ICU-acquired weakness Vanhorebeek, Ilse; Latronico, Nicola; Van den Berghe, Greet
Intensive care medicine,
04/2020, Letnik:
46, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Critically ill patients often acquire neuropathy and/or myopathy labeled ICU-acquired weakness. The current insights into incidence, pathophysiology, diagnostic tools, risk factors, short- and ...long-term consequences and management of ICU-acquired weakness are narratively reviewed. PubMed was searched for combinations of “neuropathy”, “myopathy”, “neuromyopathy”, or “weakness” with “critical illness”, “critically ill”, “ICU”, “PICU”, “sepsis” or “burn”. ICU-acquired weakness affects limb and respiratory muscles with a widely varying prevalence depending on the study population. Pathophysiology remains incompletely understood but comprises complex structural/functional alterations within myofibers and neurons. Clinical and electrophysiological tools are used for diagnosis, each with advantages and limitations. Risk factors include age, weight, comorbidities, illness severity, organ failure, exposure to drugs negatively affecting myofibers and neurons, immobility and other intensive care-related factors. ICU-acquired weakness increases risk of in-ICU, in-hospital and long-term mortality, duration of mechanical ventilation and of hospitalization and augments healthcare-related costs, increases likelihood of prolonged care in rehabilitation centers and reduces physical function and quality of life in the long term. RCTs have shown preventive impact of avoiding hyperglycemia, of omitting early parenteral nutrition use and of minimizing sedation. Results of studies investigating the impact of early mobilization, neuromuscular electrical stimulation and of pharmacological interventions were inconsistent, with recent systematic reviews/meta-analyses revealing no or only low-quality evidence for benefit. ICU-acquired weakness predisposes to adverse short- and long-term outcomes. Only a few preventive, but no therapeutic, strategies exist. Further mechanistic research is needed to identify new targets for interventions to be tested in adequately powered RCTs.
Recent trials have questioned the benefit of early parenteral nutrition in adults. The effect of early parenteral nutrition on clinical outcomes in critically ill children is unclear.
We conducted a ...multicenter, randomized, controlled trial involving 1440 critically ill children to investigate whether withholding parenteral nutrition for 1 week (i.e., providing late parenteral nutrition) in the pediatric intensive care unit (ICU) is clinically superior to providing early parenteral nutrition. Fluid loading was similar in the two groups. The two primary end points were new infection acquired during the ICU stay and the adjusted duration of ICU dependency, as assessed by the number of days in the ICU and as time to discharge alive from ICU. For the 723 patients receiving early parenteral nutrition, parenteral nutrition was initiated within 24 hours after ICU admission, whereas for the 717 patients receiving late parenteral nutrition, parenteral nutrition was not provided until the morning of the 8th day in the ICU. In both groups, enteral nutrition was attempted early and intravenous micronutrients were provided.
Although mortality was similar in the two groups, the percentage of patients with a new infection was 10.7% in the group receiving late parenteral nutrition, as compared with 18.5% in the group receiving early parenteral nutrition (adjusted odds ratio, 0.48; 95% confidence interval CI, 0.35 to 0.66). The mean (±SE) duration of ICU stay was 6.5±0.4 days in the group receiving late parenteral nutrition, as compared with 9.2±0.8 days in the group receiving early parenteral nutrition; there was also a higher likelihood of an earlier live discharge from the ICU at any time in the late-parenteral-nutrition group (adjusted hazard ratio, 1.23; 95% CI, 1.11 to 1.37). Late parenteral nutrition was associated with a shorter duration of mechanical ventilatory support than was early parenteral nutrition (P=0.001), as well as a smaller proportion of patients receiving renal-replacement therapy (P=0.04) and a shorter duration of hospital stay (P=0.001). Late parenteral nutrition was also associated with lower plasma levels of γ-glutamyltransferase and alkaline phosphatase than was early parenteral nutrition (P=0.001 and P=0.04, respectively), as well as higher levels of bilirubin (P=0.004) and C-reactive protein (P=0.006).
