Skeletal muscle predicts ventilator-free days, ICU-free days, and mortality in elderly ICU patients

Diagnosis of obesity based on body composition-associated health risks-Time for a change in paradigm

Traditional diagnosis and understanding of the pathophysiology of obesity are based on excessive fat storage due to a chronically positive energy balance characterized by body mass index (BMI). Quantitative and qualitative analysis of lean and adipose tissue compartments by body composition analysis reveals that characterization of obesity as "overfat" does not facilitate a comprehensive understanding of obesity-associated health risk. Instead of being related to fat mass, body composition characteristics underlying BMI-associated prognosis may depend (i) on accelerated growth by a gain in lean mass or fat-free mass (FFM) in children with early BMI rebound or adolescents with early puberty; (ii) on a low muscle mass in aging, associated chronic disease, or severe illness; and (iii) on impaired adipose tissue expandability with respect to cardiometabolic risk. It is therefore time to call the adipocentric paradigm of obesity into question and to avoid the use of BMI and body fat percentage. By contrast, obesity should be seen in face of a limited FFM/muscle mass together with a limited capacity of fat storage.

A rapid point-of-care ultrasound marker for muscle mass and muscle strength in older adults

BACKGROUND/OBJECTIVES

Sarcopenia is defined as the gradual age-associated loss of both muscle quantity and strength in older adults, and is associated with increased mortality, falls, fractures and hospitalisations. Current sarcopenia criteria use dual-energy X-ray absorptiometry (DXA) measures of muscle mass, a test that cannot be performed at the bedside, unlike point-of-care ultrasound (PoCUS). We examined the association between ultrasonic measures of muscle thickness (MT, vastus medialis muscle thickness) and measures of muscle quantity and strength in older adults.

METHODS

A total of 150 older adults (age ≥ 65; mean age 80.0 ± 0.5 years, 66 women, 84 men) were recruited sequentially from geriatric medicine clinics. Each subject had lean body mass (LBM, by bioimpedance assay), grip strength, mid-arm biceps circumference (MABC), gait speed and MT measured. All initial models were adjusted for biological sex.

RESULTS

In our final parsimonious models, MT showed a strong significant correlation with all measures of muscle mass, including LBM (Standardised β = 0.204 ± 0.058, R2 = 0.577, P < 0.001) and MABC (Standardised β = 0.141 ± 0.067, R2 = 0.417, P = 0.038). With respect to measures of muscle quality, there was a strong significant correlation with grip strength (Standardised β = 0.118 ± 0.115, R2 = 0.511, P < 0.001) but not with subject performance (gait speed).

CONCLUSIONS

MT showed strong correlations with both measures of muscle mass (LBM and MABC) and with muscle strength (grip strength). Although more work needs to be done, PoCUS shows potential as a screening tool for sarcopenia in older adults.

CT-derived sarcopenia should not preclude surgical stabilization of traumatic rib fractures

BACKGROUND

Rib fractures are associated with considerable morbidity and mortality. Surgical stabilization of rib fractures (SSRF) can be performed to mitigate complications. Sarcopenia is in general known to be associated with poor clinical outcomes. We investigated if sarcopenia impacted number of days of mechanical ventilation, intensive care unit (ICU) stay, and total hospital stay in patients who underwent SSRF.

METHODS

A retrospective single institutional review was performed including patients who underwent SSRF (2009-2017). Skeletal muscle index (SMI) was semiautomatically calculated at the L3 spinal level on computed tomography (CT) images and normalized by patient height. Sarcopenia was defined as SMI < 55 cm²/m² in males and < 39 cm²/m² in females. Demographics, operative details, and postoperative outcomes were reviewed. Univariate and multivariate analyses were performed.

RESULTS

Of 238 patients, 88 (36.9%) had sarcopenia. There was no significant difference in number of days of mechanical ventilation (2.8 ± 4.9 versus 3.1 ± 4.3, p = 0.304), ICU stay (5.9 ± 6.5 versus 4.9 ± 5.7 days, p = 0.146), or total hospital stay (13.3 ± 7.2 versus 12.9 ± 8.2 days, p = 0.183) between sarcopenic and nonsarcopenic patients. Sarcopenic patients demonstrated increased modified frailty index scores (1.5 ± 1.1 versus 0.9 ± 0.9, p < 0.001) compared to nonsarcopenic patients.

CONCLUSIONS

For patients who underwent SSRF for rib fractures, sarcopenia did not increase the number of days of mechanical ventilation, ICU stay, or total hospital stay. Sarcopenia should not preclude the utilization of SSRF in these patients.

Influence of sarcopenia focused on critically ill patients

A systemic review was performed to evaluate the epidemiological, pathophysiological, and clinical features of sarcopenia, the relationship of sarcopenia with critical illness and its impact on mortality, and diagnostic methods and treatment modalities. Generally, in the presence of critical illness, sarcopenia is not included in the treatment approach strategies. An intensivist should be aware that sarcopenia may be present in critically ill patients. Although the main modalities against sarcopenia are early mobilization and nutritional support, they can only prevent its development and may have positive effects on prognosis rather than treating the existing sarcopenia.

Is sarcopenia really a risk factor in the development of postoperative complications?

PURPOSE

This study was aimed to evaluate the impact of sarcopenia, which was defined by total psoas area (TPA) and total psoas volume (TPV) measurements, on the development of major postoperative complications.

MATERIAL-METHODS

Sarcopenia was assessed in 225 patients with gastrointestinal cancer who underwent surgery between October 2015 and March 2020. The impact of sarcopenia defined by TPA and TPV on major postoperative complications was assessed using multivariate analysis.

RESULTS

Both the median TPA and TPV were higher in men than that in women (p < 0.001). The cut-off value of TPA to define sarcopenia was 526.5 mm²/m² and 495.68 mm²/m² for men and women, respectively, and the cut-off value of TPV was 79.6 cm³/m² for men and 83.1 cm³/m² for women, While 102 patients (45.3%) had sarcopenia defined by TPA, 54 (24%) had sarcopenia defined by TPV. Seventy-eight patients had at least one complication; 36 (46%) had major complications, and 15 patients died during the study. In logistic regression analysis, only sex was found as a risk factor for the development of sarcopenia (OR = 13.403, p = 0.014). There was a positive correlation between TPA and TPV in male and female patients separately (r = 0.841 and r = 0.883, respectively, p < 0.001). Only sarcopenia defined by TPV was found as a risk factor for the development of major postoperative complication (OR: 35.349, p = 0.028).

CONCLUSION

Sarcopenia defined by TPV is an independent risk factor in predicting major postoperative complications, not TPA. We believe that volume measurement instead of area is a more accurate method for evaluating sarcopenia in gastrointestinal cancer surgery.

Automated Muscle Measurement on Chest CT Predicts All-Cause Mortality in Older Adults From the National Lung Screening Trial

BACKGROUND

Muscle metrics derived from computed tomography (CT) are associated with adverse health events in older persons, but obtaining these metrics using current methods is not practical for large datasets. We developed a fully automated method for muscle measurement on CT images. This study aimed to determine the relationship between muscle measurements on CT with survival in a large multicenter trial of older adults.

METHOD

The relationship between baseline paraspinous skeletal muscle area (SMA) and skeletal muscle density (SMD) and survival over 6 years was determined in 6,803 men and 4,558 women (baseline age: 60-69 years) in the National Lung Screening Trial (NLST). The automated machine learning pipeline selected appropriate CT series, chose a single image at T12, and segmented left paraspinous muscle, recording cross-sectional area and density. Associations between SMA and SMD with all-cause mortality were determined using sex-stratified Cox proportional hazards models, adjusted for age, race, height, weight, pack-years of smoking, and presence of diabetes, chronic lung disease, cardiovascular disease, and cancer at enrollment.

RESULTS

After a mean 6.44 ± 1.06 years of follow-up, 635 (9.33%) men and 265 (5.81%) women died. In men, higher SMA and SMD were associated with a lower risk of all-cause mortality, in fully adjusted models. A one-unit standard deviation increase was associated with a hazard ratio (HR) = 0.85 (95% confidence interval [CI] = 0.79, 0.91; p < .001) for SMA and HR = 0.91 (95% CI = 0.84, 0.98; p = .012) for SMD. In women, the associations did not reach significance.

