Acute skeletal muscle wasting and dysfunction predict physical disability at hospital discharge in patients with critical illness

Ultrasound-derived rates of muscle wasting in the intensive care unit and in the post-intensive care ward for patients with critical illness: Post hoc analysis of an international, multicentre randomised controlled trial of early rehabilitation

BACKGROUND AND AIMS

Muscle wasting results in weakness for patients with critical illness. We aim to explore ultrasound-derived rates of change in skeletal muscle in the intensive care unit (ICU) and following discharge to the post-ICU ward.

DESIGN

Post hoc analysis of a multicentre randomised controlled trial of functional-electrical stimulated cycling, recumbent cycling, and usual care delivered in intensive care.

METHOD

Participants underwent ultrasound assessment of rectus femoris at ICU admission, weekly in the ICU, upon awakening, ICU discharge, and hospital discharge. The primary outcome was rate of change in rectus femoris cross-sectional area (ΔRFCSA) in mm2/day in the ICU (enrolment to ICU discharge) and in the post-ICU ward (ICU discharge to hospital discharge). Secondary outcomes included rate of change in echo intensity (ΔEI), standard deviation of echo intensity (ΔEISD), and the intervention effect on ultrasound measures. Echo intensity is a quantitative assessment of muscle quality. Elevated echo intensity may indicate fluid infiltration, adipose tissue, and reduced muscle quality.

RESULTS

154 participants were included (mean age: 58 ± 15 years, 34% female). Rectus femoris cross-sectional area declined in the ICU (-4 mm2/day [95% confidence interval {CI}: -9 to 1]) and declined further in the ward (-9 mm2/day [95% CI: -14 to -3]) with a mean difference between ICU and ward of -5 mm2/day ([95% CI: -2, to 11]; p = 0.1396). There was a nonsignificant difference in ΔEI between in-ICU and the post-ICU ward of 1.2 ([95% CI: -0.1 to 2.6]; p = 0.0755), a statistically significant difference in ΔEISD between in-ICU and in the post-ICU ward of 1.0 ([95% CI, 0.5 to 1.5]; p = 0.0003), and no difference in rate of change in rectus femoris cross-sectional area between groups in intensive care (p = 0.411) or at hospital discharge (p = 0.1309).

CONCLUSIONS

Muscle wasting occurs in critical illness throughout the hospital admission. The average rate of loss in muscle cross-sectional area does not slow after ICU discharge, even with active rehabilitation.

Association between changes in disease severity and physical function after surviving a critical illness: A multicentre retrospective observational study

BACKGROUND

Whilst disease severity can significantly impact functional outcomes, the ability to predict the scale of this impact has not been consistent.

AIM

We aimed to investigate whether changes in disease severity within the first 48 h of ICU admission are more strongly associated with physical dysfunction than a single-time assessment of disease severity at ICU admission.

METHODS

A multicentre retrospective study in seven tertiary ICUs in Japan, including all consecutive adult ICU patients (>48 h ICU stay) between September 2019 and February 2020. The primary outcome was physical function defined as the Barthel Index, which is an ordinal scale (0-100: larger indicates better function) to measure physical independence and performance. The association between Barthel Index score at hospital discharge and the Sequential Organ Failure Assessment (SOFA) scores, measured at ICU admission, the highest recorded score within 48 h of ICU admission, and the level of change between these two timepoints were investigated in multivariable analysis.

RESULTS

A total of 199 patients were included. Median SOFA score at ICU admission and the highest recorded score within the first 48 h were 6 (interquartile range: 5-10) and 8 (interquartile range: 6-11), respectively. A quarter of patients had a Barthel Index score of 60 or less at hospital discharge. The highest SOFA score within 48 h of ICU admission and the level of change in SOFA scores between ICU admission and the highest recorded score within 48 h were significantly associated with lower Barthel Index scores at hospital discharge. No significant association was identified with regard to Barthel Index scores and SOFA score at ICU admission. An increase in SOFA score of 1 or more within the first 48 h of ICU admission was the threshold to predict a Barthel Index score of 60 or less at hospital discharge. Larger changes in SOFA scores over the first 48 h of ICU admission were also significantly associated with smaller changes in Barthel Index scores from ICU discharge to hospital discharge.

CONCLUSIONS

The level of change in SOFA score between ICU admission and the highest recorded score within the first 48 h of ICU stay can more accurately predict the presence of physical dysfunction at hospital discharge than a single-time assessment of disease severity at ICU admission. The larger worsening in SOFA potentially indicates lower recovery after a critical illness.

Effect of an evidence-based early rehabilitation program on adult patients with venovenous extracorporeal membrane oxygenation: A cohort study

OBJECTIVES

To assess the efficacy of early rehabilitation program for VV-ECMO patients and observe the influence on the respiratory and skeletal muscles.

DESIGN

A cohort study.

SETTING

The study was conducted with VVECMO patients in a comprehensive ICU with 32 beds.

MAIN OUTCOME MEASURES

Ultrasound measurements were performed on each patients on day 1, 4, 7, 10, and 14, including diaphragmatic excursion (DE), diaphragmatic thickening fraction (DTF), intercostal muscle thickening fraction (ICMTF), thickness of the rectus femoris (RF), thickness of vastus intermedius (VI), and rectus femoris cross-sectional area (RF-CSA). Data on basic characteristics, results of ultrasound measurements, patients outcomes and adverse events were collected.

RESULTS

22 patients received usual rehabilitation measures were set as the control group and 23 patients underwent early rehabilitation program were set as the study group. There were no differences in diaphragmatic excursion, diaphragmatic thickening fraction, intercostal muscle thickening fraction, thickness of rectus femoris, thickness of vastus intermedius, rectus femoris cross-sectional area between two groups on day 1 after VV-ECMO treatment (P > 0.05). The variation of diaphragmatic thickening fraction and intercostal muscle thickening fraction decreased on the day 7 and 14 after treatment (P < 0.05). The variation of vastus intermedius thickness and rectus femoris cross-sectional area in the study group was less compared with those in the control group on day 4, 7, 10 and 14. The ECMO duration in the study group was shorter than that in the control group (12.00 [10.00-16.25] days vs. 8.00 [6.00-12.25] days, P = 0.002), but there was no difference in the duration of mechanical ventilation.

CONCLUSION

Early rehabilitation program can ameliorate muscle atrophy. We recommend implementation of our rehabilitation program in VV-ECMO patients. This program can improve skeletal muscle atrophy and dysfunction in patients with VV-ECMO effectively and perhaps improve quality of life for patients in the future.

IMPLICATIONS FOR CLINICAL PRACTICE

Early rehabilitation program put higher demands bedside nurses. It requires them to observe conditions of VVECMO patients closely, assess the feasibility of rehabilitation promptly, and monitor for any adverse reactions. Ultrasound measurement is a noninvasive and useful tool to assess muscle atrophy in ICU patients. Early rehabilitation program can improve skeletal muscle atrophy and dysfunction in patients with VV-ECMO effectively.

Association between comorbidities at ICU admission and post-Sepsis physical impairment: A retrospective cohort study

PURPOSE

Few studies have measured the association between pre-existing comorbidities and post-sepsis physical impairment. The study aimed to estimate the risk of physical impairment at hospital discharge among sepsis patients, adjusting for pre-existing physical impairment prior to ICU admission and in-hospital mortality.

MATERIALS AND METHODS

We analyzed all consecutive adult patients admitted to an ICU in a tertiary community hospital, Kameda Medical Center, with sepsis diagnosis from September 2014 to October 2020. Inverse probability attrition weighting using machine learning was employed to estimate the risk of physical impairment at hospital discharge for sepsis patients with and without pre-existing comorbidities at ICU admission. This estimation was adjusted for baseline covariates, pre-ICU physical impairment, and in-hospital mortality.

RESULTS

Of 889 sepsis patients analyzed, 668 [75.1%] had at least one comorbidity and 221 [24.9%] had no comorbidities at ICU admission. Upon adjusting for baseline covariates, pre-ICU physical impairment, and in-hospital mortality, pre-existing comorbidities were not associated with an elevated risk of physical impairment at hospital discharge (RR: 1.02, 95% CI: 0.92, 1.14).

CONCLUSIONS

Pre-existing comorbidities prior to ICU admission were not associated with an increased risk of physical impairment at hospital discharge among sepsis patients after adjusting for baseline covariates and in-hospital mortality.

