Neuromuscular complications in the intensive care unit: critical illness polyneuromyopathy

The impact of disease-related immobilization on thigh muscle mass and strength in older hospitalized patients

Background

We assessed the quantitative changes in muscle mass and strength during 2 weeks of hospitalization in immobile and mobile acutely ill hospitalized older adults.

Methods

Forty-one patients (82.4 ± 6.6 years, 73.0% females) participated in this prospective longitudinal observational study. Mobility status was defined according to walking ability as described in the Barthel-Index. Functional status, including handgrip strength and isometric knee-extension strength, and mid-thigh magnetic resonance imaging (MRI) measurements of cross-sectional area (CSA) were conducted on admission and at discharge.

Results

Twenty-two participants (54%) were immobile and 19 (46%) mobile. In all, 54.0 and 12.0% were at risk of malnutrition and malnourished, respectively. The median time between baseline and follow-up for MRI scans were 13 days in mobile and immobile participants (P = 0.072). Mid-thigh muscle and subcutaneous fat CSA significantly decreased by 3.9cm² (5.0%, P = 0.002) and 5.3cm² (5.7%, P = 0.036) during hospitalization whereas intermuscular fat remained unchanged in immobile subjects. No significant changes were observed in mobile patients. In a regression analysis, mobility was the major independent risk factor for changes in mid-thigh muscle CSA as a percentage of initial muscle area (P = 0.022) whereas other variables such as age (P = 0.584), BMI (P = 0.879), nutritional status (P = 0.835) and inflammation (P = 0.291) were not associated with muscle mass changes. There was a significant decrease in isometric knee extension strength (P = 0.002) and no change in handgrip strength (P = 0.167) in immobile patients whereas both parameters increased significantly over time in mobile patients (P = 0.048 and P = 0.012, respectively).

Conclusions

Two weeks of disease-related immobilization result in a significant loss of thigh muscle mass and muscle strength in older patients with impaired mobility. Concomitantly, there was a significant reduction of subcutaneous adipose tissue in immobile older hospitalized patients whereas no changes were observed in intermuscular fat among these patients. These data highlight the importance of mobility support in maintaining muscle mass and function in older hospitalized patients.

Electrophysiologic alterations in the excitability of the sciatic and vagus nerves during early stages of sepsis

Background

Nonspecific and delayed diagnosis of neurologic damage contributes to the development of neuropathies in patients with severe sepsis. The present study assessed the electrophysiologic parameters related to the excitability and conductibility of sciatic and vagus nerves during early stages of sepsis.

Materials and methods

Twenty-four hours after sepsis induced by cecal ligation and puncture (CLP) model, sciatic and vagus nerves of septic (CLP group) and control (sham group) rats were removed, and selected electric stimulations were applied to measure the parameters of the first and second components of the compound action potential. The first component originated from fibers with motor and sensory functions (Types Aα and Aβ fibers) with a large conduction velocity (70-120 m/s), and the second component originated from fibers (Type Aγ) with sensorial function. To evaluate the presence of sensorial alterations, the sensitivity to non-noxious mechanical stimuli was measured by using the von Frey test. Hematoxylin and eosin staining of the nerves was performed.

Results

We observed an increase of rheobase followed by a decrease in the first component amplitude and a higher paw withdrawal threshold in response to the application of von Frey filaments in sciatic nerves from the CLP group compared to the sham group. Differently, a decrease in rheobase and an increase in the first component amplitude of vagal C fibers from CLP group were registered. No significant morphologic alteration was observed.

Conclusion

Our data showed that the electrophysiologic alterations in peripheral nerves vary with the fiber type and might be identified in the first 24 h of sepsis, before clinical signs of neuromuscular disorders.

Muscle atrophy in intensive care unit patients

Introduction:

The muscle atrophy is one of the most important and frequent problems observed in patients in Intensive Care Units. The term describes the disorder in the structure and in the function of the muscle while incidence rates range from 25-90 % in patients with prolonged hospitalization.

Purpose:

This is a review containing all data related to the issue of muscle atrophy and is especially referred to its causes and risk factors. The importance of early diagnosis and early mobilization are also highlighted in the study.

Material and methods:

a literature review was performed on valid databases such as Scopus, PubMed, Cinhal for the period 2000-2013 in English language. The following keywords were used: loss of muscle mass, ICU patients, immobilization, bed rest.

