ICU-acquired weakness: mechanisms of disability

Improving Outcomes in Mechanically Ventilated Adult ICU Patients Following Implementation of the ICU Liberation (ABCDEF) Bundle Across a Large Healthcare System

OBJECTIVES

To measure how the ICU Liberation Bundle (aka ABCDEF Bundle or the Bundle) affected clinical outcomes in mechanically ventilated (MV) adult ICU patients, as well as bundle sustainability and spread across a healthcare system.

DESIGN

We conducted a multicenter, prospective, cohort observational study to measure bundle performance versus patient outcomes and sustainability in 11 adult ICUs at six community hospitals. We then prospectively measured bundle spread and performance across the other 28 hospitals of the healthcare system.

SETTING

A large community-based healthcare system.

PATIENTS

In 11 study ICUs, we enrolled 1,914 MV patients (baseline n = 925, bundle performance/outcomes n = 989), 3,019 non-MV patients (baseline n = 1,323, bundle performance/outcomes n = 1,696), and 2,332 MV patients (bundle sustainability). We enrolled 9,717 MV ICU patients in the other 28 hospitals to assess bundle spread.

INTERVENTIONS

We used evidence-based strategies to implement the bundle in all 34 hospitals.

MEASUREMENTS AND MAIN RESULTS

We compared outcomes for the 12-month baseline and bundle performance periods. Bundle implementation reduced ICU length of stay (LOS) by 0.5 days (p = 0.02), MV duration by 0.6 days (p = 0.01), and ICU LOS greater than or equal to 7 days by 18.1% (p < 0.01). Performance period bundle compliance was compared with the preceding 3-month baseline compliance period. Compliance with pain management and spontaneous awakening trial (SAT) and spontaneous breathing trial (SBT) remained high, and reintubation rates remained low. Sedation assessments increased (p < 0.01) and benzodiazepine sedation use decreased (p < 0.01). Delirium assessments increased (p = 0.02) and delirium prevalence decreased (p = 0.02). Patient mobilization and ICU family engagement did not significantly improve. Bundle element sustainability varied. SAT/SBT compliance dropped by nearly half, benzodiazepine use remained low, sedation and delirium monitoring and management remained high, and patient mobility and family engagement remained low. Bundle compliance in ICUs across the healthcare system exceeded that of study ICUs.

CONCLUSIONS

The ICU Liberation Bundle improves outcomes in MV adult ICU patients. Evidence-based implementation strategies improve bundle performance, spread, and sustainability across large healthcare systems.

Risk Factors Associated With Peripheral Neuropathy in Heart Failure Patients Candidates for Transplantation

INTRODUCTION

Peripheral neuropathy can affect patients with heart failure, though its prevalence is unknown. After heart transplantation, it can influence the postoperative course and quality of life, but screening for neuromuscular disease is not routinely performed.

OBJECTIVE

The aim of this study was to identify the factors associated with neuropathy in a population of patients with heart failure who are candidates for heart transplantation.

STUDY DESIGN

Data regarding patients' clinical history, including recent hospitalizations, were collected. All patients underwent a complete neurological examination and a neurophysiological protocol including nerve conduction studies and concentric needle electromyography.

RESULTS

Thirty-two patients were included in the study, and neuropathy was diagnosed in 10 (31.3%). Neuropathy was associated with the number of admissions ( P = .023; odds ratio [OR]: 1.96) and the total number of days of hospitalization in the year prior to inclusion in the study ( P = .010; OR: 1.03). The majority of hospitalizations occurred in the step-down unit (85%), with acute heart failure the leading cause of admission (42%).

CONCLUSIONS

This study shows that neuropathy is frequent in patients with advanced heart failure and that hospitalization for cardiac care, also in the absence of intensive care, is a marker of high risk of neurologic damage. These data can help physicians in selecting and managing candidates for transplantation and can guide decisions on the best immunosuppressive regimen or rehabilitation strategy.

Upregulation of Heme Oxygenase-1 by Hemin Alleviates Sepsis-Induced Muscle Wasting in Mice

