Differential contractile response of critically ill patients to neuromuscular electrical stimulation

Unlocking the potential of neuromuscular electrical stimulation: achieving physical activity benefits for all abilities

Neuromuscular Electrical Stimulation (NMES) uses electrical impulses to induce muscle contractions, providing benefits in rehabilitation, muscle activation, and as an adjunct to exercise, particularly for individuals experiencing immobilization or physical disability. NMES technology has significantly progressed, with advancements in device development and a deeper understanding of treatment parameters, such as frequency, intensity, and pulse duration. These improvements have expanded NMES applications beyond rehabilitation to include enhanced post-exercise recovery, improved blood glucose uptake, and increased lower limb venous return, potentially reducing thrombotic risks. Despite its benefits, NMES faces challenges in user compliance, often due to improper electrode placement and discomfort during treatment. Research highlights the importance of optimizing stimulation parameters, including electrode positioning, to improve both comfort and treatment efficacy. Recent innovations, such as automated processes for locating optimal stimulation points and adaptable electrode sizes, aim to address these issues. When combined with wearable technologies, these innovations could improve NMES treatment adherence and deliver more consistent, long-term therapeutic outcomes for patients with various physical limitations. Together, these developments indicate a promising future for NMES, presenting a valuable tool to enhance the benefits of physical activity across diverse populations, from rehabilitative care to broader health and wellness applications.

[Positioning therapy for intensive care patients]

The current S3 guideline, "Positioning Therapy and Mobilization of Critically Ill Patients in Intensive Care Units", introduces methodological changes and substantive updates compared to the previous version. Additionally, new evidence-based insights with specified PICO questions have been integrated, aiming for a more precise application of recommendations in clinical practice and thus enhancing the care of critically ill patients.A notable aspect is the more nuanced approach to early mobilization, which is recommended to commence within the first 72 hours of ICU admission. A staged concept and score-based mobilization schema facilitate improved patient rehabilitation. Mobilization should be standard of care, i.e., immobilization should be ordered by the physician. The guideline provides suggestions for the duration and additional mobilization measures to ensure patients stand, transfer actively from bed to chair, or walk as frequently as possible. These recommendations apply even during ECMO therapy, highlighting the importance of early mobilization.Further updates include semi-recumbent positions of at least 40° in intubated patients, with careful consideration of potential side effects. Continuous lateral rotation therapy (CLRT) is not advised due to the progress in intensive care therapy, shifting from deep sedation toward responsive patient management.Prone positioning (PP) involves rotating the patient 180° onto the ventral side. It is recommended as a therapeutic option for invasively ventilated patients with ARDS and impaired arterial oxygenation (PaO2/FiO2 <150mmHg), with a recommended minimum duration of 12 hours, ideally 16 hours. Special recommendations apply, for example, to COVID-19 patients with acute hypoxemic respiratory failure, where awake proning should be considered.Additionally, new chapters have been introduced focusing on assistive devices and neuromuscular electrical stimulation.

Pathophysiology and Therapeutic Management of Bone Loss in Patients with Critical Illness

Patients with critical illnesses are at higher risk of comorbidities, which can include bone mineral density loss, bone turnover marker increase, and fragility fractures. Patients admitted to intensive care units (ICUs) have a higher risk of bone fractures. Since hypermetabolism is a characteristic of ICU patients, such patients are often rapidly affected by systemic deterioration, which often results in systemic wasting disease. Major risk factors for ICU-related bone loss include physical restraint, inflammation, neuroendocrine stress, malnutrition, and medications. A medical history of critical illness should be acknowledged as a risk factor for impaired bone metabolism. Bone loss associated with ICU admission should be recognized as a key component of post-intensive care syndrome, and further research that focuses on treatment protocols and prevention strategies is required. Studies aimed at maintaining gut integrity have emphasized protein administration and nutrition, while research is ongoing to evaluate the therapeutic benefits of anti-resorptive agents and physical therapy. This review examines both current and innovative clinical strategies that are used for identifying risk factors of bone loss. It provides an overview of perioperative outcomes and discusses the emerging novel treatment modalities. Furthermore, the review presents future directions in the treatment of ICU-related bone loss.

