Ultrasound Evaluation of Quadriceps Muscle Dysfunction in Respiratory Disease

Clinical evaluation of AI-assisted muscle ultrasound for monitoring muscle wasting in ICU patients

Muscle ultrasound has been shown to be a valid and safe imaging modality to assess muscle wasting in critically ill patients in the intensive care unit (ICU). This typically involves manual delineation to measure the rectus femoris cross-sectional area (RFCSA), which is a subjective, time-consuming, and laborious task that requires significant expertise. We aimed to develop and evaluate an AI tool that performs automated recognition and measurement of RFCSA to support non-expert operators in measurement of the RFCSA using muscle ultrasound. Twenty patients were recruited between Feb 2023 and July 2023 and were randomized sequentially to operators using AI (n = 10) or non-AI (n = 10). Muscle loss during ICU stay was similar for both methods: 26 ± 15% for AI and 23 ± 11% for the non-AI, respectively (p = 0.13). In total 59 ultrasound examinations were carried out (30 without AI and 29 with AI). When assisted by our AI tool, the operators showed less variability between measurements with higher intraclass correlation coefficients (ICCs 0.999 95% CI 0.998-0.999 vs. 0.982 95% CI 0.962-0.993) and lower Bland Altman limits of agreement (± 1.9% vs. ± 6.6%) compared to not using the AI tool. The time spent on scans reduced significantly from a median of 19.6 min (IQR 16.9-21.7) to 9.4 min (IQR 7.2-11.7) compared to when using the AI tool (p < 0.001). AI-assisted muscle ultrasound removes the need for manual tracing, increases reproducibility and saves time. This system may aid monitoring muscle size in ICU patients assisting rehabilitation programmes.

MyoVision-US: an Artificial Intelligence-Powered Software for Automated Analysis of Skeletal Muscle Ultrasonography

Introduction/Aims

Muscle ultrasound has high utility in clinical practice and research; however, the main challenges are the training and time required for manual analysis to achieve objective quantification of morphometry. This study aimed to develop and validate a software tool powered by artificial intelligence (AI) by measuring its consistency and predictability of expert manual analysis quantifying lower limb muscle ultrasound images across healthy, acute, and chronic illness subjects.

Methods

Quadriceps complex (QC [rectus femoris and vastus intermedius]) and tibialis anterior (TA) muscle ultrasound images of healthy, intensive care unit, and/or lung cancer subjects were captured with portable devices. Automated analyses of muscle morphometry were performed using a custom-built deep-learning model (MyoVision-US), while manual analyses were performed by experts. Consistency between manual and automated analyses was determined using intraclass correlation coefficients (ICC), while predictability of MyoVision -US was calculated using adjusted linear regression (adj.R 2 ).

Results

Manual analysis took approximately 24 hours to analyze all 180 images, while MyoVision - US took 247 seconds, saving roughly 99.8%. Consistency between the manual and automated analyses by ICC was good to excellent for all QC (ICC:0.85-0.99) and TA (ICC:0.93-0.99) measurements, even for critically ill (ICC:0.91-0.98) and lung cancer (ICC:0.85-0.99) images. The predictability of MyoVision-US was moderate to strong for QC (adj.R 2 :0.56-0.94) and TA parameters (adj.R 2 :0.81-0.97).

Discussion

The application of AI automating lower limb muscle ultrasound analyses showed excellent consistency and strong predictability compared with human analysis. Future work needs to explore AI-powered models for the evaluation of other skeletal muscle groups.

Muscle Dysfunction and Functional Status in COVID-19 Patients during Illness and after Hospital Discharge

BACKGROUND

COVID-19 pneumonia is associated with SIRS and hypercatabolism. The aim of this study was to determine muscle loss during the acute phase of COVID-19 pneumonia and evaluate long-term sequelae in discharged patients.

METHODS

A total of 16 patients with COVID-19 pneumonia and respiratory insufficiency were included in the study. Selected parameters (weight, BMI, LBM = lean body mass, albumin, CRP, NLR = neutrophil-to-lymphocyte ratio, ultrasound measured thickness of rectus femoris muscle = US RF and rectus femoris + vastus intermedius = US RF + VI, handgrip strength, quality of life = EQ-5D questionnaire, and activities of daily living = Barthel's ADLs) were recorded on admission, discharge, and 1, 3, and 6 months after discharge.

