Intensive care unit-acquired weakness (ICUAW) and muscle wasting in critically ill patients with severe sepsis and septic shock

Poly (ADP-ribose) synthetase inhibitor has a heart protective effect in a rat model of experimental sepsis

The aim of this study is to investigate whether PARP inhibitor could reduce cell apoptosis and injury in the heart during sepsis.

MATERIALS AND METHODS

60 healthy male Sprague-Dawley (SD) rats were randomly divided into 4 groups---sham group, modal group, 3-AB pretreatment group and 3-AB treatment group, 15 rats per group. The cecal ligation and puncture (CLP) model of sepsis was used. The following were determined--levels of malondialdehyde (MDA), ATP and nicotinamide adenine dinucleotide (NAD+), expression of PARP, Bcl-2, Bax, cytochrome C and caspase 3 activity in the myocardium tissue, levels of serum creatine kinase muscle brain (CK-MB) fraction and troponin I.

RESULTS

Histological and molecular analyses showed that myocardial cells apoptosis were associated with mitochondria injury, with an increase in the amount of PARP and a decrease in ATP and NAD+ levels in model group. In addition, the levels of Bax, cytochrome C and caspase 3 activity, serum levels of CK-MB and troponin I increased, but levels of Bcl-2 significantly decreased. Inhibition of PARP upregulated the levels of ATP, NAD + and Bcl-2, and significantly reduced the activation of PARP and caspase 3, decreased the levels of MDA, cytochrome C, CK-MB and troponin I. As a result, apoptosis in the heart was attenuated.

CONCLUSION

These results indicate that PARP activation may be involved in apoptosis in the heart induced by sepsis and 3-AB could improve it.

Non-sedation versus sedation with a daily wake-up trial in critically ill patients receiving mechanical ventilation--effects on physical function: study protocol for a randomized controlled trial: a substudy of the NONSEDA trial

Background

Critically ill patients rapidly loose much of their muscle mass and strength. This can be attributed to prolonged admission, prolonged mechanical ventilation and increased mortality, and it can have a negative impact on the degree of independence and quality of life. In the NONSEDA trial we randomize critically ill patients to non-sedation or sedation with a daily wake-up trial during mechanical ventilation in the intensive care unit. It has never been assessed whether non-sedation affects physical function. The aim of this study is to assess the effects of non-sedation versus sedation with a daily wake-up trial on physical function after discharge from intensive care unit.

Methods/Design

Investigator-initiated, randomized, clinical, parallel-group, superiority trial, including 700 patients in total, with a substudy concerning 200 of these patients. Inclusion criteria will be intubated, mechanically ventilated patients with expected duration of mechanical ventilation >24 h. Exclusion criteria will be patients with severe head trauma, coma at admission or status epilepticus, patients treated with therapeutic hypothermia, patients with PaO₂/FiO₂<9 where sedation might be necessary to ensure sufficient oxygenation or placing the patient in a prone position. The experimental intervention will be non-sedation supplemented with pain management during mechanical ventilation. The control intervention will be sedation with a daily wake-up trial. The co-primary outcome will be quality of life regarding physical function (SF-36, physical component) and degree of independence in activities of daily living (Barthel Index), and this will be assessed for all 700 patients participating in the NONSEDA trial. The secondary outcomes, which will be assessed for the subpopulation of 200 NONSEDA patients in the trial site, Kolding, will be 6-min walking distance, handgrip strength, muscle size (ultrasonographic measurement of the rectus femoris muscle cross-sectional area) and biomechanical data on lower extremity function (maximal voluntary contraction, rate of force development and endurance).

Discussion

This study is the first to investigate the effect of no sedation during critical illness on physical function. If an effect is found, it will add important information on how to prevent muscle weakness following critical illness.

Trial registration

The study has been approved by the relevant scientific ethics committee and is registered at ClinicalTrials.gov (ID: NCT02034942, 9 January 2014).

[Variation of muscle mass and weight in critical patient]

OBJECTIVES

Quantify the muscle mass and body weight variation in critically ill patients and to identify associated factors.

