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

Adipose tissue protects against sepsis-induced muscle weakness in mice: from lipolysis to ketones

Background

ICU-acquired weakness is a debilitating consequence of prolonged critical illness that is associated with poor outcome. Recently, premorbid obesity has been shown to protect against such illness-induced muscle wasting and weakness. Here, we hypothesized that this protection was due to increased lipid and ketone availability.

Methods

In a centrally catheterized, fluid-resuscitated, antibiotic-treated mouse model of prolonged sepsis, we compared markers of lipolysis and fatty acid oxidation in lean and obese septic mice (n = 117). Next, we compared markers of muscle wasting and weakness in septic obese wild-type and adipose tissue-specific ATGL knockout (AAKO) mice (n = 73), in lean septic mice receiving either intravenous infusion of lipids or standard parenteral nutrition (PN) (n = 70), and in lean septic mice receiving standard PN supplemented with either the ketone body 3-hydroxybutyrate or isocaloric glucose (n = 49).

Results

Obese septic mice had more pronounced lipolysis (p ≤ 0.05), peripheral fatty acid oxidation (p ≤ 0.05), and ketogenesis (p ≤ 0.05) than lean mice. Blocking lipolysis in obese septic mice caused severely reduced muscle mass (32% loss vs. 15% in wild-type, p < 0.001) and specific maximal muscle force (59% loss vs. 0% in wild-type; p < 0.001). In contrast, intravenous infusion of lipids in lean septic mice maintained specific maximal muscle force up to healthy control levels (p = 0.6), whereas this was reduced with 28% in septic mice receiving standard PN (p = 0.006). Muscle mass was evenly reduced with 29% in both lean septic groups (p < 0.001). Lipid administration enhanced fatty acid oxidation (p ≤ 0.05) and ketogenesis (p < 0.001), but caused unfavorable liver steatosis (p = 0.01) and a deranged lipid profile (p ≤ 0.01). Supplementation of standard PN with 3-hydroxybutyrate also attenuated specific maximal muscle force up to healthy control levels (p = 0.1), but loss of muscle mass could not be prevented (25% loss in both septic groups; p < 0.001). Importantly, this intervention improved muscle regeneration markers (p ≤ 0.05) without the unfavorable side effects seen with lipid infusion.

Conclusions

Obesity-induced muscle protection during sepsis is partly mediated by elevated mobilization and metabolism of endogenous fatty acids. Furthermore, increased availability of ketone bodies, either through ketogenesis or through parenteral infusion, appears to protect against sepsis-induced muscle weakness also in the lean.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2506-6) contains supplementary material, which is available to authorized users.

Pseudomonas aeruginosa-derived pyocyanin reduces adipocyte differentiation, body weight, and fat mass as mechanisms contributing to septic cachexia

Pseudomonas aeruginosa, a leading cause of sepsis, produces pyocyanin, a blue-pigmented virulence factor. Sepsis is associated with cachexia, but mechanisms are unknown and conventional nutrition approaches are not effective treatments. Pyocyanin has affinity for the aryl hydrocarbon receptor (AhR), which is expressed on adipocytes and regulates adipocyte differentiation. The purpose of this study was to define in vitro and in vivo effects of pyocyanin on adipocyte differentiation and body weight regulation as relates to septic cachexia. In 3T3-L1 preadipocytes, pyocyanin activated AhR and its downstream marker CYP1a1, and reduced differentiation. Administration of pyocyanin to male C57BL/6J mice acutely reduced body temperature with altered locomotion, but caused sustained weight loss. Chronic pyocyanin administration to male and female C57BL/6J mice resulted in sustained reductions in body weight and fat mass, with adipose-specific AhR activation. Pyocyanin-treated male mice had decreased energy expenditure and physical activity, and increased adipose explant lipolysis. In females, pyocyanin caused robust reductions in body weight, adipose-specific AhR activation, and increased expression of inflammatory cytokines in differentiated adipocytes. These results demonstrate that pyocyanin reduces adipocyte differentiation and decreases body weight and fat mass in male and female mice, suggesting that pyocyanin may play a role in septic cachexia.

Alleviating Sepsis-Induced Neuromuscular Dysfunction Linked With Acetylcholine Receptors by Agrin

BACKGROUND

Abnormal expression and distribution of nicotinic acetylcholine receptors (nAChRs) in skeletal muscle caused by sepsis can lead to neuromuscular dysfunction. Here, we asked whether neural agrin regulates nAChRs to ameliorate muscle function, which could be associated with the agrin/muscle-specific kinase pathway.

METHODS

Rats were subjected to cecal ligation and puncture (CLP) group, sham group, or control group to observe the alteration caused by sepsis. To verify the effect of improving function, rats were injected with agrin or normal saline intramuscularly after CLP. Electromyogram was used to measure neuromuscular function. Cytokines levels of serum and the expression of related proteins and mRNA were tested after treatment.

RESULTS

Compared with the rats in control or sham group, CLP-treated rats showed an acute inflammatory status and a reduction of neuromuscular dysfunction in tibialis anterior muscle, which was associated with abnormal expression in agrin/muscle-specific kinase pathway and increased expression of γ- and α7-nAChR. Exogenous agrin alleviated neuromuscular dysfunction and decreased the expression of γ- and α7-nAChR through agrin-related signaling pathway.

CONCLUSIONS

The decreased expression of agrin may lead to skeletal muscle dysfunction. Early enhancement of intramuscular agrin levels after sepsis may be a potential strategy for the treatment of sepsis-induced muscle dysfunction.

Dysphagia in the intensive care unit: epidemiology, mechanisms, and clinical management

Dysphagia may present in all critically ill patients and large-scale clinical data show that e.g. post-extubation dysphagia (PED) is commonly observed in intensive care unit (ICU) patients. Recent data demonstrate that dysphagia is mostly persisting and that its presence is independently associated with adverse patient-centered clinical outcomes. Although several risk factors possibly contributing to dysphagia development were proposed, the underlying exact mechanisms in ICU patients remain incompletely understood and no current consensus exists on how to best approach ICU patients at risk.From a clinical perspective, dysphagia is well-known to be associated with an increased risk of aspiration and aspiration-induced pneumonia, delayed resumption of oral intake/malnutrition, decreased quality of life, prolonged ICU and hospital length of stay, and increased morbidity and mortality. Moreover, the economic burden on public health care systems is high.In light of high mortality rates associated with the presence of dysphagia and the observation that dysphagia is not systematically screened for on most ICUs, this review describes epidemiology, terminology, and potential mechanisms of dysphagia on the ICU. Furthermore, the impact of dysphagia on affected individuals, health care systems, and society is discussed in addition to current and future potential therapeutic approaches.

Clinical Approaches to Assess Post-extubation Dysphagia (PED) in the Critically Ill

Swallowing disorders and respective consequences (including aspiration-induced pneumonia) are often observed in extubated ICU patients with data indicating that a large number of patients are affected. We recently demonstrated in a large-scale analysis that the incidence of post-extubation dysphagia (PED) is 12.4% in a general ICU population and about 18% in emergency admissions to the ICU. Importantly, PED was mostly sustained until hospital discharge and independently predicted 28- and 90-day mortality. Although oropharyngeal/laryngeal trauma, neuromuscular ICU-acquired weakness, reduced sensation/sensorium, dyssynchronous breathing, and gastrointestinal reflux, are all considered to contribute to PED, little is known about the underlying pathomechanisms and risk factors leading to PED in critically ill patients. Systematic screening of all potential ICU patients for oropharyngeal dysphagia (OD) seems key for early recognition and follow-up, as well as the design and testing of novel therapeutic interventions. Today, screening methods and clinical investigations for dysphagia differ considerably. In the context of a recently proposed pragmatic screening algorithm introduced by us, we provide a concise review on currently available non-instrumental techniques that could potentially serve for non-instrumental OD assessment in critically ill patients. Following systematic literature review, we find that non-instrumental OD assessments were mostly tested in different patient populations with only a minority of studies performed in critically ill patients. Due to little available data on non-instrumental dysphagia assessment in the ICU, future investigations should aim to validate respective approaches in the critically ill against an instrumental (gold) standard, for example, flexible endoscopic evaluation of swallowing. An international expert panel is encouraged to addresses critical illness-related definitions, screening and confirmatory assessment approaches, treatment recommendations, and identifies optimal patient-centered outcome measures for future clinical investigations.

