Bedside Ultrasonography Can and Should Be Used in the Intensive Care Unit to Evaluate Muscle Atrophy

Acute Skeletal Muscle Wasting is Associated with Prolonged Hospital Stay in Critical Illness with Brain Injury

BACKGROUND

Acute muscle wasting is common in critically ill patients, and this can lead to unfavorable clinical outcomes. The aim of this study was to identify factors associated with muscle wasting and to investigate the association between skeletal muscle wasting and prolonged hospital stay in critically ill patients with acute brain injury.

METHODS

This single-center prospective observational study was conducted in critically ill patients with acute brain injury who stayed in the intensive care unit for at least 1 week. The rectus femoris cross-sectional area was measured via ultrasound at baseline and a week after the first assessment. Univariate and multivariate logistic regression analyses were performed to identify factors that predicted prolonged hospital stay.

RESULTS

A total of 86 patients were included in the study. Their mean age was 49.4 ± 16.9 years, 57% were male, and 46.5% had an admission diagnosis of subarachnoid hemorrhage. The percentage change in the rectus femoris cross-sectional area was 15.8% (95% confidence interval [CI] - 19.8% to - 12.0%; p < 0.001), and 57% of all patients had acute muscle wasting. According to the univariate analysis, there was a significant association between prolonged hospital stay and acute muscle wasting (odds ratio [OR] 3.677; 95% CI 1.487-9.043; p = 0.005), mechanical ventilation status (OR 3.600; 95% CI 1.455-8.904; p = 0.006), and Glasgow Coma Scale score (OR 0.888; 95% CI 0.808-0.976; p = 0.014) at intensive care unit admission. The multivariate analysis demonstrated that acute muscle wasting (OR 3.449; 95% CI 1.344-8.853; p = 0.010) was an independent risk factor for prolonged hospital stay.

CONCLUSIONS

There was considerable muscle wasting in critically ill patients with brain injuries over a 1-week period. Acute muscle wasting was associated with prolonged hospital stay in critically ill patients with acute brain injury.

Rectus Femoris Mimicking Ultrasound Phantom for Muscle Mass Assessment: Design, Research, and Training Application

Ultrasound has become widely used as a means to measure the rectus femoris muscle in the acute and chronic phases of critical illness. Despite its noninvasiveness and accessibility, its accuracy highly depends on the skills of the technician. However, few ultrasound phantoms for the confirmation of its accuracy or to improve technical skills exist. In this study, the authors created a novel phantom model and used it for investigating the accuracy of measurements and for training. Study 1 investigated how various conditions affect ultrasound measurements such as thickness, cross-sectional area, and echogenicity. Study 2 investigated if the phantom can be used for the training of various health care providers in vitro and in vivo. Study 1 showed that thickness, cross-sectional area, and echogenicity were affected by probe compression strength, probe angle, phantom compression, and varying equipment. Study 2 in vitro showed that using the phantom for training improved the accuracy of the measurements taken within the phantom, and Study 2 in vivo showed the phantom training had a short-term effect on improving the measurement accuracy in a human volunteer. The new ultrasound phantom model revealed that various conditions affected ultrasound measurements, and phantom training improved the measurement accuracy.

Muscle atrophy in critically ill patients : a review of its cause, evaluation, and prevention

Critically ill patients exhibit prominent muscle atrophy, which occurs rapidly after ICU admission and leads to poor clinical outcomes. The extent of atrophy differs among muscles as follows: upper limb: 0.7%-2.4% per day, lower limb: 1.2%-3.0% per day, and diaphragm 1.1%-10.9% per day. This atrophy is caused by numerous risk factors such as inflammation, immobilization, nutrition, hyperglycemia, medication, and mechanical ventilation. Muscle atrophy should be monitored noninvasively by ultrasound at the bedside. Ultrasound can assess muscle mass in most patients, although physical assessment is limited to almost half of all critically ill patients due to impaired consciousness. Important strategies to prevent muscle atrophy are physical therapy and electrical muscular stimulation. Electrical muscular stimulation is especially effective for patients with limited physical therapy. Regarding diaphragm atrophy, mechanical ventilation should be adjusted to maintain spontaneous breathing and titrate inspiratory pressure. However, the sufficient timing and amount of nutritional intervention remain unclear. Further investigation is necessary to prevent muscle atrophy and improve long-term outcomes. J. Med. Invest. 67 : 1-10, February, 2020.