METHOD

A descriptive follow-up study. Data for demographic variables, body weight, fluid balance, daily kilocalories, the amount of sedation and muscle relaxants received and motor physiotherapy applied were collected. Three consecutive measurements were performed in the brachial biceps and quadriceps rectus by using ultrasound, upon admission and every 5 days until discharge.

RESULTS

68 patients were included. Average age was of 73.5 [57-78,5] years. The median length of stay was 9.5 [5.5 -15] days. The median 16 (SD=5.7) daily kilocalories per kg/weight, 91.2% received sedation, 44.1% received muscle relaxants and 20% received physiotherapy. The patients presented a muscle wasting of 4.9 (SD=3.9)mm, p <.001 in the brachial biceps and 5.6 (SD=4.8)mm, p <.001 in the quadriceps rectus. Regression analysis selected the length of stay and the muscle relaxants are the most influential variables in the brachial biceps muscle wasting (R2=0.4), and length of stay as the most influential in the quadriceps rectus muscle wasting (R2=0.3). Patient's mean body weight on admission was of 81.1 (SD=15)kg and 81.2 (SD=14.2)kg on discharge, p=.95.

CONCLUSIONS

The critically ill patient presents a significant muscle waste related with the length of stay and the treatment received with muscle relaxants. Patients are being discharged with a similar body weight to which they were admitted but with a significant reduction of muscle mass.

The Sick and the Weak: Neuropathies/Myopathies in the Critically Ill

Critical illness polyneuropathies (CIP) and myopathies (CIM) are common complications of critical illness. Several weakness syndromes are summarized under the term intensive care unit-acquired weakness (ICUAW). We propose a classification of different ICUAW forms (CIM, CIP, sepsis-induced, steroid-denervation myopathy) and pathophysiological mechanisms from clinical and animal model data. Triggers include sepsis, mechanical ventilation, muscle unloading, steroid treatment, or denervation. Some ICUAW forms require stringent diagnostic features; CIM is marked by membrane hypoexcitability, severe atrophy, preferential myosin loss, ultrastructural alterations, and inadequate autophagy activation while myopathies in pure sepsis do not reproduce marked myosin loss. Reduced membrane excitability results from depolarization and ion channel dysfunction. Mitochondrial dysfunction contributes to energy-dependent processes. Ubiquitin proteasome and calpain activation trigger muscle proteolysis and atrophy while protein synthesis is impaired. Myosin loss is more pronounced than actin loss in CIM. Protein quality control is altered by inadequate autophagy. Ca(2+) dysregulation is present through altered Ca(2+) homeostasis. We highlight clinical hallmarks, trigger factors, and potential mechanisms from human studies and animal models that allow separation of risk factors that may trigger distinct mechanisms contributing to weakness. During critical illness, altered inflammatory (cytokines) and metabolic pathways deteriorate muscle function. ICUAW prevention/treatment is limited, e.g., tight glycemic control, delaying nutrition, and early mobilization. Future challenges include identification of primary/secondary events during the time course of critical illness, the interplay between membrane excitability, bioenergetic failure and differential proteolysis, and finding new therapeutic targets by help of tailored animal models.

Use of miRNAs as biomarkers in sepsis

Sepsis is one of the most common causes of death in critical patients. Severe generalized inflammation, infections, and severe physiological imbalances significantly decrease the survival rate with more than 50%. Moreover, monitoring, evaluation, and therapy management often become extremely difficult for the clinician in this type of patients. Current methods of diagnosing sepsis vary based especially on the determination of biochemical-humoral markers, such as cytokines, components of the complement, and proinflammatory and anti-inflammatory compounds. Recent studies highlight the use of new biomarkers for sepsis, namely, miRNAs. miRNAs belong to a class of small, noncoding RNAs with an approximate content of 19-23 nucleotides. Following biochemical and physiological imbalances, the expression of miRNAs in blood or other body fluids changes significantly. Moreover, its stability, specificity, and selectivity make miRNAs ideal candidates for sepsis biomarkers. In conclusion, we can affirm that stable species of circulating miRNAs represent potential biomarkers for monitoring the evolution of sepsis.