Results:

From the review is concluded that bed rest and immobilization in order to reduce total energy costs, are the main causes for the appearance of the problem. The results of the reduction of the muscle mass mainly affect the musculoskeletal, cardiovascular and respiratory system. The administration of the cortisone, the immobility, the sepsis and hyperglycemia are included in the risk factors. The prevention is the primary therapeutic agent and this is achieved due to the early mobilization of the patients, the use of neuromuscular electrical stimulation and the avoidance of exposure to risk factors.

Conclusions:

The prevention of muscle atrophy is a primary goal of treatment for the patients in the ICU, because it reduces the incidence of the disease, reduces the time spent in ICU and finally improves the quality of patients’ life.

Critical illness myopathy and polyneuropathy - A challenge for physiotherapists in the intensive care units

The development of critical patient related generalized neuromuscular weakness, referred to as critical illness polyneuropathy (CIP) and critical illness myopathy (CIM), is a major complication in patients admitted to intensive care units (ICU). Both CIP and CIM cause muscle weakness and paresis in critically ill patients during their ICU stay. Early mobilization or kinesiotherapy have shown muscle weakness reversion in critically ill patients providing faster return to function, reducing weaning time, and length of hospitalization. Exercises in the form of passive, active, and resisted forms have proved to improve strength and psychological well being. Clinical trials using neuromuscular electrical stimulation to increase muscle mass, muscle strength and improve blood circulation to the surrounding tissue have proved beneficial. The role of electrical stimulation is unproven as yet. Recent evidence indicates no difference between treated and untreated muscles. Future research is recommended to conduct clinical trials using neuromuscular electrical stimulation, exercises, and early mobilization as a treatment protocol in larger populations of patients in ICU.

Joint contractures in the intensive care unit: association with resource utilization and ambulatory status at discharge

PURPOSE

The objectives of our study were (1) to explore the link between joint contractures acquired in the ICU and the ambulatory status of patients at discharge home, to determine (2) when and how many patients received physiotherapy services in ICU and on the hospital ward, and (3) the differences in the use of hospital resources in the presence or absence of joint contractures.

METHOD

Data on ICU joint contractures were extracted from an existing contracture database containing information on 155 Canadian patients with a tertiary ICU stay of 14 days or more.

RESULTS

Of 155 patients, 115 (74.2%) received a range of motion assessment in the ICU. The assessment took place a median of 7 days (IQR 0-36) after ICU admission. Significantly fewer patients with joint contractures than without joint contractures were mobilized on the hospital ward (21/38 [55.3%] vs. 27/34 [79.4%], P = 0.03). At discharge home, more patients with joint contractures had a low ambulatory status (38 [64.4%]) compared with patients without joint contractures (26 [51.0%]; P = 0.002).

CONCLUSION

The median delay of 7 days before musculoskeletal assessment in the ICU together with failure to assess 26% of patients may have allowed the development of contractures, which affected the patients' ambulatory status at discharge from hospital.

Chronic Escherichia coli infection induces muscle wasting without changing acetylcholine receptor numbers

OBJECTIVE

Muscle weakness in septic patients is a serious problem as it complicates and lengthens hospital stays, prolongs rehabilitation and increases costs. We examined the effects of a chronic infection with Escherichia coli on muscle function, muscle mass, and the expression of nicotinic acetylcholine receptors (AChRs).

DESIGN AND SETTING

Prospective, randomized animal study in an animal laboratory, university hospital.

SUBJECTS

Sprague-Dawley rats.

INTERVENTIONS

A catheter was implanted into the external jugular vein of anesthetized rats, and a dose of 3.2x10(8) CFU of E. coli bacteria was injected; the catheter was then sealed and tunneled subcutaneously.

MEASUREMENTS AND RESULTS

Animals injected with E. coli bacteria showed a significant decrease in body and muscle mass over the 14-day experimental period. Neuromuscular function was tested by mechanomyography on days 3, 7, and 14 following injection. Tetanic tension decreased over the time course of sepsis, without effecting tetanic fade. Serum levels of acute-phase protein, alpha1-acid glycoprotein, were increased by day 3, and remained significantly higher until day 14. AChRs were quantitated using 125I-labeled bungarotoxin and revealed no differences between groups.

CONCLUSIONS

Central venous injection of E. coli bacteria induces systemic inflammation evidenced as loss of body weight, muscle mass and increased alpha1-acid glycoprotein levels. The inflammation-induced muscle weakness is due to muscle atrophy and not to upregulated AChRs. This model may prove useful for studying maneuvers to prevent muscle wasting with inflammation.