Computed Tomography Evidence of Psoas Muscle Atrophy Without Concomitant Tendon Wasting in Early Sepsis

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

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

Sepsis-Associated Muscle Wasting: A Comprehensive Review from Bench to Bedside

Sepsis-associated muscle wasting (SAMW) is characterized by decreased muscle mass, reduced muscle fiber size, and decreased muscle strength, resulting in persistent physical disability accompanied by sepsis. Systemic inflammatory cytokines are the main cause of SAMW, which occurs in 40-70% of patients with sepsis. The pathways associated with the ubiquitin-proteasome and autophagy systems are particularly activated in the muscle tissues during sepsis and may lead to muscle wasting. Additionally, expression of muscle atrophy-related genes Atrogin-1 and MuRF-1 are seemingly increased via the ubiquitin-proteasome pathway. In clinical settings, electrical muscular stimulation, physiotherapy, early mobilization, and nutritional support are used for patients with sepsis to prevent or treat SAMW. However, there are no pharmacological treatments for SAMW, and the underlying mechanisms are still unknown. Therefore, research is urgently required in this field.

Ultrasound Versus Computed Tomography for Diaphragmatic Thickness and Skeletal Muscle Index during Mechanical Ventilation

Background: Diaphragmatic alterations occurring during mechanical ventilation (MV) can be monitored using ultrasound (US). The performance of computed tomography (CT) to evaluate diaphragmatic thickness is limited. Further, the association between muscle mass and outcome is increasingly recognized. However, no data are available on its correlation with diaphragmatic thickness. We aimed to determine correlation and agreement of diaphragmatic thickness between CT and US; and its association with muscle mass and MV parameters. Methods: Prospective observational study. US measurements of the diaphragmatic thickness were collected in patients undergoing MV within 12 h before or after performing a CT scan of the thorax and/or upper abdomen. Data on skeletal muscle index (SMI), baseline, and ventilatory data were recorded and correlated with US and CT measures of diaphragmatic thickness. Agreement was explored between US and CT data. Results: Twenty-nine patients were enrolled and the diaphragm measured by CT resulted overall thicker than US-based measurement of the right hemidiaphragm. The US thickness showed the strongest correlation with the left posterior pillar at CT (r = 0.49, p = 0.008). The duration of the controlled MV was negatively correlated with US thickness (r = -0.45, p = 0.017), the thickness of the right anterior pillar (r = -0.41, p = 0.029), and splenic dome by CT (r = -0.43, p = 0.023). SMI was positively correlated with US diaphragmatic thickness (r = 0.50, p = 0.007) and inversely correlated with the duration of MV before enrollment (r = -0.426, p = 0.027). Conclusions: CT scan of the left posterior pillar can estimate diaphragmatic thickness and is moderately correlated with US measurements. Both techniques show that diaphragm thickness decreases with MV duration. The diaphragmatic thickness by US showed a good correlation with SMI.

Evaluation of the effect of high protein supply on diaphragm atrophy in critically ill patients receiving prolonged mechanical ventilation

BACKGROUND

Our aim was to evaluate the effect of high protein to the target of 2.0 g/kg/d on diaphragm atrophy and clinical prognosis of patients receiving prolonged mechanical ventilation (MV).

METHODS

This prospective, randomized, controlled, single-center study included 41 patients who were treated with ≥7 days' MV. The patients were randomly divided into a standard nutrition treatment (SNT) group and intensive nutrition treatment (INT) group, followed by evaluation of computer tomography-analyzed diaphragm volume, the level of butyrylcholinesterase (BChE) as a muscle mass indicator, and respiratory mechanics indices weekly to observe and compare the differences between the groups.