RESULTS

The most significant changes were between hospital admission and discharge: US RF and RF + VI (-1.28 ± 1.97 mm, p = 0.046; -1.76 ± 2.94 mm, p = 0.05), EQ-5D score (14.6 ± 19.2, p = 0.02), and ADLs (17.1 ± 22.6; p = 0.02). There was a significant positive correlation between US RF + VI and handgrip strength (p = 0.014) and a negative correlation between weight and Barthel index (p = 0.012). There was an association between muscle function with an EQ-5D score and ADLs during outpatient check-ups, most noticeably between handgrip strength, US RF+VI, and ADLs (p = 0.08; p = 0.1, respectively). Conclusions: In patients with COVID-19 pneumonia, there is a significant reduction of health-related quality of life, impaired even 6 months after hospital discharge, influenced mainly by muscle loss. During the hospital stay, there was a significant muscle mass reduction. Ultrasound measurement of thigh muscle thickness may be a useful method to monitor muscle loss.

Ultrasound assessment of muscle mass and correlation with clinical outcomes in critically ill patients: a prospective observational study

PURPOSE

Muscular atrophy implies structural and functional alterations related to muscular force production and movement. This condition has been reported to be the main reason for generalized muscle weakness; it reflects the severity of the disease and can have a profound impact on short- and long-term clinical outcomes. The purpose of this study was to determine whether muscle atrophy ultrasound parameters early predict muscle weakness, morbidity, or 28-days mortality.

METHODS

This was a prospective, observational single center cohort study. Ultrasound was used to determine the cross-sectional area and muscle thickness of the rectus femoris on the first and third day of ICU stay. The main outcome was the incidence of significant muscle atrophy (≥ 10%).

RESULTS

Ultrasound measurements were made in 31 patients, 58% (18/31) of which showed significant muscle atrophy. The relative loss of muscle mass per day was 1.78 at 5% per day. The presence of muscle atrophy presents increased risk for limb muscle weakness and handgrip weakness. The 28-days mortality rate was similar in both subgroups.

CONCLUSION

The presence of muscle atrophy presents an increased clinical risk for the development of limb ICUAW and handgrip, although these observations were not statistically significant. The results could be used to plan future studies on this topic.

Effect of a postoperative home-based exercise and self-management programme on physical function in people with lung cancer (CAPACITY): protocol for a randomised controlled trial

INTRODUCTION

Exercise is important in the postoperative management of lung cancer, yet no strong evidence exists for delivery of home-based programmes. Our feasibility (phase I) study established feasibility of a home-based exercise and self-management programme (the programme) delivered postoperatively. This efficacy (phase II) study aims to determine whether the programme, compared with usual care, is effective in improving physical function (primary outcome) in patients after lung cancer surgery.

METHODS AND ANALYSIS

This will be a prospective, multisite, two-arm parallel 1:1, randomised controlled superiority trial with assessors blinded to group allocation. 112 participants scheduled for surgery for lung cancer will be recruited and randomised to usual care (no exercise programme) or, usual care plus the 12-week programme. The primary outcome is physical function measured with the EORTC QLQ c30 questionnaire. Secondary outcomes include health-related quality of life (HRQoL); exercise capacity; muscle strength; physical activity levels and patient reported outcomes. HRQoL and patient-reported outcomes will be measured to 12 months, and survival to 5 years. In a substudy, patient experience interviews will be conducted in a subgroup of intervention participants.

ETHICS AND DISSEMINATION

Ethics approval was gained from all sites. Results will be submitted for publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ACTRN12617001283369.

Reliability of lumbar multifidus and iliocostalis lumborum thickness and echogenicity measurements using ultrasound imaging

Purpose

To establish the test-retest and inter-rater reliability of lumbar multifidus (LM) and iliocostalis lumborum (IL) muscle thickness and echogenicity as derived using ultrasound imaging.