GSDMD KNOCKOUT ALLEVIATES SEPSIS-ASSOCIATED SKELETAL MUSCLE ATROPHY BY INHIBITING IL18/AMPK SIGNALING

ABSTRACT

Background: Sepsis commonly leads to skeletal muscle atrophy, characterized by substantial muscle weakness and degeneration, ultimately contributing to an adverse prognosis. Studies have shown that programmed cell death is an important factor in the progression of muscle loss in sepsis. However, the precise role and mechanism of pyroptosis in skeletal muscle atrophy are not yet fully comprehended. Therefore, we aimed to examine the role and mechanism of action of the pyroptosis effector protein GSDMD in recognized cellular and mouse models of sepsis. Methods: The levels of GSDMD and N-GSDMD in skeletal muscle were evaluated 2, 4, and 8 days after cecal ligation and puncture. Sepsis was produced in mice that lacked the Gsdmd gene (Gsdmd knockout) and in mice with the normal Gsdmd gene (wild-type) using a procedure called cecal ligation and puncture. The degree of muscular atrophy in the gastrocnemius and tibialis anterior muscles was assessed 72 h after surgery in the septic mouse model. In addition, the architecture of skeletal muscles, protein expression, and markers associated with pathways leading to muscle atrophy were examined in mice from various groups 72 h after surgery. The in vitro investigations entailed the use of siRNA to suppress Gsdmd expression in C2C12 cells, followed by stimulation of these cells with lipopolysaccharide to evaluate the impact of Gsdmd downregulation on muscle atrophy and the related signaling cascades. Results: This study has demonstrated that the GSDMD protein, known as the "executive" protein of pyroptosis, plays a crucial role in the advancement of skeletal muscle atrophy in septic mice. The expression of N-GSDMD in the skeletal muscle of septic mice was markedly higher compared with the control group. The Gsdmd knockout mice exhibited notable enhancements in survival, muscle strength, and body weight compared with the septic mice. Deletion of the Gsdmd gene reduced muscular wasting in the gastrocnemius and tibialis anterior muscles caused by sepsis. Studies conducted in living organisms ( in vivo ) and in laboratory conditions ( in vitro ) have shown that the absence of the Gsdmd gene decreases indicators of muscle loss associated with sepsis by blocking the IL18/AMPK signaling pathway. Conclusion: The results of this study demonstrate that the lack of Gsdmd has a beneficial effect on septic skeletal muscle atrophy by reducing the activation of IL18/AMPK and inhibiting the ubiquitin-proteasome system and autophagy pathways. Therefore, our research provides vital insights into the role of pyroptosis in sepsis-related skeletal muscle wasting, which could potentially lead to the development of therapeutic and interventional approaches for preventing septic skeletal muscle atrophy.

Inability to Sit-to-Stand in Medical ICUs Survivors: When and Why We Should Care

OBJECTIVES

To investigate the prevalence and association with mortality of inability to perform sit-to-stand independently in critically ill survivors 3 months following medical ICU (MICU) discharge.

DESIGN

Prospective cohort study.

SETTING

Six MICUs at a tertiary care hospital.

PATIENTS

MICU survivors who could sit-to-stand independently before the index hospitalization.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Inability to sit-to-stand (yes/no) was measured at four points following MICU discharge: upon ICU discharge, 1, 2, and 3 months afterward. Mortality was evaluated at 6- and 12-month post-MICU discharge. Among 194 participants, 128 (66%) had inability to sit-to-stand upon MICU discharge. Recovery occurred, with rates decreasing to 50% at 1 month, 38% at 2 months, and 36% at 3 months post-MICU discharge, plateauing at 2 months. Inability to sit-to-stand at 3 months was significantly associated with 21% mortality at 12 months and a 4.2-fold increased risk of mortality (adjusted hazard ratio, 4.2; 95% CI, 1.61-10.99), independent of age, Sequential Organ Failure Assessment score, and ICU-acquired weakness. Notably, improvement in sit-to-stand ability, even from "totally unable" to "able with assistance," correlates with reduced mortality risk.

CONCLUSIONS

Inability to sit-to-stand affects about 36% of MICU survivors even at 3 months post-ICU discharge, highlighting rehabilitation challenges. Revisiting sit-to-stand ability post-ICU discharge is warranted. Additionally, using sit-to-stand as a screening tool for interventions to improve return of its function and mortality is suggested.

Five days of bed rest in young and old adults: Retainment of skeletal muscle mass with neuromuscular electrical stimulation

The consequences of short-term disuse are well known, but effective countermeasures remain elusive. This study investigated the effects of neuromuscular electrical stimulation (NMES) during 5 days of bed rest on retaining lower limb muscle mass and muscle function in healthy young and old participants. One leg received NMES of the quadriceps muscle (3 × 30min/day) (NMES), and the other served as a control (CON). Isometric quadriceps strength (MVC), rate of force development (RFD), lower limb lean mass, and muscle thickness were assessed pre-and post-intervention. Muscle thickness remained unaltered with NMES in young and increased in old following bed rest, while it decreased in CON legs. In old participants, mid-thigh lean mass (MTLM) was preserved with NMES while decreased in CON legs. In the young, only a tendency to change with bed rest was detected for MTLM. MVC and early-phase RFD decreased in young and old, irrespective of NMES. In contrast, late-phase RFD was retained in young participants with NMES, while it decreased in young CON legs, and in the old, irrespective of NMES. NMES during short-term bed rest preserved muscle thickness but not maximal muscle strength. While young and old adults demonstrated similar adaptive responses in preventing the loss of skeletal muscle thickness, RFD was retained in the young only.

Impact of Muscle Changes Assessed by Ultrasonography on Muscle Strength and Functioning after ICU Discharge: A Systematic Review with Meta-Analysis

BACKGROUND

Ultrasonography has been used to identify structural, quantitative, and qualitative muscle changes. These changes have been assessed in different muscles during ICU stays; however, it is unclear if it can predict functioning after ICU discharge.

OBJECTIVE

To analyze the relationship between muscle changes assessed by ultrasonography and the strength and functioning of ICU survivors.

METHODS

A systematic review with a meta-analysis was performed according to the MOOSE guidelines and registered in PROSPERO. Searches of the following databases were performed by two of the authors: PubMed, Cinahl, Embase, Scopus, LILACS, Web of Science, and Science Direct. Qualitative analysis was performed using NOS and AHRQ scales. Meta-analysis was performed using the "R", "metafor" package. Heterogeneity was assessed by I2 and Cochran's Q test. Meta-regression analyses were performed to verify the moderators, and funnel plots and Egger's regression intercept test were used to analyze the publication bias.

RESULTS

Sixteen articles were included in the qualitative assessment, and nine were used in the quantitative assessment. There is evidence of correlations between MT and muscle strength (r = 0.20 [0.11; 0.27]; p < 0.0001), and MT (r = 0.35 [0.19; 0.49]; p < 0.0001), CSA (r = 0.30 [0.10; 0.47]; p = 0.0038), EI (r = -0.29 [-0.53; -0.01]; p = 0.043) and mobility. In the subgroup analyses, some evidence of a correlation between specific muscles and strength and mobility were found.

CONCLUSIONS

There is evidence for the correlation between muscle characteristics assessed by US and functioning outcomes.

Effect of high-protein peptide-based formula compared with isocaloric isonitrogenous polymeric formula in critically ill surgical patient

BACKGROUND

Malnutrition is common in critically ill patients, and it is associated with an increased risk of complications. Early enteral nutrition with adequate caloric and protein intake is critical nevertheless it is difficult to achieve. Peptide-based formulas have been shown to be beneficial in patients with feeding intolerance. However, there are limited studies showing the efficacy and safety of high-protein peptide-based formula in critically ill surgical patients.

AIM

To determine the effects of a high-protein peptide formulation on gastrointestinal tolerance, nutritional status, biochemical changes, and adverse events in patients in the surgery intensive care unit (SICU) compared to an isocaloric isonitrogenous standard polymeric formulation.

METHODS

This study was a multi-center double-blind, randomized controlled trial. We enrolled adult patients in the surgical intensive care unit, age ≥ 15 years and expected to receive enteral feeding for at least 5-14 d post-operation. They were randomly assigned to receive either the high-protein peptide-based formula or the isocaloric isonitrogenous standard formula for 14 d. Gastric residual volume (GRV), nutritional status, body composition and biochemical parameters were assessed at baseline and on days 3, 5, 7, 9, 11, and 14.

RESULTS

A total of 19 patients were enrolled, 9 patients in the peptide-based formula group and 10 patients in the standard formula group. During the study period, there were no differences of the average GRV, body weight, body composition, nutritional status and biochemical parameters in the patients receiving peptide-based formula, compared to the standard regimen. However, participants in the standard formula lost their body weight, body mass index (BMI) and skeletal muscle mass significantly. While body weight, BMI and muscle mass were maintained in the peptide-based formula, from baseline to day 14. Moreover, the participants in the peptide-based formula tended to reach their caloric target faster than the standard formula.

CONCLUSION

The study emphasizes the importance of early nutritional support in the SICU and showed the efficacy and safety of a high-protein, peptide-based formula in meeting caloric and protein intake targets while maintaining body weight and muscle mass.

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.

Assessing the oral and suprahyoid muscles in healthy adults using muscle ultrasound to inform the swallowing process: a proof-of-concept study

The oral and suprahyoid muscles are responsible for movements of swallowing. Our study aimed to determine the reproducibility of static and dynamic measurements of these muscles using bedside ultrasound equipment. Forty healthy participants were recruited prospectively. Primary outcomes were evaluation of mass measurements of the anterior bellies of the digastric, mylohyoid, geniohyoid and tongue in B-mode ultrasound. Secondary outcomes were evaluation of geniohyoid muscle layer thickness and function using M-mode. Muscle mass measurements demonstrated little within-participant variability. Coefficient of Variance (CoV) across muscles were: anterior belly digastric (5.0%), mylohyoid (8.7%), geniohyoid (5.0%) and tongue (3.2%). A relationship between sex (r2 = 0.131 p = 0.022) was demonstrated for the geniohyoid muscle, with males having higher transverse Cross Sectional Area (CSA) (14.3 ± 3.6 mm vs. 11.9 ± 2.5 mm, p = 0.002). Tongue size was correlated with weight (r2 = 0.356, p = 0.001), height (r2 = 0.156, p = 0.012) and sex (r2 = 0.196, p = 0.004). Resting thickness of the geniohyoid muscle layer changed with increasing bolus sizes (f = 3.898, p = 0.026). Velocity increased with bolus size (p =  < 0.001, F = 8.974). However swallow time and slope distance did not, potentially influenced by higher coefficients of variation. Oral and suprahyoid muscle mass are easily assessed using bedside ultrasound. Ultrasound may provide new information about muscle mass and function during swallowing.