Insulin ameliorating endotoxaemia-induced muscle wasting is associated with the alteration of hypothalamic neuropeptides and inflammation in rats

OBJECTIVES

Septic patients always develop muscle wasting, which delays the rehabilitation and contributes to the increased complications and mortality. Previous studies have implied the crucial role of central inflammation and neuropeptides in the energy balance and muscle metabolism. Insulin has been confirmed to attenuate muscle degradation and inhibit inflammation. We tested the hypothesis whether insulin ameliorating muscle wasting was associated with modulating hypothalamic inflammation and neuropeptides.

DESIGN AND SUBJECTS

Thirty-two adult male Sprague-Dawley rats were in intraperitoneally injected with lipopolysaccharide (LPS) (5 mg/kg) or saline, followed by subcutaneous injection of insulin (5 IU/kg) or saline. Twenty-four hours after injection, skeletal muscle and hypothalamus tissues were harvested. Muscle wasting was measured by the mRNA expression of two E3 ubiquitin ligases, muscle ring finger 1 (MuRF-1) and muscle atrophy F-box (MAFbx), as well as 3-methylhistidine (3-MH) and tyrosine release. Hypothalamic inflammatory markers and neuropeptides expression were also measured in four groups.

RESULTS

LPS injection led to significant increase in hypothalamic inflammation as well as muscle wasting. Also, increased hypothalamic neuropeptides, proopiomelanocortin (POMC), cocaine and amphetamine-related transcript (CART) and neuropeptides Y (NPY) and decreased agouti-related protein (AgRP) were observed. Insulin treatment ameliorated endotoxaemia-induced muscle wasting and hypothalamic inflammation, and attenuated the alteration of neuropeptides, POMC, CART and AgRP.

CONCLUSION

Hypothalamic inflammation and neuropeptides are involved in the endotoxaemia-induced muscle wasting. Insulin treatment can reduce muscle wasting, which is associated with reduced hypothalamic inflammation and alteration of hypothalamic neuropeptides.

Cachexia: clinical features when inflammation drives malnutrition

Cachexia is a clinically relevant syndrome which impacts on quality of life, morbidity and mortality of patients suffering from acute and chronic diseases. The hallmark of cachexia is muscle loss, which is triggered by disease-associated inflammatory response. Cachexia is a continuum and therefore a staging system is needed. Initially, a three-stage system (i.e. pre-cachexia, cachexia and refractory cachexia) was proposed. More recent evidence supports the use of a five-stage classification system, based on patient's BMI and severity of weight loss, to better predict clinical outcome. Also, large clinical trials in cancer patients demonstrated that cachexia emerging during chemotherapy has greater influence on survival than weight loss at baseline. Therefore, becoming widely accepted is the importance of routinely monitoring patients' nutritional status to detect early changes and diagnose cachexia in its early phases. Although cachexia is associated with the presence of anabolic resistance, it has been shown that sustained yet physiological hyperaminoacidaemia, as well as the use of specific nutrients, is able to overcome impaired protein synthesis and revert catabolism. More importantly, clinical evidence demonstrates that preservation of nutritional status during chemotherapy or improvement of body weight after weight loss is associated with longer survival in cancer patients.

Dysphagia--a common, transient symptom in critical illness polyneuropathy: a fiberoptic endoscopic evaluation of swallowing study*

OBJECTIVES

Critical illness polyneuropathy is a common disorder in the neurological ICU. Dysphagia is well known to deteriorate outcome in the ICU. The prevalence of dysphagia in critical illness polyneuropathy is not known. The aim of this study was to evaluate the prevalence of dysphagia in critical illness polyneuropathy using fiberoptic endoscopic evaluation of swallowing.

DESIGN

Prospective, cohort study.

SETTING

Neurological rehabilitation ICU.

PATIENTS

Twenty-two patients with critical illness polyneuropathy.

INTERVENTIONS

Clinical swallowing examination and serial fiberoptic endoscopic evaluation of swallowing (days 3, 14, and 28 after admission).

