and to continuous training [n = 14 (50%WRp)]. Methods All patients performed a symptom-limited cardiopulmonary exercise test on a cycle ergometer before and after the completion of the program. Measurements included peak oxygen uptake (VO2p), anaerobic threshold (AT), WRp, first degree slope of VO2 during the first minute of recovery (VO2/t-slope), chronotropic response [% chronotropic reserve (CR) = (peak HR - resting HR) × 100/(220 - age - resting HR)], HRR1 (HR difference from peak exercise to one minute after). Results After the completion of the rehabilitation program there was a significant increase of WRp, VO2p, AT and VO2/t-slope (by 30%, P=0.01; 6%, P=0.01; 10%, P=0.02; and 27%, P=0.03 respectively for continuous training and by 21%, P≤0.05; 8%, P=0.01; 6%, P=NS; and 48%, P=0.02 respectively for interval training). However, only patients exercised under the continuous training regime had a significant increase in HRR1 (15.0±9.0 to 24.0±12bpm; P=0.02) and CR (57±19 to 72±21%, P=0.02), in contrast with those assigned to interval training (HRR1: 21 ± 11 to 21 ± 8 bpm; P=NS and CR: 57 ± 18 to 59 ± 21%, P=NS). Conclusions Both continuous and interval exercise training program improves exercise capacity in CHF patients. However, continuous rather than interval exercise training improves early HRR1, a marker of parasympathetic activity, suggesting a greater contribution to the autonomic nervous system.

Predisposing factors for critical illness polyneuromyopathy in a multidisciplinary intensive care unit.

Objective –  To investigate risk factors of critical illness polyneuromyopathy (CIPM) in a general multidisciplinary intensive care unit (ICU).

Neuromuscular electrical stimulation for preventing skeletal-muscle weakness and wasting in critically ill patients: a systematic review

BackgroundNeuromuscular electrical stimulation (NMES) therapy may be useful in early musculoskeletal rehabilitation during acute critical illness. The objective of this systematic review was to evaluate the effectiveness of NMES for preventing skeletal-muscle weakness and wasting in critically ill patients, in comparison with usual care.MethodsWe searched PubMed, CENTRAL, CINAHL, Web of Science, and PEDro to identify randomized controlled trials exploring the effect of NMES in critically ill patients, which had a well-defined NMES protocol, provided outcomes related to skeletal-muscle strength and/or mass, and for which full text was available. Two independent reviewers extracted data on muscle-related outcomes (strength and mass), and participant and intervention characteristics, and assessed the methodological quality of the studies. Owing to the lack of means and standard deviations (SDs) in some studies, as well as the lack of baseline measurements in two studies, it was impossible to conduct a full meta-analysis. When means and SDs were provided, the effect sizes of individual outcomes were calculated, and otherwise, a qualitative analysis was performed.ResultsThe search yielded 8 eligible studies involving 172 patients. The methodological quality of the studies was moderate to high. Five studies reported an increase in strength or better preservation of strength with NMES, with one study having a large effect size. Two studies found better preservation of muscle mass with NMES, with small to moderate effect sizes, while no significant benefits were found in two other studies.ConclusionsNMES added to usual care proved to be more effective than usual care alone for preventing skeletal-muscle weakness in critically ill patients. However, there is inconclusive evidence for its benefit in prevention of muscle wasting.

Respiratory Muscles Performance Is Related to Oxygen Kinetics During Maximal Exercise and Early Recovery in Patients With Congestive Heart Failure

BACKGROUND Dyspnea and fatigue are the main causes of exercise limitation in chronic heart failure (CHF) patients, whose peak inspiratory (Pi(max)) and expiratory pressures (Pe(max)) are often reduced. The aim of this study was to examine the relationship between respiratory muscle performance and oxygen kinetics. METHODS AND RESULTS A total of 55 patients (NYHA class I to III) and 11 healthy subjects underwent cardiopulmonary exercise tests (CPET) on a treadmill. In 45 of the 55 patients (group I) and in healthy subjects (group II), pulmonary function tests, Pi(max), and Pe(max) were measured before and 10 minutes after exercise, and oxygen kinetics were monitored throughout and during early recovery from CPET. The first degree slope of oxygen consumption (VO(2)) decline during early recovery (VO(2)/t-slope) and VO(2) half-time (T(1/2)) were calculated. In 10 of the 55 CHF patients (group III), the measurements of Pi(max) were repeated 2, 5, and 10 minutes after CPET. A >10% reduction in Pi(max) after CPET (subgroup IA) was measured in 11 of 45 patients. In contrast, 34 of 45 CHF patients (subgroup IB) and all control subjects (group II) had Pi(max)>90% of baseline value after CPET. Subgroup IA patients had significantly lower peak VO(2) (13.5+/-2.1 versus 17.8+/-5.6 mL. kg(-1). min(-1); P<0.001), lower anaerobic thresholds (10.1+/-2.4 versus 13.6+/-4.6 mL. kg(-1). min(-1); P=0.003) and lower VO(2)/t-slopes (0.365+/-0.126 versus 0.519+/-0.227 L. min(-1). min(-1); P=0.008) than subgroup IB patients. CONCLUSIONS The reduction of Pi(max) after exercise is associated with prolonged early recovery of oxygen kinetics, which may explain, in part, the role played by respiratory muscles in exercise intolerance in CHF patients.