Nutrition determinants of acute skeletal muscle loss in critically ill patients: A prospective observational cohort study

BACKGROUND

Skeletal muscle loss is associated with adverse outcomes in critically ill patients and risk factors of acute skeletal muscle loss are not well described. This study aims to determine the factors associated with acute skeletal muscle loss in critically ill patients.

METHODS

This prospective observational cohort study was conducted with patients who were expected to stay in the intensive care unit (ICU) for at least a week. Rectus femoris cross-sectional area (RFCSA) measurements were performed within 48 h of ICU admission and on study day 7. The percentage change in RFCSA and variables associated with this change were evaluated by univariate and multivariate regression analysis.

RESULTS

Over a 12-month period, 518 patients were assessed for eligibility and 44 critically ill patients with a mean age of 59.3 ± 10.9 years were enrolled; 52.3% of them were female. There were significant reductions in RFCSA (16.8 ± 16.5%; P < 0.001). The mean amounts of protein and energy consumed compared with those prescribed were 67.0 ± 28.8% and 71.5 ± 38.3%, respectively. Multivariate regression analysis revealed that frailty was independently associated with acute skeletal muscle loss after adjusting for confounding factors in our cohort of patients.

CONCLUSION

Frailty status before ICU admission is associated with acute skeletal muscle loss and may be important for identifying critically ill patients at high risk of muscle wasting.

Opportunistic screening for long-term muscle wasting in critically ill patients: insights from an acute pancreatitis cohort

OBJECTIVES

To assess the feasibility of long-term muscle monitoring, we implemented an AI-guided segmentation approach on clinically indicated Computed Tomography (CT) examinations conducted throughout the hospitalization period of patients admitted to the intensive care unit (ICU) with acute pancreatitis (AP). In addition, we aimed to investigate the potential of muscle monitoring for early detection of patients at nutritional risk and those experiencing adverse outcomes. This cohort served as a model for potential integration into clinical practice.

MATERIALS

Retrospective cohort study including 100 patients suffering from AP that underwent a minimum of three CT scans during hospitalization, totaling 749 assessments. Sequential segmentation of psoas muscle area (PMA) was performed and was relative muscle loss per day for the entire monitoring period, as well as for the interval between each consecutive scan was calculated. Subgroup and outcome analyses were performed including ANOVA. Discriminatory power of muscle decay rates was evaluated using ROC analysis.

RESULTS

Monitoring PMA decay revealed significant long-term losses of 48.20% throughout the hospitalization period, with an average daily decline of 0.98%. Loss rates diverged significantly between survival groups, with 1.34% PMA decay per day among non-survivors vs. 0.74% in survivors. Overweight patients exhibited significantly higher total PMA losses (52.53 vs. 42.91%; p = 0.02) and average PMA loss per day (of 1.13 vs. 0.80%; p = 0.039). The first and the maximum decay rate, in average available after 6.16 and 17.03 days after ICU admission, showed convincing discriminatory power for survival in ROC analysis (AUC 0.607 and 0.718). Both thresholds for maximum loss (at 3.23% decay per day) and for the initial loss rate (at 1.98% per day) proved to be significant predictors of mortality.

CONCLUSIONS

The innovative AI-based PMA segmentation method proved robust and effortless, enabling the first comprehensive assessment of muscle wasting in a large cohort of intensive care pancreatitis patients. Findings revealed significant muscle wasting (48.20% on average), particularly notable in overweight individuals. Higher rates of initial and maximum muscle loss, detectable early, correlated strongly with survival. Integrating this tool into routine clinical practice will enable continuous muscle status tracking and early identification of those at risk for unfavorable outcomes.

Plasma beta-hydroxy-beta-methylbutyrate availability after enteral administration during critical illness after trauma: An exploratory study

BACKGROUND

During critical illness skeletal muscle wasting occurs rapidly. Although beta-hydroxy-beta-methylbutyrate (HMB) is a potential treatment to attenuate this process, the plasma appearance and muscle concentration is uncertain.

METHODS

This was an exploratory study nested within a blinded, parallel group, randomized clinical trial in which critically ill patients after trauma received enteral HMB (3 g daily) or placebo. Plasma samples were collected at 0, 60, and 180 min after study supplement administration on day 1. Needle biopsies of the vastus lateralis muscle were collected (baseline and day 7 of the HMB treatment intervention period). An external standard curve was used to calculate HMB concentrations in plasma and muscle.

RESULTS

Data were available for 16 participants (male n = 12 (75%), median [interquartile range] age 50 [29-58] years) who received placebo and 18 participants (male n = 14 (78%), age 49 [34-55] years) who received HMB. Plasma HMB concentrations were similar at baseline but increased after HMB (T = 60 min: placebo 0.60 [0.44-1.31]  µM; intervention 51.65 [22.76-64.72]  µM). Paired muscle biopsies were collected from 11 participants (placebo n = 7, HMB n = 4). Muscle HMB concentrations were similar at baseline between groups (2.35 [2.17-2.95]; 2.07 [1.78-2.31] µM). For participants in the intervention group who had the repeat biopsy within 4 h of HMB administration, concentrations were greater (7.2 and 12.3 µM) than those who had the repeat biopsy >4 h after HMB (2.7 and 2.1 µM).

CONCLUSION

In this exploratory study, enteral HMB administration increased plasma HMB availability. The small sample size limits interpretation of the muscle HMB findings.

Association of Psoas Muscle Mass at Intensive Care Unit Admission With Physical Function and Post-discharge Destination in Survivors of Critical Illness

OBJECTIVE

Survivors of critical illness may have physical impairments, known as post-intensive care syndrome (PICS). Early screening for the risk of PICS is recommended to prevent PICS. Skeletal muscle mass is a clinically important indicator associated with various outcomes. This study aimed to examine the association of psoas muscle mass at intensive care unit (ICU) admission with the destination and physical function at hospital discharge.

METHODS

In this single-center retrospective cohort study, we reviewed the medical records of adult patients who had required emergency ICU admission and who had been intubated and mechanically ventilated. Psoas major muscle was measured as an indicator of skeletal muscle mass from abdominal computed tomography images at ICU admission. Physical function was assessed using the functional status score for the ICU and ICU mobility scale at hospital discharge. Multinomial logistic and multivariable linear regression were used to analyze the associations of the psoas muscle mass with the discharge destination and physical function at discharge.

RESULTS

We enrolled 124 patients (79 men and 45 women) with a median (interquartile range) age of 72.0 (62.0-80.0) years; 39 (31.5%) were discharged to home, 50 (40.3%) were transferred to rehabilitation wards, and 35 (28.2%) were transferred to long-term care settings. The psoas muscle area and volume were 16.9 (11.3-20.6) cm2 and 228.3 (180.2-282.0) cm3 in home discharge patients, 17.5 (11.5-21.5) cm2 and 248.4 (162.0-311.4) cm3 in rehabilitation ward patients, and 15.9 (10.3-19.5) cm2 and 184.0 (137.0-251.1) cm3 in long-term care patients. The areas and volumes of the psoas muscle were not significantly different in the three groups. Furthermore, psoas muscle mass was not significantly associated with the discharge destination and physical function.

CONCLUSIONS

Discharge destination and physical function at hospital discharge were not significantly associated with psoas muscle mass at ICU admission.

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.

Clinical practice guidelines for nutritional assessment and monitoring of adult ICU patients in China

The Chinese Society of Critical Care Medicine (CSCCM) has developed clinical practice guidelines for nutrition assessment and monitoring for patients in adult intensive care units (ICUs) in China. This guideline focuses on nutrition evaluation and metabolic monitoring to achieve optimal and personalized nutrition therapy for critically ill patients. This guideline was developed by experts in critical care medicine and evidence-based medicine methodology and was developed after a thorough review of the system and a summary of relevant trials or studies published from 2000 to July 2023. A total of 18 recommendations were formed and consensus was reached through discussions and reviews by expert groups in critical care medicine, parenteral and enteral nutrition, and surgery. The recommendations are based on currently available evidence and cover several key fields, including screening and assessment, evaluation and assessment of enteral feeding intolerance, metabolic and nutritional measurement and monitoring during nutrition therapy, and organ function evaluation related to nutrition supply. Each question was analyzed according to the Population, Intervention, Comparison, and Outcome (PICO) principle. In addition, interpretations were provided for four questions that did not reach a consensus but may have potential clinical and research value. The plan is to update this nutrition assessment and monitoring guideline using the international guideline update method within 3-5 years.

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.