Interventions for the management and prevention of sarcopenia in the critically ill: A systematic review

PURPOSE

In the critically ill, sarcopenia is associated with a variety of adverse outcomes however there is no consensus regarding its management. This study aimed to systematically review the evidence for interventions for the management and prevention of sarcopenia in critically ill patients.

MATERIALS AND METHODS

Bibliographic databases were searched according to pre-specified criteria (PROSPERO-CRD42018086271). Randomised controlled trials (RCTs) investigating interventions to preserve muscle mass and/or function in critically ill patients were included. Two independent authors selected the articles and assessed bias using the Cochrane Risk of Bias Tool.

RESULTS

Twenty-two eligible RCTs were identified comprising 2792 patients. Three main groups of interventions were implemented in these trials: neuromuscular electrical stimulation (NMES), exercise-based and nutritional. Both the interventions and outcomes measured varied significantly between studies. NMES was most frequently studied as an intervention to preserve muscle mass whilst exercise-based treatments were evaluated as interventions to preserve muscle function. There was significant variation in the efficacy of the interventions on sarcopenia markers and secondary outcomes.

CONCLUSIONS

NMES and exercise-based interventions may preserve muscle mass and function in patients with critical illness. There is a lack of consistency seen in the effects of these interventions. Further, large, high quality RCTs are required.

Evolution of protein-bound uremic toxins indoxyl sulphate and p-cresyl sulphate in acute kidney injury

BACKGROUND

There is a gradual increase in serum concentrations of protein-bound colon-derived uremic toxins indoxyl sulphate (IxS) and p-cresyl sulphate (pCS) as chronic kidney disease (CKD) progresses. In acute kidney injury (AKI), up till now, the retention pattern has not been studied.

METHODS

In this study, 194 adult patients admitted with sepsis to the intensive care unit were included. IxS, pCS and serum creatinine (sCrea) were quantified at inclusion (D0) and at day 4, unless follow-up ended earlier (D_end).

RESULTS

Serum levels of sCrea (P < 0.001), IxS (P < 0.001) and pCS (P < 0.05) were higher in patients with AKI according to RIFLE classification at D0. In contrast with sCrea, IxS and pCS levels only increased from stage I (IxS) and F (pCS) on. When grouped according to evolution in RIFLE class from D0 to D_end, all solute concentrations were higher (P < 0.001) in the group with unfavourable evolution. In this group, there was a marked rise in sCrea (P < 0.001), a moderate one for pCS (P < 0.05), but no change for IxS (P = 0.112). There was a decrease (P < 0.001) of all solute concentrations in the group with favourable evolution. Comparing AKI with CKD patients matched for sCrea, total levels of both IxS and pCS were higher (P < 0.01) in patients with CKD.

CONCLUSIONS

Although concentrations of IxS and pCS both tend to rise in sepsis patients with AKI, their evolution does not conform with that of sCrea. For the same level of sCrea, IxS and pCS concentrations are lower in AKI compared with CKD.

Nutrient pattern analysis in critically ill patients using Omics technology (NAChO) - Study protocol for a prospective observational study

INTRODUCTION

Intensive care unit-acquired weakness (ICU-AW) is often observed in critically ill patients with prolonged intensive care unit (ICU) stay. We hypothesized that evolving metabolic abnormalities during prolonged ICU stay are reflected by changing nutrient patterns in blood, urine and skeletal muscle, and that these patterns differ in patients with/without ICU-AW and between patients with/without sepsis.

METHODS

In a prospective single-center observational trial, we aim to recruit 100 critically ill patients (ICU length of stay ≥ 5 days) with severe sepsis/septic shock ("sepsis group", n = 50) or severe head trauma/intracerebral hemorrhage ("CNS group", n = 50). Patients will be sub-grouped for presence or absence of ICU-AW as determined by the Medical Research Council sum score. Blood and urine samples will be collected and subjected to comprehensive nutrient analysis at different time points by targeted quantitative mass spectrometric methods. In addition, changes in muscular tissue (biopsy, when available), muscular architecture (ultrasound), electrophysiology, body composition analyses (bioimpedance, cerebral magnetic resonance imaging), along with clinical status will be assessed. Patients will be followed-up for 180 and 360 days including assessment of quality of life.

DISCUSSION

Key objective of this trial is to assess changes in nutrient pattern in blood and urine over time in critically ill patients with/without ICU-AW by using quantitative nutrient analysis techniques. Peer-reviewed published NAChO data will allow for a better understanding of metabolic changes in critically ill patients on standard liquid enteral nutrition and will likely open up new avenues for future therapeutic and nutritional interventions.

Reliability of ultrasound measurements of quadriceps muscle thickness in critically ill patients

BACKGROUND

Muscle wasting in critically ill patients is associated with negative clinical outcomes. Ultrasound quadriceps femoris muscle assessment may constitute a convenient tool to evaluate muscle wasting. Nevertheless, its reliability remains uncertain. Our primary aim was to study the intra- and inter-observer reliability of this technique. Our secondary aim was to assess the evolution of the quadriceps muscle during the first 3 weeks after ICU admission and its possible association with nutritional intake.

METHODS

This observational study included patients expected to stay more than 7 days in the ICU. Ultrasound quadriceps muscle thickness was measured with a 12 MHz linear transducer, by two trained physicians, on D1, D3, D5, D7 and D21. Two measurements sites were evaluated: on the midpoint or on the two-thirds of the length between the anterior superior iliac spine and the upper border of the patella. Intra and inter-observer reliability was assessed by calculating the intra-class correlation coefficient (ICC).

RESULTS

A total of 280 ultrasound quadriceps thickness measurements were performed on 29 critically ill patients. Intra-observer reliability's ICC was 0.74 [95% CI 0.63; 0.84] at the "midpoint" site and 0.83 [95% CI 0.75; 0.9] at the "two-thirds" site. Inter-observer reliability's ICC was 0.76 [95% CI, 0.66; 0.86] at the "midpoint" site and 0.81 [95% CI, 0.7; 0.9] at the "two-thirds" site. Quadriceps femoris muscle thickness decreased over 16% within the first week after ICU admission. No correlation was found between muscle loss and caloric (p = 0.96) or protein (p = 0.80) debt over the first week.

CONCLUSION

The assessment by ultrasonography of the quadriceps muscle thickness reveals good intra- and inter-observer reliability and may constitute a promising tool to evaluate the effect of nutritional-based interventions on muscle wasting in critically ill patients.

TRIAL REGISTRATION

"Committee for the Protection of Human Subjects in Biomedical Research" - Paris Ile de France VI Pitié-Salpêtrière - 10/07/2014. French Data Protection Committee ("Commission Nationale Informatique et Libertés") - #1771144.

What is the diagnostic accuracy of single nerve conduction studies and muscle ultrasound to identify critical illness polyneuromyopathy: a prospective cohort study

Background

Critical illness polyneuromyopathy (CIPNM) is a major cause of weakness in intensive care unit (ICU) patients, but current diagnostic tests are limited. We evaluated the generalizability and validity of single nerve conduction studies (NCS) and muscle ultrasound testing to identify CIPNM, and we also assessed the ability of muscle ultrasound to prognosticate patient outcomes.

Methods

This was a prospective cohort study of mechanically ventilated medical, cardiac, surgical, and neurosurgical ICU patients. We performed weekly strength testing, NCS, electromyography (EMG), and muscle ultrasound. We calculated the sensitivity, specificity, and other test characteristics of single NCS and muscle ultrasound, and we used multivariable regression models to assess the prognostic ability of muscle ultrasound.

