Journal CME, February 2022: Inter-rater Reliability of Quantitative Ultrasound Measures of Muscle in Critically Ill Patients-Inter-rater Reliability article

Inter-rater Reliability article - pdf

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This article discusses the interrater reliability and feasibility of using quantitative ultrasound to measure muscle parameters in critically ill patients. The study was conducted by researchers from the University of Pennsylvania, Weill Cornell Medical Center, Oregon Health Sciences University, and the University of Washington. They aimed to validate the reliability of ultrasound measurements of muscle thickness and cross-sectional area in the ICU setting, which poses unique challenges due to equipment, patient positioning, and other factors.<br /><br />The study involved 15 critically ill patients. A standardized protocol was used to measure elbow flexor, knee extensor, and tibialis anterior muscle depth, as well as the cross-sectional area of the rectus femoris. Two different investigators performed the measurements independently to assess interrater reliability. The results showed good to excellent reliability, with intraclass correlation coefficients (ICCs) between 0.87 and 0.99. The feasibility of obtaining these measurements ranged from 75% to 100%, depending on the site.<br /><br />Feasibility was primarily affected by the patients' body habitus, with limitations observed in morbidly obese participants. The study found that a summary index combining multiple measures of muscle depth provided even higher reliability (ICC of 0.99).<br /><br />The importance of this study lies in establishing a reliable and non-invasive method to assess muscle pathology and atrophy in critically ill patients. This could potentially aid in early diagnosis and monitoring of conditions like critical illness myopathy and polyneuropathy, which are significant sources of morbidity and mortality. The study concludes that, when using a standardized protocol, ultrasound is a reliable and feasible method for these measurements in the ICU, though body habitus can be a limiting factor.

Keywords

interrater reliability

quantitative ultrasound

muscle parameters

critically ill patients

ICU

muscle thickness

cross-sectional area

intraclass correlation coefficients

feasibility

critical illness myopathy