CONCLUSION

Higher paraspinous SMA and SMD, automatically derived from CT exams, were associated with better survival in a large multicenter cohort of community-dwelling older men.

Imaging Software-Based Sarcopenia Assessment in Gastroenterology: Evolution and Clinical Meaning

Sarcopenia is gaining attention as a negative prognostic factor in different fields of medicine, including chronic liver failure. However, the assessment of sarcopenia in patients with liver diseases is often neglected due to unawareness of reliable tools and methods and thus is limited to research studies. Cross-sectional imaging is a diffuse diagnostic tool and is commonly performed in patients with chronic liver failure. The last advancements in radiology image analysis using dedicated software allow an easy and standardized method to assess skeletal muscle volume. Several measures can be obtained from cross-sectional imaging analysis to evaluate sarcopenia in patients affected by chronic liver disease. We aimed to review the recent advances in imaging-based sarcopenia assessment, in particular in patients with chronic liver diseases. As a result, we found that the skeletal muscle index (SMI) seems to be a reliable method to assess sarcopenia in cirrhotic patients. Even if further studies are needed to validate proper cut-offs for each clinical endpoint, physicians are invited to consider the assessment of sarcopenia in the work-up of patients with chronic liver disease.

The association between L1 skeletal muscle index derived from routine CT and in-hospital mortality in CAP patients in the ED

INTRODUCTION

Low muscle mass is associated with an increased mortality risk due to medical comorbidities such as chronic obstructive pulmonary disease, cardiovascular disease, and cerebrovascular disease. Computed tomography (CT) has been identified as the gold standard for measuring body composition. We evaluated the relationship between the L1 SMI measured from CT and in-hospital mortality in patients with community-acquired pneumonia (CAP).

METHODS

From January 2015 to June 2015, 311 patients who were diagnosed with CAP and underwent CT in the ED were retrospectively analyzed. Multivariate binary logistic regression analysis was used to assess independent predictors of in-hospital mortality. All variables with a significance level < 0.1 by univariate analysis were included in a multivariate logistic regression model. The primary outcome was all-cause in-hospital mortality.

RESULTS

Among the 311 patients, 33 (10.6%) died. We divided the patients into two groups based on the optimal sex-specific cut-off value of the L1 SMI (45 cm²/m² in males and 40 cm²/m² in females). A low L1 SMI was present in 90 (28.9%) of the 311 patients. In multivariate analysis, low L1 SMI, diabetes mellitus, albumin and APACHE II score were significantly associated with in-hospital mortality (aOR 3.39, 3.73, 0.09 and 1.10, respectively).

CONCLUSION

SMI assessment at L1 is achievable in patients with CAP receiving routine chest CT, and the L1 SMI is associated with high in-hospital mortality, more hospitalizations and ventilator application in patients with CAP in the ED. This could help establish an early strategy for critical care of patients with L1 SMI obtained by chest CT for diagnosis in CAP patients in the ED.

Comparison of Ventilator-free Days at 14 and 28 days as a Clinical Trial Outcome in Low- and Middle-income Countries

Aims and objectives

Reporting ventilator-free days (VFDs) with time frame of 28 days is a popular composite outcome measure (COM) in trials. However, early deaths and shorter pediatric intensive care unit (PICU) stay predominate in low- and middle-income countries (LMICs). A shorter time frame may reduce sample size required. We planned to compute sample size requirements for different effect sizes from datasets of previously conducted prospective studies for 28-day and 14-day time frames (VFD₂₈ vs VFD₁₄) to examine the hypothesis.

Materials and methods

The VFD₂₈ and VFD₁₄ were defined. Datasets of five prospective studies from PICU of our hospital were analyzed to estimate sample sizes for target reductions of 1–9 days in VFDs and other COMs for the two time frames. Reconfirmation of results was done with datasets of two other studies from PICUs of two geographical extremes of the country.

Results

Time-to-event occurred within 14 days in majority of patients. Sample size required for VFD₁₄ is about one-fifth to one-sixth of what is required for VFD₂₈ for target reductions of 1–9 days for all the enrolled studies. The same was true for other COMs as well. The hypothesis was supported by datasets of two other studies used for reconfirmation.

Conclusion

Choice of time frame for assessing VFDs and other COMs in clinical trials should be guided by the clinical context. A shorter time frame may be rewarding in terms of smaller sample size in the prevalent clinical setting of LMICs. Further confirmation with more datasets and prospective studies is desirable.

How to cite this article

Baranwal AK, Kumar MP, Gupta PK. Comparison of Ventilator-free Days at 14 and 28 days as a Clinical Trial Outcome in Low- and Middle-income Countries. Indian J Crit Care Med 2020;24(10):960–966.

Minimum standards of clinical practice for physical therapists working in intensive care units in Japan

OBJECTIVE

Early mobilization and rehabilitation has become common and expectations for physical therapists working in intensive care units have increased in Japan. The objective of this study was to establish consensus-based minimum clinical practice standards for physical therapists working in intensive care units in Japan. It also aimed to make an international comparison of minimum clinical practice standards in this area.

METHODS

In total, 54 experienced physical therapists gave informed consent and participated in this study. A modified Delphi method with questionnaires was used over three rounds. Participants rated 272 items as "essential/unknown/non-essential". Consensus was considered to be reached on items that over 70% of physical therapists rated as "essential" to clinical practice in the intensive care unit.

RESULTS

Of the 272 items in the first round, 188 were deemed essential. In round 2, 11 of the 62 items that failed to reach consensus in round 1 were additionally deemed essential. No item was added to the "essential" consensus in round 3. In total, 199 items were therefore deemed essential as a minimum standard of clinical practice. Participants agreed that 42 items were not essential and failed to reach agreement on 31 others. Identified 199 items were different from those in the UK and Australia due to national laws, cultural and historical backgrounds.

CONCLUSIONS

This is the first study to develop a consensus-based minimum clinical practice standard for physical therapists working in intensive care units in Japan.

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

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

Marked losses of computed tomography-derived skeletal muscle area and density over the first month of a critical illness are not associated with energy and protein delivery

OBJECTIVES

Changes in muscularity during different phases of critical illness are not well described. This retrospective study aimed to describe changes in computed tomography (CT)-derived skeletal muscle area (SMA) and density (SMD) across different weeks of critical illness and investigate associations between changes in these parameters and energy and protein delivery.

METHODS

Thirty-two adults admitted to the intensive care unit (ICU) who had ≥2 CT scans at the third lumbar area performed ≥7 d apart were included in the study. CT-derived SMA (cm²) and SMD (Hounsfield units) were determined using specialized software. A range of clinical and nutrition variables were collected for each day between comparator scans. Associations were assessed by Pearson or Spearman correlations.

RESULTS

There was a significant decrease in SMA between the two comparator scans where the first CT scan was performed in ICU wk 1 (n = 20; P < .001), wk 2 (n = 11; P < .007), and wk 3 to 4 (n = 7; P = .012). There was no significant change in SMA beyond ICU wk 5 to 7 (P = .943). A significant decline in SMD was observed across the first 3 wk of ICU admission (P < .001). Overall, patients received a mean 24 ± 6 kcal energy/kg and 1.1 ± 0.4 g protein/kg per study day and 83% of energy and protein requirements according to dietitian estimates. No association between SMA or SMD changes and nutrition delivery were found.

CONCLUSIONS

Critically ill patients experience marked losses of SMA over the first month of critical illness, attenuated after wk 5 to 7. Energy and protein delivery were not associated with degree of muscle loss.

Prognostic Value of Sarcopenia for Long-Term Mortality in Extracorporeal Membrane Oxygenation for Acute Respiratory Failure

It is unclear whether sarcopenia is responsible for long-term mortality in patients who require extracorporeal membrane oxygenation (ECMO) for acute respiratory failure. We retrospectively reviewed 127 patients who underwent computed tomography imaging before initiating ECMO from June 2014 to November 2017. The patients were divided into two groups according to the skeletal muscle index (SMI): low SMI (n = 47) and high SMI (n = 80). Mean age was lower in the high SMI group than in the low SMI group (60.2 vs. 53.9 years, p = 0.002). Mean body mass index was higher in the high SMI group than in the low SMI group (21.6 vs. 24.1 kg/m, p = 0.001). The mean Charlson comorbidity index (CCI) was lower in the high SMI group than in the low SMI group (3.0 vs. 2.2, p = 0.024). After propensity score matching for age and CCI score, no differences were observed in ECMO weaning success rate or hospital mortality between the two groups. However, the 1 year mortality rate was higher in the low SMI group than in the high SMI group (70.2% vs. 46.8%, p = 0.021). Multivariate analyses showed that renal replacement therapy (odds ratio [OR] 3.99, 95% confidence interval [CI] 1.74-9.13, p = 0.001) and low SMI (OR 5.47, 95% CI 2.31-12.98, p < 0.001) were associated with 1 year mortality. Kaplan-Meier analyses revealed that a low SMI predicted mortality (χ = 13.20, p < 0.001). Sarcopenia predicted worse 1 year mortality in patients who underwent respiratory ECMO.