MEASUREMENTS AND MAIN RESULTS

Swallowing of saliva, pureed consistencies, and liquids was tested using fiberoptic endoscopic evaluation of swallowing at three different time points. The penetration-aspiration scale by Rosenbek et al and the secretion severity rating scale by Murray et al were used for grading. Functional outcome after rehabilitation was assessed using the functional independence measure.: Pathologic swallowing was found in 20 of 22 patients (91%). Hypesthesia of laryngeal structures was found in 17 of 22 patients (77%) during the first fiberoptic endoscopic evaluation of swallowing. Over the 4-week follow-up period, laryngeal hypesthesia resolved in 75% of affected cases. Pureed consistencies were swallowed safely in 18 of 22 cases (82%), whereas liquids and saliva showed high aspiration rates (13 of 17 [78%] and 10 of 22 [45%], respectively). Swallowing function recovered completely in 21 of 22 (95%) within 4 weeks.

CONCLUSIONS

Dysphagia is frequent among patients with critical illness polyneuropathy treated in the ICU. Old age, chronic obstructive pulmonary disease, the mode of mechanical ventilation, the prevalence of tracheal tubes, and behavioral "learned nonuse" may all be contributing factors for the development of dysphagia in critical illness polyneuropathy. Complete recovery occurs in a high percentage of affected individuals within 4 weeks.

Muscle wasting and early mobilization in acute respiratory distress syndrome

Survivors of acute respiratory distress syndrome often sustain muscle wasting and functional impairment related to intensive care unit (ICU)-acquired weakness (ICUAW) and this disability may persist for years after ICU discharge. Early diagnosis in cooperative patients by physical examination is recommended to identify patients at risk for weaning failure and to minimize prolongation of risk factors for ICUAW. When possible, early rehabilitation in critically ill patients improves functional outcomes, likely by reducing disuse atrophy. Interventions designed to correct the functional impairment are lacking and further research to delineate the molecular pathways that give rise to ICUAW are needed.

Feasibility of neuromuscular electrical stimulation in critically ill patients

OBJECTIVE

Critically ill patients often develop intensive care unit-acquired weakness. Reduction in muscle mass and muscle strength occurs early after admission to the intensive care unit (ICU). Although early active muscle training could attenuate this intensive care unit-acquired weakness, in the early phase of critical illness, a large proportion of patients are unable to participate in any active mobilization. Neuromuscular electrical stimulation (NMES) could be an alternative strategy for muscle training. The aim of this study was to investigate the safety and feasibility of NMES in critically ill patients.

DESIGN

This is an observational study.

SETTING

The setting is in the medical and surgical ICUs of a tertiary referral university hospital.

PATIENTS

Fifty patients with a prognosticated prolonged stay of at least 6 days were included on day 3 to 5 of their ICU stay. Patients with preexisting neuromuscular disorders and patients with musculoskeletal conditions limiting quadriceps contraction were excluded.

INTERVENTION

Twenty-five minutes of simultaneous bilateral NMES of the quadriceps femoris muscle. This intervention was performed 5 days per week (Monday-Friday). Effective muscle stimulation was defined as a palpable and visible contraction (partial or full muscle bulk).

MEASUREMENTS

The following parameters, potentially affecting contraction upon NMES, were assessed: functional status before admission to the ICU (Barthel index), type and severity of illness (Acute Physiology And Chronic Health Evaluation II score and sepsis), treatments possibly influencing the muscle contraction (corticosteroids, vasopressors, inotropes, aminoglycosides, and neuromuscular blocking agents), level of consciousness (Glasgow Coma Scale, score on 5 standardized questions evaluating awakening, and sedation agitation scale), characteristics of stimulation (intensity of the NMES, number of sessions per patient, and edema), and neuromuscular electrophysiologic characteristics. Changes in heart rate, blood pressure, oxygen saturation, respiratory rate, and skin reactions were registered to assess the safety of the technique.