Urinary Titin Is a Novel Biomarker for Muscle Atrophy in Nonsurgical Critically Ill Patients: A Two-Center, Prospective Observational Study

OBJECTIVES

Although skeletal muscle atrophy is common in critically ill patients, biomarkers associated with muscle atrophy have not been identified reliably. Titin is a spring-like protein found in muscles and has become a measurable biomarker for muscle breakdown. We hypothesized that urinary titin is useful for monitoring muscle atrophy in critically ill patients. Therefore, we investigated urinary titin level and its association with muscle atrophy in critically ill patients.

DESIGN

Two-center, prospective observational study.

SETTING

Mixed medical/surgical ICU in Japan.

PATIENTS

Nonsurgical adult patients who were expected to remain in ICU for greater than 5 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Urine samples were collected on days 1, 2, 3, 5, and 7 of ICU admission. To assess muscle atrophy, rectus femoris cross-sectional area and diaphragm thickness were measured with ultrasound on days 1, 3, 5, and 7. Secondary outcomes included its relationship with ICU-acquired weakness, ICU Mobility Scale, and ICU mortality. Fifty-six patients and 232 urinary titin measurements were included. Urinary titin (normal range: 1-3 pmol/mg creatinine) was 27.9 (16.8-59.6), 47.6 (23.5-82.4), 46.6 (24.4-97.6), 38.4 (23.6-83.0), and 49.3 (27.4-92.6) pmol/mg creatinine on days 1, 2, 3, 5, and 7, respectively. Cumulative urinary titin level was significantly associated with rectus femoris muscle atrophy on days 3-7 (p ≤ 0.03), although urinary titin level was not associated with change in diaphragm thickness (p = 0.31-0.45). Furthermore, cumulative urinary titin level was associated with occurrence of ICU-acquired weakness (p = 0.01) and ICU mortality (p = 0.02) but not with ICU Mobility Scale (p = 0.18).

CONCLUSIONS

In nonsurgical critically ill patients, urinary titin level increased 10-30 times compared with the normal level. The increased urinary titin level was associated with lower limb muscle atrophy, occurrence of ICU-acquired weakness, and ICU mortality.

Effect of vibration therapy on physical function in critically ill adults (VTICIA trial): protocol for a single-blinded randomised controlled trial

INTRODUCTION

Vibration therapy has been used as an additional approach in passive rehabilitation. Recently, it has been demonstrated to be feasible and safe for critically ill patients, whose muscle weakness and intensive care unit (ICU)-acquired weakness are serious problems. However, the effectiveness of vibration therapy in this population is unclear.

METHODS AND ANALYSIS

This study will enrol 188 adult critically ill patients who require further ICU stay after they can achieve sitting at the edge of the bed or wheelchair. The sample size calculation is based on a 15% improvement of Functional Status Score for the ICU. They will be randomised to vibration therapy coupled with protocolised mobilisation or to protocolised mobilisation alone; outcomes will be compared between the two groups. Therapy will be administered using a low-frequency vibration device (5.6-13 Hz) for 15 min/day from when the patient first achieves a sitting position and onward until discharge from the ICU. Outcome assessments will be blinded to the intervention. Primary outcome will be measured using the Functional Status Score for the ICU during discharge. Secondary outcomes will be identified as follows: delirium, Medical Research Council Score, ICU-acquired weakness, the change of biceps brachii and rectus femoris muscle mass measured by ultrasound, ICU mobility scale and ventilator-free and ICU-free days (number of free days during 28 days after admission). For safety assessment, vital signs will be monitored during the intervention.

ETHICS AND DISSEMINATION

This study has been approved by the Clinical Research Ethics Committee of Tokushima University Hospital. Results will be disseminated through publication in a peer-reviewed journal and presented at conferences.

TRIAL REGISTRATION NUMBER

UMIN000039616.

Urinary Titin N-Fragment as a Biomarker of Muscle Atrophy, Intensive Care Unit-Acquired Weakness, and Possible Application for Post-Intensive Care Syndrome

Titin is a giant protein that functions as a molecular spring in sarcomeres. Titin interconnects the contraction of actin-containing thin filaments and myosin-containing thick filaments. Titin breaks down to form urinary titin N-fragments, which are measurable in urine. Urinary titin N-fragment was originally reported to be a useful biomarker in the diagnosis of muscle dystrophy. Recently, the urinary titin N-fragment has been increasingly gaining attention as a novel biomarker of muscle atrophy and intensive care unit-acquired weakness in critically ill patients, in whom titin loss is a possible pathophysiology. Furthermore, several studies have reported that the urinary titin N-fragment also reflected muscle atrophy and weakness in patients with chronic illnesses. It may be used to predict the risk of post-intensive care syndrome or to monitor patients' condition after hospital discharge for better nutritional and rehabilitation management. We provide several tips on the use of this promising biomarker in post-intensive care syndrome.