Results

Ninety-five patients were enrolled. The incidence of probable CIPNM was 18% and did not differ significantly by type of ICU (p = 0.49). For diagnosing probable CIPNM, the peroneal motor NCS had a sensitivity of 94% (95% confidence interval (CI) 71–100%) and specificity of 91% (95% CI 82–96%), the sural sensory NCS had a sensitivity of 100% (95% CI 80–100%) and specificity of 42% (95% CI 31–54%), and abnormal muscle ultrasound echogenicity had a sensitivity of 82% (95% CI 48–98%) and specificity of 57% (95% CI 43–70%). Abnormal echogenicity was associated with reduced likelihood of discharge to home (9% vs 50%, p = 0.0001), fewer ICU-free days (median 3 (interquartile range 0–15) days vs 16 (9.3–19.3) days, p = 0.0002), and increased ICU mortality (42% vs 12%, p = 0.004).

Conclusions

In a diverse cohort of critically ill patients, single NCS and muscle ultrasound achieved diagnostic accuracy for patients at risk for CIPNM. The routine utilization of these tests could be beneficial for all critically ill patients at risk for CIPNM.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2281-9) contains supplementary material, which is available to authorized users.

Computed Tomography Evidence of Psoas Muscle Atrophy Without Concomitant Tendon Wasting in Early Sepsis

BACKGROUND

Morphomic studies have demonstrated a correlation between sarcopenia and clinical outcomes in septic patients. However, tendon morphomics has not yet been studied in this context. The purpose of the present study was to evaluate tendon morphology in septic patients through analytic morphomics. We hypothesized that morphomic analyses would reveal concomitant muscle and tendon wasting in sepsis patients. The results of this study may help to implement different rehabilitation modalities for critically ill patients.

MATERIALS AND METHODS

The volume and fat content of bilateral psoas muscles and tendons were measured on abdominal computed tomography scans of 25 ICU septic and 25 control trauma patients admitted to the University of Michigan between 2011 and 2012. Univariate and multivariate analyses were performed to determine the relationship between psoas muscle and tendon morphometric data, and the association with clinical variables such as smoking and comorbidities.

RESULTS

Average psoas muscle volume was 12.21 ± 5.6 cm³ for control patients and 9.318 ± 3.3 cm³ in septic patients (P = 0.0023). The average psoas muscle/fat ratio for septic patients was 0.0288 ± 0.071 cm³, compared with 0.0107 ± 0.008 cm³ in the control group (P = 0.075). Average tendon volume in the septic population (0.508 ± 0.191 cm³) was not different than the control cohort (0.493 ± 0.182 cm³) (P = 0.692).

CONCLUSIONS

Our results demonstrate significantly smaller psoas muscle volume in septic patients than in age-, gender-, and BMI-matched trauma patients but no demonstrable change in tendon morphology between patient groups. These findings begin to define the boundaries of clinical application within the field of morphomics.

[A Cellular Pharmacological Approach to the Development of Drugs to Treat Muscle Wasting]

　Skeletal muscle atrophy reduces quality of life and increases mortality. However, there are few available drugs for the treatment of muscle atrophy. Recently, cell signaling pathways involved in skeletal muscle atrophy or hypertrophy have been determined. To develop drugs for skeletal muscle atrophy, we have studied compounds which modulate pathways of myogenic differentiation, a pivotal step for the maintenance of skeletal muscle mass. First, we examined a K⁺ channel opener on myogenic differentiation, since hyperpolarization is a trigger for skeletal muscle differentiation. 5,6-Dichloro-1-ethyl-1,3-dihydro-2H-benzimidazol-2-one (DCEBIO), an opener of the small/intermediate conductance Ca²⁺ activated K⁺ (SK_Ca/IK_Ca) channels, increases myogenic differentiation in C2C12 mouse skeletal myoblasts. This effect was inhibited by TRAM-34, an IK_Ca channel blocker. This suggests that K⁺ channels in skeletal muscle stem cells are potential targets for an anti-muscle atrophy drug. Next, we searched for drugs which prevent sepsis-induced muscle atrophy. Lipopolysaccharide (LPS), an inducer of sepsis, attenuates myogenic differentiation in C2C12 myoblasts. LPS also increases the protein expression of myostatin and activates NFκB during differentiation. The TLR4 signal inhibitor TAK-242, and an anti-TNFα neutralizing antibody, reduce these inflammatory responses. Our data suggest that LPS inhibits myogenic differentiation via the NFκB/TNFα pathway. This pathway may be involved in the development of muscle wasting caused by sepsis.

Aspiration pneumonia induces muscle atrophy in the respiratory, skeletal, and swallowing systems

BACKGROUND

Repetition of the onset of aspiration pneumonia in aged patients is common and causes chronic inflammation. The inflammation induces proinflammatory cytokine production and atrophy in the muscles. The proinflammatory cytokines induce muscle proteolysis by activating calpains and caspase-3, followed by further degradation by the ubiquitin-proteasome system. Autophagy is another pathway of muscle atrophy. However, little is known about the relationship between aspiration pneumonia and muscle. For swallowing muscles, it is not clear whether they produce cytokines. The main objective of this study was to determine whether aspiration pneumonia induces muscle atrophy in the respiratory (the diaphragm), skeletal (the tibialis anterior, TA), and swallowing (the tongue) systems, and their possible mechanisms.

METHODS

We employed a mouse aspiration pneumonia model and computed tomography (CT) scans of aged pneumonia patients. To induce aspiration pneumonia, mice were inoculated with low dose pepsin and lipopolysaccharide solution intra-nasally 5 days a week. The diaphragm, TA, and tongue were isolated, and total RNA, proteins, and frozen sections were stored. Quantitative real-time polymerase chain reaction determined the expression levels of proinflammatory cytokines, muscle E3 ubiquitin ligases, and autophagy related genes. Western blot analysis determined the activation of the muscle proteolysis pathway. Frozen sections determined the presence of muscle atrophy. CT scans were used to evaluate the muscle atrophy in aged aspiration pneumonia patients.

RESULTS

The aspiration challenge enhanced the expression levels of proinflammatory cytokines in the diaphragm, TA, and tongue. Among muscle proteolysis pathways, the aspiration challenge activated caspase-3 in all the three muscles examined, whereas calpains were activated in the diaphragm and the TA but not in the tongue. Activation of the ubiquitin-proteasome system was detected in all the three muscles examined. The aspiration challenge activated autophagy in the TA and the tongue, whereas weak or little activation was detected in the diaphragm. The aspiration challenge resulted in a greater proportion of smaller myofibers than in controls in the diaphragm, TA, and tongue, suggesting muscle atrophy. CT scans clearly showed that aspiration pneumonia was followed by muscle atrophy in aged patients.

CONCLUSIONS

Aspiration pneumonia induced muscle atrophy in the respiratory, skeletal, and swallowing systems in a preclinical animal model and in human patients. Diaphragmatic atrophy may weaken the force of cough to expectorate sputum or mis-swallowed contents. Skeletal muscle atrophy may cause secondary sarcopenia. The atrophy of swallowing muscles may weaken the swallowing function. Thus, muscle atrophy could become a new therapeutic target of aspiration pneumonia.

Effect of Early Rehabilitation Activity Time on Critically Ill Patients with Intensive Care Unit-acquired Weakness: A Japanese Retrospective Multicenter Study

Objective

This study examined the risk factors in the early rehabilitation therapy of critically ill patients with weakness acquired in an intensive care unit and the impact of this therapy on walking independence after discharge from the hospital.

Method

Of the 764 consecutive patients transported to the study facilities by ambulance, newly admitted to the intensive care unit (ICU), and treated with rehabilitation during hospitalization, 88 were included in this study after eliminating those who met a detailed list of exclusion criteria. To retrospectively examine the rate of walking independence and the effect of differing durations of rehabilitation activity, the study patients were divided into two groups: those with ICU-acquired weakness (AW) and those without ICU-acquired weakness (non-ICU-AW) on discharge from the ICU.

Results

Analysis using the Kaplan-Meier estimator revealed that the non-ICU-AW group needed a markedly shorter period to achieve walking independence. In terms of the rehabilitation activities performed in the ICU, both in-bed exercises and the total duration of rehabilitation activity were significantly shorter in the ICU-AW group than in the non-ICU-AW group.