RESULTS

In 50% of the patients, an adequate quadriceps contraction was obtained in at least 75% of the NMES sessions. Univariate analysis showed that lower limb edema (P<.001), sepsis (P=.008), admission to the medical ICU (P=.041), and treatment with vasopressors (P=.011) were associated with impaired quadriceps contraction. A backward multivariate analysis identified presence of sepsis, lower limb edema, and use of vasopressors as independent predictors of impaired quadriceps contraction (R2=59.5%). Patients responded better to NMES in the beginning of their ICU stay in comparison with after 1 week of ICU stay. There was no change in any of the safety end points with NMES.

CONCLUSIONS

Critically ill patients having sepsis, edema, or receiving vasopressors were less likely to respond to NMES with an adequate quadriceps contraction. Neuromuscular electrical stimulation is a safe intervention to be administered in the ICU.

Associations between muscle-related cytokines and selected patient outcomes in the ICU

INTRODUCTION

Systemic cytokines produced by contracting skeletal muscles may affect the onset and severity of intensive care unit (ICU)-acquired weakness after critical illness.

AIMS

The purpose of this research was to determine the serum levels of interleukin (IL)-8, IL-15, and tumor necrosis factor-α (TNF-α) among patients receiving mechanical ventilation for >48 hr and examine the relationships of these myokines to outcomes of patient delirium, muscle strength, activities of daily living (ADLs), duration of mechanical ventilation, and length of ICU stay.

METHODS

In this exploratory, repeated-measures interventional study, the 36 participants received 20 min of once-daily in-bed or out-of-bed activity using an established early progressive mobility protocol after physiologic stability had been demonstrated for >4 hr in the ICU. Blood samples were drawn on 3 consecutive days, beginning on the day of study enrollment, for serum cytokine quantification.

RESULTS

IL-8, IL-15, and TNF-α were highly variable and consistently elevated in participants compared to normal healthy adults. About 1/3 of participants were positive for significant muscle weakness at discharge from ICU. Repeated values of mean postactivity IL-8 serum values were significantly associated only with ADL following ICU discharge. There were no significant associations with repeated values of mean postactivity IL-15 or TNF-α serum values and outcomes.

CONCLUSION

Results provide preliminary data for exploring the potential effects of elevated serum values IL-8 and IL-15 in muscle health and TNF-α for muscle damage, including effect sizes to calculate the sample sizes needed for future studies.

Electrical Muscle Stimulation in the Intensive Care Unit: An Integrative Review

Following a period of critical illness, physical function and health-related quality of life are slow to recover, both in the short and long term. Muscle wasting and weakness during the intensive care unit (ICU) admission is a recognised contributory factor. Enhanced rehabilitation programmes are advocated to improve outcomes, and electrical muscle stimulation (EMS) has been recommended during the early critical illness trajectory. This technique is fairly new to the ICU, and limited efficacy data exists for its use in this setting. This integrative review will examine published and on-going ICU studies with the purpose of reporting on the characteristics of EMS study participants; content of EMS treatment protocols; safety of EMS in the ICU setting; effects on EMS on muscle wasting; effects of EMS on muscle strength; and future research.

Delirium in the ICU and subsequent long-term disability among survivors of mechanical ventilation

OBJECTIVE

Survivors of critical illness are frequently left with long-lasting disability. The association between delirium and disability in critically ill patients has not been described. We hypothesized that the duration of delirium in the ICU would be associated with subsequent disability and worse physical health status following a critical illness.

DESIGN

Prospective cohort study nested within a randomized controlled trial of a paired sedation and ventilator weaning strategy.

SETTING

A single-center tertiary-care hospital.

PATIENTS

One hundred twenty-six survivors of a critical illness.