In critically ill children, withholding parenteral nutrition for 1 week in the ICU was clinically superior to providing early parenteral nutrition. (Funded by the Flemish Agency for Innovation through Science and Technology and others; ClinicalTrials.gov number, NCT01536275.).
Purpose
To assess the independent association between ICU-acquired neuromuscular complications and 5-year mortality and morbidity. To explore the optimal threshold of the Medical Research Council ...(MRC) sum score, assessing weakness, for the prediction of 5-year outcomes.
Methods
Sub-analyses of a prospective, 5-year follow-up study including 883 EPaNIC patients (Early versus Late Parenteral Nutrition in Intensive Care) (Clinicaltrials.gov:NCT00512122), systematically screened in ICU for neuromuscular complications with MRC sum score (‘MRC-cohort’,
N
= 600), electrophysiology on day 8 ± 1 to quantify compound muscle action potential (‘CMAP-cohort’,
N
= 689), or both (‘MRC&CMAP-cohort’,
N
= 415). Associations between ICU-acquired neuromuscular complications and 5-year mortality, hand-grip strength (HGF, %predicted), 6-min-walk distance (6-MWD, %predicted) and physical function of the SF-36 quality-of-life questionnaire (PF-SF-36) at 5-years were assessed with Cox regression and linear regression, adjusted for confounders. The optimal threshold for MRC at ICU discharge to predict 5-year outcomes was determined by martingale residual plots (survival) and scatterplots (morbidity).
Results
Both lower MRC sum score at ICU discharge, indicating less strength HR, per-point-increase: 0.946 (95% CI 0.928–0.968),
p
= 0.001, and abnormal CMAP, indicating nerve/muscle dysfunction HR: 1.568 (95% CI 1.165–2.186),
p
= 0.004, independently associated with increased 5-year mortality. In the MRC&CMAP-cohort, MRC HR: 0.956 (95% CI 0.934–0.980),
p
= 0.001 but not CMAP HR: 1.478 (95% CI 0.875–2.838),
p
= 0.088 independently associated with 5-year mortality. Among 205 survivors, low MRC independently associated with low HGF 0.866 (95% CI 0.237–1.527),
p
= 0.004, low 6-MWD 105.1 (95% CI 12.1–212.9),
p
= 0.043 and low PF-SF-36 − 0.119 (95% CI − 0.186 to − 0.057),
p
= 0.002, whereas abnormal CMAP did not correlate with these morbidity endpoints. Exploratory analyses suggested that MRC ≤ 55 best predicted poor long-term morbidity and mortality. Both MRC ≤ 55 and abnormal CMAP independently associated with 5-year mortality.
Conclusions
ICU-acquired neuromuscular complications may impact 5-year morbidity and mortality. MRC sum score, even if slightly reduced, may affect long-term mortality, strength, functional capacity and physical function, whereas abnormal CMAP only related to long-term mortality.
Controversy exists about the timing of the initiation of parenteral nutrition in critically ill adults in whom caloric targets cannot be met by enteral nutrition alone.
In this randomized, ...multicenter trial, we compared early initiation of parenteral nutrition (European guidelines) with late initiation (American and Canadian guidelines) in adults in the intensive care unit (ICU) to supplement insufficient enteral nutrition. In 2312 patients, parenteral nutrition was initiated within 48 hours after ICU admission (early-initiation group), whereas in 2328 patients, parenteral nutrition was not initiated before day 8 (late-initiation group). A protocol for the early initiation of enteral nutrition was applied to both groups, and insulin was infused to achieve normoglycemia.