Methods

Ultrasound images of the LM and IL were collected from 11 healthy participants on two occasions, 1 week apart, by two independent assessors. Measures of LM and IL thickness and echogenicity were subject to test-retest and inter-rater reliability, which was assessed by calculation of an F statistic, the interclass correlation coefficient (ICC), the standard error of measurement, 95% confidence intervals and Bland-Altman plots. This study was given approval by The University of Melbourne Behavioural and Social Sciences Human Ethics Sub-Committee (ref: 1749845).

Results

Assessors A and B showed good to excellent test-retest reliability for LM thickness (ICC_3,3 A: 0.89 and B: 0.98), LM echogenicity (ICC_3,3 A: 0.93 and B: 0.95) and IL echogenicity (ICC_3,3 A: 0.87 and B: 0.83). Test-retest reliability for IL thickness was poor for Assessor A but excellent for Assessor B. Both assessors demonstrated excellent inter-rater reliability for LM thickness and echogenicity (ICC_2,3: 0.79 and 0.94), but poor reliability for IL thickness and echogenicity (ICC_2,3: 0.00 and 0.39).

Conclusions

Inter-rater and test-retest reliability was excellent for LM but was less reliable for measures of the IL muscle.

Architectural anatomy of the quadriceps and the relationship with muscle strength: An observational study utilising real-time ultrasound in healthy adults

Quadriceps atrophy and morphological change is a known phenomenon that can impact significantly on strength and functional performance in patients with acute or chronic presentations conditions. Real-time ultrasound (RTUS) imaging is a noninvasive valid and reliable method of quantifying quadriceps muscle anatomy and architecture. To date, there is a paucity of normative data on the architectural properties of superficial and deep components of the quadriceps muscle group to inform assessment and evaluation of intervention programs. The aims of this study were to (1) quantify the anatomical architectural properties of the quadriceps muscle group (rectus femoris, vastus intermedius, and vastus lateralis) using RTUS in healthy older adults and (2) to determine the relationship between RTUS muscle parameters and measures of quadriceps muscle strength. Thirty middle aged to older males and females (age range 55-79 years; mean age =59.9 ± 7.08 years) were recruited. Quadriceps muscle thickness, cross-sectional area, pennation angle, and echogenicity were measured using RTUS. Quadriceps strength was measured using hand-held dynamometry. For the RTUS-derived quadriceps morphological data, rectus femoris mean results; circumference 9.3 cm; CSA 4.6 cm2 ; thickness 1.5 cm; echogenicity 100.2 pixels. Vastus intermedius mean results; thickness 1.8 cm; echogenicity 99.1 pixels. Vastus lateralis thickness 1.9 cm; pennation angle 17.3°; fascicle length 7.0 cm. Quadriceps force was significantly correlated only with rectus femoris circumference (r = 0.48, p = 0.007), RF echogenicity (r = 0.38, p = 0.037), VI echogenicity (r = 0.43, p = 0.018), and VL fascicle length (r = 0.43, p = 0.019). Quadriceps force was best predicted by a three-variable model (adjusted R2  = 0.46, p < 0.001) which included rectus femoris echogenicity (B = 0.43, p = 0.005), vastus lateralis fascicle length (B = 0.33, p = 0.025) and rectus femoris circumference (B = 0.31, p = 0.041). Thus respectively, rectus femoris echogenicity explains 43%, vastus lateralis fascicle length explains 33% and rectus femoris circumference explains 31% of the variance of quadriceps force. The study findings suggest that RTUS measures were reliable and further research is warranted to establish whether these could be used as surrogate measures for quadriceps strength in adults to inform exercise and rehabilitation programs.

Evaluating a Muscle Ultrasound Education Program: Theoretical Knowledge, Hands-on Skills, Reliability, and Satisfaction of Critical Care Physiotherapists

OBJECTIVE

To evaluate learning results of critical care physiotherapists participating in a muscle ultrasound (MUS) educational program.

DESIGN

Cross-sectional study.

SETTING

A custom-made 20-hour MUS course was performed over a 2-week time period, including knobs familiarization, patient positioning, anatomic landmarks, image acquisition, and limb muscle measurements.