RESULTS

In the INT group, the actual protein (1.70 ± 0.21 vs 1.06 ± 0.21 g/kg/d, P < .001) and calorie intake (33.46 ± 2.78 vs 25.75 ± 4.81 kcal/kg/d, P < .001) were significantly different from those of the SNT group. Compared with the SNT group, the INT group's diaphragm atrophy improved in the fourth and fifth weeks (all P < .05). The BChE after the third week was higher (all P < .05). No significant differences in respiratory mechanical indices and clinical outcomes were found in the surviving patients between the groups.

CONCLUSION

INT improved the diaphragm atrophy and muscle mass of critically ill patients receiving prolonged MV. There was no evidence that increasing protein to the target amount of 2.0 g/kg/d is related to improvement in clinical prognosis for patients receiving prolonged MV.

Assessment of muscle mass in critically ill patients: role of the sarcopenia index and images studies

PURPOSE OF REVIEW

Sarcopenia is a progressive generalized decline in skeletal muscle mass, strength, and function. This condition is highly prevalent in critically ill patients and is associated with poor outcomes in the ICU. In this review, we describe the use, evidence, and limitations of the most common validated imaging studies used to assess muscle mass in ICU, and we provide an overview of the benefits of using the sarcopenia index [(serum creatinine/serum cystatin C) × 100]) in the ICU.

RECENT FINDINGS

Currently, the determination of muscle mass using anthropometric measurements and serum biomarkers is unreliable. Several new techniques, including a dual-energy X-ray absorptiometry, computed tomography scan, ultrasonography, and bioimpedance analysis, have been studied and validated for the diagnosis and prognosis of sarcopenia in the ICU. However, these techniques are often not accessible for the majority of critically ill patients. The sarcopenia index constitutes an accurate method to diagnose sarcopenia, predict ICU outcomes, and nutritional status in critically ill patients.

SUMMARY

Diagnosis of sarcopenia has substantial implications in ICU patients. Choosing the correct test to identify patients who may need preventive or therapeutic support for this condition will favorably impact ICU outcomes.

Skeletal Muscle Index at Intensive Care Unit Admission Is a Predictor of Intensive Care Unit-Acquired Weakness in Patients With Sepsis

Background

Intensive care unit-acquired weakness (ICU-AW) can be diagnosed using the Medical Research Council (MRC) score. However, such scoring may not be possible in ICU patients who may be sedated or delirious or have encephalopathy. Currently, a quantitative assessment of the cross-sectional area of the muscle is available to assess changes in skeletal muscle mass using computed tomography (CT) images. This assessment calculates the skeletal muscle index (SMI) (cm²/m²) by dividing the cross-sectional area (cm²) of the skeletal muscle at the level of the third lumbar vertebra by the square of the patient’s height (m²) on CT. This study assessed the effectiveness of SMI, as measured by abdominal CT scans, in predicting the onset of ICU-AW in patients with sepsis admitted to the ICU.

Methods

We examined septic ICU patients admitted to the Niigata University Hospital ICU during 2012 - 2017 under mechanical ventilation. Patients were retrospectively divided into two groups by MRC score at ICU discharge: group AW comprised patients with an MRC score < 48, and group non-AW (NAW) comprised the remaining patients. Clinicopathological factors at ICU admission such as age, gender, underlying disease, body mass index, and SMI were compared between the two groups. Statistical analyses were performed using the Mann-Whitney U test, Fisher’s exact test, receiver operator characteristic (ROC) analysis and multivariate analysis.

Results

A total of 31 septic patients were examined, and 23 patients met the criteria for ICU-AW. The prevalence of women was significantly higher in group AW (P < 0.05). All clinical factors, except for gender, were not significantly different between the two groups. SMI was significantly lower in group AW than in group NAW (P < 0.05). ROC analysis revealed that the cut-off value of SMI for predicting ICU-AW was 44.1, and the multivariate analysis revealed that only low SMI was a significant factor in predicting ICU-AW (P < 0.05).

Conclusions

Our results show that SMI measurement at ICU admission is a valid predictive factor for ICU-AW progression in septic patients.