Patients in the late-initiation group had a relative increase of 6.3% in the likelihood of being discharged alive earlier from the ICU (hazard ratio, 1.06; 95% confidence interval CI, 1.00 to 1.13; P=0.04) and from the hospital (hazard ratio, 1.06; 95% CI, 1.00 to 1.13; P=0.04), without evidence of decreased functional status at hospital discharge. Rates of death in the ICU and in the hospital and rates of survival at 90 days were similar in the two groups. Patients in the late-initiation group, as compared with the early-initiation group, had fewer ICU infections (22.8% vs. 26.2%, P=0.008) and a lower incidence of cholestasis (P<0.001). The late-initiation group had a relative reduction of 9.7% in the proportion of patients requiring more than 2 days of mechanical ventilation (P=0.006), a median reduction of 3 days in the duration of renal-replacement therapy (P=0.008), and a mean reduction in health care costs of €1,110 (about $1,600) (P=0.04).
Late initiation of parenteral nutrition was associated with faster recovery and fewer complications, as compared with early initiation. (Funded by the Methusalem program of the Flemish government and others; EPaNIC ClinicalTrials.gov number, NCT00512122.).
Critical illness polyneuropathy (CIP) and myopathy (CIM) are major complications of severe critical illness and its management. CIP/CIM prolongs weaning from mechanical ventilation and physical ...rehabilitation since both limb and respiratory muscles can be affected. Among many risk factors implicated, sepsis, systemic inflammatory response syndrome, and multiple organ failure appear to play a crucial role in CIP/CIM. This review focuses on epidemiology, diagnostic challenges, the current understanding of pathophysiology, risk factors, important clinical consequences, and potential interventions to reduce the incidence of CIP/CIM. CIP/CIM is associated with increased hospital and intensive care unit (ICU) stays and increased mortality rates. Recently, it was shown in a single centre that intensive insulin therapy significantly reduced the electrophysiological incidence of CIP/CIM and the need for prolonged mechanical ventilation in patients in a medical or surgical ICU for at least 1 week. The electrophysiological diagnosis was limited by the fact that muscle membrane inexcitability was not detected. These results have yet to be confirmed in a larger patient population. One of the main risks of this therapy is hypoglycemia. Also, conflicting evidence concerning the neuromuscular effects of corticosteroids exists. A systematic review of the available literature on the optimal approach for preventing CIP/CIM seems warranted.
Critical illnesses are characterized by increased systemic cortisol availability, which is a vital part of the stress response. Relative adrenal failure (later termed critical-illness-related ...corticosteroid insufficiency (CIRCI)) is a condition in which the systemic availability of cortisol is assumed to be insufficiently high to face the stress of the illness and is most typically thought to occur in the acute phase of septic shock. Researchers suggested that CIRCI could be diagnosed by a suppressed incremental cortisol response to an injection of adrenocorticotropic hormone, irrespective of the baseline plasma cortisol. This concept triggered several randomized clinical trials on the impact of large stress doses of hydrocortisone to treat CIRCI, which gave conflicting results. Recent novel insights into the response of the hypothalamic-pituitary-adrenal axis to acute and prolonged critical illnesses challenge the concept of CIRCI, as currently defined, as well as the current practice guidelines for diagnosis and treatment. In this Review, these novel insights are integrated within a novel conceptual framework that can be used to re-appreciate adrenocortical function and dysfunction in the context of critical illness. This framework opens new avenues for further research and for preventive and/or therapeutic innovations.
Critical illnesses are hallmarked by increased systemic cortisol availability, a vital part of the stress response. Acute stress may trigger a life-threatening adrenal crisis when a disease of the ...hypothalamic-pituitary-adrenal (HPA) axis is present and not adequately treated with stress doses of hydrocortisone. Stress doses of hydrocortisone are also used to reduce high vasopressor need in patients suffering from septic shock, in the absence of adrenal insufficiency. Research performed over the last 10 years focusing on the HPA axis during critical illness has led to the insight that neither of these conditions can be labeled "critical illness-induced corticosteroid insufficiency" or CIRCI. Instead, these data suggested using the term CIRCI for a condition that may develop in prolonged critically ill patients. Indeed, when patients remain dependent on vital organ support for weeks, they are at risk of acquiring central adrenal insufficiency. The sustained increase in systemic glucocorticoid availability, mainly brought about by suppressed circulating cortisol-binding proteins and suppressed hepatic/renal cortisol metabolism, exerts negative feedback inhibition at the hypothalamus/pituitary, while high levels of other glucocorticoid receptor ligands, such as bile acids, and drugs, such as opioids, may further suppress adrenocorticotropic hormone (ACTH) secretion. The adrenal cortex, depleted from ACTH-mediated trophic signaling for weeks, may become structurally and functionally impaired, resulting in insufficient cortisol production. Such a central HPA axis suppression may be maladaptive by contributing to lingering vasopressor need and encephalopathy, hence preventing recovery. Here, we review this concept of CIRCI and we advise on how to recognize and treat this poorly understood condition.
