Monitoring muscle mass using ultrasound: a key role in critical care

Comparison of Two Techniques to Assess Muscle Mass Loss During ICU Stay: Muscle Ultrasound vs Bioelectrical Impedance Analysis

BACKGROUND AND AIMS

Muscle wasting is a prevalent issue among long-term critically ill patients and is associated with adverse clinical outcomes. Evaluating muscle mass in the ICU presents challenges due to the lack of a consistent methodology and the significant impact of fluid balance range in ICU patients. This prospective study aimed to compare the utility of bioelectrical impedance analysis (BIA) and ultrasound (US) for monitoring muscle wasting in critically ill patients over an initial seven-day period of critical illness.

METHODS

Conducted in a tertiary teaching hospital's mixed ICU, the study included adult patients with ICU stays exceeding seven days. Measurements were taken on Day 1 (within 24 hours of ICU admission), Day 5, and Day 7.

RESULTS

Out of 101 enrolled patients, 74 were male, with a mean age of 55.3 (SD 14.8) years. The mean APACHE II score was 18.2 (SD 7.2), and the Day 1 SOFA score was 7.9 (SD 3.2). The ICU survival rate was 65%, and the mean ICU length of stay was 19.2 (SD 19.2) days. Statistically significant muscle mass loss was detected by US measurement, demonstrating the relative change in general muscle thickness: -2.5% (SD 11.8) by Day 5 and -6.5% (SD 12.4) by Day 7 (P < 0.001). BIA demonstrated no significant change in phase angle, as the relative change by Day 5 was -3.3% (SD 19.9) and by Day 7 it was -1.9% (SD 21.9), with no significant difference (P = 0.374).

CONCLUSIONS

Ultrasound was a more suitable method for assessing and monitoring muscle wasting during ICU stays, while bioelectrical impedance analysis failed to demonstrate a comparable degree of muscle loss at Days 5 and 7. This study highlights the importance of selecting an appropriate assessment method based on the specific clinical context, emphasizing the reliability of US in evaluating muscle wasting among critically ill patients.

Association between quadriceps muscle thickness or echo intensity, malnutrition, and activities of daily living in an integrated medical and long-term care facility: A cross-sectional study

BACKGROUND &AIMS

Malnutrition and physical function impairment are prevalent concerns in long-term care facilities. This study investigated the relationship between quadriceps muscle thickness (QMT) or echo intensity (QEI), nutritional status, and activities of daily living (ADL) in residents of an Integrated Facility for Medical and Long-term Care (IFMLC) in Japan.

METHODS

Using a cross-sectional design, 126 residents (86 women, median age 89 years) at an IFMLC were assessed. Malnutrition was diagnosed using the Global Leadership Initiative on Malnutrition (GLIM) criteria including disease burden/inflammation, while ADL status was evaluated using the Barthel Index (BI). QMT and QEI, indicative of muscle mass and intramuscular adipose tissue, were measured by ultrasound. Multivariate logistic and linear regression analyses were conducted to explore the association of QMT or QEI with malnutrition and ADL.

RESULTS

62 residents (49%) were in the lower QMT group and 63 residents (50%) were in the upper QEI group. The prevalence of severe malnutrition in the lower QMT group was significantly higher than that in the upper QMT group. Moreover, the lower QMT group had significantly lower BI points than the upper QMT group. The upper QEI group had significantly lower BI points than the lower QEI group. lower QMT was associated with severe malnutrition (odds ratio 3.170; 95% CI 1.238 to 8.725; P = 0.016). Furthermore, both lower QMT (B = -12.520; 95% CI -17.069 to -7.973; P < 0.001) and upper QEI (B = -7.598; 95% CI -12.565 to -2.631; P = 0.003) showed an independent correlation with lower BI scores.

CONCLUSION

This study found a relationship between lower QMT correlated with severe malnutrition and poor ADL, while higher QEI is associated with poor ADL.

A systematic review to assess the impact of amino acids or their derivatives on skeletal muscle wasting in critically ill patients

BACKGROUND

It is plausible that supplementation with specific amino acids or metabolites could attenuate skeletal muscle wasting during critical illness. The aim of this systematic review was to explore if amino acids or their derivatives impact skeletal muscle wastage in critically ill adults.

METHODS

Four databases were systematically searched to identify randomised control trials which delivered enteral supplemental amino acids, or their metabolites compared with placebo, standard care or no intervention, to critically ill patients and reported outcomes of skeletal muscle mass, plasma amino acids, nitrogen balance, or muscle strength. Two authors independently completed screening, data extraction, and risk of bias assessment using the Cochrane Risk of Bias 2 Tool. A meta-analysis was planned but heterogeneity in the type of intervention used and outcome assessment precluded this. Therefore, data were synthesised using vote counting.