Conclusion

The two groups were compared, and the amount of daily activity time significantly influenced the quality of patient outcome.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2016 (J-SSCG 2016)

BACKGROUND AND PURPOSE

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2016 (J-SSCG 2016), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in February 2017 and published in the Journal of JSICM, [2017; Volume 24 (supplement 2)] 10.3918/jsicm.24S0001 and Journal of Japanese Association for Acute Medicine [2017; Volume 28, (supplement 1)] http://onlinelibrary.wiley.com/doi/10.1002/jja2.2017.28.issue-S1/issuetoc.This abridged English edition of the J-SSCG 2016 was produced with permission from the Japanese Association of Acute Medicine and the Japanese Society for Intensive Care Medicine.

METHODS

Members of the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine were selected and organized into 19 committee members and 52 working group members. The guidelines were prepared in accordance with the Medical Information Network Distribution Service (Minds) creation procedures. The Academic Guidelines Promotion Team was organized to oversee and provide academic support to the respective activities allocated to each Guideline Creation Team. To improve quality assurance and workflow transparency, a mutual peer review system was established, and discussions within each team were open to the public. Public comments were collected once after the initial formulation of a clinical question (CQ) and twice during the review of the final draft. Recommendations were determined to have been adopted after obtaining support from a two-thirds (> 66.6%) majority vote of each of the 19 committee members.

RESULTS

A total of 87 CQs were selected among 19 clinical areas, including pediatric topics and several other important areas not covered in the first edition of the Japanese guidelines (J-SSCG 2012). The approval rate obtained through committee voting, in addition to ratings of the strengths of the recommendation, and its supporting evidence were also added to each recommendation statement. We conducted meta-analyses for 29 CQs. Thirty-seven CQs contained recommendations in the form of an expert consensus due to insufficient evidence. No recommendations were provided for five CQs.

CONCLUSIONS

Based on the evidence gathered, we were able to formulate Japanese-specific clinical practice guidelines that are tailored to the Japanese context in a highly transparent manner. These guidelines can easily be used not only by specialists, but also by non-specialists, general clinicians, nurses, pharmacists, clinical engineers, and other healthcare professionals.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2016 (J-SSCG 2016)

Background and Purpose

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2016 (J-SSCG 2016), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in February 2017 in Japanese. An English-language version of these guidelines was created based on the contents of the original Japanese-language version.

Methods

Members of the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine were selected and organized into 19 committee members and 52 working group members. The guidelines were prepared in accordance with the Medical Information Network Distribution Service (Minds) creation procedures. The Academic Guidelines Promotion Team was organized to oversee and provide academic support to the respective activities allocated to each Guideline Creation Team. To improve quality assurance and workflow transparency, a mutual peer review system was established, and discussions within each team were open to the public. Public comments were collected once after the initial formulation of a clinical question (CQ), and twice during the review of the final draft. Recommendations were determined to have been adopted after obtaining support from a two-thirds (>66.6%) majority vote of each of the 19 committee members.

Results

A total of 87 CQs were selected among 19 clinical areas, including pediatric topics and several other important areas not covered in the first edition of the Japanese guidelines (J-SSCG 2012). The approval rate obtained through committee voting, in addition to ratings of the strengths of the recommendation and its supporting evidence were also added to each recommendation statement. We conducted meta-analyses for 29 CQs. Thirty seven CQs contained recommendations in the form of an expert consensus due to insufficient evidence. No recommendations were provided for 5 CQs.

Conclusions

Based on the evidence gathered, we were able to formulate Japanese-specific clinical practice guidelines that are tailored to the Japanese context in a highly transparent manner. These guidelines can easily be used not only by specialists, but also by non-specialists, general clinicians, nurses, pharmacists, clinical engineers, and other healthcare professionals.

Outcomes of ICU Patients With a Discharge Diagnosis of Critical Illness Polyneuromyopathy: A Propensity-Matched Analysis

OBJECTIVES

To assess the impact of a discharge diagnosis of critical illness polyneuromyopathy on health-related outcomes in a large cohort of patients requiring ICU admission.

DESIGN

Retrospective cohort with propensity score-matched analysis.

SETTING

Analysis of a large multihospital database.

PATIENTS

Adult ICU patients without preexisting neuromuscular abnormalities and a discharge diagnosis of critical illness polyneuropathy and/or myopathy along with adult ICU propensity-matched control patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 3,567 ICU patients with a discharge diagnosis of critical illness polyneuropathy and/or myopathy, we matched 3,436 of these patients to 3,436 ICU patients who did not have a discharge diagnosis of critical illness polyneuropathy and/or myopathy. After propensity matching and adjusting for unbalanced covariates, we used conditional logistic regression and a repeated measures model to compare patient outcomes. Compared to patients without a discharge diagnosis of critical illness polyneuropathy and/or myopathy, patients with a discharge diagnosis of critical illness polyneuropathy and/or myopathy had fewer 28-day hospital-free days (6 [0.1] vs 7.4 [0.1] d; p < 0.0001), had fewer 28-day ventilator-free days (15.7 [0.2] vs 17.5 [0.2] d; p < 0.0001), had higher hospitalization charges (313,508 [4,853] vs 256,288 [4,470] dollars; p < 0.0001), and were less likely to be discharged home (15.3% vs 32.8%; p < 0.0001) but had lower in-hospital mortality (13.7% vs 18.3%; p < 0.0001).

CONCLUSIONS

In a propensity-matched analysis of a large national database, a discharge diagnosis of critical illness polyneuropathy and/or myopathy is strongly associated with deleterious outcomes including fewer hospital-free days, fewer ventilator-free days, higher hospital charges, and reduced discharge home but also an unexpectedly lower in-hospital mortality. This study demonstrates the clinical importance of a discharge diagnosis of critical illness polyneuropathy and/or myopathy and the need for effective preventive interventions.

Dysphagia in Mechanically Ventilated ICU Patients (DYnAMICS): A Prospective Observational Trial

OBJECTIVES

Swallowing disorders may be associated with adverse clinical outcomes in patients following invasive mechanical ventilation. We investigated the incidence of dysphagia, its time course, and association with clinically relevant outcomes in extubated critically ill patients.

DESIGN

Prospective observational trial with systematic dysphagia screening and follow-up until 90 days or death.

SETTINGS

ICU of a tertiary care academic center.

PATIENTS

One thousand three-hundred four admissions of mixed adult ICU patients (median age, 66.0 yr [interquartile range, 54.0-74.0]; Acute Physiology and Chronic Health Evaluation-II score, 19.0 [interquartile range, 14.0-24.0]) were screened for postextubation dysphagia. Primary ICU admissions (n = 933) were analyzed and followed up until 90 days or death. Patients from an independent academic center served as confirmatory cohort (n = 220).

INTERVENTIONS

Bedside screening for dysphagia was performed within 3 hours after extubation by trained ICU nurses. Positive screening triggered confirmatory specialist bedside swallowing examinations and follow-up until hospital discharge.

MEASUREMENTS AND MAIN RESULTS

Dysphagia screening was positive in 12.4% (n = 116/933) after extubation (18.3% of emergency and 4.9% of elective patients) and confirmed by specialists within 24 hours from positive screening in 87.3% (n = 96/110, n = 6 missing data). The dysphagia incidence at ICU discharge was 10.3% (n = 96/933) of which 60.4% (n = 58/96) remained positive until hospital discharge. Days on feeding tube, length of mechanical ventilation and ICU/hospital stay, and hospital mortality were higher in patients with dysphagia (all p < 0.001). The univariate hazard ratio for 90-day mortality for dysphagia was 3.74 (95% CI, 2.01-6.95; p < 0.001). After adjustment for disease severity and length of mechanical ventilation, dysphagia remained an independent predictor for 28-day and 90-day mortality (excess 90-d mortality 9.2%).

CONCLUSIONS

Dysphagia after extubation was common in ICU patients, sustained until hospital discharge in the majority of affected patients, and was an independent predictor of death. Dysphagia after mechanical ventilation may be an overlooked problem. Studies on underlying causes and therapeutic interventions seem warranted.