PARTICIPANTS

Nineteen critical care physiotherapists with little to no prior experience in ultrasound (N=19).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Theoretical knowledge, hands-on skills acquisition, and satisfaction were assessed. Inter- and intrarater reliability on landmarks, thickness, and pennation angle of quadriceps between participants was evaluated using intraclass correlation coefficients (ICCs). Reliability among instructors measured prior to the course was also reported as a reference.

RESULTS

The percentage score (mean±SD) of knowledge questionnaires was 69±11 (pre-course), 89±10 (post-course), and 92±9 (hands-on skills). Course satisfaction scores ranged from 90%-100%. Pooled interrater reliability of participants (median ICC [interquartile range]) was good (0.70 [0.59-0.79]) for thickness, moderate (0.47 [0.46-0.92]) for landmarks, and absent (0.00 [0.00-0.05]) for pennation angle and the intrarater reliability was good (0.76 [0.51-0.91]) for thickness and weak (0.35 [0.29-0.52]) for pennation angle. Interrater ICC values for instructors were excellent (0.90) for thickness, good (0.67) for landmarks, and moderate (0.41) for pennation angle and intrarater ICC values were excellent (0.94) for thickness and good (0.75) for pennation angle.

CONCLUSIONS

Although our sample was quite small and homogeneous, increased theoretical knowledge, high hands-on performance acquisition, and good satisfaction of physiotherapists were observed. Reliability was moderate to excellent for thickness and landmarks and absent to weak for pennation angle. Landmarking and pennation angle remain challenges for physiotherapist training in the application of MUS. Further studies are needed to identify variables that could modify reliability during MUS training.

The effect of higher versus lower protein delivery in critically ill patients: a systematic review and meta-analysis of randomized controlled trials

Background

The optimal protein dose in critical illness is unknown. We aim to conduct a systematic review of randomized controlled trials (RCTs) to compare the effect of higher versus lower protein delivery (with similar energy delivery between groups) on clinical and patient-centered outcomes in critically ill patients.

Methods

We searched MEDLINE, EMBASE, CENTRAL and CINAHL from database inception through April 1, 2021.We included RCTs of (1) adult (age ≥ 18) critically ill patients that (2) compared higher vs lower protein with (3) similar energy intake between groups, and (4) reported clinical and/or patient-centered outcomes. We excluded studies on immunonutrition. Two authors screened and conducted quality assessment independently and in duplicate. Random-effect meta-analyses were conducted to estimate the pooled risk ratio (dichotomized outcomes) or mean difference (continuous outcomes).

Results

Nineteen RCTs were included (n = 1731). Sixteen studies used primarily the enteral route to deliver protein. Intervention was started within 72 h of ICU admission in sixteen studies. The intervention lasted between 3 and 28 days. In 11 studies that reported weight-based nutrition delivery, the pooled mean protein and energy received in higher and lower protein groups were 1.31 ± 0.48 vs 0.90 ± 0.30 g/kg and 19.9 ± 6.9 versus 20.1 ± 7.1 kcal/kg, respectively. Higher vs lower protein did not significantly affect overall mortality [risk ratio 0.91, 95% confidence interval (CI) 0.75–1.10, p = 0.34] or other clinical or patient-centered outcomes. In 5 small studies, higher protein significantly attenuated muscle loss (MD −3.44% per week, 95% CI −4.99 to −1.90; p < 0.0001).

Conclusion

In critically ill patients, a higher daily protein delivery was not associated with any improvement in clinical or patient-centered outcomes. Larger, and more definitive RCTs are needed to confirm the effect of muscle loss attenuation associated with higher protein delivery.

PROSPERO registration number: CRD42021237530

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03693-4.

Utility of Ultrasound as a Valid and Accurate Diagnostic Tool for Sarcopenia: Sex-Specific Cutoff Values in Chronic Kidney Disease

OBJECTIVES

Patients with chronic kidney disease (CKD) have aberrant changes in body composition, including low skeletal muscle mass, a feature of "sarcopenia." The measurement of the (quadriceps) rectus femoris (RF) cross-sectional area (CSA) is widely used as a marker of muscle size. Cutoff values are needed to help discriminate the condition of an individual's muscle (eg, presence of sarcopenia) quickly and accurately. This could help distinguish those at greater risk and aid in targeted treatment programs.