MEASUREMENTS AND MAIN RESULTS

Confusion Assessment Method for the ICU, Katz activities of daily living, Functional Activities Questionnaire (measuring instrumental activities of daily living), Medical Outcomes Study 36-item Short Form General Health Survey Physical Components Score, and Awareness Questionnaire were used. Associations between delirium duration and outcomes were determined via proportional odds logistic regression with generalized estimating equations (for Katz activities of daily living and Functional Activities Questionnaire scores) or via generalized least squares regression (for Medical Outcomes Study 36-item Short Form General Health Survey Physical Components Score and Awareness Questionnaire scores). Excluding patients who died prior to follow-up but including those who withdrew or were lost to follow-up, we assessed 80 of 99 patients (81%) at 3 months and 63 of 87 patients (72%) at 12 months. After adjusting for covariates, delirium duration was associated with worse activities of daily living scores (p = 0.002) over the course of the 12-month study period but was not associated with worse instrumental activities of daily living scores (p = 0.15) or worse Medical Outcomes Study 36-item Short Form General Health Survey Physical Components Score (p = 0.58). Duration of delirium was also associated with lower Awareness Questionnaire Motor/Sensory Factors scores (p 0.02).

CONCLUSION

In the setting of critical illness, longer delirium duration is independently associated with increased odds of disability in activities of daily living and worse motor-sensory function in the following year. These data point to a need for further study into the determinants of functional outcomes in ICU survivors.

Effect of physical therapy on muscle strength, respiratory muscles and functional parameters in patients with intensive care unit-acquired weakness

OBJECTIVES

The aim of this study was to evaluate the effect of an intensive physical therapy protocol in patients who contract 'intensive care unit-acquired weakness' (ICUAW), in terms of muscle strength, breathing and functional indices.

METHODS

This was a prospective, single-blinded study in a general hospital intensive care unit (ICU). Patients who required mechanical ventilation longer than 48 h and who were expected to remain mechanically ventilated for at least another 48 h were randomly divided into two intervention groups: group I (n = 9) - the routine care group, received physical therapy according to our daily custom protocol; and group II (n = 9) - the intensive treatment group, were treated by the same protocol twice a day. The main outcome measures included the Medical Research Council (MRC) physical strength examination, maximal inspiratory pressure (MIP), hand grip dynamometer and sitting balance test.

RESULTS

Significant strength improvement from first (T1) to second (T2) measurements was demonstrated for variables MIP and MRC physical strength examination in favor of the intensive treatment group (P < 0.05). The intensive treatment group also required shorter intensive care length of stay than the routine care group (P = 0.043).

CONCLUSIONS

It is possible that an intensive therapy protocol may facilitate the initial recovery process in patients who suffer from ICUAW.

Nurses' perceptions of unpleasant symptoms and signs in ventilated and sedated patients

AIMS AND OBJECTIVES

To describe intensive care nurses' perceptions and assessments of unpleasant symptoms and signs in mechanically ventilated and sedated adult intensive care patients.

BACKGROUND

Mechanically ventilated patients are unable to express themselves verbally and depend upon nurses to control their symptoms by understanding their unpleasant experiences, such as pain, anxiety or delirium and interpret the relevant signs. Nurses must have enough knowledge to adjust their analgesics and sedatives appropriately and to avoid under- or oversedation.

DESIGN

A cross-sectional survey design.

METHODS

A study with a self-administrated questionnaire was undertaken in October 2007 to February 2008, with a convenience sample of 183 intensive care nurses in Norway.

RESULTS

The questionnaire was completed by 86 (47%) nurses. Most perceived that critical illness polyneuropathy/myopathy occurred frequently. Half the nurses underestimated pain, anxiety and delirium. Signs such as a response to contact, cough reflex, wakefulness and muscle tone were considered most important in assessing oversedation. Agitation, facial grimacing, tube intolerance and wakefulness were considered most important in assessing undersedation. The Comfort Scale and Adoption of the Intensive Care Environment corresponded best to the signs identified by the nurses.

CONCLUSION

The nurses underestimated unpleasant symptoms other than critical illness polyneuropathy/myopathy. A further mapping of patients' experiences should be conducted, with an emphasis on the more 'silent' distressing symptoms. Further tools to facilitate the communication of consciousness levels and the intolerance of unpleasant symptoms must be developed and implemented.

