Lactate production without hypoxia in skeletal muscle during electrical cycling: Crossover study of femoral venous-arterial differences in healthy volunteers

Illusory movements for immobile patients with extensive burns (IMMOBILE): A randomized, controlled, cross-over trial

INTRODUCTION

Patients who have sustained extensive burns frequently exhibit substantial damage to skeletal muscle and associated complications. The rehabilitation of these patients can be challenging due to the nature of the injury and the subsequent complications. Nevertheless, there is a possibility that functional proprioceptive stimulation (illusory movements) may facilitate effective rehabilitation in patients with limited physiotherapy options. Nevertheless, this approach has yet to be tested in patients with burn injuries.

MATERIAL AND METHODOLOGY

A prospective, randomised, crossover trial was conducted at a burn centre in a tertiary teaching hospital. The objective was to assess the effects of illusory movements on energy metabolism, insulin sensitivity, and skeletal muscle biology in adult critically ill patients with deep burns covering 30 % or more of the total body surface area. Two 30-minute daily sessions of functional proprioceptive stimulation were administered in addition to the standard physical therapy or physical activity regimen. Subsequently, the patients proceeded to the next stage of the trial, which involved a two-week crossover period.

MEASUREMENTS AND MAIN RESULTS

Daily indirect calorimetry and calculation of nitrogen balance. Skeletal muscle biopsies from vastus lateralis for high resolution respirometry and euglycemic clamps to assess whole body glucose disposal were performed three times: at baseline and then fortnightly after each intervention period. The intervention was feasible and well tolerated in both early and late stages of burn disease. It did not change energy expenditure (mean change -33 [95 % CI: -292;+227] kcal .24 h-1, p = 0.79), nitrogen balance (+2.0 [95 % CI: -3.1;+7.1] g N .1.73 m-2 BSA .24 h-1), or insulin sensitivity (mean change of insulin-mediated glucose disposal -0.33 [95 % CI: -1.18;+0.53] mmol.h-1). At the cellular level, the intervention increased the capacity of mitochondria to synthesize ATP by aerobic phosphorylation and tended to increase mitochondrial coupling. Functional capacities of fatty acid oxidation and electron transfer chain complexes I, II, and IV were unaffected.

CONCLUSIONS

Compared to physical therapy alone, two daily sessions of functional proprioceptive stimulation in addition to usual physical therapy in patients with extensive burns did not change energy expenditure, insulin sensitivity, nitrogen balance, or energy substrate oxidation. At cellular level, the intervention improved the capacity of aerobic phosphorylation in skeletal muscle mitochondria. Clinical effects remain to be demonstrated in adequately powered trials.

Safety and feasibility of a functional electrical stimulation cycling-based muscular dysfunction diagnostic method in mechanically ventilated patients

BACKGROUND

A nonvolitional diagnostic method based on FES-Cycling technology has recently been demonstrated for mechanically ventilated patients. This method presents good sensitivity and specificity for detecting muscle dysfunction and survival prognosis, even in unconscious patients. As the clinical relevance of this method has already been reported, we aimed to evaluate its safety and feasibility.

METHODS

An observational prospective study was carried out with 20 critically ill, mechanically ventilated patients. The FES-cycling equipment was set in a specific diagnostic mode. For safety determination, hemodynamic parameters and peripheral oxygen saturation were measured before and immediately after the diagnostic protocol, as well as venous oxygen saturation and blood lactate. The creatine phosphokinase level (CPK) was measured before and 24, 48, and 72 h after the test. The time taken to carry out the entire diagnostic protocol and the number of patients with visible muscle contraction (capacity of perceptive muscular recruitment) were recorded to assess feasibility.