Establishment of normative biometric data for body composition based on computed tomography in a North American cohort

BACKGROUND & AIMS

Accurate and reproducible biomarkers are required to allow a more personalized approach to patient care. Body composition is one such biomarker affecting outcomes in a range of surgical and oncological conditions. The aim of this study is to determine the age and sex specific distribution of body composition data, based on information gathered from computed tomography (CT).

METHODS

This prospective study used healthy subjects from the medical records linkage of the Rochester Epidemiology Project, based in Minnesota, USA. Each patient had a CT scan without intravenous contrast performed between 1999 and 2001. Quantification was performed using previously validated semi-automated in-house developed software for body composition analysis. Subcutaneous adipose tissue area, visceral adipose tissue area, intermuscular adipose tissue area and skeletal muscle area were measured and indexed to subject height. Generalized Additive Models for Location, Scale and Shape were used to assess the location, scale, and shape of each variable across age, stratified by sex. Z-scores specific to sex were assessed for each of the parameters analyzed. Age-specific z-scores were calculated using the formula: Z = (Index Variable - μ)/σ or Z = (√ (Index Variable) - μ)/σ.

RESULTS

There were 692 subjects enrolled in the study. The fitted model equation was offered for each variable with values presented for μ and σ. Modelling with penalized splines was performed for VAT index, IMAT index and total adipose tissue index. Scatterplots of each variable were produced with lines of Z-scores as a visual representation.

CONCLUSION

This study offers comparative data to allow comparison amongst multiple populations. This will form an important reference for future research and clinical practice.

Nutritional Assessment: A Primary Component of the Multidimensional Geriatric Assessment in the Intensive Care Unit

The importance of evaluating and adjusting the nutritional state of critically ill patients has become a core principle of care. This article focuses on tools for the nutritional assessment of geriatric intensive care unit patients, including a review of imaging and other standardized techniques for evaluation of muscle mass, an indicator of malnutrition and sarcopenia. It concludes with a discussion of the interplay of malnutrition, reduced muscle mass/sarcopenia, and frailty. The goal of this multidimensional assessment is to identify those at risk and thereby initiate interventions to improve outcomes.

Creatinine-Cystatin C Ratio and Mortality in Patients Receiving Intensive Care and Continuous Kidney Replacement Therapy: A Retrospective Cohort Study

RATIONALE & OBJECTIVE

Studies have suggested associations between lower ratios of serum creatinine to cystatin C with both lower muscle mass and adverse clinical outcomes in multiple disease conditions. Identifying risk factors for mortality among patients with acute kidney injury (AKI) undergoing continuous kidney replacement therapy (CKRT) may improve assessment of prognosis. We sought to evaluate the association of creatinine-cystatin C ratio with outcomes in patients with AKI undergoing CKRT.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

1,588 patients treated with intensive care and CKRT for AKI at a tertiary Korean medical center.

PREDICTOR

Baseline serum creatinine-cystatin C ratio at the time of CKRT initiation.

OUTCOMES

Age- and sex-adjusted 90-day mortality after CKRT initiation.

ANALYTICAL APPROACH

Cox proportional hazard models to estimate the association between creatinine-cystatin C ratio and outcome.

RESULTS

Mean age was 64.7 ± 14.5 years and 635 patients (40.0%) were women. The range of creatinine-cystatin C ratios was 0.08 to 10.48. The 30- and 90-day mortality rates were significantly lower for the higher creatinine-cystatin C ratio groups. Multivariable Cox proportional hazards regression analyses revealed that mortality risk became successively lower across quartiles of greater creatinine-cystatin C ratio. When creatinine-cystatin C ratio was evaluated using cubic spline analyses, risks for both 30- and 90-day mortality were lower with higher creatinine-cystatin C ratios. These associations remained significant even after adjustment for confounding variables.

LIMITATIONS

Retrospective analysis, serum creatinine and cystatin C may not be in steady state in the setting of AKI.

CONCLUSIONS

Higher serum creatinine-cystatin C ratios were associated with better survival in patients receiving intensive care and CKRT.

Sarcopenia Aneurysm Scoring System Predicts Early and Midterm Mortality After Endovascular Repair for Abdominal Aortic Aneurysm

OBJECTIVE

The objective of the study was to develop a better model of prediction after EVAR using the psoas muscle index (PMI).

SUMMARY BACKGROUND DATA

The Glasgow Aneurysm Score (GAS), the modified Leiden Score (mLS), the Comorbidity Severity Score (CSS), and the Euro Score (ES) are known prognostic scoring after EVAR. Similarly, sarcopenia measured by PMI has been reported to be an important predictor. This study investigated a new scoring system using PMI predicting short and midterm overall mortality after EVAR.

METHODS

Three hundred ten patients were retrospectively evaluated. The primary endpoint was all-cause death. One hundred three patients were assigned to the derivation cohort and 207 patients to the validation cohort.

RESULTS

The all-cause mortality rates were 8.8% at 1 year, 23.5% at 3 years, and 32.8% at 5 years. In a multivariate analysis, age, aneurysm diameter, eGFR, and PMI were associated with all-cause mortality in the derivation cohort. The SAS system was defined as the sum of the following factors: elderly (75 years), large aneurysm (65 mm), low eGFR (30 mL/min/1.73 m), and low PMI (males: 48.2 cm/m, females: 36.8 cm/m). We compared the SAS with the other prognostic scoring for 5-year mortality evaluating the area under the receiver operating characteristic curves in the validation cohort (GAS: 0.731, mLS: 0. 718, CSS: 0. 646, ES: 0.661, and SAS: 0.785, P = 0.013).

CONCLUSION

We developed the SAS to predict all-cause mortality after elective EVAR and this scoring showed excellent predictive performance.

How does muscularity assessed by bedside methods compare to computed tomography muscle area at intensive care unit admission? A pilot prospective cross-sectional study

BACKGROUND

Low muscularity and malnutrition at intensive care unit (ICU) admission have been associated with negative clinical outcomes. There are limited data available evaluating the validity of bedside techniques to measure muscle mass in critically ill adults. We aimed to compare bedside methods for muscle mass assessment [bioimpedance spectroscopy (BIS), arm anthropometry and subjective physical assessment] against reference technology [computed tomography (CT)] at ICU admission.

METHODS

Adults who had CT scanning at the third lumbar area <72 h after ICU admission were prospectively recruited. Bedside methods were performed within 48 h of the CT scan. Pearson's correlation compared CT muscle area with BIS-derived fat-free mass (FFM) (kg) and FFM-Chamney (kg) (adjusted for overhydration), mid-upper arm circumference (cm) and mid-arm muscle circumference (cm). Depleted muscle stores were determined using published thresholds for each method. Cohen's kappa (κ) was used to evaluate the agreement between bedside and CT assessment of muscularity status (normal or low).

RESULTS

Fifty participants were enrolled. There were strong correlations between CT muscle area and FFM values and mid-arm muscle circumference (P < 0.001). Using FFM-Chamney, all six (100%) participants with low CT muscle area were detected (κ = 0.723). FFM-BIS, arm anthropometry and subjective physical assessment methods detected 28%-38% of participants with low CT muscle area.

CONCLUSIONS

BIS-derived FFM using an adjustment algorithm for overhydration was correlated with CT muscle area and had good agreement with muscularity status assessed by CT image analysis. Arm anthropometry and subjective physical assessment techniques were not able to reliably detect participants with low CT muscle area.