RESULTS

Thirty randomised control trials, comprising 1976 patients were included. The most frequently studied interventional amino acid or metabolite was glutamine (n = 12 trials), a combination (n = 9), arginine (n = 6), β-hydroxy β-methylbutyrate (HMB) (n = 2) or ornithine (n = 1). Six trials (including 284 participants) measured skeletal muscle following supplementation, four of which used HMB alone or in combination as the intervention. Of these, one trial observed an attenuation of muscle wasting with a combination of amino acids, one observed an exacerbation of muscle wasting with HMB, three trials observed no impact on muscle wasting with HMB or a combination of amino acids and one trial reported no information.

CONCLUSION

Six trials have investigated the effect of enteral amino acid or amino acid metabolite supplementation on muscle mass in critically ill. Heterogeneity of interventions, outcome assessments and direction of effects limits the certainty regarding the effect of supplemental amino acids, or their metabolites, on skeletal muscle wasting during critical illness. The trial protocol is registered on PROSPERO (CRD42021275989).

A Surface Electromyography (sEMG) System Applied for Grip Force Monitoring

Muscles play an indispensable role in human life. Surface electromyography (sEMG), as a non-invasive method, is crucial for monitoring muscle status. It is characterized by its real-time, portable nature and is extensively utilized in sports and rehabilitation sciences. This study proposed a wireless acquisition system based on multi-channel sEMG for objective monitoring of grip force. The system consists of an sEMG acquisition module containing four-channel discrete terminals and a host computer receiver module, using Bluetooth wireless transmission. The system is portable, wearable, low-cost, and easy to operate. Leveraging the system, an experiment for grip force prediction was designed, employing the bald eagle search (BES) algorithm to enhance the Random Forest (RF) algorithm. This approach established a grip force prediction model based on dual-channel sEMG signals. As tested, the performance of acquisition terminal proceeded as follows: the gain was up to 1125 times, and the common mode rejection ratio (CMRR) remained high in the sEMG signal band range (96.94 dB (100 Hz), 84.12 dB (500 Hz)), while the performance of the grip force prediction algorithm had an R2 of 0.9215, an MAE of 1.0637, and an MSE of 1.7479. The proposed system demonstrates excellent performance in real-time signal acquisition and grip force prediction, proving to be an effective muscle status monitoring tool for rehabilitation, training, disease condition surveillance and scientific fitness applications.

The impact of guideline recommended protein intake on mortality and length of intensive care unit and hospital stay in critically ill adults: A systematic review

International guidelines recommend a target protein intake of ≥1.2 g/kg/day to all critically ill patients for optimal outcomes. There are however various conflicting data related to this recommendation. The primary objective of this review was to compare a protein intake group (≥1.2 g/kg/day) with a lower protein intake group (<1.2 g/kg/day) in critically ill adult patients on mortality, length of intensive care unit (ICU) and hospital stay. Secondly, the effect of protein intake on length of mechanical ventilation, adverse nutrition-related events and muscle mass and strength parameters were investigated. Sixteen randomised controlled trials (RCTs) of adult patients admitted to an intensive or high care unit and receiving nutrition support in the form of enteral- and/or parenteral nutrition were selected against prespecified eligibility criteria. Two independent reviewers extracted relevant data and assessed the risk of bias of the included studies. Review Manager 5.4.1 was used to analyse data and GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) was used to evaluate the certainty of the evidence. The higher protein group, when compared to the lower protein group, probably results in little to no difference in mortality (risk ratio [RR] 1.01; 95% confidence interval [CI]: 0.89 to 1.14; moderate-certainty evidence); with a probable slight increase in length of ICU stay (mean difference [MD] 0.33; 95% CI -0.57 to 1.23; moderate-certainty) and length of hospital stay (MD 1.72; 95% CI -0.58 to 4.01; moderate-certainty evidence), on average. For secondary outcomes, it was found that the higher protein group probably does not reduce the length of mechanical ventilation (MD 0.08; 95% CI -0.38 to 0.53; moderate-certainty evidence). Higher protein group probably reduces the occurrence of diarrhoea and high gastric residual volume and may reduce the occurrence of constipation. It may also increase nitrogen balance (MD 3.66; 95% CI 1.81 to 5.51; low-certainty evidence). Importantly, there does not seem to be harm associated with the higher protein group, though it should be mentioned that for many of the adverse events in this study, the certainty of evidence was low or very low.

Ultrasound for measurement of skeletal muscle mass quantity and muscle composition/architecture in critically ill patients: A scoping review on studies' aims, methods, and findings

AIMS

This scoping review aimed to identify, explore, and map the objectives, methodological aspects, and results of studies that used ultrasound (US) to assess skeletal muscle (SM) in critically ill patients.