Understanding Post-Sepsis Syndrome: How Can Clinicians Help?

Sepsis is a global health challenge, with over 49 million cases annually. Recent medical advancements have increased in-hospital survival rates to approximately 80%, but the escalating incidence of sepsis, owing to an ageing population, rise in chronic diseases, and antibiotic resistance, have also increased the number of sepsis survivors. Subsequently, there is a growing prevalence of "post-sepsis syndrome" (PSS). This syndrome includes long-term physical, medical, cognitive, and psychological issues after recovering from sepsis. PSS puts survivors at risk for hospital readmission and is associated with a reduction in health- and life span, both at short and long term, after hospital discharge. Comprehensive understanding of PSS symptoms and causative factors is vital for developing optimal care for sepsis survivors, a task of prime importance for clinicians. This review aims to elucidate our current knowledge of PSS and its relevance in enhancing post-sepsis care provided by clinicians.

Insulin signaling in skeletal muscle during inflammation and/or immobilisation

BACKGROUND

The decline in the downstream signal transduction pathway of anabolic hormone, insulin, could play a key role in the muscle atrophy and insulin resistance observed in patients with intensive care unit acquired weakness (ICUAW). This study investigated the impact of immobilisation via surgical knee and ankle fixation and inflammation via Corynebacterium parvum injection, alone and in combination, as risk factors for altering insulin transduction and, therefore, their role in ICUAW.

RESULTS

Muscle weight was significantly decreased due to immobilisation [estimated effect size (95% CI) - 0.10 g (- 0.12 to - 0.08); p < 0.001] or inflammation [estimated effect size (95% CI) - 0.11 g (- 0.13 to - 0.09); p < 0.001] with an additive effect of both combined (p = 0.024). pAkt was only detectable after insulin stimulation [estimated effect size (95% CI) 85.1-fold (76.2 to 94.0); p < 0.001] irrespective of the group and phosphorylation was not impaired by the different perturbations. Nevertheless, the phosphorylation of GSK3 observed in the control group after insulin stimulation was decreased in the immobilisation [estimated effect size (95% CI) - 40.2 (- 45.6 to - 34.8)] and inflammation [estimated effect size (95% CI) - 55.0 (- 60.4 to - 49.5)] groups. The expression of phosphorylated GS (pGS) was decreased after insulin stimulation in the control group and significantly increased in the immobilisation [estimated effect size (95% CI) 70.6-fold (58.8 to 82.4)] and inflammation [estimated effect size (95% CI) 96.7 (85.0 to 108.5)] groups.

CONCLUSIONS

Both immobilisation and inflammation significantly induce insulin resistance, i.e., impair the insulin signaling pathway downstream of Akt causing insufficient GSK phosphorylation and, therefore, its activation which caused increased glycogen synthase phosphorylation, which could contribute to muscle atrophy of immobilisation and inflammation.

Disintegration of the NuRD Complex in Primary Human Muscle Stem Cells in Critical Illness Myopathy

Critical illness myopathy (CIM) is an acquired, devastating, multifactorial muscle-wasting disease with incomplete recovery. The impact on hospital costs and permanent loss of quality of life is enormous. Incomplete recovery might imply that the function of muscle stem cells (MuSC) is impaired. We tested whether epigenetic alterations could be in part responsible. We characterized human muscle stem cells (MuSC) isolated from early CIM and analyzed epigenetic alterations (CIM n = 15, controls n = 21) by RNA-Seq, immunofluorescence, analysis of DNA repair, and ATAC-Seq. CIM-MuSC were transplanted into immunodeficient NOG mice to assess their regenerative potential. CIM-MuSC exhibited significant growth deficits, reduced ability to differentiate into myotubes, and impaired DNA repair. The chromatin structure was damaged, as characterized by alterations in mRNA of histone 1, depletion or dislocation of core proteins of nucleosome remodeling and deacetylase complex, and loosening of multiple nucleosome-spanning sites. Functionally, CIM-MuSC had a defect in building new muscle fibers. Further, MuSC obtained from the electrically stimulated muscle of CIM patients was very similar to control MuSC, indicating the impact of muscle contraction in the onset of CIM. CIM not only affects working skeletal muscle but has a lasting and severe epigenetic impact on MuSC.