RELEVANCE TO CLINICAL PRACTICE

A deeper understanding of unpleasant symptoms and signs focused in learning activities may help nurses to recognize patients' early problems and allow targeted interventions. A more active stimulus-response assessment of ICU patients is required to detect oversedation, critical illness polyneuropathy/myopathy and hypoactive delirium. Assessment tools should reflect both the patient's tolerance of various unpleasant symptoms and the level of consciousness.

Highlights of mechanistic and therapeutic cachexia and sarcopenia research 2010 to 2012 and their relevance for cardiology

Sarcopenia and cachexia are significant medical problems with a high disease-related burden in cardiovascular illness. Muscle wasting and weight loss are very frequent particularly in chronic heart failure and they relate to poor prognosis. Although clinically largely underestimated, the fields of cachexia and sarcopenia are of great relevance to cardiologists. In cachexia and sarcopenia a significant number of research publications related to basic science questions of muscle wasting and lipolysis were published between 2010 and 2012. Recently, the two processes of muscle wasting and lipolysis were found to be closely linked. Treatment research in pre-clinical models involves studies on a number of different therapeutic entities, including ghrelin, selective androgen receptor modulators (SARMs), as well as drugs targeting myostatin or melanocortin-4. In the human setting, studies using enobosarm (a SARM) and anamorelin (ghrelin) are in phase III. The last 3 years have seen significant efforts to define the field using consensus statements. In the future, these definitions should also be considered for guidelines and treatment trials in cardiovascular medicine. The current review aims to summarize important information and development in the fields of muscle wasting, sarcopenia and cachexia, focusing on findings in cardiovascular research, in order for cardiologists to have a better understanding of the progress in this still insufficiently known field.

ICU-based rehabilitation and its appropriate metrics

PURPOSE OF REVIEW

Survival of critically ill patients is frequently associated with significant functional impairment and reduced health-related quality of life. Early rehabilitation of ICU patients has recently been identified as an important focus for interdisciplinary ICU teams. However, the amount of rehabilitation performed in ICUs is often inadequate. The scope of the review is to discuss recent developments in application of assessment tools and rehabilitation in critically ill patients within an interdisciplinary approach.

RECENT FINDINGS

ICU-based rehabilitation has become an important evidence-based component in the management of patients with critical illness. The assessment and evidence-based treatment of these patients should include a focus on prevention and treatment of deconditioning (muscle weakness, joint stiffness, impaired functional performance) and weaning failure (respiratory muscle weakness) to identify targets for rehabilitation. A variety of modalities for assessment and early ICU rehabilitation are supported by emerging clinical research and must be implemented according to the stage of critical illness, comorbidities, and consciousness and cooperation of the patient.

SUMMARY

Daily evaluation of every critically ill patient should include evaluation of the need for bedrest and immobility, and assessment of the potential for early rehabilitation interventions. Early ICU rehabilitation is an interdisciplinary team responsibility, involving physical therapists, occupational therapists, nurses and medical staff.

The ChIP-seq-defined networks of Bcl-3 gene binding support its required role in skeletal muscle atrophy

NF-kappaB transcriptional activation is required for skeletal muscle disuse atrophy. We are continuing to study how the activation of NF-kB regulates the genes that encode the protein products that cause atrophy. Using ChIP-sequencing we found that Bcl-3, an NF-kB transcriptional activator required for atrophy, binds to the promoters of a number of genes whose collective function describes two major aspects of muscle wasting. By means of bioinformatics analysis of ChIP-sequencing data we found Bcl-3 to be directing transcription networks of proteolysis and energy metabolism. The proteolytic arm of the Bcl-3 networks includes many E3 ligases associated with proteasomal protein degradation, including that of the N-end rule pathway. The metabolic arm appears to be involved in organizing the change from oxidative phosphorylation to glycolysis in atrophying muscle. For one gene, MuRF1, ChIP-sequencing data identified the location of Bcl-3 and p50 binding in the promoter region which directed the creation of deletant and base-substitution mutations of MuRF1 promoter constructs to determine the effect on gene transcription. The results provide the first direct confirmation that the NF-kB binding site is involved in the muscle unloading regulation of MuRF1. Finally, we have combined the ChIP-sequencing results with gene expression microarray data from unloaded muscle to map several direct targets of Bcl-3 that are transcription factors whose own targets describe a set of indirect targets for NF-kB in atrophy. ChIP-sequencing provides the first molecular explanation for the finding that Bcl3 knockout mice are resistant to disuse muscle atrophy. Mapping the transcriptional regulation of muscle atrophy requires an unbiased analysis of the whole genome, which we show is now possible with ChIP-sequencing.

