Abstract
Diagnosing pediatric intensive care unit–acquired weakness (PICU-AW) is challenging.
The Medical Research Council (MRC) score is a widely used screening method for muscle
weakness in critically ill adults; however, its utility in critically ill children
has not been established. Our objective was to determine the feasibility and interobserver
reliability of muscle strength testing using MRC score in critically ill children.
A prospective observational substudy of critically ill children aged 1 to 17 years
and limited to bed rest during the first 48 hours of PICU admission was evaluated
with weekly MRC exams independently performed by two clinical raters. MRC exams were
attempted on all 33 participants, but could be completed in only 21 (64%), 9 of who
(43%) received at least one exam while in the PICU, and in the remaining 12 (57%),
MRC exams could only be completed after PICU discharge. Of the 95 attempted MRC exams,
55 (57%) could not be conducted or completed, most commonly due to patient sedation,
and inability to comply due to cognitive ability, pain, or noncooperation. The inter-rater
reliability for MRC sum score was excellent (intraclass correlation coefficient: 0.87).
However, the inter-rater reliability was only moderate when used to determine PICU-AW
(Cohen kappa: 0.48). MRC testing in the PICU was not feasible as an early screening
tool for muscle weakness in the majority of critically ill children in this study.
Further research is needed to find an appropriate screening tool that is both feasible
and predicts clinically relevant outcomes in children, such as function and recovery
following critical illness.
Keywords
pediatrics - critical illness - muscle strength testing - muscle weakness - neuromuscular
disorder - reliability