Upper limb muscle atrophy associated with in-hospital mortality and physical function impairments in mechanically ventilated critically ill adults: a two-center prospective observational study

Background

Lower limb muscle atrophy is often observed in critically ill patients. Although upper limb muscles can undergo atrophy, it remains unclear how this atrophy is associated with clinical outcomes. We hypothesized that this atrophy is associated with mortality and impairments in physical function.

Methods

In this two-center prospective observational study, we included adult patients who were expected to require mechanical ventilation for > 48 h and remain in the intensive care unit (ICU) for > 5 days. We used ultrasound to evaluate the cross-sectional area of the biceps brachii on days 1, 3, 5, and 7 and upon ICU discharge along with assessment of physical functions. The primary outcome was the relationship between muscle atrophy ratio and in-hospital mortality on each measurement day, which was assessed using multivariate analysis. The secondary outcomes were the relationships between upper limb muscle atrophy and Medical Research Council (MRC) score, handgrip strength, ICU Mobility Scale (IMS) score, and Functional Status Score for the ICU (FSS-ICU).

Results

Sixty-four patients (43 males; aged 70 ± 13 years) were enrolled. The Acute Physiology and Chronic Health Evaluation (APACHE) II score was 27 (22–30), and in-hospital mortality occurred in 21 (33%) patients. The decreased cross-sectional area of the biceps brachii was not associated with in-hospital mortality on day 3 (p = 0.43) but was associated on days 5 (p = 0.01) and 7 (p < 0.01), which was confirmed after adjusting for sex, age, and APACHE II score. In 27 patients in whom physical functions were assessed, the decrease of the cross-sectional area of the biceps brachii was associated with MRC score (r = 0.47, p = 0.01), handgrip strength (r = 0.50, p = 0.01), and FSS-ICU (r = 0.56, p < 0.01), but not with IMS score (r = 0.35, p = 0.07) upon ICU discharge.

Conclusions

Upper limb muscle atrophy was associated with in-hospital mortality and physical function impairments; thus, it is prudent to monitor it. (321 words)

Trial registration

UMIN 000031316. Retrospectively registered on 15 February 2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-020-00507-7.

Utility of Plasma GDF-15 for Diagnosis and Prognosis Assessment of ICU-Acquired Weakness in Mechanically Ventilated Patients: Prospective Observational Study

Objective

To identify the clinical correlations between plasma growth differentiation factor-15 (GDF-15), skeletal muscle function, and acute muscle wasting in ICU patients with mechanical ventilation. In addition, to investigate its diagnostic value for ICU-acquired weakness (ICU-AW) and its predictive value for 90-day survival in mechanically ventilated patients.

Methods

95 patients with acute respiratory failure, who required mechanical ventilation therapy, were randomly selected among hospitalized patients from June 2017 to January 2019. The plasma GDF-15 level was detected by ELISA, the rectus femoris cross-sectional area (RFcsa) was measured by ultrasound, and the patient's muscle strength was assessed using the British Medical Research Council (MRC) muscle strength score on day 1, day 4, and day 7. Patients were divided into an ICU-AW group and a non-ICU-AW group according to their MRC-score on the 7th day. The differences in plasma GDF-15 level, MRC-score, and RFcsa between the two groups were compared on the 1st, 4th, and 7th day after being admitted to the ICU. Then, the correlations between plasma GDF-15 level, RFcsa loss, and MRC-score on day 7 were investigated. The receiver operating characteristic curve (ROC) was used to analyze the plasma GDF-15 level, RFcsa loss, and % decrease in RFcsa on the 7th day to the diagnosis of ICU-AW in mechanically ventilated patients. Moreover, the predictive value of GDF-15 on the 90-day survival status of patients was assessed using patient survival curves.