Efficacy and safety of neuromuscular electrical stimulation in the prevention of pressure injuries in critically ill patients: a randomized controlled trial

Background

Pressure injuries (PIs), especially in the sacral region are frequent, costly, and increase morbidity and mortality of patients in an intensive care unit (ICU). These injuries can occur as a result of prolonged pressure and/or shear forces. Neuromuscular electrical stimulation (NMES) can increase muscle mass and improve local circulation, potentially reducing the incidence of PI.

Methods

We performed a randomized controlled trial to assess the efficacy and safety of NMES in preventing PI in critically ill patients. We included patients with a period of less than 48 h in the ICU, aged ≥ 18 years. Participants were randomly selected (1:1 ratio) to receive NMES and usual care (NMES group) or only usual care (control group—CG) until discharge, death, or onset of a PI. To assess the effectiveness of NMES, we calculated the relative risk (RR) and number needed to treat (NNT). We assessed the muscle thickness of the gluteus maximus by ultrasonography. To assess safety, we analyzed the effects of NMES on vital signs and checked for the presence of skin burns in the stimulated areas. Clinical outcomes were assessed by time on mechanical ventilation, ICU mortality rate, and length of stay in the ICU.

Results

We enrolled 149 participants, 76 in the NMES group. PIs were present in 26 (35.6%) patients in the CG and 4 (5.3%) in the NMES group (p ˂ 0.001). The NMES group had an RR = 0.15 (95% CI 0.05–0.40) to develop a PI, NNT = 3.3 (95% CI 2.3–5.9). Moreover, the NMES group presented a shorter length of stay in the ICU: Δ = − 1.8 ± 1.2 days, p = 0.04. There was no significant difference in gluteus maximus thickness between groups (CG: Δ = − 0.37 ± 1.2 cm vs. NMES group: Δ = 0 ± 0.98 cm, p = 0.33). NMES did not promote deleterious changes in vital signs and we did not detect skin burns.

Conclusions

NMES is an effective and safe therapy for the prevention of PI in critically ill patients and may reduce length of stay in the ICU.

Trial registration RBR-8nt9m4. Registered prospectively on July 20th, 2018, https://ensaiosclinicos.gov.br/rg/RBR-8nt9m4

Therapeutic Potential of Electromyostimulation (EMS) in Critically Ill Patients—A Systematic Review

Ample evidence exists that intensive care unit (ICU) treatment and invasive ventilation induce a transient or permanent decline in muscle mass and function. The functional deficit is often called ICU-acquired weakness with critical illness polyneuropathy (CIP) and/or myopathy (CIM) being the major underlying causes. Histopathological studies in ICU patients indicate loss of myosin filaments, muscle fiber necrosis, atrophy of both muscle fiber types as well as axonal degeneration. Besides medical prevention of risk factors such as sepsis, hyperglycemia and pneumonia, treatment is limited to early passive and active mobilization and one third of CIP/CIM patients discharged from ICU never regain their pre-hospitalization constitution. Electromyostimulation [EMS, also termed neuromuscular electrical stimulation (NMES)] is known to improve strength and function of healthy and already atrophied muscle, and may increase muscle blood flow and induce angiogenesis as well as beneficial systemic vascular adaptations. This systematic review aimed to investigate evidence from randomized controlled trails (RCTs) on the efficacy of EMS to improve the condition of critically ill patients treated on ICU. A systematic search of the literature was conducted using PubMed (Medline), CENTRAL (including Embase and CINAHL), and Google Scholar. Out of 1,917 identified records, 26 articles (1,312 patients) fulfilled the eligibility criteria of investigating at least one functional measure including muscle function, functional independence, or weaning outcomes using a RCT design in critically ill ICU patients. A qualitative approach was used, and results were structured by 1) stimulated muscles/muscle area (quadriceps muscle only; two to four leg muscle groups; legs and arms; chest and abdomen) and 2) treatment duration (≤10 days, >10 days). Stimulation parameters (impulse frequency, pulse width, intensity, duty cycle) were also collected and the net EMS treatment time was calculated. A high grade of heterogeneity between studies was detected with major cofactors being the analyzed patient group and selected outcome variable. The overall efficacy of EMS was inconclusive and neither treatment duration, stimulation site or net EMS treatment time had clear effects on study outcomes. Based on our findings, we provide practical recommendations and suggestions for future studies investigating the therapeutic efficacy of EMS in critically ill patients.

Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/], identifier [CRD42021262287].

Sex-Specific Aspects of Skeletal Muscle Metabolism in the Clinical Context of Intensive Care Unit-Acquired Weakness

(1) Background: Female sex is considered a risk factor for Intensive Care Unit-Acquired Weakness (ICUAW). The aim is to investigate sex-specific aspects of skeletal muscle metabolism in the context of ICUAW. (2) Methods: This is a sex-specific sub-analysis from two prospectively conducted trials examining skeletal muscle metabolism and advanced muscle activating measures in critical illness. Muscle strength was assessed by Medical Research Council Score. The insulin sensitivity index was analyzed by hyperinsulinemic-euglycemic (HE) clamp. Muscular metabolites were studied by microdialysis. M. vastus lateralis biopsies were taken. The molecular analysis included protein degradation pathways. Morphology was assessed by myocyte cross-sectional area (MCSA). Multivariable linear regression models for the effect of sex on outcome parameters were performed. (3) Results: n = 83 (♂n = 57, 68.7%; ♀n = 26, 31.3%) ICU patients were included. ICUAW was present in 81.1%♂ and in 82.4%♀ at first awakening (p = 0.911) and in 59.5%♂ and in 70.6%♀ at ICU discharge (p = 0.432). Insulin sensitivity index was reduced more in women than in men (p = 0.026). Sex was significantly associated with insulin sensitivity index and MCSA of Type IIa fibers in the adjusted regression models. (4) Conclusion: This hypothesis-generating analysis suggests that more pronounced impairments in insulin sensitivity and lower MCSA of Type IIa fibers in critically ill women may be relevant for sex differences in ICUAW.

Novel protocol combining physical and nutrition therapies, Intensive Goal-directed REhabilitation with Electrical muscle stimulation and Nutrition (IGREEN) care bundle

Background

Although the combination of rehabilitation and nutrition may be important for the prevention of intensive care unit (ICU)-acquired weakness, a protocolized intervention of this combination has not yet been reported. We herein developed an original combined protocol and evaluated its efficacy.

Methods

In this single-center historical control study, we enrolled adult patients admitted to the ICU. Patients in the control group received standard care, while those in the intervention group received the protocol-based intervention. The ICU mobility scale was used to set goals for early mobilization and a neuromuscular electrical stimulation was employed when patients were unable to stand. The nutritional status was assessed for nutritional therapy, and target calorie delivery was set at 20 or 30 kcal/kg/day and target protein delivery at 1.8 g/kg/day in the intervention group. The primary endpoint was a decrease in femoral muscle volume in 10 days assessed by computed tomography.

Results

Forty-five patients in the control group and 56 in the intervention group were included in the analysis. Femoral muscle volume loss was significantly lower in the intervention group (11.6 vs 14.5%, p = 0.03). The absolute risk difference was 2.9% (95% CI 0.1–5.6%). Early mobilization to a sitting position by day 10 was achieved earlier (p = 0.03), and mean calorie delivery (20.1 vs. 16.8 kcal/kg/day, p = 0.01) and mean protein delivery (1.4 vs. 0.8 g/kg/day, p < 0.01) were higher in the intervention group.

Conclusion

The protocolized intervention, combining early mobilization and high-protein nutrition, contributed to the achievement of treatment goals and prevention of femoral muscle volume loss.