Acute muscle wasting is associated with poor prognosis in older adults with severe community-acquired pneumonia

PURPOSE

To investigate the impact of acute muscle wasting on 90-day mortality in older patients with severe pneumonia using ultrasound and chest computed tomography (CT).

METHODS

Quadriceps muscle layer thickness was measured via ultrasound on days 1, 7, and 14, and cross-sectional area of the erector spinae muscle was assessed using chest CT on days 1 and 14 in patients aged ≥ 65 years old. The primary outcome was all-cause 90-day mortality. Receiver operating characteristic curves were conducted for muscle loss to predict 90-day mortality. Cox proportional hazard models and Kaplan-Meier survival curves were employed to evaluate the association between muscle loss and 90-day mortality.

RESULTS

Sixty-two patients were enrolled with median age of 80.2 years, 29 (46.8%) were men and 28 (45.2%) patients died. Muscle mass measured using ultrasound and CT decreased significantly from baseline to day 14 in the non-survivor group. Muscle loss assessed by ultrasound (with minimum and maximum pressure) and CT independently predicted all-cause 90-day mortality (adjusted hazard ratios = 1.497, 1.400 and 1.082; P < 0.001, P = 0.002, and P = 0.004; respectively), and cutoff values of muscle loss were 0.34 cm, 0.11 cm and 4.92 cm2, correspondingly. A higher muscle loss had an increased risk of 90-day mortality.

CONCLUSIONS

Acute muscle wasting assessed by ultrasound and chest CT persisted for 14 days and was an independent predictor of adverse outcomes in older patients with severe pneumonia. A greater decline in muscle mass was associated with a higher 90-day mortality risk.

Predictors of Post-COVID-19 Functional Status Scale in Hospitalized Patients Recovering From SARS-CoV-2 Infection

OBJECTIVE

The study aimed to investigate whether peripheral and inspiratory muscle strength and architecture, functional capacity, functional mobility, fatigue, and health-related quality of life are predictors of the Post-COVID-19 Functional Status Scale score in patients with post-COVID-19 syndrome who were hospitalized.

DESIGN

A cross-sectional study included 69 patients (53.3 ± 13.2 yrs, 36 men) with post-COVID-19 syndrome. The following outcomes were assessed: peripheral (dynamometry) and inspiratory (manovacuometry) muscle strength, muscle architecture (ultrasound), functional capacity (six-minute walk test), functional mobility (Timed Up and Go), fatigue (Functional Assessment of Chronic Illness Therapy), health-related quality of life (36-item Short-Form Health Survey), and functional status (Post-COVID-19 Functional Status scale).

RESULTS

Functional mobility (β = 0.573, P < 0.001), vastus intermedius echogenicity (β = -0.491, P = 0.001), length of stay (β = 0.349, P = 0.007), and female sex (β = 0.415, P = 0.003) influenced the Post-COVID-19 Functional Status Scale.

CONCLUSIONS

Functional mobility, muscle quality of the vastus intermedius, length of stay, and female sex influence the Post-COVID-19 Functional Status Scale score in this population. It is noteworthy that functional mobility is an independent predictor of Post-COVID-19 Functional Status Scale.

Increased intramuscular adipose tissue of the quadriceps at admission is more strongly related to activities of daily living recovery at discharge compared to muscle mass loss in older patients with aspiration pneumonia

BACKGROUND

Recent studies reported that an increase in intramuscular adipose tissue of the quadriceps in older patients negatively affects the recovery of activities of daily living (ADL) more than the loss of muscle mass. However, whether intramuscular adipose tissue of the quadriceps in older patients with aspiration pneumonia is related to ADL recovery remains unclear. This study aimed to determine the relationship between intramuscular adipose tissue of the quadriceps and ADL recovery in older patients with aspiration pneumonia.

METHODS

Thirty-nine older inpatients who were diagnosed with aspiration pneumonia participated in this prospective study. The main outcome of this study was ADL at discharge. ADL were assessed using the Barthel Index (BI). The intramuscular adipose tissue and muscle mass of the quadriceps were evaluated at admission using echo intensity and muscle thickness observed on ultrasound images. A multiple linear regression analysis was performed to confirm whether the quadriceps echo intensity was related to the BI score at discharge, even after adjusting for confounding factors.

RESULTS

The medians [interquartile range] of the BI score at admission and discharge were 15.0 [0.0-35.0] and 20.0 [5.0-55.0], respectively. The BI score at discharge was significantly higher than that at admission (p = 0.002). The quadriceps echo intensity (β =  - 0.374; p = 0.036) and BI score at admission (β = 0.601; p < 0.001) were independently and significantly related to the BI score at discharge (R2 = 0.718; f2 = 2.546; statistical power = 1.000). In contrast, the quadriceps thickness (β =  - 0.216; p = 0.318) was not independently and significantly related to the BI score at discharge.

CONCLUSIONS

Increased intramuscular adipose tissue of the quadriceps at admission is more strongly and negatively related to ADL recovery at discharge than the loss of muscle mass among older patients with aspiration pneumonia. Interventions targeting the intramuscular adipose tissue of the quadriceps may improve ADL among these patients.

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.

Low skeletal muscle quality extracted from CT is associated with poor outcomes in severe acute pancreatitis patients

PURPOSE

To evaluate the association between body composition parameters derived from computed tomography (CT) scans and clinical outcomes in patients with severe acute pancreatitis (AP).

METHODS

Patients who have been diagnosed AP with a CT scan at ICU admission were included. Body composition parameters were measured on a single slice at L2-3 of the unenhanced CT scans. The intermuscular adipose tissue (IMAT), visceral adipose tissue (VAT), skeletal muscle area (SMA) and skeletal muscle density (SMD) were assessed using HUs by image analysis software. Univariable and multivariable analyses were performed to analyze the association between body composition parameters and clinical outcomes including all-cause mortality or prolonged ICU stay. The area under the curve (AUC) of a receiver operating characteristic curve was used to explore the predictive value of the body composition on treatment clinical outcomes.

RESULTS

A total of 158 patients were included. The IMAT (8.3 cm2 vs 6.0 cm2, P = 0.001) and VAT (190.3 cm2 vs 143.7 cm2, P < 0.001) were significantly higher in the severe AP group than in the moderately severe group, but were notassociatedwithoutcomes. For 1 HU of SMD increased, the risk of poor clinical outcomes decresed 11 % (adjusted OR 0.892, 95 %CI 0.806-0.987, P = 0.026), while an SMD below the median value (32.1 HU for males and 28.5 HU for females) was independently associated with worse outcomes in the multivariable analysis (adjusted OR 8.868, 95 % CI 2.146-36.650, P = 0.003). The SMD had a good predictive ability for clinical outcomes, AUC was 0.824 (95 % CI, 0.715-0.933) for males and 0.803 (95 % CI, 0.639-0.967) for females.

CONCLUSION

Low SMD was associated with poor outcomes in patients with severe and moderately severe AP and might be used as a novel marker to predict outcomes in patients suffering from severe and moderately severe AP.

Sarcopenia and Mortality in Critically Ill COVID-19 Patients

COVID-19 can manifest as either asymptomatic or progressing to a severe phase in some patients, which may require hospitalization. These patients may experience dyspnea and hypoxia, leading to the development of acute respiratory distress syndrome. Studies have reported an increased risk of severe sarcopenia in COVID-19 patients during and after recovery. This narrative review aimed to summarize and synthesize available studies on the association between sarcopenia and mortality in critically ill COVID-19 patients. A total of 22 studies conducted on hospitalized COVID-19 patients were included in this review. Of those, 17 studies reported a direct association, while 5 studies showed no association between sarcopenia and mortality in severe COVID-19 patients. It is important to maintain muscle quality and quantity in defense against COVID-19. The measurement of lean muscle mass should be included in the risk assessment of severely ill COVID-19 patients as part of the therapy plan.

Ultrasonographic Features of Muscular Weakness and Muscle Wasting in Critically Ill Patients

Muscle wasting begins as soon as in the first week of one's ICU stay and patients with multi-organ failure lose more muscle mass and suffer worse functional impairment as a consequence. Muscle wasting and weakness are mainly characterized by a generalized, bilateral lower limb weakness. However, the impairment of the respiratory and/or oropharyngeal muscles can also be observed with important consequences for one's ability to swallow and cough. Muscle wasting represents the result of the disequilibrium between breakdown and synthesis, with increased protein degradation relative to protein synthesis. It is worth noting that the resulting functional disability can last up to 5 years after discharge, and it has been estimated that up to 50% of patients are not able to return to work during the first year after ICU discharge. In recent years, ultrasound has played an increasing role in the evaluation of muscle. Indeed, ultrasound allows an objective evaluation of the cross-sectional area, the thickness of the muscle, and the echogenicity of the muscle. Furthermore, ultrasound can also estimate the thickening fraction of muscle. The objective of this review is to analyze the current understanding of the pathophysiology of acute skeletal muscle wasting and to describe the ultrasonographic features of normal muscle and muscle weakness.