Evaluation of malnutrition via modified GLIM criteria for in patients undergoing emergent gastrointestinal surgery

BACKGROUND

Malnutrition remains a critical public health issue in the US, particularly in surgery where perioperative malnutrition is commonly underdiagnosed and undertreated. In 2016, the Global Leadership Initiative on Malnutrition (GLIM) proposed a set of consensus criteria for the diagnosis of malnutrition. Our project aims to assess the post-operative outcomes of patients meeting a modified GLIM-defined (mGLIM) malnutrition criteria undergoing emergent gastrointestinal surgery (EGS) in the NSQIP database. Current GLIM-criteria were modified with addition of admission albumin (a NSQIP-defined malnutrition variable).

METHODS

Adapting NSQIP data, mGLIM criteria are (1) BMI of ≤20 for age ≤ 70 and BMI ≤22 for age ≥ 71, (2) weight loss > 10% within the past 6 months, (3) admission albumin ≤ 3.5, and (4) emergent bowel surgery as etiologic criteria of acute disease/injury. All patients undergoing emergent small bowel, colon, and rectal procedures were extracted from the NSQIP database and included in the study. Multivariate linear and logistic regression models controlling for relevant covariates were developed to evaluate mGLIM criteria on length of stay (LOS), mortality, and overall complication rates.

RESULTS

We included 31,029 patients who underwent emergent bowel surgeries from years 2011-2016. Demographically, 53.6% (n = 16,622) were female, 13.0% (n = 4023) were African American, and 78.3% (n = 24,292) were Caucasian. Case composition included 71.5% colon operations, 28.0% small bowel, and 0.5% rectal cases. Overall, 1.7% (n = 517) had data necessary to qualify as malnourished as per mGLIM. Controlling for covariates, multivariate linear and logistic regression analyses show that these patients have significantly higher mortality for both colon (p < 0.001, CI 1.55 | 2.61) and small bowel (p = 0.022, CI 1.08 | 2.67) procedures, longer LOS for colon (p < 0.001, CI 1.93 | 4.33) operations, and higher post-operative complications for both colon (p < 0.001, CI 1.61 | 2.62) and small bowel (p < 0.001, CI 1.57 | 3.37) cases.

CONCLUSION

This analysis shows that mGLIM criteria malnutrition is associated with poor clinical outcomes following EGS affecting LOS and mortality. Our data indicates the new mGLIM criteria can be a powerful and simple predictive score for malnutrition that can be used to predict malnutrition-related risk of poor outcomes after EGS.

Ultrasonography and Other Nutrition Assessment Methods to Monitor the Nutrition Status of Critically Ill Patients

BACKGROUND

This study aims to evaluate the use of ultrasonography (US) as an instrument to assess the quadriceps muscles in patients admitted to intensive care units (ICUs), comparing the evolution of US-assessed mass muscle to other nutrition methods.

METHODS

We conducted a prospective observational study of adult patients aged ≥18 years admitted to an ICU of the Hospital das Clínicas in Brazil. Quadriceps muscle measurements were performed by US, and adductor pollicis muscle thickness and arm, calf, and thigh circumferences were measured at admission and every 2 days within the first week. Nutrition status was assessed at baseline by using the Subjective Global Assessment and the Global Leadership Initiative on Malnutrition criteria. Mechanical ventilation time, length of hospital and ICU stay, and mortality were recorded.

RESULTS

Sixty patients were included. Reductions in quadriceps thickness and rectus femoris cross-sectional area were observed at landmarks two-thirds reduction of both measurements from days 1 and 3 to days 5 and 7 (P = .017 and P = .000, respectively). The mid arm circumference (MAC) was reduced. Malnourished patients had lower initial muscle mass. However, muscle mass loss was similar between nourished and malnourished individuals (P > .005). Clinical outcomes were not impacted by muscle loss.

CONCLUSIONS

US muscle mass assessment was able to detect short-term changes in critically ill patients but must be used with caution. MAC was also identified as a useful follow-up tool.

A pilot study examining the use of ultrasound to measure sarcopenia, frailty and fall in older patients

INTRODUCTION

The importance of this study is to devise an efficient tool for assessing frailty in the ED. The goals of this study are 1) to correlate ultrasonographic (US) measurements of muscle thickness in older ED patients with frailty and 2) to correlate US-measured sarcopenia with falls, subsequent hospitalizations and ED revisits.

METHODS

Participants were conveniently sampled from a single ED in this prospective cohort pilot study of patients aged 65 or older. Participants completed a Fatigue, Resistance, Ambulation, Illness and Loss of Weight (FRAIL) scale assessment and US measurements of their upper arm muscles, quadricep muscles, and abdominal wall muscles thickness. We conducted one-month follow-up phone calls to assess for falls, ED revisits, and subsequent hospital visits.

RESULTS

We enrolled 43 patients (mean age of 78.5). Ultrasound measurements of the three muscle groups were not significantly different between frail and non-frail groups. Frail participants had greater bicep asymmetry (a difference of 0.47 cm vs 0.24 cm, p < .01). A predictive logistic regression model using average quadriceps thickness and biceps asymmetry was found to identify frail patients (AUC of 0.816). Participants with subsequent falls had smaller quadriceps (1.18 cm smaller, p < .01). Subsequently hospitalized patients were found to have smaller quadriceps muscles (0.54 cm smaller, p = .03) and abdominal wall muscles (0.25 cm smaller, p = .01).

CONCLUSION

US measurements of sarcopenia in older patients had mild to moderate associations with frailty, falls and subsequent hospitalizations. Further investigation is needed to confirm these findings.

Skeletal Muscle Composition Predicts Outcome in Critically Ill Patients

Supplemental Digital Content is available in the text.

Parameters of patients’ body composition have been suggested as prognostic markers in several clinical conditions including cancer and liver transplantation, but only limited data on its value in critical illness exist to date. In this study, we aimed at evaluating a potential prognostic value of the skeletal muscle mass and skeletal muscle myosteatosis of critically ill patients at admission to the ICU.

Low Skeletal Muscle Index Adjusted for Body Mass Index Is an Independent Risk Factor for Inflammatory Bowel Disease Surgical Complications

Background

This study aims to evaluate sarcopenia defined by skeletal muscle index (SMI) with cutoffs adjusted for sex and body mass index as a predictive marker for postoperative outcomes among individuals with inflammatory bowel disease.

Methods

The SMI was measured using the cross-sectional computed tomography images at the lumbar spine. Multivariate logistic regression was performed to identify independent risk factors of postoperative complications.

Results

Ninety-one patients were included in the study. In multivariate analysis, sarcopenia (odds ratio = 5.37; confidence interval: 1.04-27.6) was predictive of infectious postoperative complications.

Conclusions

Sarcopenia as defined by the SMI is a predictor for 30-day postoperative infection complications in inflammatory bowel disease surgeries.

The clinical relevance and mechanism of skeletal muscle wasting

Skeletal muscle wasting occurs in both chronic and acute diseases. Increasing evidence has shown this debilitating process is associated with short- and long-term outcomes in critical, cancer and surgical patients. Both muscle quantity and quality, as reflected by the area and density of a given range of attenuation in CT scan, impact the patient prognosis. In addition, ultrasound and bioelectrical impedance analysis (BIA) are also widely used in the assessment of body composition due to their bedside viability and no radioactivity. Mechanism researches have revealed complicated pathways are involved in muscle wasting, which include altered IGF1-Akt-FoxO signaling, elevated levels of myostatin and activin A, activation of NF-κB pathway and glucocorticoid effects. Particularly, central nervous system (CNS) has been proven to participate in regulating muscle wasting in various conditions, such as infection and tumor. Several promising therapeutic agents have been under developing in the treatment of muscle atrophy, such as myostatin antagonist, ghrelin analog, non-steroidal selective androgen receptor modulators (SARMs). Notably, nutritional therapy is still the fundamental support in combating muscle wasting. However, the optimizing and tailored nutrition regimen relies on accurate metabolism measurement and large clinical trials in the future. Here, we will discuss the current understanding of muscle wasting and potential treatment in clinical practice.

Ultrasound Measurement of Septic Shock-induced Acute Skeletal Muscle Atrophy in Intensive Care Unit

BACKGROUND

Skeletal muscle wasting progresses rapidly during critical care. However, the effect of skeletal muscle changes on physical function during intensive care remain poorly understood.

OBJECTIVE

To examine the changes in skeletal muscle thickness of patients admitted to the intensive care unit (ICU) for septic shock and the relationship between skeletal muscle thickness and physical function following intensive care.

DESIGN

Longitudinal observational study.

SETTING

Single emergency hospital.