RESULTS

Heart rate [91 ± 23 vs. 94 ± 23 bpm (p = 0.0837)], systolic [122 ± 19 vs. 124 ± 19 mm Hg (p = 0.4261)] and diastolic blood pressure [68 ± 13 vs. 70 ± 15 mm Hg (p = 0.3462)], and peripheral [98 (96-99) vs. 98 (95-99) % (p = 0.6353)] and venous oxygen saturation [71 ± 14 vs. 69 ± 14% (p = 0.1317)] did not change after the diagnostic protocol. Moreover, blood lactate [1.48 ± 0.65 vs. 1.53 ± 0.71 mmol/L (p = 0.2320)] did not change. CPK did not change up to 72 h after the test [99 (59-422) vs. 125 (66-674) (p = 0.2799) vs. 161 (66-352) (p > 0.999) vs. 100 (33-409) (p = 0.5901)]. The time taken to perform the diagnostic assessment was 11.3 ± 1.1 min. In addition, 75% of the patients presented very visible muscle contractions, and 25% of them presented barely visible muscle contractions.

CONCLUSIONS

The FES cycling-based muscular dysfunction diagnostic method is safe and feasible. Hemodynamic parameters, peripheral oxygen saturation, venous oxygen saturation, and blood lactate did not change after the diagnostic protocol. The muscle damage marker (CPK) did not increase up to 72 h after the diagnostic protocol.

Should We Use the Functional Electrical Stimulation-Cycling Exercise in Clinical Practice? Physiological and Clinical Effects Systematic Review With Meta-analysis

OBJECTIVE

To examine the evidence regarding functional electrical stimulation cycling's (FES-cycling's) physiological and clinical effects.

DATA SOURCES

The study was conducted in accordance with the preferred reporting items for systematic reviews and meta-analyses protocol. PubMed, Embase, Cochrane Review, CINAHL, Scopus, Sport Discus, and Web of Science databases were used.

STUDY SELECTION

Randomized controlled trials involving FES-cycling were included. Studies that did not involve FES-cycling in the intervention group or without the control group were excluded. Two reviewers screened titles and abstracts and then conducted a blinded full-text evaluation. A third reviewer resolved the discrepancies.

DATA EXTRACTION

Meta-analysis was performed using inverse variance for continuous data, with effects measured using the mean difference and random effects analysis models. A 95% confidence interval was adopted. The significance level was set at P<.05, and trends were declared at P=.05 to ≤.10. The I2 method was used for heterogeneity analysis. The minimal clinically important difference was calculated. Methodological quality was assessed using the risk of bias tool for randomized trials. The Grading of Recommendations Assessment, Development, and Evaluation method was used for the quality of the evidence analysis.

DATA SYNTHESIS

A total of 52 studies were included. Metabolic, cardiocirculatory, ventilatory, and peripheral muscle oxygen extraction variables presented statistical (P<.05) and clinically important differences favoring FES-cycling, with moderate-to-high certainty of evidence. It also presented statistical (P<.05) and clinically important improvements in cardiorespiratory fitness, leg and total body lean mass, power, physical fitness in intensive care (moderate-to-high certainty of evidence), and torque (low certainty of evidence). It presented a trend (P=.05 to ≤.10) of improvement in muscle volume, spasticity, and mobility (low-to-moderate certainty of evidence). It showed no difference (P>.10) in 6-minute walking distance, muscle cross-sectional area, bone density, and length of intensive care unit stay (low-to-moderate certainty of evidence).

CONCLUSIONS

FES-cycling exercise is a more intense stimulus modality than other comparative therapeutic modalities and presented clinically important improvement in several clinical outcomes.

Femoral blood gas analysis, another tool to assess hemorrhage severity following trauma: an exploratory prospective study

BACKGROUND

Veno-arterial carbon dioxide tension difference (ΔPCO2) and mixed venous oxygen saturation (SvO2) have been shown to be markers of the adequacy between cardiac output and metabolic needs in critical care patients. However, they have hardly been assessed in trauma patients. We hypothesized that femoral ΔPCO2 (ΔPCO2 fem) and SvO2 (SvO2 fem) could predict the need for red blood cell (RBC) transfusion following severe trauma.