Increase in protein intake is related to decreasing intramuscular adipose tissue of the quadriceps in older inpatients: A longitudinal study

BACKGROUND & AIM

Several randomized controlled trials indicated that an increase in protein intake decreases intramuscular adipose tissue of the thigh in mobility-limited or pre-frail older persons and stroke patients. However, whether the increase in protein intake in older inpatients is related to decreasing intramuscular adipose tissue remains unclear. The aim of this study was to examine the longitudinal relationship between intramuscular adipose tissue of the quadriceps and protein intake in older inpatients.

METHODS

This longitudinal study included 193 older inpatients (aged ≥65 years) (median [IQR] age: 83.0 [77.0-88.0]). The primary outcomes were changes in intramuscular adipose tissue of the quadriceps and protein intake. Intramuscular adipose tissue and muscle mass of the quadriceps were examined using ultrasound images (i.e., quadriceps echo intensity and thickness). The changes in quadriceps echo intensity and protein intake were calculated by subtracting the quadriceps echo intensity and protein intake at admission from those values at discharge. Multiple linear regression analysis adjusting for confounding factors was used to determine whether the change in protein intake was independently and significantly related to changes in quadriceps echo intensity and thickness.

RESULTS

Quadriceps echo intensity at discharge (81.3 ± 20.6 [a.u.]) was significantly lower than at admission (84.0 ± 20.5 [a.u.]). Protein intake at discharge (1.2 [1.0-1.4] g/kg/day) was significantly higher than at admission (1.2 [0.9-1.4] g/kg/day). Change in protein intake was negatively and significantly related to the change in quadriceps echo intensity. In contrast, change in protein intake was not independently and significantly related to change in quadriceps thickness.

CONCLUSIONS

Our results indicate that an increase in protein intake is related to a decrease in intramuscular adipose tissue of the quadriceps in older inpatients. Nutritional intervention for increasing protein intake in older inpatients may be essential for decreasing intramuscular adipose tissue of the quadriceps.

Acute muscle wasting rate assessment and long-term mortality in critically ill trauma

BACKGROUND AND OBJECTIVES

To evaluate the relationship between acute muscle wasting rate and long-term mortality in critically ill trauma.

METHODS AND STUDY DESIGN

A single-center, retrospective study was conducted in critically ill trauma. Patients with Computed Tomography scans including the L3 vertebra within 24 hours and at 1 week after trauma were recruited. Acute muscle wasting rate was defined as the mean percent variation per day of skeletal muscle index in the first week after trauma. Multivariate logistic regression analysis and receiver operating characteristic curve analysis were performed to determine whether acute muscle wasting rate could help predict hospital malnutrition and 1-year mortality.

RESULTS

Skeletal muscle index was 49.3±10.7 cm2/m2 at baseline and decreased to 45.1±9.6 cm2/m2 (p<0.001) at 1 week and 39.8±10.8cm2/m2 (p<0.001) at 1 month after trauma. A sustained decrease of skeletal muscle index was observed from baseline up to 6 months (33.7±8.4cm2/m2, p<0.001) post trauma, and lasted for 1 year (37.7±5.6cm2/m2, p=0.004). Logistic regression analysis showed that acute muscle wasting rate was an independent risk factor for hospital malnutrition and 1-year mortality. Every 1% absolute increase of acute muscle wasting rate was associated with 1.82-fold higher odds of 1-year mortality in critically ill trauma. The area under curve of acute muscle wasting rate was 0.813 for hospital malnutrition prediction and 0.715 for 1-year mortality prediction.

CONCLUSIONS

Acute muscle wasting rate was independently associated with higher 1-year mortality and hospital malnutrition in critically ill trauma.

Relationship of Age And Mobility Levels During Physical Rehabilitation With Clinical Outcomes in Critical Illness

Objective

To determine whether age, mobility level, and change in mobility level across the first 3 physical rehabilitation sessions associate with clinical outcomes of patients who are critically ill.

Design

Retrospective, observational cohort study.

Setting

Medical Intensive Care Unit (MICU).

Participants

Hospitalized adults (n = 132) who received 3 or more, consecutive rehabilitation sessions in the MICU.

Interventions

Not applicable.

Measurements and Main Results

Sample included 132 patients with 60 (45%) classified as younger (18-59 years) and 72 (55%) as older (60+ years). The most common diagnosis was sepsis/septicemia (32.6%). Older relative to younger patients had a significantly slower rate of improvement in ICU Mobility Scale (IMS) scores across rehabilitation sessions (mean slope coefficient 0.3 vs 0.6 points, P<.001), were less likely to be discharged to home (30.6% vs 55.0%, P=.005), and were more likely to die within 12 months (41.7% vs 25.0%, P=.046). Covariate-adjusted models indicated greater early improvement in IMS scores were associated with discharge home (P=.005). Longer time to first rehabilitation session, lower initial IMS scores, and slower improvement in IMS scores were associated with increased ICU days (all P<.03).

Conclusion

Older age and not achieving the mobility milestone of sitting at edge of bed or limited progression of mobility across sessions is associated with poor patient outcomes. Our findings suggest that age and mobility level contribute to outcome prognostication, and can aide in clinical phenotyping and rehabilitative service allocation.

Muscle ultrasound and its application to point-of-care ultrasonography: a narrative review

Technological advances of hand-held ultrasound devices and educational programmes for their use, such as point-of-care ultrasonography (POCUS) training, have contributed to the increasing application of these devices in clinical practice. With the greater impact of frailty and sarcopenia in aging societies, attention is being focused on the use of ultrasound for skeletal muscle assessment. In this narrative review, we discuss how ultrasound can be applied to skeletal muscle assessment, especially that of the quadriceps muscle, in clinical practice. Muscle thickness by ultrasound has been shown to have good reliability and validity for the evaluation of muscle size, and echo intensity has been used to evaluate muscle quality. Muscle ultrasound has not only been useful to diagnose sarcopenia in various settings, but has also been validated to predict health-related outcomes such as death and functional disability. Recommended methods for muscle ultrasound was published recently, and the results of future studies are expected to be comparable. Although several challenging issues with muscle ultrasound remain, if it could be incorporated into educational programmes such as POCUS training, more clinicians may be able to use ultrasound for skeletal muscle assessment in the future.KEY MESSAGESThe evolution of hand-held ultrasound devices enables physicians to perform ultrasound at the bedside as part of regular medical examinations.Muscle ultrasound is considered an effective tool for evaluating muscle size and quality, and has been studied in various settings.More clinicians may be able to evaluate skeletal muscle assessment with the development of educational programmes on muscle ultrasound in the future.

Illness Weakness, Polyneuropathy and Myopathy: Diagnosis, treatment, and long-term outcomes

BACKGROUND

Severe weakness associated with critical illness (CIW) is common. This narrative review summarizes the latest scientific insights and proposes a guide for clinicians to optimize the diagnosis and management of the CIW during the various stages of the disease from the ICU to the community stage.

MAIN BODY

CIW arises as diffuse, symmetrical weakness after ICU admission, which is an important differentiating factor from other diseases causing non-symmetrical muscle weakness or paralysis. In patients with adequate cognitive function, CIW can be easily diagnosed at the bedside using manual muscle testing, which should be routinely conducted until ICU discharge. In patients with delirium or coma or those with prolonged, severe weakness, specific neurophysiological investigations and, in selected cases, muscle biopsy are recommended. With these exams, CIW can be differentiated into critical illness polyneuropathy or myopathy, which often coexist. On the general ward, CIW is seen in patients with prolonged previous ICU treatment, or in those developing a new sepsis. Respiratory muscle weakness can cause neuromuscular respiratory failure, which needs prompt recognition and rapid treatment to avoid life-threatening situations. Active rehabilitation should be reassessed and tailored to the new patient's condition to reduce the risk of disease progression. CIW is associated with long-term physical, cognitive and mental impairments, which emphasizes the need for a multidisciplinary model of care. Follow-up clinics for patients surviving critical illness may serve this purpose by providing direct clinical support to patients, managing referrals to other specialists and general practitioners, and serving as a platform for research to describe the natural history of post-intensive care syndrome and to identify new therapeutic interventions. This surveillance should include an assessment of the activities of daily living, mood, and functional mobility. Finally, nutritional status should be longitudinally assessed in all ICU survivors and incorporated into a patient-centered nutritional approach guided by a dietician.

CONCLUSIONS

Early ICU mobilization combined with the best evidence-based ICU practices can effectively reduce short-term weakness. Multi-professional collaborations are needed to guarantee a multi-dimensional evaluation and unitary community care programs for survivors of critical illnesses.