METHODS

Transverse images of the RF were obtained by B-mode 2-dimensional ultrasound imaging. Sarcopenic levels of muscle mass were defined by established criteria (1, appendicular skeletal muscle mass [ASM]; 2, ASM/height² ; and 3, ASM/body mass index) based on the ASM and total muscle mass measured by a bioelectrical impedance analysis. The discriminative power of RF-CSA was assessed by receiver operating characteristic curves, and optimal cutoffs were determined by the maximum Youden index (J).

RESULTS

One hundred thirteen patients with CKD (mean age [SD], 62.0 [14.1] years; 48% male; estimated glomerular filtration rate, 38.0 [21.5] mL/min/1.73m² ) were included. The RF-CSA was a moderate predictor of ASM (R² = 0.426; P < .001) and total muscle mass (R² = 0.438; P < .001). With a maximum J of 0.47, in male patients, an RF-CSA cutoff of less than 8.9 cm² was deemed an appropriate cutoff for detecting sarcopenic muscle mass. In female patients, an RF-CSA cutoff of less than 5.7 cm² was calculated on the basis of ASM/height² (J = 0.71).

CONCLUSIONS

Ultrasound may provide a low-cost and simple means to diagnose sarcopenia in patients with CKD. This would allow for early management and timely intervention to help mitigate the effects in this group.

Intensive Care Unit-Acquired Weakness: A Review of Recent Progress With a Look Toward the Future

Intensive care unit-acquired weakness (ICU-AW), a common neuromuscular complication associated with patients in the ICU, is a type of skeletal muscle dysfunction that commonly occurs following sepsis, mobility restriction, hyperglycemia, and the use of glucocorticoids or neuromuscular blocking agents. ICU-AW can lead to delayed withdrawal of mechanical ventilation and extended hospitalization. Patients often have poor prognosis, limited mobility, and severely affected quality of life. Currently, its pathogenesis is uncertain, with unavailability of specific drugs or targeted therapies. ICU-AW has gained attention in recent years. This manuscript reviews the current research status of the epidemiology, pathogenesis, diagnosis, and treatment methods for ICU-AW and speculates the novel perspectives for future research.

Interrater Reliability of Muscle Ultrasonography Image Acquisition by Physical Therapists in Patients Who Have or Who Survived Critical Illness

OBJECTIVE

Previous studies have demonstrated that muscle ultrasound (US) can be reliably performed at the patient bedside by novice assessors with minimal training. The primary objective of this study was to determine the interrater reliability of muscle US image acquisition by physical therapists and physical therapist students. Secondarily, this study was designed to elucidate the process for training physical therapists to perform peripheral skeletal muscle US.

METHODS

This was a cross-sectional observational study. Four novices and 1 expert participated in the study. Novice sonographers engaged in a structured training program prior to implementation. US images were obtained on the biceps brachii, quadriceps femoris, and tibialis anterior muscles in 3 groups: patients in the intensive care unit, patients on the hospital ward, and participants in the outpatient gym who were healthy. Reliability of image acquisition was analyzed compared with the expert sonographer.

RESULTS

Intraclass correlation coefficient values ranged from 0.76 to 0.97 with an average for all raters and all muscles of 0.903, indicating excellent reliability of image acquisition. In general, the experienced physical therapist had higher or similar intraclass correlation coefficient values compared with the physical therapist students in relation to the expert sonographer.

CONCLUSIONS

Excellent interrater reliability for US was observed regardless of the level of experience, severity of patient illness, or patient setting. These findings indicate that the use of muscle US by physical therapists can accurately capture reliable images in patients with a range of illness severity and different clinical practice settings across the continuum of care.

IMPACT

Physical therapists can utilize US to obtain images to assess muscle morphology.