METHODS

We conducted a prospective and observational study in a French level I trauma center. Patients admitted to the trauma room following severe trauma with an Injury Severity Score (ISS) > 15, who had arterial and venous femoral catheters inserted were included. ΔPCO2 fem, SvO2 fem and arterial blood lactate were measured over the first 24 h of admission. Their abilities to predict the transfusion of at least one pack of RBC (pRBCH6) or hemostatic procedure during the first six hours of admission were assessed using receiver operating characteristics curve.

RESULTS

59 trauma patients were included in the study. Median ISS was 26 (22-32). 28 patients (47%) received at least one pRBCH6 and 21 patients (35,6%) had a hemostatic procedure performed during the first six hours of admission. At admission, ΔPCO2 fem was 9.1 ± 6.0 mmHg, SvO2 fem 61.5 ± 21.6% and blood lactate was 2.7 ± 1.9 mmol/l. ΔPCO2 fem was significantly higher (11.6 ± 7.1 mmHg vs. 6.8 ± 3.7 mmHg, P = 0.003) and SvO2 fem was significantly lower (50 ± 23 mmHg vs. 71.8 ± 14.1 mmHg, P < 0.001) in patients who were transfused than in those who were not transfused. Best thresholds to predict pRBCH6 were 8.1 mmHg for ΔPCO2 fem and 63% for SvO2 fem. Best thresholds to predict the need for a hemostatic procedure were 5.9 mmHg for ΔPCO2 fem and 63% for SvO2 fem. Blood lactate was not predictive of pRBCH6 or the need for a hemostatic procedure.

CONCLUSION

In severe trauma patients, ΔPCO2 fem and SvO2 fem at admission were predictive for the need of RBC transfusion and hemostatic procedures during the first six hours of management while admission lactate was not. ΔPCO2 fem and SvO2 fem appear thus to be more sensitive to blood loss than blood lactate in trauma patients, which might be of importance to early assess the adequation of tissue blood flow with metabolic needs.

Early Mobilization for Critically Ill Patients

Advances in the field of critical care medicine have helped improve the survival rate of these ill patients. Several studies have demonstrated the potential benefits of early mobilization as an important component of critical care rehabilitation. However, there have been some inconsistent results. Moreover, the lack of standardized mobilization protocols and the associated safety concerns are a barrier to the implementation of early mobilization in critically ill patients. Therefore, determining the appropriate modalities of implementation of early mobilization is a key imperative to leverage its potential in these patients. In this paper, we review the contemporary literature to summarize the strategies for early mobilization of critically ill patients, assess the implementation and validity based on the International Classification of Functioning, Disability and Health, as well as discuss the safety aspects of early mobilization.

Metabolic, ventilatory and cardiovascular responses to FES-cycling: A comparison to NMES and passive cycling

BACKGROUND

Cyclergometry with functional electrical stimulation (FES-cycling) is a feasible method for rehabilitation. The concept is to promote exercise induced by depolarization of the motoneuron and muscular contraction.

OBJECTIVE

To measure acute physiological responses to FES-cycling.

METHODS

Retrospective study of data from ten healthy volunteers who performed FES-cycling, passive cycling and neuromuscular electrical stimulation (NMES) alone. Metabolic, ventilatory and cardiovascular parameters were analyzed.

RESULTS

Oxygen uptake enhanced 97 ± 15% during FES-cycling, with medium effect size compared to NMES and large effect size compared to passive cycling. Energy expenditure enhanced 102 ± 15% during FES-cycling, with medium effect size compared to NMES and large effect size compared to passive cycling. Minute ventilation enhanced 115 ± 26% during FES-cycling, with small effect size compared to NMES and medium effect size compared to passive cycling. Cardiac output enhanced 21 ± 4% during FES-cycling, with medium effect size compared to NMES and passive cycling. Arterial - mixed venous oxygen content difference enhanced 60 ± 8% during FES-cycling, with a medium effect size compared to NMES and large effect size compared to passive cycling.

CONCLUSIONS

FES-cycling enhances metabolic, ventilatory and cardiovascular demands and the physiological responses are higher than NMES and passive cycling.