Construct and criterion validity of muscle ultrasonography for assessment of skeletal muscle in patients recovering from COVID-19

Background: The purpose was to investigate the content, construct, and criterion validity of muscle ultrasound in a mixed cohort of participants recovering from mild and critical COVID-19. Methods: A secondary analysis of a prospective cross-sectional study was conducted on data obtained from a battery of muscle and physical function assessments including a muscle biopsy and muscle ultrasonography (US). Rectus femoris (RF) muscle thickness (mT), quadricep complex (QC) mT, RF muscle cross-sectional area (CSA) using 2D freeform trace and estimated from Feret's diameter, and RF echo intensity (EI) were assessed with US. Muscle fiber CSA, fiber type, protein content in muscle fibers, extracellular matrix content (ECM; wheat-germ agglutin), and percent area of collagen in ECM (picrosirius red) were examined from vastus lateralis muscle biopsies. Spearman rho correlations (r) were performed to assess validity of ultrasound parameters. Results: Thirty-three individuals participated including 11 patients surviving critical COVID-19, 15 individuals recovering from mild-COVID, and 7 controls. There were several significant correlations between RF mT, QC mT, RF CSA, and RF EI with age, comorbid burden, body-mass index, and measures of muscle strength, muscle power, and physical function (range r = 0.35-0.83). RF Feret's CSA correlated to CSA of type II muscle fibers (r = 0.41, p = 0.022) and the average size of all muscle fibers (r = 0.39, p = 0.031). RF EI was correlated with collagen in muscle ECM (r = 0.53, p = 0.003) and protein content in muscle tissue (r = -0.52, p = 0.012). Conclusion: Muscle size and quality measured using US has moderate content and construct validity, and to lesser extent, fair to moderate criterion validity in a mixed cohort of individuals recovering from COVID. Muscle ultrasound quality (EI) appears to be sensitive at detecting muscle dysfunction as it is associated with strength, power, physical function, and collagen distribution in a mixed group of individuals recovering from COVID-19.

Androgen action on myogenesis throughout the lifespan; comparison with neurogenesis

Androgens' pleiotropic actions in promoting sex differences present not only a challenge to providing a comprehensive account of their function, but also an opportunity to gain insights by comparing androgenic actions across organ systems. Although often overlooked by neuroscientists, skeletal muscle is another androgen-responsive organ system which shares with the nervous system properties of electrochemical excitability, behavioral relevance, and remarkable capacity for adaptive plasticity. Here we review androgenic regulation of mitogenic plasticity in skeletal muscle with the goal of identifying areas of interest to those researching androgenic mechanisms mediating sexual differentiation of neurogenesis. We use an organizational-activational framework to relate broad areas of similarity and difference between androgen effects on mitogenesis in muscle and brain throughout the lifespan, from early organogenesis, through pubertal organization, adult activation, and aging. The focus of the review is androgenic regulation of muscle-specific stem cells (satellite cells), which share with neural stem cells essential functions in development, plasticity, and repair, albeit with distinct, muscle-specific features. Also considered are areas of paracrine and endocrine interaction between androgen action on muscle and nervous system, including mediation of neural plasticity of innervating and distal neural populations by muscle-produced trophic factors.

The Good, the Bad, and the Serum Creatinine: Exploring the Effect of Muscle Mass and Nutrition

Muscle wasting (sarcopenia) is one of the hallmarks of critical illness. Patients admitted to intensive care unit develop sarcopenia through increased protein catabolism, a decrease in protein syntheses, or both. Among the factors known to promote wasting are chronic inflammation and cytokine imbalance, insulin resistance, hypermetabolism, and malnutrition. Moreover, muscle wasting, known to develop in chronic kidney disease patients, is a harmful consequence of numerous complications associated with deteriorated renal function. Plenty of published data suggest that serum creatinine (SCr) reflects increased kidney damage and is also related to body weight. Based on the concept that urea and creatinine are nitrogenous end products of metabolism, the urea:creatinine ratio (UCR) could be applied but with limited clinical usability in case of kidney damage, hypovolemia, excessive, or protein intake, where UCR can be high and independent of catabolism. Recent data suggest that the sarcopenia index should be considered an alternative to serum creatinine. It is more reliable in estimating muscle mass than SCr. However, the optimal biomarker of catabolism is still an unresolved issue. The SCr is not a promising biomarker for renal function and muscle mass based on the influence of several factors. The present review highlights recent findings on the limits of SCr as a surrogate marker of renal function and the assessment modalities of nutritional status and muscle mass measurements.

Study protocol for TARGET protein: The effect of augmented administration of enteral protein to critically ill adults on clinical outcomes: A cluster randomised, cross-sectional, double cross-over, clinical trial

Background

It is unknown whether increasing dietary protein to 1.2-2.0 g/kg/day as recommended in international guidelines compared to current practice improves outcomes in intensive care unit (ICU) patients. The TARGET Protein trial will evaluate this.

Objective

To describe the study protocol for the TARGET Protein trial.

Design setting and participants

TARGET Protein is a cluster randomised, cross-sectional, double cross-over, pragmatic clinical trial undertaken in eight ICUs in Australia and New Zealand. Each ICU will be randomised to use one of two trial enteral formulae for three months before crossing over to the other formula, which is then repeated, with enrolment continuing at each ICU for 12 months. All patients aged ≥16 years in their index ICU admission commencing enteral nutrition will be eligible for inclusion. Eligible patients will receive the trial enteral formula to which their ICU is allocated. The two trial enteral formulae are isocaloric with a difference in protein dose: intervention 100g/1000 ml and comparator 63g/1000 ml. Staggered recruitment commenced in May 2022.

Main outcomes measures

The primary outcome is days free of the index hospital and alive at day 90. Secondary outcomes include days free of the index hospital at day 90 in survivors, alive at day 90, duration of invasive ventilation, ICU and hospital length of stay, incidence of tracheostomy insertion, renal replacement therapy, and discharge destination.

Conclusion

TARGET Protein aims to determine whether augmented enteral protein delivery reduces days free of the index hospital and alive at day 90.

Trial registration

Australian New Zealand Clinical Trials Registry (ACTRN12621001484831).

Activin A level is associated with physical function in critically ill patients

BACKGROUND

Activin A is a potent negative regulator of muscle mass elevated in critical illness. It is unclear whether muscle strength and physical function in critically ill humans are associated with elevated activin A levels.

OBJECTIVES

The objective of this study was to investigate the relationship between serum activin A levels, muscle strength, and physical function at discharge from the intensive care unit (ICU) and hospital.

METHODS

Thirty-six participants were recruited from two tertiary ICUs in Melbourne, Australia. Participants were included if they were mechanically ventilated for >48 h and expected to have a total ICU stay of >5 days. The primary outcome measure was the Six-Minute Walk Test distance at hospital discharge. Secondary outcome measures included handgrip strength, Medical Research Council Sum Score, Physical Function ICU Test Scored, Six-Minute Walk Test, and Timed Up and Go Test assessed throughout the hospital admission. Total serum activin A levels were measured daily in the ICU.

RESULTS

High peak activin A was associated with worse Six-Minute Walk Test distance at hospital discharge (linear regression coefficient, 95% confidence interval, p-value: -91.3, -154.2 to -28.4, p = 0.007, respectively). Peak activin A concentration was not associated with the secondary outcome measures.

CONCLUSIONS

Higher peak activin A may be associated with the functional decline of critically ill patients. Further research is indicated to examine its potential as a therapeutic target and a prospective predictor for muscle wasting in critical illness.

STUDY REGISTRATION

ACTRN12615000047594.

[Intensive care unit-acquired weakness-Diagnostic value of neuromuscular ultrasound]

Intensive care unit-acquired weakness (ICUAW) is one of the most common neuromuscular complications in intensive care medicine. The clinical diagnosis and assessment of the severity using established diagnostic methods (e.g., clinical examination using the Medical Research Council Sum Score or electrophysiological examination) can be difficult or even impossible, especially in sedated, ventilated and delirious patients. Neuromuscular ultrasound (NMUS) has increasingly been investigated in ICUAW as an easy to use noninvasive and mostly patient compliance-independent diagnostic alternative. It has been shown that NMUS appears to be a promising tool to detect ICUAW, to assess the severity of muscular weakness and to monitor the clinical progression. Further studies are needed to standardize the methodology, to evaluate the training effort and to optimize outcome predication. The formulation of an interdisciplinary neurological and anesthesiological training curriculum is warranted to establish NMUS as a complementary diagnostic method of ICUAW in daily clinical practice.

Blood flow restriction as a potential therapy to restore physical function following COVID-19 infection

Accumulating evidence indicates that some COVID-19 survivors display reduced muscle mass, muscle strength, and aerobic capacity, which contribute to impairments in physical function that can persist for months after the acute phase of illness. Accordingly, strategies to restore muscle mass, muscle strength, and aerobic capacity following infection are critical to mitigate the long-term consequences of COVID-19. Blood flow restriction (BFR), which involves the application of mechanical compression to the limbs, presents a promising therapy that could be utilized throughout different phases of COVID-19 illness. Specifically, we hypothesize that: 1) use of passive BFR modalities can mitigate losses of muscle mass and muscle strength that occur during acute infection and 2) exercise with BFR can serve as an effective alternative to high-intensity exercise without BFR for regaining muscle mass, muscle strength, and aerobic capacity during convalescence. The various applications of BFR may also serve as a targeted therapy to address the underlying pathophysiology of COVID-19 and provide benefits to the musculoskeletal system as well as other organ systems affected by the disease. Consequently, we present a theoretical framework with which BFR could be implemented throughout the progression from acute illness to outpatient rehabilitation with the goal of improving short- and long-term outcomes in COVID-19 survivors. We envision that this paper will encourage discussion and consideration among researchers and clinicians of the potential therapeutic benefits of BFR to treat not only COVID-19 but similar pathologies and cases of acute critical illness.