Metabolic Inflammatory Complex in Sepsis: Septic Cachexia as a Novel Potential Therapeutic Target

Despite several decades of focused investigation, sepsis remains a major cause of mortality in critically ill patients. Advancements in intensive care have enabled more patients to survive the acute phase of sepsis than previously, but a growing number of them progress to chronic critical illness. The failure of previous randomized clinical trials of anti-inflammatory agents to show any pro-survival benefit in septic patients underscores current thought that simple anti-inflammatory strategies are ineffective because the inhibitory effect of anti-inflammatory agents undermines the immune response to pathogens. New strategies with the dual capability of ameliorating inflammation in organs while stimulating antimicrobial activity are eagerly awaited. On the other hand, the metabolic alterations associated with systemic inflammatory response, including mitochondrial dysfunction and metabolic shift, are closely linked through a nexus of signaling pathways and signaling molecules. Preventing these metabolic derangements may be an alternative way to control excessive inflammation, an intriguing possibility that has not been fully explored. New insight into the molecular pathogenesis of sepsis and sepsis-associated chronic critical illness has led to the recognition of septic cachexia, a life-threatening form of metabolic inflammatory complex associated with multiple organ dysfunction. The potential for septic cachexia to serve as a novel target disease state to improve the clinical outcome of septic patients is discussed in this review.

The inhibition of MyD88 and TRIF signaling serve equivalent roles in attenuating myocardial deterioration due to acute severe inflammation

Myeloid differentiation factor 88 (MyD88) and Toll or interleukin-1 receptor-domain-containing adaptor-inducing interferon-β (IFN-β) (TRIF) are two pivotal downstream adaptors of Toll-like receptors. Activation of MyD88 or TRIF signaling in cardiac immune pathology of severe inflammation negatively influences heart function. In the present study, severe septic cardiac injury was induced in C57BL/6 mice by cecum ligation and puncture (CLP). A total of 64 mice were divided randomly into the following four groups (n=16/group; 8 for observation of survival rate, 8 for heart sample analysis): Sham, CLP, anti-MyD88-CLP and anti-TRIF-CLP. Anti-MyD88 and anti-TRIF antibodies were administered to the respective mice through the tail veins 2 h before CLP. Measurements of cardiac function, including M-modes, velocity vector imaging and cardiac troponin I, were performed. Myocardial inflammatory cytokines were examined by reverse transcription-polymerase chain reaction (RT-PCR), myocardial neutrophil infiltration was measured by a myeloperoxidase activity assay, intracellular adhesion molecule and vascular cell adhesion molecule mRNA expression levels were investigated, and histopathological characteristics were evaluated. Levels of mRNA transcripts encoding genes for apoptosis production and MyD88, TRIF, nuclear factor-κB and IFN regulatory factor 3 were investigated by RT-PCR. Mice challenged with CLP demonstrated deleterious cardiac function, increased levels of interleukin-1β (IL-1β), IL-6β, and tumor necrosis factor-α mRNA, increased neutrophil infiltration, and increased apoptosis. In contrast, mice in the anti-MyD88 CLP and anti-TRIF CLP groups retained cardiac function with reduced cytokine release, decreased neutrophil infiltration, and reduced apoptosis. In addition, there was no significant difference between the anti-MyD88 CLP and anti-TRIF CLP groups. Thus, the present study indicated that MyD88 and TRIF blockades serve notable and equivalent roles in protecting cardiac deterioration from severe sepsis by attenuating cytokine release, reducing neutrophil infiltration and alleviating apoptosis.

Translational evidence for two distinct patterns of neuroaxonal injury in sepsis: a longitudinal, prospective translational study

Background

Brain homeostasis deteriorates in sepsis, giving rise to a mostly reversible sepsis-associated encephalopathy (SAE). Some survivors experience chronic cognitive dysfunction thought to be caused by permanent brain injury. In this study, we investigated neuroaxonal pathology in sepsis.

Methods

We conducted a longitudinal, prospective translational study involving (1) experimental sepsis in an animal model; (2) postmortem studies of brain from patients with sepsis; and (3) a prospective, longitudinal human sepsis cohort study at university laboratory and intensive care units (ICUs). Thirteen ICU patients with septic shock, five ICU patients who died as a result of sepsis, fourteen fluid-resuscitated Wistar rats with fecal peritonitis, eleven sham-operated rats, and three human and four rat control subjects were included. Immunohistologic and protein biomarker analysis were performed on rat brain tissue at baseline and 24, 48, and 72 h after sepsis induction and in sham-treated rats. Immunohistochemistry was performed on human brain tissue from sepsis nonsurvivors and in control patients without sepsis. The clinical diagnostics of SAE comprised longitudinal clinical data collection and magnetic resonance imaging (MRI) and electroencephalographic assessments. Statistical analyses were performed using SAS software (version 9.4; SAS Institute, Inc., Cary, NC, USA). Because of non-Gaussian distribution, the nonparametric Wilcoxon test general linear models and the Spearman correlation coefficient were used.

Results

In postmortem rat and human brain samples, neurofilament phosphoform, β-amyloid precursor protein, β-tubulin, and H&E stains distinguished scattered ischemic lesions from diffuse neuroaxonal injury in septic animals, which were absent in controls. These two patterns of neuroaxonal damage were consistently found in septic but not control human postmortem brains. In experimental sepsis, the time from sepsis onset correlated with tissue neurofilament levels (R = 0.53, p = 0.045) but not glial fibrillary acidic protein. Of 13 patients with sepsis who had clinical features of SAE, MRI detected diffuse axonal injury in 9 and ischemia in 3 patients.

Conclusions

Ischemic and diffuse neuroaxonal injury to the brain in experimental sepsis, human postmortem brains, and in vivo MRI suggest these two distinct lesion types to be relevant. Future studies should be focused on body fluid biomarkers to detect and monitor brain injury in sepsis. The relationship of neurofilament levels with time from sepsis onset may be of prognostic value.

Trial registration

ClinicalTrials.gov, NCT02442986. Registered on May 13, 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1850-7) contains supplementary material, which is available to authorized users.

Intensive Care Unit-Acquired Weakness: Implications for Case Management

PURPOSE

The purpose of this case study is to provide a specific example of the disease trajectory for one patient's experience with intensive care unit-acquired weakness (ICUAW). This case study provides those in case management with an overview of some of the common signs and symptoms of ICUAW, as well as the possible prognosis and recovery from ICUAW.

PRIMARY PRACTICE SETTING

The events in this case study take place in the acute care setting including the intensive care unit of a mid-sized health center, a general medical-surgical (med-surg) unit, and a long-term acute care facility.

CONCLUSIONS

ICUAW affects the clinical, functional, and financial outcomes of patients. If the patient survives, their quality of life and the quality of life of their family members could be severely impacted. Case management practice has a significant role in coordinating care for those diagnosed with ICUAW. Case managers can use knowledge about ICUAW to improve the patient's transition throughout the hospital stay, improve discharge recommendations, and improve the patient's short-term and long-term outcomes. This may reduce unnecessary utilization of health care resources.

Mild hypothermia ameliorates muscle wasting in septic rats associated with hypothalamic AMPK-induced autophagy and neuropeptides

Sepsis, always developing muscle wasting, contributes to serious complications and mortality. Mild hypothermia has been reported to have protective effects on the prognosis of septic patients. However, the underlying mechanisms remain unclear. We therefore hypothesized that mild hypothermia could ameliorate muscle wasting during sepsis and whether it was associated with hypothalamus AMPK-induced autophagy and neuropeptides. Adult male Sprague-Dawley rats were intraperitoneally injected with lipopolysaccharide (LPS) (5 mg/kg) or saline. Mild hypothermia was instantly induced at 33 °C for 3h after LPS injected. Meanwhile, the control and sepsis groups were simultaneously placed on the thermal mattress to maintain the a normal temperature in control group whatever the changes induced by anesthesia. Twenty-four hours after injection, skeletal muscle and hypothalamus tissues were obtained. Muscle wasting was measured by the mRNA expression of two muscle atrophic genes, muscle ring finger 1 (MuRF-1) and muscle atrophy F-box (MAFbx), as well as 3-methylhistidine (3-MH) and tyrosine release. Hypothalamic AMPK-induced autophagy markers and neuropeptides expression were also detected. Results showed that LPS administration significantly decreased hypothalamic AMPK-induced autophagy together with muscle wasting. Also, increased hypothalamic neuropeptides, proopiomelanocortin (POMC), cocaine and amphetamine-related transcript (CART) and neuro-peptides Y (NPY) and decreased agouti-related protein (AgRP) were observed. Mild hypothermia significantly increased hypothalamic AMPK-induced autophagy and ameliorated LPS-induced muscle wasting, and attenuated the alteration of neuropeptides, POMC, CART and NPY. In conclusion, mild hypothermia could alleviate muscle wasting by LPS injection, which was associated with reversing the level of hypothalamic AMPK-induced autophagy and the alteration of neuropeptides. These results suggested that mild hypothermia could be a potential treatment concept and a novel mechanism in management of muscle wasting in critically ill patients.