PATIENTS

Ten septic shock patients who were mechanically ventilated in the ICU were recruited.

INTERVENTIONS

Not applicable.

METHODS

Ultrasound measurements of thickness of rectus femoris (RF) were conducted within 24 hours after admission and repeated every two days until the 14th hospital day. The correlations between TRF and various parametric data (i.e., age, severity classification, mechanically ventilated period, length of stay (LOS) at the ICU, and physical function) correlations were assessed with Pearson's product moment coefficient of correlation.

MAIN OUTCOME MEASURE(S)

Curve estimation for best fit for chronological changes in TRF with respect to the HD and the correlation between TRF and clinical indicators.

RESULTS

Eight septic shock patients were observed completely for 14 days. TRF decreased linearly by 30.6% (IQR: 23.9-45.7) during the first 14 days. The correlation between TRF at admission and physical function at the 30th hospital day was close to significant. The TRF at the 14th hospital day was negatively correlated with disease severity and age. A positive correlation was observed between the decrease in rate of TRF and LOS at the ICU.

CONCLUSION

Skeletal muscle thickness of septic shock patients rapidly decreased in a linear manner over 14 days and may predict physical function after critical care.

Sonographic muscle mass assessment in patients after cardiac surgery

BACKGROUND

Patients undergoing cardiac surgery particularly those with comorbidities and frailty, experience frequently higher rates of post-operative morbidity, mortality and prolonged hospital length of stay. Muscle mass wasting seems to play important role in prolonged mechanical ventilation (MV) and consequently in intensive care unit (ICU) and hospital stay.

AIM

To investigate the clinical value of skeletal muscle mass assessed by ultrasound early after cardiac surgery in terms of duration of MV and ICU length of stay.

METHODS

In this observational study, we enrolled consecutively all patients, following their admission in the Cardiac Surgery ICU within 24 h of cardiac surgery. Bedside ultrasound scans, for the assessment of quadriceps muscle thickness, were performed at baseline and every 48 h for seven days or until ICU discharge. Muscle strength was also evaluated in parallel, using the Medical Research Council (MRC) scale.

RESULTS

Of the total 221 patients enrolled, ultrasound scans and muscle strength assessment were finally performed in 165 patients (patients excluded if ICU stay < 24 h). The muscle thickness of rectus femoris (RF), was slightly decreased by 2.2% [(95% confidence interval (CI): - 0.21 to 0.15), n = 9; P = 0.729] and the combined muscle thickness of the vastus intermedius (VI) and RF decreased by 3.5% [(95%CI: - 0.4 to 0.22), n = 9; P = 0.530]. Patients whose combined VI and RF muscle thickness was below the recorded median values (2.5 cm) on day 1 (n = 80), stayed longer in the ICU (47 ± 74 h vs 28 ± 45 h, P = 0.02) and remained mechanically ventilated more (17 ± 9 h vs 14 ± 9 h, P = 0.05). Moreover, patients with MRC score ≤ 48 on day 3 (n = 7), required prolonged MV support compared to patients with MRC score ≥ 49 (n = 33), (44 ± 14 h vs 19 ± 9 h, P = 0.006) and had a longer duration of extracorporeal circulation was (159 ± 91 min vs 112 ± 71 min, P = 0.025).

CONCLUSION

Skeletal quadriceps muscle thickness assessed by ultrasound shows a trend to a decrease in patients after cardiac surgery post-ICU admission and is associated with prolonged duration of MV and ICU length of stay.

Quantifying Response to Nutrition Therapy During Critical Illness: Implications for Clinical Practice and Research? A Narrative Review

Critical illness causes substantial muscle loss that adversely impacts recovery and health-related quality of life. Treatments are therefore needed that reduce mortality and/or improve the quality of survivorship. The purpose of this Review is to describe both patient-centered and surrogate outcomes that quantify responses to nutrition therapy in critically ill patients. The use of these outcomes in randomized clinical trials will be described and the strengths and limitations of these outcomes detailed. Outcomes used to quantify the response of nutrition therapy must have a plausible mechanistic relationship to nutrition therapy and either be an accepted measure for the quality of survivorship or highly likely to lead to improvements in survivorship. This Review identified that previous trials have utilized diverse outcomes. The variety of outcomes observed is probably due to a lack of consensus as to the most appropriate surrogate outcomes to quantify response to nutrition therapy during research or clinical practice. Recent studies have used, with some success, measures of muscle mass to evaluate and monitor nutrition interventions administered to critically ill patients.

Computed Tomography-Measured Psoas Muscle Density as a Predictive Factor for Hypophosphatemia Associated With Refeeding

BACKGROUND

Initiation of parenteral nutrition (PN) after a period of starvation can be complicated by refeeding syndrome (RFS). RFS is associated with electrolyte abnormalities including hypomagnesemia, hyponatremia, and hypophosphatemia. Risk factors include recent weight loss, low body mass index, and electrolyte deficiencies; however, these associations are not strong. We hypothesized that a validated measure of nutrition risk, computed tomography (CT)-measured psoas muscle density, can be used to predict the development of hypophosphatemia associated with RFS.

METHODS

A retrospective analysis of surgical patients initiated on PN with an abdominal CT scan within the past 3 months was conducted. CT-measured psoas muscle density was assessed as a predictive variable for the development of electrolyte abnormalities. Daily electrolyte and clinical outcome measures were recorded.

RESULTS

One hundred nine patients were stratified based on Hounsfield unit average calculation (HUAC). The lowest 25th percentile of patients had HUAC <25. Low HUAC was associated with a significant percent decrease in phosphate levels from baseline to PN day 3 (P < .01) and significant difference in serum phosphate value on PN day 3 (P < .01). The low muscle density quartile also experienced longer days on the mechanical ventilator (P = .01) compared with patients with a higher psoas muscle density.

CONCLUSION

Psoas muscle density predicted the development of hypophosphatemia in patients initiated on PN. This measurement may aid in identifying patients at highest risk of experiencing RFS. A mean psoas HU <25 may prompt additional precautions, including additional phosphate replacement and slower initiation of PN.

Advanced Skeletal Muscle Mass Reduction (Sarcopenia) Secondary to Neuromuscular Disease

We describe a young male patient chronically on a ventilator secondary to decreased mobility from amyotrophic lateral sclerosis (ALS). He had both a tracheostomy for breathing and percutaneous endoscopic gastrostomy (PEG) for feeding. Using 24-hour urinary creatinine excretion data, we calculated an estimate of skeletal muscle (SM) mass. SM mass was indexed to height and weight to obtain the SM index. The SM index is used as a determinant to define sarcopenia. From the data, we found that this patient had the smallest SM index ever recorded at 2.2 kg/m², consistent with extremely advanced sarcopenia. As a comparison, "severe" sarcopenia in a male is defined as a SM index ≤ 8.5 kg/m². This method can be used in ICU patients to evaluate for sarcopenia which is a predictive marker for mortality.

The impact of frailty in major trauma in older patients

As our population ages and increasing numbers of older patients experience major trauma it is important to understand factors that influence outcomes in this patient cohort. The aim of this study is to assess the impact of frailty in older patients who experience major trauma (Injury Severity Score (ISS) greater than 15). A retrospective cohort review using the national trauma registry data (Trauma Audit and Research Network) and an institutional database was carried out on all patients aged 60 years or older with an ISS> 15 who were treated at the regional Major Trauma Centre from 2014 to 2017 following major trauma. Frailty was assessed using the modified frailty index (mFI). Outcomes assessed included mortality, complications, hospital stay, functional outcome and discharge destination. 819 patients were included in the study. The most common mechanism of injury was fall from a height less than 2m (57.4%). 412 (51.3%) patients had a low frailty score, 280 (35%) had an intermediate frailty score and 110 (14%) had high frailty score. Increased frailty was associated with increased mortality at discharge (18.7%, 14.6% and 26.4% for low, intermediate and high frailty groups) and at one year (26.2%, 35.2% and 51%, respectively). Other predictors of mortality included male sex, age >90 years and the occurrence of a serious complication. Increasing frailty was also associated with an increased risk of serious complications including unplanned intubation, infection and progressive renal failure, and discharge to a destination other than home. This is the first study that has delineated the impact of frailty in older patients who experience major trauma and provides important information for patients, their families and healthcare providers. Future studies should focus on identifying care pathways that counteract the impact of frailty in this setting.

