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

Abstract

Background Muscle ultrasound represents a promising approach to aid diagnoses of neuromuscular diseases in critically ill patients. Unfortunately, standardization of ultrasound measurements in clinical research is lacking, making direct comparisons between studies difficult. Protocols are required to assess qualitative muscle changes during an ICU stay in patients at high risk for the development of neuromuscular acquired weakness (ICUAW). Methods We conducted a retrospective, observational analysis comprised of three prospective observational studies with the aim of diagnosing muscle changes by ultrasound measurement of the quadriceps muscle. Different protocols were used in each of the three studies. In total, 62 surgical, neurocritical care and trauma intensive care patients were serially assessed by different ultrasound protocols during the first week of critical illness. The relative change in ultrasound measurements was calculated for all possible locations, methods and sides. Comparison was obtained using mixed effect models with the location, the height and the side as influencing variables and patients as fixed effect. The relationship between variables and outcomes was assessed by multivariable regression analysis. Results Ultrasound methods and measurement sites of the quadriceps muscles from all protocols were equally effective in detecting muscle changes. During the first week of an ICU stay, two groups were identified: patients with decreased muscle mass on ultrasound (n = 42) and a cohort with enlargement (n = 23). Hospital mortality was significantly increased in the cohort with muscle swelling (8 (19%) versus 12 (52%), p = .013). Conclusions Different approaches of ultrasound measurement during critical-illness are equally able to detect muscle changes. While some patients have a decrease in muscle mass, others show swelling, which may result in a reduced probability of surviving the hospital stay. Causative reasons for these results still remain unclear.

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“…44 A retrospective, observational analysis comprising three prospective observational studies evaluated muscle changes by US measurement of the quadriceps muscle by different protocols used in each of the studies. 45 A total of 62 patients (surgical, neurocritical care, and trauma intensive care) were serially assessed by different US protocols during the first week of critical illness. The relative change in US measurements was calculated for all possible locations, methods, and sides.…”

“…Whereas some patients have a decrease in muscle mass, others show swelling, which may result in a reduced probability of surviving the hospital stay. 45 In a single-center study in 35 critically ill patients, Fetterplace et al 46 compared paired assessments, within a 72-h window, of muscle mass by US (quadriceps muscle layer thickness [QMLT] in centimeters, with maximal and minimal pressure) and CT axial crosssectional area (cm 2 ). The main results were that US assessment of the quadriceps muscle using maximal pressure reasonably predicted the skeletal muscle at the third lumbar vertebra level of critically ill patients.…”

“…Moreover, the availability of US devices and appropriate training of medical staff in measuring skeletal muscle mass using sonography are further determinants for the implementation in routine clinical practice. 45,47 Current recommendations and latest evidence on protein dosing in MNT Adequate protein supply within an energy-balanced MNT is of particular importance in the critical care setting to stimulate muscle protein synthesis, reduce muscle protein breakdown, and limit amino acid oxidation after disease-related alterations in substrate utilization and metabolism. 48 Besides targeted medication and exercise, protein intake higher than the amount…”

“…The authors concluded that different approaches of US measurement during critical illness are equally able to detect muscle changes. Whereas some patients have a decrease in muscle mass, others show swelling, which may result in a reduced probability of surviving the hospital stay 45 …”

“…International, standardized protocols are required to assess qualitative muscle changes during the ICU stay of patients at high risk for developing neuromuscular acquired weakness (ICUAW), also taking into account method‐inherent limitations (eg, reliability may be affected by the fluid status and position of the patients when performing measurements). Moreover, the availability of US devices and appropriate training of medical staff in measuring skeletal muscle mass using sonography are further determinants for the implementation in routine clinical practice 45,47 …”