Gut Microbiota as the Link between Elevated BCAA Serum Levels and Insulin Resistance

The microbiota-harboring human gut is an exquisitely active ecosystem that has evolved in a constant symbiosis with the human host. It produces numerous compounds depending on its metabolic capacity and substrates availability. Diet is the major source of the substrates that are metabolized to end-products, further serving as signal molecules in the microbiota-host cross-talk. Among these signal molecules, branched-chain amino acids (BCAAs) has gained significant scientific attention. BCAAs are abundant in animal-based dietary sources; they are both produced and degraded by gut microbiota and the host circulating levels are associated with the risk of type 2 diabetes. This review aims to summarize the current knowledge on the complex relationship between gut microbiota and its functional capacity to handle BCAAs as well as the host BCAA metabolism in insulin resistance development. Targeting gut microbiota BCAA metabolism with a dietary modulation could represent a promising approach in the prevention and treatment of insulin resistance related states, such as obesity and diabetes.

Functional electrical stimulation-assisted cycle ergometry-based progressive mobility programme for mechanically ventilated patients: randomised controlled trial with 6 months follow-up

PURPOSE

Functional electrical stimulation-assisted cycle ergometry (FESCE) enables in-bed leg exercise independently of patients' volition. We hypothesised that early use of FESCE-based progressive mobility programme improves physical function in survivors of critical care after 6 months.

METHODS

We enrolled mechanically ventilated adults estimated to need >7 days of intensive care unit (ICU) stay into an assessor-blinded single centre randomised controlled trial to receive either FESCE-based protocolised or standard rehabilitation that continued up to day 28 or ICU discharge.

RESULTS

We randomised in 1:1 ratio 150 patients (age 61±15 years, Acute Physiology and Chronic Health Evaluation II 21±7) at a median of 21 (IQR 19-43) hours after admission to ICU. Mean rehabilitation duration of rehabilitation delivered to intervention versus control group was 82 (IQR 66-97) versus 53 (IQR 50-57) min per treatment day, p<0.001. At 6 months 42 (56%) and 46 (61%) patients in interventional and control groups, respectively, were alive and available to follow-up (81.5% of prespecified sample size). Their Physical Component Summary of SF-36 (primary outcome) was not different at 6 months (50 (IQR 21-69) vs 49 (IQR 26-77); p=0.26). At ICU discharge, there were no differences in the ICU length of stay, functional performance, rectus femoris cross-sectional diameter or muscle power despite the daily nitrogen balance was being 0.6 (95% CI 0.2 to 1.0; p=0.004) gN/m2 less negative in the intervention group.

CONCLUSION

Early delivery of FESCE-based protocolised rehabilitation to ICU patients does not improve physical functioning at 6 months in survivors.

TRIAL REGISTRATION NUMBER

NCT02864745.

Can functional electrical stimulation-assisted cycle ergometry replace insulin infusion in patients? A nested substudy in a randomized controlled trial with 6 months' follow-up

BACKGROUND

Functional electrical stimulation-assisted cycle ergometry (FESCE) can deliver active exercise to critically ill patients, including those who are sedated. Aerobic exercise is known to stimulate skeletal muscle glucose uptake. We asked whether FESCE can reduce intravenous insulin requirements and improve insulin sensitivity in intensive care unit (ICU) patients.

METHOD

We performed an a priori-planned secondary analysis of data from an outcome-based randomized controlled trial (NCT02864745) of FESCE-based early-mobility program vs standard of care in mechanically ventilated patients. We analyzed glucose profile, glucose intake, and insulin requirements during ICU stay in all enrolled patients. In a nested subgroup, we performed hyperinsulinemic (120 mIU/min/m² ) euglycemic clamps at days 0, 7, and 180 (n = 30, 23, and 11, respectively).