METHODS

A scoping review was conducted according to the Joanna Briggs Institute's methodology. All studies that evaluated SM parameters from the US in patients admitted to the intensive care unit (ICU) were considered eligible. We categorized muscle thickness and cross-sectional area as parameters for assessing SM quantity, while echogenicity, fascicle length, and pennation angle analysis were used to evaluate muscle "quality" (composition/architecture). A literature search was conducted using four databases for articles published until December 2022. Independent reviewers selected the studies and extracted data. Descriptive statistics were calculated to present the results.

RESULTS

A total of 107 studies were included, the majority of which were prospective cohort studies (59.8 %) conducted in general ICUs (49.5 %). The most frequent objective of the studies was to evaluate SM quantity depletion during the ICU stay (25.2 %), followed by determining whether a specific intervention would modify SM (21.5 %). Most studies performed serial SM evaluations (76.1 %). The rectus femoris muscle thickness was evaluated in most studies (67.9 %), followed by the rectus femoris cross-sectional area (54.3 %) and the vastus intermedius muscle thickness (40.2 %). The studies demonstrated the feasibility and reproducibility of US for SM evaluation, especially related to quantitative parameters. Most studies (70.3 %) reported significant SM quantity depletion during hospitalization. However, the accuracy of the US in measuring SM varied across the studies.

CONCLUSIONS

The lack of detailed description and standardization in the protocols adopted by the studies included in this scoping review precludes the translation of the evidence related to US for SM assessment into clinical practice.

Early detection and assessment of intensive care unit-acquired weakness: a comprehensive review

Intensive care unit-acquired weakness (ICU-AW) is a serious complication in critically ill patients. Therefore, timely and accurate diagnosis and monitoring of ICU-AW are crucial for effectively preventing its associated morbidity and mortality. This article provides a comprehensive review of ICU-AW, focusing on the different methods used for its diagnosis and monitoring. Additionally, it highlights the role of bedside ultrasound in muscle assessment and early detection of ICU-AW. Furthermore, the article explores potential strategies for preventing ICU-AW. Healthcare providers who manage critically ill patients utilize diagnostic approaches such as physical exams, imaging, and assessment tools to identify ICU-AW. However, each method has its own limitations. The diagnosis of ICU-AW needs improvement due to the lack of a consensus on the appropriate approach for its detection. Nevertheless, bedside ultrasound has proven to be the most reliable and cost-effective tool for muscle assessment in the ICU. Combining the Sequential Organ Failure Assessment (SOFA) score, Acute Physiology and Chronic Health Evaluation (APACHE) II score assessment, and ultrasound can be a convenient approach for the early detection of ICU-AW. This approach can facilitate timely intervention and prevent catastrophic consequences. However, further studies are needed to strengthen the evidence.

Ultrasound utilized by registered dietitians for body composition measurement, nutritional assessment, and nutritional management

BACKGROUND AND AIMS

Ultrasound has been used primarily as a tool for body composition measurement in the field of clinical nutrition. Although many recent reports have demonstrated that ultrasound could be a useful tool for nutritional assessment, it is not well incorporated into registered dietitians' (RDs) practice. The aim of this review was to summarize the usefulness of ultrasound in assessing body composition and nutritional status and in nutritional management by RDs.

METHODS

Studies on ultrasonography, nutritionists, body composition, nutritional assessment, and diet therapy was searched using the MEDLINE databases.

RESULTS

After reviewing the articles, we categorized them into the following topics; 1) principles of muscle measurement using the ultrasound, types of muscle that can be measured, 2) indices of muscle and muscle mass and quality as assessed using ultrasound and its relationship to nutritional indicator, 3) diagnosis of the Global Leadership Initiative on Malnutrition (GLIM) criteria malnutrition using ultrasound, 4) practical nutritional management using ultrasound and 5) education and issues for ultrasound implementation. Ultrasound can evaluate low body mass index, unintentional loss of body weight, low skeletal muscle mass index, decreased food intake/assimilation, and disease burden/inflammation, all which are essential items of the phenotypic and etiologic criteria of the GLIM.

CONCLUSION

Ultrasound may be useful for RDs to perform body composition measurement, nutritional assessment, and nutritional management. It will be important to identify the cutoff values for ultrasound-based measurements of muscle mass. In order for RDs to perform a body composition measurement, nutritional assessment, and nutritional management using ultrasound, educational issues need to be addressed.

Thigh muscles are more susceptible to age-related muscle loss when compared to lower leg and pelvic muscles

BACKGROUND

A key hallmark of aging is the progressive loss of skeletal muscle mass. Due to limitations of the various methods typically applied to assess muscle mass, only limited information is available on age-related differences between various muscle groups. This study assessed differences in individual lower body muscle group volumes between healthy young and older males.