Trial registration number

The present study is registered at the University Hospital Medical Information Network-clinical trials registry (UMIN000040290, Registration date: May 7, 2020).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03827-8.

Patterns of vascular response immediately after passive mobilization in patients with sepsis: an observational transversal study

Sepsis is a serious organ dysfunction leading to endothelial damage in critical patients. Physiologically, there is an augment of vascular diameter in response to increased vascular blood flow and shear stress stimulus. However, the pattern of vascular response in face of passive mobilization (PM), an early mobilization physical strategy, has not yet been explored in patients with sepsis. To explore patterns of vascular response to PM and associations with clinical and cardiovascular profile in patients with sepsis. Cross-sectional, single-arm study. Thirty-two patients diagnosed with sepsis were enrolled. Vascular response was assessed by flow-mediated dilation (FMD) using brachial artery ultrasound, before and after PM. The PM (to assess the response pattern) and SR (shear rate) were also calculated. PM protocol consisted of knees, hips, wrists, elbows, shoulders, dorsiflexion/plantar flexion movements 3 × 10 repetitions each (15 min). Arterial stiffness was assessed by Sphygmocor®, by analyzing the morphology and pulse wave velocity. Cardiac autonomic modulation (CAM) was assessed by analyzing heart rate variability indexes (mean HR, RMSSD, LF, HF, ApEn, SampEn, DFA). Different vascular responses were observed after PM: (1) increased vascular diameter (responders) (n = 13, %FMD = 11.89 ± 5.64) and (2) reduced vascular diameter (non-responders) (n = 19, %FMD= -7.42 ± 6.44). Responders presented a higher non-linear DFA2 index (p = 0.02). There was a positive association between FMD and DFA (r = 0.529; p = 0.03); FMD and SampEn (r = 0.633; p < 0.01). A negative association was identified between FMD and LF (Hz) (r= -0.680; p < 0.01) and IL-6 (r= -0.469; p = 0.037) and SR and CRP (r= -0.427; p = 0.03).

A randomized controlled trial to determine whether beta-hydroxy-beta-methylbutyrate and/or eicosapentaenoic acid improves diaphragm and quadriceps strength in critically Ill mechanically ventilated patients

Background

Intensive care unit acquired weakness is a serious problem, contributing to respiratory failure and reductions in ambulation. Currently, there is no pharmacological therapy for this condition. Studies indicate, however, that both beta-hydroxy-beta-methylbutyrate (HMB) and eicosapentaenoic acid (EPA) increase muscle function in patients with cancer and in older adults. The purpose of this study was to determine whether HMB and/or EPA administration would increase diaphragm and quadriceps strength in mechanically ventilated patients.

Methods

Studies were performed on 83 mechanically ventilated patients who were recruited from the Medical Intensive Care Units at the University of Kentucky. Diaphragm strength was assessed as the trans-diaphragmatic pressure generated by supramaximal magnetic phrenic nerve stimulation (PdiTw). Quadriceps strength was assessed as leg force generated by supramaximal magnetic femoral nerve stimulation (QuadTw). Diaphragm and quadriceps thickness were assessed by ultrasound. Baseline measurements of muscle strength and size were performed, and patients were then randomized to one of four treatment groups (placebo, HMB 3 gm/day, EPA 2 gm/day and HMB plus EPA). Strength and size measurements were repeated 11 days after study entry. ANCOVA statistical testing was used to compare variables across the four experimental groups.

Results

Treatments failed to increase the strength and thickness of either the diaphragm or quadriceps when compared to placebo. In addition, treatments also failed to decrease the duration of mechanical ventilation after study entry.

Conclusions

These results indicate that a 10-day course of HMB and/or EPA does not improve skeletal muscle strength in critically ill mechanically ventilated patients. These findings also confirm previous reports that diaphragm and leg strength in these patients are profoundly low. Additional studies will be needed to examine the effects of other anabolic agents and innovative forms of physical therapy.