Intermittent body composition analysis as monitoring tool for muscle wasting in critically ill COVID-19 patients

OBJECTIVES

SARS-CoV-2 virus infection can lead to acute respiratory distress syndrome (ARDS), which can be complicated by severe muscle wasting. Until now, data on muscle loss of critically ill COVID-19 patients are limited, while computed tomography (CT) scans for clinical follow-up are available. We sought to investigate the parameters of muscle wasting in these patients by being the first to test the clinical application of body composition analysis (BCA) as an intermittent monitoring tool.

MATERIALS

BCA was conducted on 54 patients, with a minimum of three measurements taken during hospitalization, totaling 239 assessments. Changes in psoas- (PMA) and total abdominal muscle area (TAMA) were assessed by linear mixed model analysis. PMA was calculated as relative muscle loss per day for the entire monitoring period, as well as for the interval between each consecutive scan. Cox regression was applied to analyze associations with survival. Receiver operating characteristic (ROC) analysis and Youden index were used to define a decay cut-off.

RESULTS

Intermittent BCA revealed significantly higher long-term PMA loss rates of 2.62% (vs. 1.16%, p < 0.001) and maximum muscle decay of 5.48% (vs. 3.66%, p = 0.039) per day in non-survivors. The first available decay rate did not significantly differ between survival groups but showed significant associations with survival in Cox regression (p = 0.011). In ROC analysis, PMA loss averaged over the stay had the greatest discriminatory power (AUC = 0.777) for survival. A long-term PMA decline per day of 1.84% was defined as a threshold; muscle loss beyond this cut-off proved to be a significant BCA-derived predictor of mortality.

CONCLUSION

Muscle wasting in critically ill COVID-19 patients is severe and correlates with survival. Intermittent BCA derived from clinically indicated CT scans proved to be a valuable monitoring tool, which allows identification of individuals at risk for adverse outcomes and has great potential to support critical care decision-making.

Greater intramuscular adipose tissue of the quadriceps in older inpatients at post-acute hospital admission is more strongly related to a low rate of home discharge than a loss of muscle mass

This study aimed to examine the relationships between intramuscular adipose tissue and muscle mass of the quadriceps at post-acute hospital admission and the low rate of home discharge. This prospective study included 389 inpatients aged ≥ 65 years. Patients were divided into two groups according to the destination: home discharge (n = 279) and no-home discharge (n = 110) groups. The primary outcome was hospital discharge destination (home discharge or not). Intramuscular adipose tissue and muscle mass of the quadriceps were assessed at post-acute hospital admission using echo intensity and muscle thickness on ultrasound images, respectively. Logistic regression analysis was used for determining whether quadriceps echo intensity is related to home discharge. Quadriceps echo intensity was significantly and independently associated with home discharge (odds ratio [per 1 SD increase] = 1.43, p = 0.045). Quadriceps thickness was not associated with home discharge (odds ratio [per 1 SD increase] = 1.00, p = 0.998). Our study indicates that greater intramuscular adipose tissue of the quadriceps in older inpatients at post-acute hospital admission is more strongly related to a low rate of home discharge than a loss of muscle mass.

Association of longitudinal changes in skeletal muscle mass with prognosis and nutritional intake in acutely hospitalized patients with abdominal trauma: a retrospective observational study

Background

The objective of this study was to explore whether longitudinal changes in skeletal muscle mass, from hospital admission to 3  weeks post-trauma, are associated with poor prognosis and nutritional intake in acutely hospitalized patients with abdominal trauma.

Methods

A single-center retrospective observational review was conducted on 103 patients with abdominal trauma admitted to the Affiliated Jinling Hospital, Medical School of Nanjing University between January 2010 and April 2020. Skeletal muscle mass was assessed by abdominal computed tomography (CT) performed within 14 days before surgery and on post-trauma days 1-3 (week 0), 7-10 (week 1), 14-17 (week 2), and 21-24 (week 3). The skeletal muscle index (SMI) at L3, change in SMI per day (ΔSMI/day), and percent change in SMI per day (ΔSMI/day [%]) were calculated. The receiver-operating characteristic (ROC) curve was used to evaluate the discriminatory performance of ΔSMI/day (%) for mortality. Linear correlation analysis was used to evaluate the associations between ΔSMI/day (%) and daily caloric or protein intake.

Results

Among the included patients, there were 91 males and 12 females (mean age ± standard deviation 43.74 ± 15.53 years). ΔSMI_4-1/d (%) had a ROC-area under the curve of 0.747 (p = 0.048) and a cut-off value of -0.032 for overall mortality. There were significant positive correlations between ΔSMI_4-1/d (%) and daily caloric intake and protein intake (Y = 0.0007501*X - 1.397, R² = 0.282, R = 0.531, p < 0.001; Y = 0.008183*X - 0.9228, R² = 0.194, R = 0.440, p < 0.001). Δ SMI/day (%) was positively correlated with daily caloric intake ≥80% of resting energy expenditure in weeks 2, 3, and 1-3 post-trauma and with protein intake >1.2 g/kg/d in weeks 3 and 1-3 post-trauma.

Conclusion

Loss of skeletal muscle mass is associated with poor prognosis and nutritional intake in patients admitted to hospital with abdominal trauma.

Critical illness myopathy and trajectory of recovery in acute kidney injury requiring continuous renal replacement therapy: a prospective observational trial protocol

INTRODUCTION

Acute kidney injury requiring renal replacement therapy (AKI-RRT) is common in the intensive care unit (ICU) and is associated with significant morbidity and mortality. Continuous RRT (CRRT) non-selectively removes large amounts of amino acids from plasma, lowering serum amino acid concentrations and potentially depleting total-body amino acid stores. Therefore, the morbidity and mortality associated with AKI-RRT may be partly mediated through accelerated skeletal muscle atrophy and resulting muscle weakness. However, the impact of AKI-RRT on skeletal muscle mass and function during and following critical illness remains unknown. We hypothesise that patients with AKI-RRT have higher degrees of acute muscle loss than patients without AKI-RRT and that AKI-RRT survivors are less likely to recover muscle mass and function when compared with other ICU survivors.

METHODS AND ANALYSIS

This protocol describes a prospective, multicentre, observational trial assessing skeletal muscle size, quality and function in ICU patients with AKI-RRT. We will perform musculoskeletal ultrasound to longitudinally evaluate rectus femoris size and quality at baseline (within 48 hours of CRRT initiation), day 3, day 7 or at ICU discharge, at hospital discharge, and 1-3 months postdischarge. Additional skeletal muscle and physical function tests will be performed at hospital discharge and postdischarge follow-up. We will analyse the effect of AKI-RRT by comparing the findings in enrolled subjects to historical controls of critically ill patients without AKI-RRT using multivariable modelling.

ETHICS AND DISSEMINATION

We anticipate our study will reveal that AKI-RRT is associated with greater degrees of muscle loss and dysfunction along with impaired postdischarge recovery of physical function. These findings could impact the in-hospital and postdischarge treatment plan for these patients to include focused attention on muscle strength and function. We intend to disseminate findings to participants, healthcare professionals, the public and other relevant groups via conference presentation and publication without any publication restrictions.

TRIAL REGISTRATION NUMBER

NCT05287204.

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.

Inter-Examiner and Intra-Examiner Reliability of Quantitative and Qualitative Ultrasonography Assessment of Peripheral and Respiratory Muscles in Critically Ill Patients

ICU patients are exposed to several factors that can lead to muscle structural and functional changes, and ultrasonography can identify them. Although several studies have analyzed the reliability of muscle ultrasonography assessment, a protocol with more muscle assessments becomes a challenge. The aim of this study was to analyze the inter and intra-examiner reliability of peripheral and respiratory muscle ultrasonography assessment in critically ill patients. The sample size was 10 individuals aged ≥ 18 years who were admitted to the ICU. Practical training of four health professionals from different backgrounds was performed. After training, each examiner acquired three images to assess the thickness and echogenicity of the muscle groups: biceps brachii, forearm flexor group, quadriceps femoris, tibialis anterior and diaphragm. For the reliability analysis, an intraclass correlation coefficient was performed. Six hundred US images were analyzed for muscle thickness and 150 for echogenicity. Excellent intra-examiner reliability for echogenicity (ICC: 0.867-0.973) and inter-examiner reliability for thickness were found in all muscle groups (ICC: 0.778-0.942). For muscle thickness intra-examiner reliability, excellent results were found (ICC: 0.798-0.988), with a "good" correlation in one diaphragm assessment (ICC: 0.718). Excellent inter- and intra-examiner reliability of the thickness assessment and intra-examiner echogenicity of all muscles analyzed were found.

COVID-19 and Frailty

Older age is a major risk factor for adverse outcomes of COVID-19, potentially due to immunosenescence and chronic low-grade inflammation, both characteristics of older adults which synergistically contribute to their vulnerability. Furthermore, older age is also associated with decreased kidney function and is consequently associated with an increased risk of cardiovascular disease. All of this in the course of COVID-19 infection can worsen and promote the progression of chronic kidney damage and all its sequelae. Frailty is a condition characterized by the decline in function of several homeostatic systems, leading to increased vulnerability to stressors and risk of adverse health outcomes. Thus, it is very likely that frailty, together with comorbidities, may have contributed to the high vulnerability to severe clinical manifestations and deaths from COVID-19 among older people. The combination of viral infection and chronic inflammation in the elderly could cause multiple unforeseen harmful consequences, affecting overall disability and mortality rates. In post-COVID-19 patients, inflammation has been implicated in sarcopenia progression, functional activity decline, and dementia. After the pandemic, it is imperative to shine a spotlight on these sequelae so that we can be prepared for the future outcomes of the ongoing pandemic. Here, we discuss the potential long-term consequences of SARS-CoV-2 infection and its possibility of causing permanent damage to the precarious balance existing in the frail elderly with multiple pathologies.