METHODS

Lower body muscle mass assessments were performed in 10 young (age: 27 ± 4 y) and 10 older (age: 71 ± 6 y) healthy, male adults using Dual-energy X-ray Absorptiometry (DXA), single slice (thigh) Computed Tomography (CT), as well as Magnetic Resonance Imaging (MRI). Muscle volumes of all individual muscle groups in the lower body were assessed by MRI.

RESULTS

Leg lean mass, as assessed with DXA, was not significantly different between older (9.2 ± 1.0 kg) and young (10.5 ± 2.0 kg) men (P = 0.075). Thigh muscle cross-sectional area, as assessed with CT, was significantly lower (by 13 %) in the older (137 ± 17 cm²) compared to young (157 ± 24 cm²) participants (P = 0.044). MRI-derived lower body muscle volume was also significantly lower (by 20 %) in older (6.7 ± 0.9 L) compared to young (8.3 ± 1.3 L) men (P = 0.005). This was primarily attributed to substantial differences in thigh (24 %), rather than lower leg (12 %) and pelvis (15 %) muscle volume in the older vs the young. Thigh muscle volume averaged 3.4 ± 0.5 L in older and 4.5 ± 0.7 L in young men (P = 0.001). Of all thigh muscle groups, the quadriceps femoris showed the most profound difference (30 %) between young (2.3 ± 0.4 L) and older (1.6 ± 0.2 L) men (P < 0.001).

CONCLUSIONS

The most profound differences in lower body muscle volume between young and older men are observed in the thigh. Within the thigh muscle groups, the quadriceps femoris shows the largest difference in muscle volume between young and older men. Finally, DXA appears less sensitive when compared to CT and MRI to assess age-related differences in muscle mass.

Neuromuscular Ultrasound in Intensive Care Unit-Acquired Weakness: Current State and Future Directions

Intensive care unit-acquired weakness (ICUAW) is one of the most common causes of muscle atrophy and functional disability in critically ill intensive care patients. Clinical examination, manual muscle strength testing and monitoring are frequently hampered by sedation, delirium and cognitive impairment. Many different attempts have been made to evaluate alternative compliance-independent methods, such as muscle biopsies, nerve conduction studies, electromyography and serum biomarkers. However, they are invasive, time-consuming and often require special expertise to perform, making them vastly impractical for daily intensive care medicine. Ultrasound is a broadly accepted, non-invasive, bedside-accessible diagnostic tool and well established in various clinical applications. Hereby, neuromuscular ultrasound (NMUS), in particular, has been proven to be of significant diagnostic value in many different neuromuscular diseases. In ICUAW, NMUS has been shown to detect and monitor alterations of muscles and nerves, and might help to predict patient outcome. This narrative review is focused on the recent scientific literature investigating NMUS in ICUAW and highlights the current state and future opportunities of this promising diagnostic tool.

Comparison of Different Ultrasound Methods to Assess Changes in Muscle Mass in Critically ill Patients

BACKGROUND

Muscle ultrasound represents a promising approach to aid diagnoses of neuromuscular diseases in critically ill patients. Unfortunately, standardization of ultrasound measurements in clinical research is lacking, making direct comparisons between studies difficult. Protocols are required to assess qualitative muscle changes during an ICU stay in patients at high risk for the development of neuromuscular acquired weakness (ICUAW).

METHODS

We conducted a retrospective, observational analysis comprised of three prospective observational studies with the aim of diagnosing muscle changes by ultrasound measurement of the quadriceps muscle. Different protocols were used in each of the three studies. In total, 62 surgical, neurocritical care and trauma intensive care patients were serially assessed by different ultrasound protocols during the first week of critical illness. The relative change in ultrasound measurements was calculated for all possible locations, methods and sides. Comparison was obtained using mixed effect models with the location, the height and the side as influencing variables and patients as fixed effect. The relationship between variables and outcomes was assessed by multivariable regression analysis.

RESULTS

Ultrasound methods and measurement sites of the quadriceps muscles from all protocols were equally effective in detecting muscle changes. During the first week of an ICU stay, two groups were identified: patients with decreased muscle mass on ultrasound (n = 42) and a cohort with enlargement (n = 23). Hospital mortality was significantly increased in the cohort with muscle swelling (8 (19%) versus 12 (52%), p = .013).

CONCLUSIONS

Different approaches of ultrasound measurement during critical-illness are equally able to detect muscle changes. While some patients have a decrease in muscle mass, others show swelling, which may result in a reduced probability of surviving the hospital stay. Causative reasons for these results still remain unclear.

Diagnostic Utility of Point-of-Care Ultrasound in the Pediatric Cardiac Intensive Care Unit

Purpose of Review

Recent Findings

Summary

Supplementary Information