Lipopolysaccharide inhibits myogenic differentiation of C2C12 myoblasts through the Toll-like receptor 4-nuclear factor-κB signaling pathway and myoblast-derived tumor necrosis factor-α

Background

Circulating lipopolysaccharide (LPS) concentrations are often elevated in patients with sepsis or with various endogenous diseases that are associated with metabolic endotoxemia. Involuntary loss of skeletal muscle, termed muscle wasting, is commonly observed in these conditions, suggesting that circulating LPS might play an essential role in its development. Although impairment of muscle regeneration is an important determinant of skeletal muscle wasting, it is unclear whether LPS affects this process and, if so, by what mechanism. Here, we used the C2C12 myoblast cell line to investigate the effects of LPS on myogenesis.

Methods

C2C12 myoblasts were grown to 80% confluence and induced to differentiate in the absence or presence of LPS (0.1 or 1 μg/mL); TAK-242 (1 μM), a specific inhibitor of Toll-like receptor 4 (TLR4) signaling; and a tumor necrosis factor (TNF)-α neutralizing antibody (5 μg/mL). Expression of a skeletal muscle differentiation marker (myosin heavy chain II), two essential myogenic regulatory factors (myogenin and MyoD), and a muscle negative regulatory factor (myostatin) was analyzed by western blotting. Nuclear factor-κB (NF-κB) DNA-binding activity was measured using an enzyme-linked immunosorbent assay.

Results

LPS dose-dependently and significantly decreased the formation of multinucleated myotubes and the expression of myosin heavy chain II, myogenin, and MyoD, and increased NF-κB DNA-binding activity and myostatin expression. The inhibitory effect of LPS on myogenic differentiation was reversible, suggesting that it was not caused by nonspecific toxicity. Both TAK-242 and anti-TNF-α reduced the LPS-induced increase in NF-κB DNA-binding activity, downregulation of myogenic regulatory factors, and upregulation of myostatin, thereby partially rescuing the impairment of myogenesis.

Conclusions

Our data suggest that LPS inhibits myogenic differentiation via a TLR4–NF-κB-dependent pathway and an autocrine/paracrine TNF-α-induced pathway. These pathways may be involved in the development of muscle wasting caused by sepsis or metabolic endotoxemia.

Low-intensity exercise in the acute phase of lipopolysaccharide-induced sepsis improves lipid metabolism and survival in mice by stimulating PGC-1α expression

BACKGROUND

The effect of exercise during the acute phase following sepsis onset is poorly understood. We investigated how low-intensity exercise during acute sepsis alters energy-substrate metabolism and survival in mice with lipopolysaccharide (LPS)-induced sepsis.

METHODS

Mice were divided into control (C, saline), low-dose LPS (L, 1 mg/kg), medium-dose LPS (M, 5 mg/kg), and high-dose LPS (H, 10 mg/kg) groups. Each group was subdivided into sedentary (SED) and exercise (EX) groups; the EX group mice were exercised at low intensity on a treadmill after LPS administration. Survival proportions and vital functions were measured, and indirect calorimetry through respiratory gas analysis was performed until 72 hours after treatment. Organ weight and lipid levels in the plasma and liver were measured, and the messenger RNA and protein levels of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) were evaluated using quantitative polymerase chain reaction and Western blotting.

RESULTS

Survival proportions of H-EX mice were higher than those of H-SED mice. At 16 hours after LPS administration, fatty acid oxidation was decreased in M-SED and H-SED groups but increased in all EX groups and was higher in surviving mice in H-SED and H-EX groups than in nonsurviving mice, suggesting that fatty acid oxidation is related to survival. Epididymal fat weight was lower in the EX groups than in the SED groups, whereas plasma and liver lipid levels were elevated in all EX groups; this suggests that exercise induces the transport of lipids from endogenous fat into the blood and the liver for use as the energy source. Lastly, PGC-1α messenger RNA and protein levels were lower in L-, M-, and H-SED groups than in the C-SED group but were high in all EX groups.

CONCLUSION

Our study provides the revolutionary finding that exercise during the acute phase following sepsis onset might exert a therapeutic effect.

Secreted Frizzled-Related Protein 2 and Inflammation-Induced Skeletal Muscle Atrophy

OBJECTIVE

In sepsis, the disease course of critically ill patients is often complicated by muscle failure leading to ICU-acquired weakness. The myokine transforming growth factor-β1 increases during inflammation and mediates muscle atrophy in vivo. We observed that the transforming growth factor-β1 inhibitor, secreted frizzled-related protein 2, was down-regulated in skeletal muscle of ICU-acquired weakness patients. We hypothesized that secreted frizzled-related protein 2 reduction enhances transforming growth factor-β1-mediated effects and investigated the interrelationship between transforming growth factor-β1 and secreted frizzled-related protein 2 in inflammation-induced atrophy.

DESIGN

Observational study and prospective animal trial.

SETTING

Two ICUs and research laboratory.

PATIENTS/SUBJECTS

Twenty-six critically ill patients with Sequential Organ Failure Assessment scores greater than or equal to 8 underwent a skeletal muscle biopsy from the vastus lateralis at median day 5 in ICU. Four patients undergoing elective orthopedic surgery served as controls. To search for signaling pathways enriched in muscle of ICU-acquired weakness patients, a gene set enrichment analysis of our recently published gene expression profiles was performed. Quantitative reverse transcriptase-polymerase chain reaction, Western blot, and immunohistochemistry were used to analyze secreted frizzled-related protein 2 expression and protein content. A mouse model of inflammation-induced skeletal muscle atrophy due to polymicrobial sepsis and cultured myocytes were used for mechanistic analyses.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Gene set enrichment analysis uncovered transforming growth factor-β1 signaling activation in vastus lateralis from ICU-acquired weakness patients. Muscular secreted frizzled-related protein 2 expression was reduced after 5 days in ICU. Likewise, muscular secreted frizzled-related protein 2 expression was decreased early and continuously in mice with inflammation-induced atrophy. In muscle, secreted frizzled-related protein 2 was predominantly contained in fast twitch/type II myofibers. Secreted frizzled-related protein 2 physically interacted and colocalized with transforming growth factor-β1 through its cysteine-rich domain. Finally, secreted frizzled-related protein 2 prevented transforming growth factor-β1-induced atrophy in C2C12 myotubes.

CONCLUSIONS

Muscular secreted frizzled-related protein 2 is down-regulated in ICU-acquired weakness patients and mice with inflammation-induced muscle atrophy. Decreased secreted frizzled-related protein 2 possibly establishes a positive feedback loop enhancing transforming growth factor-β1-mediated atrophic effects in inflammation-induced atrophy.