A substantial number of patients admitted to the ICU because of an acute illness, complicated surgery, severe trauma, or burn injury will develop a de novo form of muscle weakness during the ICU stay ...that is referred to as "intensive care unit acquired weakness" (ICUAW). This ICUAW evoked by critical illness can be due to axonal neuropathy, primary myopathy, or both. Underlying pathophysiological mechanisms comprise microvascular, electrical, metabolic, and bioenergetic alterations, interacting in a complex way and culminating in loss of muscle strength and/or muscle atrophy. ICUAW is typically symmetrical and affects predominantly proximal limb muscles and respiratory muscles, whereas facial and ocular muscles are often spared. The main risk factors for ICUAW include high severity of illness upon admission, sepsis, multiple organ failure, prolonged immobilization, and hyperglycemia, and also older patients have a higher risk. The role of corticosteroids and neuromuscular blocking agents remains unclear. ICUAW is diagnosed in awake and cooperative patients by bedside manual testing of muscle strength and the severity is scored by the Medical Research Council sum score. In cases of atypical clinical presentation or evolution, additional electrophysiological testing may be required for differential diagnosis. The cornerstones of prevention are aggressive treatment of sepsis, early mobilization, preventing hyperglycemia with insulin, and avoiding the use parenteral nutrition during the first week of critical illness. Weak patients clearly have worse acute outcomes and consume more healthcare resources. Recovery usually occurs within weeks or months, although it may be incomplete with weakness persisting up to 2 years after ICU discharge. Prognosis appears compromised when the cause of ICUAW involves critical illness polyneuropathy, whereas isolated critical illness myopathy may have a better prognosis. In addition, ICUAW has shown to contribute to the risk of 1-year mortality. Future research should focus on new preventive and/or therapeutic strategies for this detrimental complication of critical illness and on clarifying how ICUAW contributes to poor longer-term prognosis.
Introduction: Muscle weakness often complicates critical illness and is associated with devastating short‐ and long‐term consequences. For interventional studies, reliable measurements of muscle ...force in the intensive care unit (ICU) are needed. Methods: To examine interobserver agreement, two observers independently measured Medical Research Council (MRC) sum‐score (n = 75) and handgrip strength (n = 46) in a cross‐sectional ICU sample. Results: The intraclass correlation coefficient (ICC) for MRC sum‐score was 0.95 (0.92–0.97). The kappa coefficient for identifying “significant weakness” (MRC sum‐score <48, MRC subtotal upper limbs <24) and “severe weakness” (MRC sum‐score <36) was 0.68 ± 0.09, 0.88 ± 0.07, and 0.93 ± 0.07, respectively. The ICC for left and right handgrip strength was 0.97 (0.94–0.98) and 0.93 (0.86–0.97), respectively. Conclusions: Interobserver agreement on MRC sum‐score and handgrip strength in the ICU was very good. Agreement on “severe weakness” (MRC sum‐score <36) was excellent and supports its use in interventional studies. Agreement on “significant weakness” (MRC sum‐score <48) was good, but even better using the equivalent cut‐off in the upper limbs. It remains to be determined whether this may serve as a substitute. Muscle Nerve 45: 18–25, 2012
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