Hemin, an inducer of heme oxygenase-1 (HO-1), can enhance the activation of HO-1. HO-1 exhibits a variety of activities, such as anti-inflammatory, antioxidative, and antiapoptotic functions. The objective of this study was to investigate the effects of hemin on sepsis-induced skeletal muscle wasting and to explore the mechanisms by which hemin exerts its effects. Cecal ligation and perforation (CLP) was performed to create a sepsis mouse model. Mice were randomly divided into four groups: control, CLP, CLP plus group, and CLP-hemin-ZnPP (a HO-1 inhibitor). The weight of the solei from the mice was measured, and histopathology was examined. Cytokines were measured by enzyme-linked immunosorbent assay (ELISA). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blotting were used to assess the expression levels of HO-1 and atrogin-1. Furthermore, we investigated the antioxidative effects of HO-1 by detecting malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity. CLP led to dramatic skeletal muscle weakness and atrophy, but pretreatment with hemin protected mice against CLP-mediated muscle atrophy. Hemin also induced high HO-1 expression, which resulted in suppressed proinflammatory cytokine and reactive oxygen species (ROS) production. The expression of MuRF1 and atrogin-1, two ubiquitin ligases of the ubiquitin-proteasome system- (UPS-) mediated proteolysis, was also inhibited by increased HO-1 levels. Hemin-mediated increases in HO-1 expression exert protective effects on sepsis-induced skeletal muscle atrophy at least partly by inhibiting the expression of proinflammatory cytokines, UPS-mediated proteolysis, and ROS activation. Therefore, hemin might be a new treatment target against sepsis-induced skeletal muscle atrophy.

Effects of 3-hydroxybutyrate and free fatty acids on muscle protein kinetics and signaling during LPS-induced inflammation in humans: anticatabolic impact of ketone bodies

Background

Acute inflammation, and subsequent release of bacterial products (e.g. LPS), inflammatory cytokines, and stress hormones, is catabolic, and the loss of lean body mass predicts morbidity and mortality. Lipid intermediates may reduce protein loss, but the roles of free fatty acids (FFAs) and ketone bodies during acute inflammation are unclear.

Objective

We aimed to test whether infusions of 3-hydroxybutyrate (3OHB), FFAs, and saline reduce protein catabolism during exposure to LPS and Acipimox (to restrict and control endogenous lipolysis).

Design

A total of 10 healthy male subjects were randomly tested 3 times, with: 1) LPS, Acipimox (Olbetam) and saline, 2) LPS, Acipimox, and nonesterified fatty acids (Intralipid), and 3) LPS, Acipimox, and 3OHB, during a 5-h basal period and a 2-h hyperinsulinemic, euglycemic clamp. Labeled phenylalanine, tyrosine, and urea tracers were used to estimate protein kinetics, and muscle biopsies were taken for Western blot analysis of protein metabolic signaling.

Results

3OHB infusion increased 3OHB concentrations (P < 0.0005) to 3.5 mM and decreased whole-body phenylalanine-to-tyrosine degradation. Basal and insulin-stimulated net forearm phenylalanine release decreased by >70% (P < 0.005), with both appearance and phenylalanine disappearance being profoundly decreased. Phosphorylation of eukaryotic initiation factor 2α at Ser51 was increased in skeletal muscle, and S6 kinase phosphorylation at Ser235/236 tended (P = 0.074) to be decreased with 3OHB infusion (suggesting inhibition of protein synthesis), whereas no detectable effects were seen on markers of protein breakdown. Lipid infusion did not affect phenylalanine kinetics, and insulin sensitivity was unaffected by interventions.

Conclusion

During acute inflammation, 3OHB has potent anticatabolic actions in muscle and at the whole-body level; in muscle, reduction of protein breakdown overrides inhibition of synthesis. This trial was registered at clinicaltrials.gov as NCT01752348.

Physiotherapy management of intensive care unit-acquired weakness

[Hodgson CL, Tipping CJ (2016) Physiotherapy management of intensive care unit-acquired weakness.Journal of Physiotherapy63: 4-10].

Short-term Gains with Long-term Consequences: The Evolving Story of Sepsis Survivorship

Sepsis is an acute, life-threatening condition that afflicts millions of patients annually. Advances in care and heightened awareness have led to substantial declines in short-term mortality. An expanding body of literature describes the long-term impact of sepsis, revealing long-term cognitive and functional impairments, sustained inflammation and immune dysfunction, increased healthcare resource use, reduced health-related quality of life, and increased mortality. The evidence challenges the notion that sepsis is an acute, transient illness, revealing rather that sepsis is an acute illness with lingering consequences. This article provides a state-of-the-art review of the emerging literature of the long-term consequences of sepsis.

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.

Predicting intensive care and hospital outcome with the Dalhousie Clinical Frailty Scale: a pilot assessment