Trial registration: ClinicalTrials.gov, NCT01270516. Registered 5 January 2011, https://clinicaltrials.gov/ct2/show/NCT01270516?term=Supinski&draw=2&rank=4.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03737-9.

Does Standard Physical Therapy Increase Quadriceps Strength in Chronically Ventilated Patients? A Pilot Study

OBJECTIVES

Physical therapy is standard care for mechanically ventilated patients, but there is no evidence, using nonvolitional, objective measurements, that physical therapy increases muscle strength in this population. The present study tested the hypothesis that 2 weeks of standard, conventional physical therapy provided at a ventilator weaning facility would increase quadriceps strength in mechanically ventilated patients.

DESIGN

Prospective observational study.

SETTING

Ventilator weaning unit.

PATIENTS

Patients who were transferred from an acute care hospital because of failure to wean from mechanical ventilation and who were receiving physical therapy as prescribed by facility staff.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We employed a novel, nonvolitional objective technique, quadriceps twitch force generation in response to femoral nerve magnetic stimulation, to assess leg strength before and after 2 weeks of conventional physical therapy. The duration and specific exercises provided to patients were also recorded. In a subset of patients, we measured muscle activation intensity using wireless electromyogram recordings. Indices of respiratory function (maximum inspiratory pressure generation and the rapid shallow breathing index) were also assessed. Patients' responses to 2 weeks of physical therapy were poor; on average, quadriceps twitch fell by -1.02 ± 0.71 Newtons. Neither physical therapy duration nor specific forms of exercise were identified to positively impact quadriceps twitch. Electromyogram recordings indicated that during training, muscle activation was poor. Consequently, therapists spent substantial time performing exercises that elicited little muscle activation. Physical therapy did not improve respiratory function.

CONCLUSIONS

Standard physical therapy delivered in a ventilator weaning facility failed to improve quadriceps leg strength in a majority of mechanically ventilated patients. The fact that mechanically ventilated patients fail to achieve high levels of muscle activation during physical therapy provides a potential explanation as to why physical therapy may often be ineffective. We speculate that use of novel methods which increase muscle activation during exercise may improve responses of mechanically ventilated patients to physical therapy.

A reappraisal of the strength-duration test to assess neuromuscular impairment of critically ill patients

INTRODUCTION

Neuromuscular impairment (NMI) affects almost half of critically ill patients. The purpose was to investigate the role of neuromuscular electrical stimulation (NMES) to gain more insight into the nature of the NMI associated with ICU admission. To this aim, we analyzed the strength-duration (S-D) curves of the rectus femoris muscles of ICU patients compared to healthy volunteers.

METHODS

S-D curves were recorded from 44 healthy volunteers and 29 ICU patients. Three electrophysiological parameters were used to classify the neuromuscular function, from grade 0 (normal function), to grade 3 (no evocable muscle contraction). ICU patients underwent electroneurographic peroneal nerve testing (PENT) to analyze NMI by electroneurography (ENG).

RESULTS

Three patients were classified as Grade 0; nine as mild NMI (Grade 1), 13 as Grade 2, and four showed unexcitable muscles (Grade 3). Mean CMAP amplitudes were 6.1, 3.4, 2.9 and 0.81 mV from Grade 0 to Grade 3, respectively. CMAP was inversely correlated to NMI grade (-1.7 mV, R² = 0.946, p < 0.05).

CONCLUSIONS

The normative parameters of the S-D curves obtained by NMES in healthy volunteers allowed identification of NMI in ICU patients. NMES was an affordable tool to evaluate NMI in ICU patients, providing additional information to that obtained by ENG.

Long-term outcomes after critical illness: recent insights

Intensive care survivors often experience post-intensive care sequelae, which are frequently gathered together under the term “post-intensive care syndrome” (PICS). The consequences of PICS on quality of life, health-related costs and hospital readmissions are real public health problems. In the present Viewpoint, we summarize current knowledge and gaps in our understanding of PICS and approaches to management.