Results

Based on whether the 7th day MRC-score was <48, 50 cases were included in the ICU-AW group and 45 cases in the non-ICU-AW group. The length of mechanical ventilation, ICU length of stay, and hospital length of stay were significantly longer in the ICU-AW group than in the non-ICU-AW group (all P < 0.05), while the other baseline indicators were not statistically significant between the two groups. As the treatment time increased, the plasma GDF-15 level was significantly increased, the ICU-AW group demonstrated a significant decreasing trend in the MRC-score and RFcsa, while no significant changes were found in the non-ICU-AW group. In the ICU-AW group, the plasma GDF-15 level was significantly higher than that in the non-ICU-AW group, while the RFcsa and the MRC-score were significantly lower than those in the non-ICU-AW group (GDF-15 (pg/ml): 2542.44 ± 629.38 vs. 1542.86 ± 502.86; RFcsa (cm²): 2.04 ± 0.64 vs. 2.34 ± 0.61; MRC-score: 41.22 ± 3.42 vs. 51.42 ± 2.72, all P < 0.05), while the other baseline indicators were not statistically significant between the two groups. As the treatment time increased, the plasma GDF-15 level was significantly increased, the ICU-AW group demonstrated a significant decreasing trend in the MRC-score and RFcsa, while no significant changes were found in the non-ICU-AW group. In the ICU-AW group, the plasma GDF-15 level was significantly higher than that in the non-ICU-AW group, while the RFcsa and the MRC-score were significantly lower than those in the non-ICU-AW group (GDF-15 (pg/ml): 2542.44 ± 629.38 vs. 1542.86 ± 502.86; RFcsa (cm²): 2.04 ± 0.64 vs. 2.34 ± 0.61; MRC-score: 41.22 ± 3.42 vs. 51.42 ± 2.72, all r = −0.60), while it was significantly positively correlated with the RFcsa loss (r = −0.60), while it was significantly positively correlated with the RFcsa loss (r = −0.60), while it was significantly positively correlated with the RFcsa loss (r = −0.60), while it was significantly positively correlated with the RFcsa loss (P < 0.05), while the other baseline indicators were not statistically significant between the two groups. As the treatment time increased, the plasma GDF-15 level was significantly increased, the ICU-AW group demonstrated a significant decreasing trend in the MRC-score and RFcsa, while no significant changes were found in the non-ICU-AW group. In the ICU-AW group, the plasma GDF-15 level was significantly higher than that in the non-ICU-AW group, while the RFcsa and the MRC-score were significantly lower than those in the non-ICU-AW group (GDF-15 (pg/ml): 2542.44 ± 629.38 vs. 1542.86 ± 502.86; RFcsa (cm²): 2.04 ± 0.64 vs. 2.34 ± 0.61; MRC-score: 41.22 ± 3.42 vs. 51.42 ± 2.72, all P < 0.05), while the other baseline indicators were not statistically significant between the two groups. As the treatment time increased, the plasma GDF-15 level was significantly increased, the ICU-AW group demonstrated a significant decreasing trend in the MRC-score and RFcsa, while no significant changes were found in the non-ICU-AW group. In the ICU-AW group, the plasma GDF-15 level was significantly higher than that in the non-ICU-AW group, while the RFcsa and the MRC-score were significantly lower than those in the non-ICU-AW group (GDF-15 (pg/ml): 2542.44 ± 629.38 vs. 1542.86 ± 502.86; RFcsa (cm²): 2.04 ± 0.64 vs. 2.34 ± 0.61; MRC-score: 41.22 ± 3.42 vs. 51.42 ± 2.72, all P < 0.05), while the other baseline indicators were not statistically significant between the two groups. As the treatment time increased, the plasma GDF-15 level was significantly increased, the ICU-AW group demonstrated a significant decreasing trend in the MRC-score and RFcsa, while no significant changes were found in the non-ICU-AW group. In the ICU-AW group, the plasma GDF-15 level was significantly higher than that in the non-ICU-AW group, while the RFcsa and the MRC-score were significantly lower than those in the non-ICU-AW group (GDF-15 (pg/ml): 2542.44 ± 629.38 vs. 1542.86 ± 502.86; RFcsa (cm²): 2.04 ± 0.64 vs. 2.34 ± 0.61; MRC-score: 41.22 ± 3.42 vs. 51.42 ± 2.72, all

Conclusion

The plasma GDF-15 concentration level was significantly associated with skeletal muscle function and muscle wasting on day 7 in ICU patients with mechanical ventilation. Therefore, it can be concluded that the plasma GDF-15 level on the 7th day has a high diagnostic yield for ICU-acquired muscle weakness, and it can predict the 90-day survival status of ICU mechanically ventilated patients.