Muscle Mass Loss in the Older Critically Ill Population: Potential Therapeutic Strategies

Skeletal muscle plays a critical role in everyday life, and its age-associated reduction has severe health consequences. The pre-existing presence of sarcopenia, combined with anabolic resistance, protein undernutrition, and the pro-catabolic/anti-anabolic milieu induced by aging and exacerbated in critical care, may accelerate the rate at which skeletal muscle is lost in patients with critical illness. Advancements in intensive care unit (ICU)-care provision have drastically improved survival rates; therefore, attention can be redirected toward other significant issues affecting ICU patients (e.g., length of stay, days on ventilation, nosocomial disease development, etc.). Thus, strategies targeting muscle mass and function losses within an ICU setting are essential to improve patient-related outcomes. Notably, loading exercise and protein provision are the most compelling. Many older ICU patients seldom meet the recommended protein intake, and loading exercise is difficult to conduct in the ICU. Nevertheless, the incorporation of physical therapy (PT), neuromuscular electrical stimulation, and early mobilization strategies may be beneficial. Furthermore, a number of nutrition practices within the ICU have been shown to improve patient-related outcomes ((e.g., feeding strategy [i.e., oral, early enteral, or parenteral]), be hypocaloric (∼70%-80% energy requirements), and increase protein provision (∼1.2-2.5 g/kg/d)). The aim of this brief review is to discuss the dysregulation of muscle mass maintenance in an older ICU population and highlight the potential benefits of strategic nutrition practice, specifically protein, and PT within the ICU. Finally, we provide some general guidelines that may serve to counteract muscle mass loss in patients with critical illness.

Approaches to Assessment of Muscle Mass and Myosteatosis on Computed Tomography: A Systematic Review

BACKGROUND/OBJECTIVE

There is increasing use of computed tomography (CT) in sarcopenia research using a wide variety of techniques. We performed a systematic review of the CT literature to identify the differences between approaches used.

METHODS

A comprehensive search of PubMed from 1983 to 2017 was performed to identify studies that used CT muscle measurements to assess muscle mass and myosteatosis. The CT protocols were evaluated based on anatomic landmark(s), thresholding, muscle(s) segmented, key measurement (ie, muscle attenuation, cross-sectional area, volume), derived variables, and analysis software. From the described search, 657 articles were identified and 388 studies met inclusion criteria for this systematic review.

RESULTS

Muscle mass was more commonly assessed than myosteatosis (330 vs. 125). The most commonly assessed muscle or muscle groups were total abdominal wall musculature (142/330 and 49/125 for muscle mass and myosteatosis, respectively) and total thigh musculature (90/330 and 48/125). The most commonly used landmark in the abdomen was the L3 vertebra (123/142 and 45/49 for muscle mass and myosteatosis, respectively). Skeletal muscle index and intermuscular adipose tissue were the most commonly used measures of abdominal wall muscle mass (114/142) and myosteatosis (27/49), respectively. Cut points varied across studies. A significant majority of studies failed to report important CT technical parameters, such as use of intravenous contrast and slice thickness (94% and 63%, respectively).

CONCLUSIONS

There is considerable variation in the CT approaches used for the assessment of muscle mass and myosteatosis. There is a need to develop consensus for CT-based evaluation of sarcopenia and myosteatosis.

Muscle mass gain is positively associated with functional recovery in patients with sarcopenia after stroke

OBJECTIVE

Intervention for treating sarcopenia is of great concern in clinical settings. The aim of this study was to investigate the relationship between changes in skeletal muscle mass and functional outcomes in patients with sarcopenia after stroke.

METHODS

A retrospective cohort study of stroke patients with sarcopenia consecutively admitted to a single center's convalescent rehabilitation wards was conducted from 2015 to 2018. Sarcopenia was defined as a loss of skeletal muscle mass index (SMI) with bioelectrical impedance and decreased muscle strength as measured by handgrip strength; cut-off values were adopted from the 2019 Asian Working Group for Sarcopenia. Changes in SMI during hospitalization were measured. Outcomes included the motor domain of Functional Independence Measure at discharge and its gain. Multivariate analysis determined whether the changes in SMI were associated with these outcomes.

RESULTS

During the study period, 272 stroke patients were enrolled. Of those, 120 patients (44%) (mean age 79 years, 70 females) were diagnosed with sarcopenia. The mean (SD) for changes in SMI was 0.2 (0.5) kg/m². Multiple linear regression analysis showed that changes in SMI were significantly associated with Functional Independence Measure - motor at discharge (β=0.175, P=0.003) and Functional Independence Measure - motor gain (β=0.247, P=0.003).

CONCLUSIONS

Muscle mass gain may be positively associated with functional recovery in patients with sarcopenia after stroke. Exercise and nutritional therapy to increase skeletal muscle mass, in addition to conventional stroke rehabilitation, is needed for these patients.

A retrospective observational study of sarcopenia and outcomes in critically ill patients

Frailty assessment in patients admitted to intensive care is often limited using traditional clinical frailty assessment tools. Opportunistic use of contemporary computed tomography (CT) can provide an objective estimate of low skeletal muscle mass (sarcopenia) as a proxy for frailty. The aim of this study was to establish the prevalence of sarcopenia in an Australian intensive care unit (ICU) population and to examine the relationship between sarcopenia and clinical outcomes. We undertook a single centre retrospective study of 1085 adult patients admitted to a single ICU over 12 months. Patients with a contemporary CT scan including the L3 vertebral body were included. Patients were categorised as sarcopenic or non-sarcopenic using previously published data. A total of 279 patients with a mean age of 67 years had an eligible CT scan; 163 (58%) were male. Higher 30-day mortality was associated with the use of CRRT (continuous renal replacement therapy) during the ICU admission (OR 6.84, P < 0.001) and also associated with lower cross-sectional muscle area (odds ratio (OR) 0.98, P = 0.004). Sarcopenia was found to be highly prevalent in this particular Australian ICU population (68%) and associated with older age (68 versus 55 years, P < 0.001), lower body mass index (27 versus 32 kg m-2, P < 0.001), more comorbidities (3 versus 2, P = 0.009), and longer stays in hospital (279 versus 223 h, P = 0.043). As a continuous predictor, lumbar muscle mass was associated with 30-day mortality with and without adjusting for other covariates.

Opportunistic Measurement of Skeletal Muscle Size and Muscle Attenuation on Computed Tomography Predicts 1-Year Mortality in Medicare Patients

BACKGROUND

Opportunistic assessment of sarcopenia on CT examinations is becoming increasingly common. This study aimed to determine relationships between CT-measured skeletal muscle size and attenuation with 1-year risk of mortality in older adults enrolled in a Medicare Shared Savings Program (MSSP).

METHODS

Relationships between skeletal muscle metrics and all-cause mortality were determined in 436 participants (52% women, mean age 75 years) who had abdominopelvic CT examinations. On CT images, skeletal muscles were segmented at the level of L3 using two methods: (a) all muscles with a threshold of -29 to +150 Hounsfield units (HU), using a dedicated segmentation software, (b) left psoas muscle using a free-hand region of interest tool on a clinical workstation. Muscle cross-sectional area (CSA) and muscle attenuation were measured. Cox regression models were fit to determine the associations between muscle metrics and mortality, adjusting for age, sex, race, smoking status, cancer diagnosis, and Charlson comorbidity index.

RESULTS

Within 1 year of follow-up, 20.6% (90/436) participants died. In the fully-adjusted model, higher muscle index and muscle attenuation were associated with lower risk of mortality. A one-unit standard deviation (SD) increase was associated with a HR = 0.69 (95% CI = 0.49, 0.96; p = .03) for total muscle index, HR = 0.67 (95% CI = 0.49, 0.90; p < .01) for psoas muscle index, HR = 0.54 (95% CI = 0.40, 0.74; p < .01) for total muscle attenuation, and HR = 0.79 (95% CI = 0.66, 0.95; p = .01) for psoas muscle attenuation.

CONCLUSION

In older adults, higher skeletal muscle index and muscle attenuation on abdominopelvic CT examinations were associated with better survival, after adjusting for multiple risk factors.