Functional electrical stimulation in-bed cycle ergometry in mechanically ventilated patients: a multicentre randomised controlled trial

PURPOSE

To investigate the effect of functional electrical stimulation-assisted cycle ergometry (FES-cycling) on muscle strength, cognitive impairment and related outcomes.

METHODS

Mechanically ventilated patients aged ≥18 years with sepsis or systemic inflammatory response syndrome were randomised to either 60 min of FES-cycling >5 days/week while in the intensive care unit (ICU) plus usual care rehabilitation versus usual care rehabilitation alone, with evaluation of two primary outcomes: (1) muscle strength at hospital discharge and (2) cognitive impairment at 6-month follow-up.

RESULTS

We enrolled 162 participants, across four study sites experienced in ICU rehabilitation in Australia and the USA, to FES-cycling (n=80; mean age±SD 59±15) versus control (n=82; 56±14). Intervention participants received a median (IQR) of 5 (3-9) FES-cycling sessions with duration of 56 (34-63) min/day plus 15 (10-23) min/day of usual care rehabilitation. The control group received 15 (8-15) min/day of usual care rehabilitation. In the intervention versus control group, there was no significant differences for muscle strength at hospital discharge (mean difference (95% CI) 3.3 (-5.0 to 12.1) Nm), prevalence of cognitive impairment at 6 months (OR 1.1 (95% CI 0.30 to 3.8)) or secondary outcomes measured in-hospital and at 6 and 12 months follow-up.

CONCLUSION

In this randomised controlled trial, undertaken at four centres with established rehabilitation programmes, the addition of FES-cycling to usual care rehabilitation did not substantially increase muscle strength at hospital discharge. At 6 months, the incidence of cognitive impairment was almost identical between groups, but potential benefit or harm of the intervention on cognition cannot be excluded due to imprecision of the estimated effect.

TRIAL REGISTRATION NUMBER

ACTRN 12612000528853, NCT02214823.

Early neuromuscular electrical stimulation reduces the loss of muscle mass in critically ill patients - A within subject randomized controlled trial

PURPOSE

To investigate the effect of Neuromuscular Electrical Stimulation (NMES) on muscle thickness, strength and morphological and molecular markers of the quadriceps.

MATERIALS AND METHODS

Adult critically ill patients with an expected prolonged stay received unilateral quadriceps NMES sessions for 7 consecutive days. Before and after the intervention period, quadriceps thickness was measured with ultrasound. After the intervention period, strength was assessed in cooperative patients and muscle biopsies were taken. Multivariable regression was performed to identify factors affecting muscle thickness loss.

RESULTS

Muscle thickness decreased less in the stimulated leg (-6 ± 16% versus -12 ± 15%, p = 0.014, n = 47). Strength was comparable. Opioid administration, minimal muscle contraction and more muscle thickness loss in the non-stimulated muscle were independently associated with better muscle thickness preservation. Stimulated muscles showed a shift towards larger myofibers and higher MyHC-I gene expression. NMES did not affect gene expression of other myofibrillary proteins, MuRF-1 or atrogin-1. Signs of myofiber necrosis and inflammation were comparable for both muscles.

CONCLUSIONS

NMES attenuated the loss of muscle mass, but not of strength, in critically ill patients. Preservation of muscle mass was more likely in patients receiving opioids, patients with a minimal muscle contraction during NMES and patients more prone to lose muscle mass.

TRIAL REGISTRATION

clinicaltrials.govNCT02133300.

Upper limb muscle atrophy associated with in-hospital mortality and physical function impairments in mechanically ventilated critically ill adults: a two-center prospective observational study

Background

Lower limb muscle atrophy is often observed in critically ill patients. Although upper limb muscles can undergo atrophy, it remains unclear how this atrophy is associated with clinical outcomes. We hypothesized that this atrophy is associated with mortality and impairments in physical function.