Frailty may help to predict intensive care unit (ICU) patient outcome. The Dalhousie Clinical Frailty Scale (DCFS) is validated to assess frailty in ambulatory settings but has not been investigated in Australian ICUs. We conducted a prospective three-month study of patients admitted to a tertiary level ICU. Within 24 hours of ICU admission, the next of kin or nurse in charge assigned a DCFS score to the patient. Data were obtained to assess the association between frailty and patient outcome. The DCFS score was completed in 205 of 348 (59%) of eligible patient admissions. The mean DCFS score was 3.2 (±1.6). Overall frailty (DCFS>4) occurred in 28 of 205 patients (13%, confidence interval 9% to 17%), 13 of 93 (15%, confidence interval 10% to 25%) in patients aged >65 years and 5 of 11 (45%, confidence interval 21% to 71%) in those>85 years. Patients with chronic liver disease (P<0.001) and end-stage renal failure (P=0.009) were more likely to be frail. The DCFS score was not significantly associated with ICU or hospital mortality: odds ratio 0.98 (95% confidence interval 0.6 to 1.6) and odds ratio 1.07 (95% confidence interval 0.8 to 1.4), respectively. However, after adjustment for illness severity and requirement for palliative care, the DCFS score was significantly associated with increased (log) hospital length-of-stay (P=0.04) and age (P=0.001). Approximately 1 in 10 ICU patients were frail and this frequency increased with age. The DCFS was associated with patient age and comorbidities and potentially predicts increased hospital length-of-stay but not other outcomes. Strategies to improve compliance with DCFS completion are needed.

Initiation of nutritional support is delayed in critically ill obese patients: a multicenter cohort study

BACKGROUND

A high catabolic rate characterizes the acute phase of critical illness. Guidelines recommend an early nutritional support, regardless of the previous nutritional status.

OBJECTIVE

We aimed to assess whether the nutritional status of patients, which was defined by the body mass index (BMI) at admission in an intensive care unit (ICU), affected the time of nutritional support initiation.

DESIGN

We conducted a cohort study that reported a retrospective analysis of a multicenter ICU database (OUTCOMEREA) by using data prospectively entered from January 1997 to October 2012. Patients who needed orotracheal intubation within the first 72 h and >3 d were included.

RESULTS

Data from 3257 ICU stays were analyzed. The delay before feeding was different according to BMI groups (P = 0.035). The delay was longer in obese patients [BMI (in kg/m²) ≥30; n = 663] than in other patients with either low weight (BMI <20; n = 501), normal weight (BMI ≥20 and <25; n = 1135), or overweight (BMI ≥25 and <30; n = 958). The association between nutritional status and a delay in nutrition initiation was independent of potential confounding factors such as age, sex, and diabetes or other chronic diseases. In comparison with normal weight, the adjusted RR (95% CI) associated with a delayed nutrition initiation was 0.92 (0.86, 0.98) for patients with low weight, 1.00 (0.94, 1.05) for overweight patients, and 1.06 (1.00, 1.12) for obese patients (P = 0.004).

CONCLUSIONS

The initiation of nutritional support was delayed in obese ICU patients. Randomized controlled trials that address consequences of early compared with delayed beginnings of nutritional support in critically ill obese patients are needed.

Strategies to combat chronic critical illness

PURPOSE OF REVIEW

The population of chronically critically ill patients is growing as advances in intensive care management improve survival from the acute phase of critical illness. These patients are characterized by complex medical needs and heavy resource utilization. This article reviews evidence supporting a comprehensive approach to the prevention and management of chronic critical illness (CCI).

RECENT FINDINGS

The most efficient approach to weaning patients with CCI at long-term acute care hospitals is daily unassisted breathing trials through a tracheostomy collar. However, a substantial number of patients transferred to long-term acute care hospitals pass their spontaneous weaning trials. Transfer to long-term acute care hospitals is associated with higher acute care costs and payments, but lower costs through the entire episode of illness. Universal decontamination is more effective than targeted decontamination or screening and isolation for preventing nosocomial bloodstream infections.

SUMMARY

Combating CCI begins with prevention in the acute phase of illness. Management strategies include a spectrum of ventilatory, nutritional, and rehabilitation support. Further patient-centered outcome-based research in this specific population is needed to continue to help guide optimal care.

Intensive care unit acquired weakness in children: Critical illness polyneuropathy and myopathy

BACKGROUND AND AIMS

Intensive care unit acquired weakness (ICUAW) is a common occurrence in patients who are critically ill. It is most often due to critical illness polyneuropathy (CIP) or to critical illness myopathy (CIM). ICUAW is increasingly being recognized partly as a consequence of improved survival in patients with severe sepsis and multi-organ failure, partly related to commonly used agents such as steroids and muscle relaxants. There have been occasional reports of CIP and CIM in children, but little is known about their prevalence or clinical impact in the pediatric population. This review summarizes the current understanding of pathophysiology, clinical presentation, diagnosis and treatment of CIP and CIM in general with special reference to published literature in the pediatric age group.

SUBJECTS AND METHODS

Studies were identified through MedLine and Embase using relevant MeSH and Key words. Both adult and pediatric studies were included.

RESULTS

ICUAW in children is a poorly described entity with unknown incidence, etiology and unclear long-term prognosis.

CONCLUSIONS

Critical illness polyneuropathy and myopathy is relatively rare, but clinically significant sequelae of multifactorial origin affecting morbidity, length of intensive care unit (ICU) stay and possibly mortality in critically ill children admitted to pediatric ICU.