Comparison of Ultrasound-Derived Muscle Thickness With Computed Tomography Muscle Cross-Sectional Area on Admission to the Intensive Care Unit: A Pilot Cross-Sectional Study

INTRODUCTION

The development of bedside methods to assess muscularity is an essential critical care nutrition research priority. We aimed to compare ultrasound-derived muscle thickness at 5 landmarks with computed tomography (CT) muscle area at intensive care unit (ICU) admission. Secondary aims were to (1) combine muscle thicknesses and baseline covariates to evaluate correlation with CT muscle area and (2) assess the ability of the best-performing ultrasound model to identify patients with low CT muscle area.

METHODS

Adult patients who underwent CT scanning at the third lumbar area <72 hours after ICU admission were prospectively recruited. Muscle thickness was measured at mid-upper arm, forearm, abdomen, and thighs. Low CT muscle area was determined using published cutoffs. Pearson correlation compared ultrasound-derived muscle thickness and CT muscle area. Linear regression was used to develop ultrasound prediction models. Bland-Altman analyses compared ultrasound-predicted and CT-measured muscle area.

RESULTS

Fifty ICU patients were enrolled, aged 52 ± 20 years. Ultrasound-derived muscle thickness at each landmark correlated with CT muscle area (P < .001). The sum of muscle thickness at mid-upper arm and bilateral thighs, including age, sex, and the Charlson Comorbidity Index, improved the correlation with CT muscle area (r = 0.85; P < .001). Mean difference between ultrasound-predicted and CT-measured muscle area was -2 cm² (95% limits of agreement, -40 cm² to +36 cm² ). The best-performing ultrasound model demonstrated good ability to identify 14 patients with low CT muscle area (area under curve = 0.79).

CONCLUSION

Ultrasound shows potential for assessing muscularity at ICU admission (Clinicaltrials.gov NCT03019913).

A retrospective analysis of associations between BMI and days spent on mechanical ventilation in a level 1 trauma facility

OBJECTIVE

To examine whether BMI impacts the outcomes of mechanically ventilated patients.

METHODS

Data was collected retrospectively among patients involved in motor vehicle accidents in intensive care at a major trauma center in Atlanta, GA. Patients were categorized into five BMI groups: underweight (BMI < 18.5), normal weight (BMI of 18.5-24.9), overweight (BMI of 25-29.9), obese (BMI of 30-39.9), and morbidly obese (BMI of >40).

RESULTS

Among all patients (n=2,802), 3% of patients were underweight, 34% were of normal weight, 30% were overweight, 27% were obese, and 6% were morbidly obese. The mean number of ventilator days for normal weight patients was 4.6, whereas the mean number of ventilator days for underweight and morbidly obese patients were higher (10.3 and 7.4, respectively).

CONCLUSIONS

Underweight and morbidly obese populations may require additional interventions during their ICU stays to address the challenges presented by having an unhealthy BMI.

Reference Values for Skeletal Muscle Mass - Current Concepts and Methodological Considerations

Assessment of a low skeletal muscle mass (SM) is important for diagnosis of ageing and disease-associated sarcopenia and is hindered by heterogeneous methods and terminologies that lead to differences in diagnostic criteria among studies and even among consensus definitions. The aim of this review was to analyze and summarize previously published cut-offs for SM applied in clinical and research settings and to facilitate comparison of results between studies. Multiple published reference values for discrepant parameters of SM were identified from 64 studies and the underlying methodological assumptions and limitations are compared including different concepts for normalization of SM for body size and fat mass (FM). Single computed tomography or magnetic resonance imaging images and appendicular lean soft tissue by dual X-ray absorptiometry (DXA) or bioelectrical impedance analysis (BIA) are taken as a valid substitute of total SM because they show a high correlation with results from whole body imaging in cross-sectional and longitudinal analyses. However, the random error of these methods limits the applicability of these substitutes in the assessment of individual cases and together with the systematic error limits the accurate detection of changes in SM. Adverse effects of obesity on muscle quality and function may lead to an underestimation of sarcopenia in obesity and may justify normalization of SM for FM. In conclusion, results for SM can only be compared with reference values using the same method, BIA- or DXA-device and an appropriate reference population. Limitations of proxies for total SM as well as normalization of SM for FM are important content-related issues that need to be considered in longitudinal studies, populations with obesity or older subjects.

Psoas Muscle Area Measured with Computed Tomography at Admission to Intensive Care Unit: Prediction of In-Hospital Mortality in Patients with Pulmonary Embolism

Aim

Sarcopenia, a core component of physical frailty, is an independent risk factor for suboptimal health outcomes in hospitalized patients, especially in the intensive care patients. Psoas muscle areas can be assessed to identify sarcopenia. The aim of this study was to determine the prognostic value of psoas muscle area measured with CT for the prediction of in-hospital mortality in patients with pulmonary embolism at admission to the intensive care unit.

Methods

Patients with an admission abdominal computed tomography scan and requiring intensive care unit (ICU) stay were reviewed. Selected clinical data of patients admitted to intensive care unit for the management of pulmonary embolism were collected. Using CT scan images at the level of L3 vertebra, the psoas muscle area value was obtained by dividing the sum of the right and left psoas muscle areas into the body surface area.

Results

In-hospital mortality rate was 22.5% in 89 patients. The pulmonary embolism patients with in-hospital mortality had higher PESI and lower value of psoas muscle area, in addition to the lower systolic blood pressure and arterial oxygen saturation at admission. The increase in the value of psoas muscle area is associated with a decrease in the rate of in-hospital mortality. In patients with in-hospital mortality related to pulmonary embolism, the higher PESI and the lower value of psoas muscle area were considered in accordance with the outcome of patients.

Conclusions

For the prediction of in-hospital mortality risk in patients with pulmonary embolism managed in intensive care unit, the psoas muscle area value has a merit to be used among the routine diagnostic procedures after further studies conducted with different severity of pulmonary embolism.

The psoas muscle index as a predictor of mortality and morbidity of geriatric trauma patients: experience of a major trauma center in Kobe

PURPOSE

An association between the prognoses of trauma and sarcopenia has not been well documented. The purpose of this study was to compare the outcomes of elderly Japanese trauma patients with sarcopenia and those without sarcopenia.

METHODS

The medical records of patients aged ≧ 65 years old and Injury Severity Scores above 15 treated for trauma between 2010 and 2017 were reviewed, retrospectively. We measured the psoas muscle index (PMI), defined as the psoas muscle area at the third lumbar vertebra level divided by the body surface area. Patients of each gender with a PMI less than the lower interquartile range were included in the sarcopenia group. A questionnaire was mailed to the patients or their families to collect data on 1-year mortality and activities of daily living.

RESULTS

There were 405 patients included in this study: 304 in the non-sarcopenia group (Group NS) and 101 in the sarcopenia group (Group S). Mortality was significantly higher in Group S than in Group NS (NS; 7.9% vs. S; 15.8%, OR, 2.20; 95% CI, 1.12-4.32; p = 0.027). Only 175 of the questionnaires were completed and the responses did not reveal any significant differences between the groups.

CONCLUSIONS

Sarcopenia as defined by the PMI may be used as an indicator for mortality risk for geriatric trauma patients.

Protein Requirements in Critical Illness: Do We Really Know Why to Give So Much?

The protein and energy requirements of critically ill patients treated in intensive care units (ICUs) have been actively discussed recently. Currently published clinical recommendations and reviews suggest significant increases of protein provision to 2-2.5 g/kg/d in some populations of ICU patients. However, a detailed analysis of the main sources of these recommendations reveals a number of serious contradictions, as well as an absence of obvious evidence supporting the allotment of high doses of protein. We went through these recommendations and reviewed cited articles and other studies, and we have separated our arguments against excessive protein provision into sections.

Association of Low Baseline Diaphragm Muscle Mass With Prolonged Mechanical Ventilation and Mortality Among Critically Ill Adults

Importance

Low diaphragm muscle mass at the outset of mechanical ventilation may predispose critically ill patients to poor clinical outcomes.

Objective

To determine whether lower baseline diaphragm thickness (Tdi) is associated with delayed liberation from mechanical ventilation and complications of acute respiratory failure (reintubation, tracheostomy, prolonged ventilation >14 days, or death in the hospital).

Design, Setting, and Participants

Secondary analysis (July 2018 to June 2019) of a prospective cohort study (data collected May 2013 to January 2016). Participants were 193 critically ill adult patients receiving invasive mechanical ventilation at 3 intensive care units in Toronto, Ontario, Canada.