Protein Kinetics and Metabolic Effects Related to Disease States in the Intensive Care Unit

Evaluating protein kinetics in the critically ill population remains a very difficult task. Heterogeneity in the intensive care unit (ICU) population and wide spectrum of disease processes creates complexity in assessing protein kinetics. Traditionally, protein has been delivered in the context of total energy. Focus on energy delivery has recently come into question, as the importance of supplemental protein in patient outcomes has been shown in several recent trials. The ICU patient is prone to catabolism, immobilization, and impaired immunity, which is a perfect storm for massive loss of lean body tissue with a unidirectional flow of amino acids from muscle to immune tissue for immunoglobulin production, as well as liver for gluconeogenesis and acute phase protein synthesis. The understanding of protein metabolism in the ICU has been recently expanded with the discovery of how the mammalian target of rapamycin complex 1 is regulated. The concept of "anabolic resistance" and identifying the quantity of protein required to overcome this resistance is gaining support among critical care nutrition circles. It appears that a minimum of at least 1.2 g/kg/d with levels up to 2.0 g/kg/d of protein or amino acids appears safe for delivery in the ICU setting and may yield a better clinical outcome.

Premorbid obesity, but not nutrition, prevents critical illness-induced muscle wasting and weakness

BACKGROUND

The 'obesity paradox' of critical illness refers to better survival with a higher body mass index. We hypothesized that fat mobilized from excess adipose tissue during critical illness provides energy more efficiently than exogenous macronutrients and could prevent lean tissue wasting.

METHODS

In lean and premorbidly obese mice, the effect of 5 days of sepsis-induced critical illness on body weight and composition, muscle wasting, and weakness was assessed, each with fasting and parenteral feeding. Also, in lean and overweight/obese prolonged critically ill patients, markers of muscle wasting and weakness were compared.

RESULTS

In mice, sepsis reduced body weight similarly in the lean and obese, but in the obese with more fat loss and less loss of muscle mass, better preservation of myofibre size and muscle force, and less loss of ectopic lipids, irrespective of administered feeding. These differences between lean and obese septic mice coincided with signs of more effective hepatic fatty acid and glycerol metabolism, and ketogenesis in the obese. Also in humans, better preservation of myofibre size and muscle strength was observed in overweight/obese compared with lean prolonged critically ill patients.

CONCLUSIONS

During critical illness premorbid obesity, but not nutrition, optimized utilization of stored lipids and attenuated muscle wasting and weakness.

Critical Illness Myopathy (CIM) and Ventilator-Induced Diaphragm Muscle Dysfunction (VIDD): Acquired Myopathies Affecting Contractile Proteins

Critical care and intensive care units (ICUs) have undergone dramatic changes and improvements in recent years, and critical care is today one of the fastest growing hospital disciplines. Significant improvements in treatments, removal of inefficient and harmful interventions, and introduction of advanced technological support systems have improved survival among critically ill ICU patients. However, the improved survival is associated with an increased number of patients with complications related to modern critical care. Severe muscle wasting and impaired muscle function are frequently observed in immobilized and mechanically ventilated ICU patients. Approximately 30% of mechanically ventilated and immobilized ICU patients for durations of five days and longer develop generalized muscle paralysis of all limb and trunk muscles. These patients typically have intact sensory and cognitive functions, a condition known as critical illness myopathy (CIM). Mechanical ventilation is a lifesaving treatment in critically ill ICU patients; however, the being on a ventilator creates dependence, and the weaning process occupies as much as 40% of the total time of mechanical ventilation. Furthermore, 20% to 30% of patients require prolonged intensive care due to ventilator-induced diaphragm dysfunction (VIDD), resulting in poorer outcomes, and greatly increased costs to health care providers. Our understanding of the mechanisms underlying both CIM and VIDD has increased significantly in the past decade and intervention strategies are presently being evaluated in different experimental models. This short review is restricted CIM and VIDD pathophysiology rather than giving a comprehensive review of all acquired muscle wasting conditions associated with modern critical care. © 2017 American Physiological Society. Compr Physiol 7:105-112, 2017.

Human limb skeletal muscle wasting and architectural remodeling during five to ten days intubation and ventilation in critical care - an observational study using ultrasound

BACKGROUND

Critically ill patients frequently suffer muscle weakness whilst in critical care. Ultrasound can reliably track loss of muscle size, but also quantifies the arrangement of the muscle fascicles, known as the muscle architecture. We sought to measure both pennation angle and fascicle length, as well as tracking changes in muscle thickness in a population of critically ill patients.

METHODS

On days 1, 5 and 10 after admission to critical care, muscle thickness was measured in ventilated critically ill patients using bedside ultrasound. Elbow flexor compartment, medial head of gastrocnemius and vastus lateralis muscle were investigated. In the lower limb, we determined the pennation angle to derive the fascicle length.

RESULTS

We recruited and scanned 22 patients on day 1 after admission to critical care, 16 were re-scanned on day 5 and 9 on day 10. We found no changes to the size of the elbow flexor compartment over 10 days of admission. In the gastrocnemius, there were no significant changes to muscle thickness or pennation angle over 5 or 10 days. In the vastus lateralis, we found significant losses in both muscle thickness and pennation angle on day 5, but found that fascicle length is unchanged. Loss of muscle on day 5 was related to decreases in pennation angle. In both lower limb muscles, a positive relationship was observed between the pennation angle on day 1, and the percentage of angle lost by days 5 and 10.

DISCUSSION

Muscle loss in critically ill patients preferentially affects the lower limb, possibly due to the lower limb becoming prone to disuse atrophy. Muscle architecture of the thigh changes in the first 5 days of admission, in particular, we have demonstrated a correlation between muscle thickness and pennation angle. It is hypothesised that weakness in the lower limb occurs through loss of force generation via a reduced pennation angle.

CONCLUSION

Using ultrasound, we have been able to demonstrate that muscle thickness and architecture of vastus lateralis undergo rapid changes during the early phase of admission to a critical care environment.

Publication trends in cachexia and sarcopenia in elderly heart failure patients

The loss of skeletal mass - sarcopenia and cachexia - is considered to be a major contributor to morbidity and mortality in chronic heart failure (CHF). Unfortunately, sarcopenia is generally considered to be a geriatric syndrome, but not necessarily seen as a comorbidity in CHF, even though it has a wide range of adverse health outcomes. While there were 15,574 publication with the title word "heart failure" in PubMed in the 5‑year period from 1 June 2011 to 31 May 2016, only 22 or 71 publications were found with the search combination "sarcopenia" or "cachexia" (title word) and "heart failure" (all fields), respectively. This shows very clearly that loss of muscle quality and function due to heart failure is still an underappreciated problem in the medical field.

Sarcopenia in critically ill patients

Sarcopenia occurring as a primary consequence of aging and secondary due to certain medical problems including chronic disease, malnutrition and inactivity is a progressive generalized loss of skeletal muscle mass, strength and function. The prevalence of sarcopenia increases with aging (approximately 5-13 % in the sixth and seventh decades). However, data showing the prevalence and clinical outcomes of sarcopenia in intensive care units (ICUs) are limited. A similar condition to sarcopenia in the ICU, called ICU-acquired weakness (ICU-AW), has been reported more frequently. Here, we aim to examine the importance of sarcopenia, especially ICU-AW, in ICU patients via related articles in Medline.

Assessment and predictors of physical functioning post-hospital discharge in survivors of critical illness

Background

Prior studies of physical functioning after critical illness have been mostly limited to survivors of acute respiratory distress syndrome. The purpose of this study was to objectively assess muscle strength and physical functioning in survivors of critical illness from a general ICU and the associations of these measures to health-related quality of life (HRQL), mental health and critical illness variables.

Methods

This was a prospective cohort study of 56 patients admitted to a medical ICU (length of stay ≥4 days) from April 1, 2009, and March 31, 2010. Patients were assessed in clinic at 3 months post-hospital discharge. Muscle strength and physical functioning were measured using hand-held dynamometry and the 6-min walk test. HRQL was assessed using the short-form 36 (SF-36) and EuroQol-5D (EQ-5D) questionnaires.

Results

Three months post-hospital discharge, median age- and sex-matched muscle strength was reduced across all muscle groups. The median 6-min walk distance was 72 % of predicted. Physical functioning was associated with reductions in self-reported HRQL (SF-36, EQ-5D) and increased anxiety. Univariate regression modeling showed that reduced muscle strength and 6-min walk distance were associated with sepsis but not ICU length of stay. Multivariate regression modeling showed that sepsis and corticosteroid use were associated with a reduced 6-min walk distance, but again ICU length of stay was not.