RESULTS

We randomized 150 patients 1:1 to receive intervention or standard of care. Seventeen (23%) patients in each study arm had a history of diabetes. During ICU stay, patients received 137 ± 65 and 137 ± 88 g/day carbohydrate (P = .97), and 31 vs 35 (P = .62) of them required insulin infusion to maintain blood glucose 8.61 ± 2.82 vs 8.73 ± 2.67 mM (P = .75, n = 11,254). In those treated with insulin, median daily dose was 53 IU (interquartile range [IQR], 25-95) vs 62 IU (IQR, 26-96) in the intervention and control arm, respectively (P = .44). In the subgroup of patients undergoing hyperglycemic clamps, insulin sensitivities improved similarly and significantly from acute and protracted critical illness to 6 months after discharge.

CONCLUSION

The FESCE-based early-mobility program does not significantly reduce insulin requirements in critically ill patients on mechanical ventilation.

Effects of Rehabilitation Interventions on Clinical Outcomes in Critically Ill Patients: Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

To assess the impact of rehabilitation in ICU on clinical outcomes.

DATA SOURCES

Secondary data analysis of randomized controlled trials published between 1998 and October 2019 was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

STUDY SELECTION

We have selected trials investigating neuromuscular electrical stimulation or cycling exercises or protocolized physical rehabilitation as compared to standard of care in critically ill adults.

DATA EXTRACTION

Mortality, length of stay in ICU and at hospital, days on mechanical ventilator, and adverse events.

DATA SYNTHESIS

We found 43 randomized controlled trials (nine on cycling, 14 on neuromuscular electrical stimulation alone and 20 on protocolized physical rehabilitation) into which 3,548 patients were randomized and none of whom experienced an intervention-related serious adverse event. The exercise interventions had no influence on mortality (odds ratio 0.94 [0.79-1.12], n = 38 randomized controlled trials) but reduced duration of mechanical ventilation (mean difference, -1.7 d [-2.5 to -0.8 d], n = 32, length of stay in ICU (-1.2 d [-2.5 to 0.0 d], n = 32) but not at hospital (-1.6 [-4.3 to 1.2 d], n = 23). The effects on the length of mechanical ventilation and ICU stay were only significant for the protocolized physical rehabilitation subgroup and enhanced in patients with longer ICU stay and lower Acute Physiology and Chronic Health Evaluation II scores. There was no benefit of early start of the intervention. It is likely that the dose of rehabilitation delivered was much lower than dictated by the protocol in many randomized controlled trials and negative results may reflect the failure to implement the intervention.

CONCLUSIONS

Rehabilitation interventions in critically ill patients do not influence mortality and are safe. Protocolized physical rehabilitation significantly shortens time spent on mechanical ventilation and in ICU, but this does not consistently translate into long-term functional benefit. Stable patients with lower Acute Physiology and Chronic Health Evaluation II at admission (<20) and prone to protracted ICU stay may benefit most from rehabilitation interventions.

Functional electrical stimulation-assisted cycle ergometry in the critically ill: protocol for a randomized controlled trial

BACKGROUND

Intensive care unit (ICU)-acquired weakness is the most important cause of failed functional outcome in survivors of critical care. Most damage occurs during the first week when patients are not cooperative enough with conventional rehabilitation. Functional electrical stimulation-assisted cycle ergometry (FES-CE) applied within 48 h of ICU admission may improve muscle function and long-term outcome.

METHODS

An assessor-blinded, pragmatic, single-centre randomized controlled trial will be performed. Adults (n = 150) mechanically ventilated for < 48 h from four ICUs who are estimated to need > 7 days of critical care will be randomized (1:1) to receive either standard of care or FES-CE-based intensified rehabilitation, which will continue until ICU discharge.

PRIMARY OUTCOME

quality of life measured by 36-Item Short Form Health Survey score at 6 months.

SECONDARY OUTCOMES

functional performance at ICU discharge, muscle mass (vastus ultrasound, N-balance) and function (Medical Research Council score, insulin sensitivity). In a subgroup (n = 30) we will assess insulin sensitivity and perform skeletal muscle biopsies to look at mitochondrial function, fibre typing and regulatory protein expression.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02864745. Registered on 12 August 2016.