Determinants of in-hospital muscle loss in acute ischemic stroke - Results of the Muscle Assessment in Stroke Study (MASS)

BACKGROUND & AIMS

There is a change in the mass and composition of paretic and non-paretic skeletal muscles in the chronic phase of stroke. The multi-center, prospective, and observational Muscle Assessment in Stroke Study (MASS) was performed to evaluate the degree of muscle loss during the in-hospital acute stroke setting and determine factors contributing to this loss.

METHODS

Acute dysphagic ischemic stroke patients (n = 107) admitted to neuro-intensive care units were evaluated by computed tomography on days 1 and 14 after admission to determine the cross-sectional muscle area (CSMA) at the level of the mid-humerus, mid-thigh, and third lumbar vertebra. The percentage change in CSMA and variables associated with this change were evaluated by univariate and multivariate analyses.

RESULTS

There were significant reductions in CSMA in all the muscle groups analyzed; the most prominent change was observed in the arms (both: 14.2 ± 10.7%; paretic: 17.7 ± 11.6%; non-paretic: 10.1 ± 12.5%), followed by the muscles in the legs (both: 12.4 ± 8.7%; paretic: 12.9 ± 9.9%; non-paretic: 12.0 ± 9.3%) and L3-vertebra level (5.6 ± 9.8%) (P < 0.001 for all). Higher calorie (r = -0.378, P < 0.001) or protein (r = -0.352, P < 0.001) intake was negatively associated with the decrease in CSMA of upper extremities. A substantial protein (≥0.4 g/kg/d) or calorie (≥5 kcal/kg/d) gap between targeted or actual intake was related to a larger decrease in CSMA in all the anatomic regions (P ≤ 0.05 for all). Other significant predictors of muscle loss included history of diabetes mellitus, male sex, higher BMI, in-hospital infections, and the necessity for invasive mechanical ventilation.

CONCLUSIONS

There is a considerable degree of loss in the global muscle mass in acute ischemic stroke patients over a two-week period. Along with several factors, falling significantly behind the daily protein or calorie targets was related to the decrease in the muscle area. TRIAL REGISTRATION INFORMATION: clinicaltrials.gov identifier NCT03825419.

Intensive Care Unit-Acquired Weakness in Patients With Acute Kidney Injury: A Contemporary Review

Acute kidney injury (AKI) and intensive care unit-acquired weakness (ICU-AW) are 2 frequent complications of critical illness that, until recently, have been considered unrelated processes. The adverse impact of AKI on ICU mortality is clear, but its relationship with muscle weakness-a major source of ICU morbidity-has not been fully elucidated. Furthermore, improving ICU survival rates have refocused the field of intensive care toward improving long-term functional outcomes of ICU survivors. We begin our review with the epidemiology of AKI in the ICU and of ICU-AW, highlighting emerging data suggesting that AKI and AKI treated with kidney replacement therapy (AKI-KRT) may independently contribute to the development of ICU-AW. We then delve into human and animal data exploring the pathophysiologic mechanisms linking AKI and acute KRT to muscle wasting, including altered amino acid and protein metabolism, inflammatory signaling, and deleterious removal of micronutrients by KRT. We next discuss the currently available interventions that may mitigate the risk of ICU-AW in patients with AKI and AKI-KRT. We conclude that additional studies are needed to better characterize the epidemiologic and pathophysiologic relationship between AKI, AKI-KRT, and ICU-AW and to prospectively test interventions to improve the long-term functional status and quality of life of AKI survivors.

Update on Lean Body Mass Diagnostic Assessment in Critical Illness

Acute critical illnesses can alter vital functions with profound biological, biochemical, metabolic, and functional modifications. Despite etiology, patient's nutritional status is pivotal to guide metabolic support. The assessment of nutritional status remains complex and not completely elucidated. Loss of lean body mass is a clear marker of malnutrition; however, the question of how to investigate it still remains unanswered. Several tools have been implemented to measure lean body mass, including a computed tomography scan, ultrasound, and bioelectrical impedance analysis, although such methods unfortunately require validation. A lack of uniform bedside measurement tools could impact the nutrition outcome. Metabolic assessment, nutritional status, and nutritional risk have a pivotal role in critical care. Therefore, knowledge about the methods used to assess lean body mass in critical illnesses is increasingly required. The aim of the present review is to update the scientific evidence regarding lean body mass diagnostic assessment in critical illness to provide the diagnostic key points for metabolic and nutritional support.

Feasibility and Safety of Active Physiotherapy in the Intensive Care Unit for Intubated Patients with Malignancy

OBJECTIVES

Physiotherapy leads to improvements in critically ill patients who receive mechanical ventilation. However, cancer patients have not been included in previous studies on this subject. This study explored the feasibility and safety of physiotherapy in the intensive care unit for patients with malignancy.

DESIGN

Observational prospective single-centre study, comparing cancer and control patients.

PATIENTS

All consecutive patients admitted to the intensive care unit who needed invasive mechanical ventilation for more than 2 days with no contraindication to physiotherapy were included in the study.

METHODS

The main outcome was the proportion of physiotherapy sessions at the prescribed level in each group.

RESULTS

A total of 60 patients were included within 1 year. A total of 576 days were screened for physiotherapy sessions and 367 physiotherapy-days were analysed (137 days for control patients and 230 days for cancer patients). The ratio of physiotherapy sessions performed/prescribed did not differ between groups: 0.78 (0.47-1) in the control group vs 0.69 (0.6-1) in the cancer group (odds ratio 1.18 (IC95% 0.74-1.89); p = 0.23). A sensitivity analysis including patient effect as random variable confirmed those results (odds ratio 1.16 (0.56-2.38), p = 0.69). Adverse events occurred with the same frequency in cancer patients and non-cancer patients.

CONCLUSION

Physiotherapy in cancer patients who require intubation is feasible and safe. However, only two-thirds of prescribed physiotherapy sessions were performed. Studies are warranted to explore the barriers to physiotherapy in the intensive care unit setting.

Longitudinal relationship between muscle mass and intramuscular adipose tissue of the quadriceps in older inpatients at different activities of daily living levels

BACKGROUND & AIMS

Whether there is a longitudinal relationship between muscle mass and intramuscular adipose tissue of the quadriceps at different activities of daily living (ADL) levels remains unclear. This study aimed to examine the longitudinal relationship between muscle mass and intramuscular adipose tissue of the quadriceps in older inpatients at different ADL levels.

METHODS

This prospective cohort study was hospital-based and included 198 inpatients aged ≥65 years. Ultrasound images were acquired using B-mode ultrasound imaging. Muscle mass and intramuscular adipose tissue of the quadriceps were assessed based on muscle thickness and echo intensity, respectively. The changes in quadriceps thickness and echo intensity were calculated by subtracting these baseline values from these values at discharge. ADL were assessed at admission using the Barthel Index (BI). The participants were divided into the low BI (BI score <60) and high BI (BI score ≥60) groups in accordance with the BI score. Multiple regression analysis was performed to examine whether the change in quadriceps echo intensity was independently and significantly related to change in quadriceps thickness, even after adjusting for confounding factors in the total participants and high and low BI groups.

RESULTS

The number of the high and low BI groups were 54 and 144. Change in quadriceps echo intensity was independently and significantly related to changes in quadriceps thickness of the total participants (β = -0.53, p < 0.01) and low BI (β = - 0.51, p < 0.01) and high BI (β = -0.70, p < 0.01) groups.

CONCLUSIONS

The results of this study indicate that there is a longitudinal negative relationship between muscle mass and intramuscular adipose tissue of the quadriceps in older inpatients regardless of ADL level. Intramuscular adipose tissue may be an important contributing factor for muscle mass.

Incidence of muscle wasting in the critically ill: a prospective observational cohort study

Loss of muscle mass occurs rapidly during critical illness and negatively affects quality of life. The incidence of clinically significant muscle wasting in critically ill patients is unclear. This study aimed to assess the incidence of and identify predictors for clinically significant loss of muscle mass in this patient population. This was a single-center observational study. We used ultrasound to determine the rectus femoris cross-sectional area (RFcsa) on the first and seventh day of ICU stay. The primary outcome was the incidence of significant muscle wasting. We used a logistic regression model to determine significant predictors for muscle wasting. Ultrasound measurements were completed in 104 patients. Sixty-two of these patients (59.6%) showed ≥ 10% decreases in RFcsa. We did not identify any predictor for significant muscle wasting, however, age was of borderline significance (p = 0.0528). The 28-day mortality rate was higher in patients with significant wasting, but this difference was not statistically significant (30.6% versus 16.7%; p = 0.165). Clinically significant muscle wasting was frequent in our cohort of patients. Patient age was identified as a predictor of borderline significance for muscle wasting. The results could be used to plan future studies on this topic.Trial registration: ClinicalTrials.gov NCT03865095, date of registration: 06/03/2019.