Neuromuscular blockade and skeletal muscle weakness in critically ill patients: time to rethink the evidence?

Neuromuscular blocking agents are commonly used in critical care. However, concern after observational reports of a causal relationship with skeletal muscle dysfunction and intensive care-acquired weakness (ICU-AW) has resulted in a cautionary and conservative approach to their use. This integrative review, interpreted in the context of our current understanding of the pathophysiology of ICU-AW and integrated into our current conceptual framework of clinical practice, challenges the established clinical view of an adverse relationship between the use of neuromuscular blocking agents and skeletal muscle weakness. In addition to discussing data, this review identifies potential confounders and alternative etiological factors responsible for ICU-AW and provides evidence that neuromuscular blocking agents may not be a major cause of weakness in a 21st century critical care setting.

[Intensive care unit-acquired weakness in the critically ill : critical illness polyneuropathy and critical illness myopathy]

Intensive care unit-acquired weakness (ICUAW) is a severe complication in critically ill patients which has been increasingly recognized over the last two decades. By definition ICUAW is caused by distinct neuromuscular disorders, namely critical illness polyneuropathy (CIP) and critical illness myopathy (CIM). Both CIP and CIM can affect limb and respiratory muscles and thus complicate weaning from a ventilator, increase the length of stay in the intensive care unit and delay mobilization and physical rehabilitation. It is controversially discussed whether CIP and CIM are distinct entities or whether they just represent different organ manifestations with common pathomechanisms. These basic pathomechanisms, however, are complex and still not completely understood but metabolic, inflammatory and bioenergetic alterations seem to play a crucial role. In this respect several risk factors have recently been revealed: in addition to the administration of glucocorticoids and non-depolarizing muscle relaxants, sepsis and multi-organ failure per se as well as elevated levels of blood glucose and muscular immobilization have been shown to have a profound impact on the occurrence of CIP and CIM. For the diagnosis, careful physical and neurological examinations, electrophysiological testing and in rare cases nerve and muscle biopsies are recommended. Nevertheless, it appears to be difficult to clearly distinguish between CIM and CIP in a clinical setting. At present no specific therapy for these neuromuscular disorders has been established but recent data suggest that in addition to avoidance of risk factors early active mobilization of critically ill patients may be beneficial.

Sarcopenia in stroke-facts and numbers on muscle loss accounting for disability after stroke

Stroke is the third leading cause of death and the leading cause of disability in Western countries. More than 60% of patients remain disabled, 50% of patients suffer from some hemiparesis and 30% remain unable to walk without assistance. The skeletal muscle is the main effector organ accountable for disability in stroke. This disability is, however, traditionally attributed to the brain injury itself and less attention is paid to structural, metabolic and functional aspects of muscle tissue. Hemiparetic stroke leads to various muscle abnormalities. A combination of denervation, disuse, inflammation, remodelling and spasticity account for a complex pattern of muscle tissue phenotype change and atrophy. While the molecular mechanisms of muscle degradation after stroke are only incompletely understood, a stroke-related sarcopenia may be concluded. Reinnervation, fiber-type shift, disuse atrophy and local inflammatory activation are only some of the key features to be addressed. Despite the importance for optimum post stroke recovery, stroke-related sarcopenia is not recognised in current guidelines for stroke therapy and rehabilitation. A total of not more than 500 patients forms the basis for all available evidence on clinical muscle changes after stroke. A lack of robust evidence on muscle pathology after stroke and on treatment strategies becomes apparent that needs to be addressed in an interdisciplinary integrated approach.