LAY SUMMARY

Physical therapists can use noninvasive US as an imaging tool to assess the size and quality of peripheral skeletal muscle. This study demonstrates that physical therapists can receive training to reliably obtain muscle images in patients admitted to the intensive care unit who may be at risk for muscle wasting and may benefit from early rehabilitation.

Association between ultrasound quadriceps muscle status with premorbid functional status and 60-day mortality in mechanically ventilated critically ill patient: A single-center prospective observational study

BACKGROUND & AIMS

In critically ill patients, direct measurement of skeletal muscle using bedside ultrasound (US) may identify a patient population that might benefit more from optimal nutrition practices. When US is not available, survey measures of nutrition risk and functional status that are associated with muscle status may be used to identify patients with low muscularity. This study aims to determine the association between baseline and changing ultrasound quadriceps muscle status with premorbid functional status and 60-day mortality.

METHODS

This single-center prospective observational study was conducted in a general ICU. Mechanically ventilated critically ill adult patients (age ≥18 years) without pre-existing systemic neuromuscular diseases and expected to stay for ≥96 h in the ICU were included. US measurements were performed within 48 h of ICU admission (baseline), at day 7, day 14 of ICU stay and at ICU discharge (if stay >14 days). Quadriceps muscle layer thickness (QMLT), rectus femoris cross sectional area (RFCSA), vastus intermedius pennation angle (PA) and fascicle length (FL), and rectus femoris echogenicity (mean and standard deviation [SD]) were measured. Patients' next-of-kin were interviewed by using established questionnaires for their pre-hospitalization nutritional risk (nutrition risk screening-2002) and functional status (SARC-F, clinical frailty scale [CFS], Katz activities of daily living [ADL] and Lawton Instrumental ADL).

RESULTS

Ninety patients were recruited. A total of 86, 53, 24 and 10 US measures were analyzed, which were performed at a median of 1, 7, 14 and 22 days from ICU admission, respectively. QMLT, RFCSA and PA reduced significantly over time. The overall trend of change of FL was not significant. The only independent predictor of 60-day mortality was the change of QMLT from baseline to day 7 (adjusted odds ratio 0.95 for every 1% less QMLT loss, 95% confidence interval 0.91-0.99; p = 0.02). Baseline measures of high nutrition risk (modified nutrition risk in critically ill ≥5), sarcopenia (SARC-F ≥4) and frailty (CFS ≥5) were associated with lower baseline QMLT, RFCSA and PA and higher 60-day mortality.

CONCLUSIONS

Every 1% loss of QMLT over the first week of critical illness was associated with 5% higher odds of 60-day mortality. SARC-F, CFS and mNUTRIC are associated with quadriceps muscle status and 60-day mortality and may serve as a potential simple and indirect measures of premorbid muscle status at ICU admission.

Effect of in-bed cycling on acute muscle wasting in critically ill adults: A randomised clinical trial

PURPOSE

To examine whether in-bed cycling assists critically ill adults to reduce acute muscle wasting, improve function and improve quality of life following a period of critical illness.

MATERIALS AND METHODS

A single-centre, two-group, randomised controlled trial with blinded assessment of the primary outcome was conducted in a tertiary ICU. Critically ill patients expected to be mechanically ventilated for at least 48 h were randomised to 30 min daily in-bed cycling in addition to usual-care physiotherapy (n = 37) or usual-care physiotherapy (n = 37). The primary outcome was muscle atrophy of rectus femoris cross-sectional area (RF_CSA) measured by ultrasound at Day 10 following study enrolment. Secondary outcomes included manual muscle strength, handgrip strength, ICU mobility score, six-minute walk test distance and health-related quality of life up to six-months following hospital admission.

RESULTS

Analysis included the 72 participants (mean age, 56-years; male, 68%) who completed the study. There were no significant between-group differences in muscle atrophy of RF_CSA at Day 10 (mean difference 3.4, 95% CI -6.9% to 13.6%; p = .52), or for secondary outcomes (p-values ranged p = .11 to p = .95).

CONCLUSIONS AND RELEVANCE

In-bed cycling did not reduce muscle wasting in critically ill adults, but this study provides useful effect estimates for large-scale clinical trials.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN12616000948493.