Methods

In this two-center prospective observational study, we included adult patients who were expected to require mechanical ventilation for > 48 h and remain in the intensive care unit (ICU) for > 5 days. We used ultrasound to evaluate the cross-sectional area of the biceps brachii on days 1, 3, 5, and 7 and upon ICU discharge along with assessment of physical functions. The primary outcome was the relationship between muscle atrophy ratio and in-hospital mortality on each measurement day, which was assessed using multivariate analysis. The secondary outcomes were the relationships between upper limb muscle atrophy and Medical Research Council (MRC) score, handgrip strength, ICU Mobility Scale (IMS) score, and Functional Status Score for the ICU (FSS-ICU).

Results

Sixty-four patients (43 males; aged 70 ± 13 years) were enrolled. The Acute Physiology and Chronic Health Evaluation (APACHE) II score was 27 (22–30), and in-hospital mortality occurred in 21 (33%) patients. The decreased cross-sectional area of the biceps brachii was not associated with in-hospital mortality on day 3 (p = 0.43) but was associated on days 5 (p = 0.01) and 7 (p < 0.01), which was confirmed after adjusting for sex, age, and APACHE II score. In 27 patients in whom physical functions were assessed, the decrease of the cross-sectional area of the biceps brachii was associated with MRC score (r = 0.47, p = 0.01), handgrip strength (r = 0.50, p = 0.01), and FSS-ICU (r = 0.56, p < 0.01), but not with IMS score (r = 0.35, p = 0.07) upon ICU discharge.

Conclusions

Upper limb muscle atrophy was associated with in-hospital mortality and physical function impairments; thus, it is prudent to monitor it. (321 words)

Trial registration

UMIN 000031316. Retrospectively registered on 15 February 2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-020-00507-7.

Breath-synchronized electrical stimulation of the expiratory muscles in mechanically ventilated patients: a randomized controlled feasibility study and pooled analysis

BACKGROUND

Expiratory muscle weakness leads to difficult ventilator weaning. Maintaining their activity with functional electrical stimulation (FES) may improve outcome. We studied feasibility of breath-synchronized expiratory population muscle FES in a mixed ICU population ("Holland study") and pooled data with our previous work ("Australian study") to estimate potential clinical effects in a larger group.

METHODS

Holland: Patients with a contractile response to FES received active or sham expiratory muscle FES (30 min, twice daily, 5 days/week until weaned). Main endpoints were feasibility (e.g., patient recruitment, treatment compliance, stimulation intensity) and safety. Pooled: Data on respiratory muscle thickness and ventilation duration from the Holland and Australian studies were combined (N = 40) in order to estimate potential effect size. Plasma cytokines (day 0, 3) were analyzed to study the effects of FES on systemic inflammation.

RESULTS

Holland: A total of 272 sessions were performed (active/sham: 169/103) in 20 patients (N = active/sham: 10/10) with a total treatment compliance rate of 91.1%. No FES-related serious adverse events were reported. Pooled: On day 3, there was a between-group difference (N = active/sham: 7/12) in total abdominal expiratory muscle thickness favoring the active group [treatment difference (95% confidence interval); 2.25 (0.34, 4.16) mm, P = 0.02] but not on day 5. Plasma cytokine levels indicated that early FES did not induce systemic inflammation. Using a survival analysis approach for the total study population, median ventilation duration and ICU length of stay were 10 versus 52 (P = 0.07), and 12 versus 54 (P = 0.03) days for the active versus sham group. Median ventilation duration of patients that were successfully extubated was 8.5 [5.6-12.2] versus 10.5 [5.3-25.6] days (P = 0.60) for the active (N = 16) versus sham (N = 10) group, and median ICU length of stay was 10.5 [8.0-14.5] versus 14.0 [9.0-19.5] days (P = 0.36) for those active (N = 16) versus sham (N = 8) patients that were extubated and discharged alive from the ICU. During ICU stay, 3/20 patients died in the active group versus 8/20 in the sham group (P = 0.16).

CONCLUSION

Expiratory muscle FES is feasible in selected ICU patients and might be a promising technique within a respiratory muscle-protective ventilation strategy. The next step is to study the effects on weaning and ventilator liberation outcome.

TRIAL REGISTRATION

ClinicalTrials.gov, ID NCT03453944. Registered 05 March 2018-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03453944 .