Short-term Systemic Effect of Electrical Muscle Stimulation in Critically Ill Patients

BACKGROUND Our study assessed the short-term effect of electrical muscle stimulation (EMS) of the lower extremities on the thenar muscle microcirculation of patients who are critically ill. METHODS Twenty-nine hospital ICU patients (19 men; mean [+/- SD] age, 58 +/- 19 years; mean acute physiology and chronic health evaluation score, 17 +/- 5; mean sequential organ failure assessment score, 9 +/- 3) underwent a 45-min session of EMS of the lower extremities. BP and heart rate were measured, and blood samples were retrieved. Tissue oxygen saturation (Sto(2)) was assessed with near infrared spectroscopy at the thenar muscle with a vascular occlusion before and after EMS. A control group of six patients who were critically ill (4 men; mean age, 50 +/- 19 years) also were included in the study. RESULTS The mean Sto(2) did not differ significantly before and after the EMS session (81 +/- 16% vs 83 +/- 16%, respectively). The oxygen consumption rate during vascular occlusion differed significantly before the beginning and at the end of the session (20 +/- 9%/min vs 22 +/- 9%/min, respectively; p < 0.05). The reperfusion rate differed significantly before the beginning and at the end of the session (299 +/- 177%/min vs 375 +/- 182%/min, respectively; p < 0.05). Heart rate increased significantly at the end of the session (94 +/- 16 beats/min vs 99 +/- 16 beats/min, respectively; p < 0.05) as did systolic BP (127 +/- 21 mm Hg vs 133 +/- 23 mm Hg; p < 0.05, respectively). The Sto(2) value did not differ between the two measurements in control patients. CONCLUSION The data suggest that EMS has a systemic effect on microcirculation. These results suggest that further studies are needed to explore the potential use of EMS as a preventive and rehabilitation tool in critically ill patients.

Dynamic hyperinflation and tolerance to interval exercise in patients with advanced COPD

Dynamic hyperinflation (DH) contributes importantly to the limitation of constant-load exercise (CLE) in patients with chronic obstructive pulmonary disease (COPD). However, its role in the limitation of interval exercise (IE) remains to be explored. The change (Δ) in inspiratory capacity (IC) was measured to reflect changes in DH in 27 COPD patients (forced expiratory volume in one second mean±sem % predicted: 40±3) at the end of a symptom-limited CLE test at 80% of peak work capacity (WRmax) and an IE test at 100% WRmax (30 s of work, alternated with 30 s of unloaded pedalling). At the limit of tolerance in both IE and CLE, patients exhibited similar DH (ΔIC: 0.39±0.05 L and 0.45±0.05 L, respectively). However, exercise endurance time (tend) for IE (32.7±3.0 min) was significantly greater than for CLE (10.3±1.6 min). The IE tend correlated with resting IC, expressed as % pred normal. At 30 and 90% of total IE tend, ΔIC (0.43±0.06 and 0.39±0.05 L, respectively) and minute ventilation (31.1±1.6 and 32.7±2.2 L·min−1, respectively) were not significantly different. Resting hyperinflation helps to explain the limitation of interval exercise. Implementation of interval exercise for rehabilitation should provide important clinical benefits because it prolongs exercise endurance time and allows sustaining higher stable ventilation.

The effects of exercise training on the kinetics of oxygen uptake in patients with chronic heart failure.

Background Prolonged oxygen uptake kinetics (O2 kinetics), following the onset of a constant workload of exercise has been associated with a poor prognosis in patients with chronic heart failure. This study aimed to determine both continuous and interval training effects on the different O2-kinetics phases in these patients. Design Twenty-one patients (60 ± 8 years) with stable chronic heart failure participated in a 36-session exercise rehabilitation program (three times weekly). Patients were randomly assigned to interval training (n = 11; 100% of peak work rate for 30 s, alternating with 30s-rest) and to continuous training (n = 10; 50% of peak work rate). Methods Before and after the completion of the program, all patients performed both incremental symptom-limited and constant workload submaximal cardiopulmonary exercise tests. Phase I O2-kinetics was evaluated by time (t), from the start of exercise until the onset of decreased respiratory exchange ratio and phase II by the time constant (τ) of the response from the end of phase I until steady state. Results After training, there was a significant increase in peak oxygen uptake and peak work rate in both continuous (15.3 ± 4.4 vs. 16.6 ± 4.5 ml/kg per min; P=0.03 and 81.8 ± 40.1 vs. 94.7 ± 46.1 W; P=0.03) and interval training groups (14.2 ± 3.1 vs. 15.4 ± 4.2 ml/kg per min; P=0.03 and 82.5 ± 24.1 vs. 93.7 ± 30.1 W; P=0.04). Patients who underwent interval training had a significant decrease in t (39.7 ± 3.7 to 36.1 ± 6.9s; P=0.05), but not τ (59.6 ± 9.4 to 58.9 ± 8.5 s; P=ns), whereas those assigned to continuous training had a significant decrease in both t (40.6 ± 6.1 to 36.4 ± 5.4 s; P=0.01) and τ (63.3 ± 23.6 to 42.5 ± 16.7 s; P=0.03). Conclusions Exercise training improves O2 kinetics in chronic heart failure patients. Both continuous and interval training improve phase I O2-kinetics, but continuous training results in superior improvement of the phase II O2-kinetics, an indirect index of muscle oxidative capacity.