Conclusions

Survivors of critical illness have reduced strength in multiple muscle groups and impaired exercise tolerance impacting both HRQL and mental health. These outcomes were worsened by sepsis and corticosteroid use in the ICU but not ICU length of stay. Interventions to minimizing the burden of sepsis in critically ill patients may improve long-term outcomes.

Dysfunction of respiratory muscles in critically ill patients on the intensive care unit

Muscular weakness and muscle wasting may often be observed in critically ill patients on intensive care units (ICUs) and may present as failure to wean from mechanical ventilation. Importantly, mounting data demonstrate that mechanical ventilation itself may induce progressive dysfunction of the main respiratory muscle, i.e. the diaphragm. The respective condition was termed 'ventilator-induced diaphragmatic dysfunction' (VIDD) and should be distinguished from peripheral muscular weakness as observed in 'ICU-acquired weakness (ICU-AW)'. Interestingly, VIDD and ICU-AW may often be observed in critically ill patients with, e.g. severe sepsis or septic shock, and recent data demonstrate that the pathophysiology of these conditions may overlap. VIDD may mainly be characterized on a histopathological level as disuse muscular atrophy, and data demonstrate increased proteolysis and decreased protein synthesis as important underlying pathomechanisms. However, atrophy alone does not explain the observed loss of muscular force. When, e.g. isolated muscle strips are examined and force is normalized for cross-sectional fibre area, the loss is disproportionally larger than would be expected by atrophy alone. Nevertheless, although the exact molecular pathways for the induction of proteolytic systems remain incompletely understood, data now suggest that VIDD may also be triggered by mechanisms including decreased diaphragmatic blood flow or increased oxidative stress. Here we provide a concise review on the available literature on respiratory muscle weakness and VIDD in the critically ill. Potential underlying pathomechanisms will be discussed before the background of current diagnostic options. Furthermore, we will elucidate and speculate on potential novel future therapeutic avenues.

Functional Status in ICU Survivors and Out of Hospital Outcomes: A Cohort Study

OBJECTIVES

Functional status at hospital discharge may be a risk factor for adverse events among survivors of critical illness. We sought to examine the association between functional status at hospital discharge in survivors of critical care and risk of 90-day all-cause mortality after hospital discharge.

DESIGN

Single-center retrospective cohort study.

SETTING

Academic Medical Center.

PATIENTS

Ten thousand three hundred forty-three adults who received critical care from 1997 to 2011 and survived hospitalization.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The exposure of interest was functional status determined at hospital discharge by a licensed physical therapist and rated based on qualitative categories adapted from the Functional Independence Measure. The main outcome was 90-day post hospital discharge all-cause mortality. A categorical risk-prediction score was derived and validated based on a logistic regression model of the function grades for each assessment. In an adjusted logistic regression model, the lowest quartile of functional status at hospital discharge was associated with an increased odds of 90-day postdischarge mortality compared with patients with independent functional status (odds ratio, 7.63 [95% CI, 3.83-15.22; p < 0.001]). In patients who had at least 7 days of physical therapy treatment prior to hospital discharge (n = 2,293), the adjusted odds of 90-day postdischarge mortality in patients with marked improvement in functional status at discharge was 64% less than patients with no change in functional status (odds ratio, 0.36 [95% CI, 0.24-0.53]; p < 0.001).

CONCLUSIONS

Lower functional status at hospital discharge in survivors of critical illness is associated with increased postdischarge mortality. Furthermore, patients whose functional status improves before discharge have decreased odds of postdischarge mortality.

Measurement of muscle strength with handheld dynamometer in Intensive Care Unit

BACKGROUND

Intensive Care Unit (ICU) acquired weakness is a common complication in critically ill patients affecting their prognosis. The handheld dynamometry is an objective method in detecting minimum muscle strength change, which has an impact on the physical function of ICU survivors. The minimal change in the force can be measured in units of weight such as pounds or kilograms.

AIM OF THE STUDY

To detect the changes in peripheral muscle strength with handheld dynamometer in the early stage of ICU stay and to observe the progression of muscle weakness.

METHODOLOGY

Three upper and three lower limb muscles force measured with handheld dynamometer during ICU stay. Data were analyzed using repeated measures ANOVA to detect changes in force generated by muscle on alternate days of ICU stay.

RESULTS

There was a reduction in peripheral muscle strength from day 3 to day 5 as well from day 5 to day 7 of ICU stay (P < 0.01). The average reduction in peripheral muscle strength was 11.8% during ICU stay.

CONCLUSION

This study showed a progressive reduction in peripheral muscle strength as measured by handheld dynamometer during early period of ICU stay.

Utility of blood procalcitonin concentration in the management of cancer patients with infections

Diagnosis of infections in cancer patients is usually problematic since differentiating between infection and fever of unknown origin is often a considerable clinical challenge. In general, increase concentration of blood procalcitonin (PCT) is associated with severe bacterial infection. PCT with an optimal cutoff level of 0.5 ng/mL seems to be the most helpful biochemical parameter in detecting severe infections, mainly bloodstream infection, in patients with hematological cancers. In all clinical situations, the elevated level of PCT should be carefully analyzed, always with a thorough physical examination and an appropriate microbiological assessment.

Assessment of intensive care unit-acquired weakness in young and old mice: An E. coli septic peritonitis model

INTRODUCTION

There are few reports of in vivo muscle strength measurements in animal models of ICU-acquired weakness (ICU-AW). In this study we investigated whether the Escherichia coli (E. coli) septic peritonitis mouse model may serve as an ICU-AW model using in vivo strength measurements and myosin/actin assays, and whether development of ICU-AW is age-dependent in this model.

METHODS

Young and old mice were injected intraperitoneally with E. coli and treated with ceftriaxone. Forelimb grip strength was measured at multiple time points, and the myosin/actin ratio in muscle was determined.

RESULTS

E. coli administration was not associated with grip strength decrease, neither in young nor in old mice. In old mice, the myosin/actin ratio was lower in E. coli mice at t = 48 h and higher at t = 72 h compared with controls.

CONCLUSIONS

This E. coli septic peritonitis mouse model did not induce decreased grip strength. In its current form, it seems unsuitable as a model for ICU-AW.

Single baseline serum creatinine measurements predict mortality in critically ill patients hospitalized for acute heart failure

Background

Acute heart failure (AHF) is a leading cause of death in critically ill patients and is often accompanied by significant renal dysfunction. Few data exist on the predictive value of measures of renal dysfunction in large cohorts of patients hospitalized for AHF.

Methods

Six hundred and eighteen patients hospitalized for AHF (300 male, aged 73.3 ± 10.3 years, 73% New York Heart Association Class 4, mean hospital length of stay 12.9 ± 7.7 days, 97% non‐ischaemic AHF) were included in a retrospective single‐centre data analysis. Echocardiographic data, serum creatinine/urea levels, estimated glomerular filtration rate (eGFR), and clinical/laboratory markers were recorded. Mean follow‐up time was 2.9 ± 2.1 years. All‐cause mortality was recorded, and univariate/multivariate analyses were performed.

Results

Normal renal function defined as eGFR > 90 mL/min/1.73 m² was noted in only 3% of AHF patients at baseline. A significant correlation of left ventricular ejection fraction with serum creatinine levels and eGFR (all P < 0.002) was noted. All‐cause mortality rates were 12% (90 days) and 40% (at 2 years), respectively. In a multivariate model, increased age, higher New York Heart Association class at admission, higher total cholesterol levels, and lower eGFR independently predicted death. Patients with baseline eGFR < 30 mL/min/1.73 m² had an exceptionally high risk of death (odds ratio 2.80, 95% confidence interval 1.52–5.15, P = 0.001).

Conclusions

In a large cohort of patients with mostly non‐ischaemic AHF, enhanced serum creatinine levels and reduced eGFR independently predict death. It appears that patients with eGFR < 30 mL/min/1.73 m² have poorest survival rates. Our data add to mounting data indicating that impaired renal function is an important risk factor for non‐survival in patients hospitalized for AHF.