Exposures

Diaphragm thickness was measured by ultrasonography within 36 hours of intubation and then daily. Patients were classified as having low or high diaphragm muscle mass according to the median baseline Tdi.

Main Outcomes and Measures

The primary outcome was time to liberation from ventilation accounting for the competing risk of death and adjusting for age, body mass index, severity of illness, sepsis, change in Tdi during ventilation, baseline comorbidity, and study center. Secondary outcomes included in-hospital death and complications of acute respiratory failure.

Results

A total of 193 patients were available for analysis; the mean (SD) age was 60 (15) years, 73 (38%) were female, and the median (interquartile range) Sequential Organ Failure Assessment score was 10 (8-13). Median (interquartile range) baseline Tdi was 2.3 (2.0-2.7) mm. In the primary prespecified analysis, baseline Tdi of 2.3 mm or less was associated with delayed liberation from mechanical ventilation (adjusted hazard ratio for liberation, 0.51; 95% CI, 0.36-0.74). Lower baseline Tdi was associated a higher risk of complications of acute respiratory failure (adjusted odds ratio, 1.77; 95% CI, 1.20-2.61 per 0.5-mm decrement) and prolonged weaning (adjusted odds ratio, 2.30; 95% CI, 1.42-3.74). Lower baseline Tdi was also associated with a higher risk of in-hospital death (adjusted odds ratio, 1.47; 95% CI, 1.00-2.16 per 0.5-mm decrement), particularly after discharge from the intensive care unit (adjusted odds ratio, 2.68; 95% CI, 1.35-5.32 per 0.5-mm decrement).

Conclusions and Relevance

In this study, low baseline diaphragm muscle mass in critically ill patients was associated with prolonged mechanical ventilation, complications of acute respiratory failure, and an increased risk of death in the hospital.

Automated body composition analysis of clinically acquired computed tomography scans using neural networks

BACKGROUND & AIMS

The quantity and quality of skeletal muscle and adipose tissue is an important prognostic factor for clinical outcomes across several illnesses. Clinically acquired computed tomography (CT) scans are commonly used for quantification of body composition, but manual analysis is laborious and costly. The primary aim of this study was to develop an automated body composition analysis framework using CT scans.

METHODS

CT scans of the 3rd lumbar vertebrae from critically ill, liver cirrhosis, pancreatic cancer, and clear cell renal cell carcinoma patients, as well as renal and liver donors, were manually analyzed for body composition. Ninety percent of scans were used for developing and validating a neural network for the automated segmentation of skeletal muscle and adipose tissues. Network accuracy was evaluated with the remaining 10 percent of scans using the Dice similarity coefficient (DSC), which quantifies the overlap (0 = no overlap, 1 = perfect overlap) between human and automated segmentations.

RESULTS

Of the 893 patients, 44% were female, with a mean (±SD) age and body mass index of 52.7 (±15.8) years old and 28.0 (±6.1) kg/m², respectively. In the testing cohort (n = 89), DSC scores indicated excellent agreement between human and network-predicted segmentations for skeletal muscle (0.983 ± 0.013), and intermuscular (0.900 ± 0.034), visceral (0.979 ± 0.019), and subcutaneous (0.986 ± 0.016) adipose tissue. Network segmentation took ~350 milliseconds/scan using modern computing hardware.

CONCLUSIONS

Our network displayed excellent ability to analyze diverse body composition phenotypes and clinical cohorts, which will create feasible opportunities to advance our capacity to predict health outcomes in clinical populations.

Comparing the performance of SOFA, TPA combined with SOFA and APACHE-II for predicting ICU mortality in critically ill surgical patients: A secondary analysis

INTRODUCTION

Total psoas muscle area (TPA) can indicate the status of the entire human body's skeletal muscle mass. It has been reported that lower TPA can increase the risk of mortality in critically ill patients. The aim of our study was to evaluate the relationship between TPA and ICU mortality and to compare the performance of Sequential Organ Failure Assessment (SOFA), TPA combined with SOFA and Acute Physiology, Chronic Health Evaluation (APACHE-II) for predicting ICU mortality in critically ill surgical patients.

METHODS

This study was a retrospective observational cohort study with a total of 96 critically ill surgical patients, ages 21-96 years old. Main outcome measures included difficult-to-wean (DTW), operation methods, ICU mortality, ICU stay, APACHE II, sepsis and SOFA. CT-scan assessed the TPA. It is acknowledged that the entire study was completed by Hao-Wei Kou et al. and the data were uploaded from plosone.com. The authors used this data only for secondary analysis.

RESULTS

The results showed that TPA is a protective factor for ICU mortality (OR: 0.99 95% [0.99, 1.00], P = 0.0269). In addition, when we defined sarcopenia-based TPA, our study showed that sarcopenia increased the risk of ICU mortality (OR:3.73 (1.27, 10.98) P = 0.0167. Furthermore, discrimination of ICU mortality was significantly higher using SOFA (AUROC, 0.7810 [99% CI, 0.6658-0.8962]) than either TPA (AUROC, 0.7023 [99% CI, 0.5552-0.8494]) or APACHE II score (AUROC, 0.7447 [99% CI, 0.6289-0.8604]). Additionally, when we combined TPA with SOFA score, the ROC of TPA + SOFA (AUROC, 0.8647 [99% CI, 0.7881-0.9412]) was the highest when compared to the other three models.

CONCLUSION

The relationship between TPA and ICU mortality is negative in critically ill surgical patients. In addition, the combination of TPA and SOFA was the best tool among the three scoring systems in providing significant discriminative ability when predicting ICU mortality in critically ill surgical patients.

Getting to grips with sarcopenia: recent advances and practical management for the gastroenterologist

Sarcopenia is a progressive and generalised disorder of skeletal muscle strength, function and mass, that is most commonly associated with the normal ageing process. It is increasingly recognised that sarcopenia can also develop as a consequence of malabsorptive and inflammatory conditions, such as those seen by gastroenterologists and hepatologists. It affects 1%-30% of the general population, but is seen in approximately 40% of patients with gastrointestinal conditions including inflammatory bowel disease and cirrhosis. Within this group of patients, it is associated with increased complications and mortality. The pathogenesis of sarcopenia is multifactorial with several risk factors implicated in its development including undernutrition, physical inactivity and coexistent multimorbidity. The SARC-F questionnaire has been developed to screen for patients at risk of sarcopenia, however, this focuses on the functional consequences and will therefore not identify those patients who are early in the progression of sarcopenia. There are several different non-invasive techniques available to assess muscle quantity and quality including; grip strength, dual energy X-ray absorptiometry, CT which can be used together to diagnose sarcopenia. Assessment and correction of malnutrition, particularly protein intake, in those at risk of sarcopenia is important in preventing the development and progression of sarcopenia. There are no specific drugs that are available for the treatment of sarcopenia, however, resistance exercise programmes combined with nutritional interventions show promise. It is important that this common condition is screened for and recognised, with any contributing factors addressed to reduce the risk of its progression.

The immense heterogeneity of frailty in neurosurgery: a systematic literature review

The aim of this study was to review and analyze the neurosurgery body of literature to document the current knowledge of frailty within neurosurgery, standardizing terminology and how frailty is defined, including the different levels of frailty, while determining what conclusions can be drawn about frailty's impact on neurosurgical outcomes. While multiple studies on frailty in neurosurgery exist, no literature reviews have been conducted. Therefore, we performed a literature review in order to organize, tabulate, and present findings from the data to broaden the understanding about what we know from frailty and neurosurgery. We performed a PubMed search to identify studies that evaluated frailty and neurosurgery. The terms "frail," "frailty," "neurosurgery," "spine surgery," "craniotomy," and "neurological surgery" were all used in the query. We then organized, analyzed, and summarized the comprehensive frailty and neurosurgical literature. The literature contained 25 published studies analyzing frailty in neurosurgery between December 2015 and December 2018. Five of these studies were cranial neurosurgical studies, the remaining studies focused on spinal neurosurgery. Over 100,000 surgical cases were analyzed among the 25 studies. Of these, 18 studies demonstrated that increasing frailty was associated with increased rate of complications, 10 studies showed that frailty was associated with higher mortality rates, 11 studies demonstrated an association between frailty and increased hospital length of stay, and 5 studies noted that higher frailty was associated with discharge to a higher level of care. The current body of literature repeatedly demonstrates that frailty is associated with worse outcomes across the neurosurgical subspecialties.