title: The interobserver agreement of handheld dynamometry for muscle strength assessment in critically ill patients.
abstract: OBJECTIVE
  Muscle weakness often complicates critical illness and is associated with increased risk of morbidity, mortality, and limiting functional outcome even years later. To assess the presence of muscle weakness and to examine the effects of interventions, objective and reliable muscle strength measurements are required. The first objective of this study is to determine interobserver reliability of handheld dynamometry. Secondary objectives are to quantify muscle weakness, to evaluate distribution of muscle weakness, and to evaluate gender-related differences in muscle strength.
  
  
  METHODS
  Cross-sectional observational study.
  
  
  METHODS
  The surgical and medical intensive care units of a large, tertiary referral, university hospital.
  
  
  METHODS
  A cross-sectional, randomly selected sample of awake and cooperative critically ill patients.
  
  
  METHODS
  None.
  
  
  RESULTS
  Handheld dynamometry was performed in critically ill patients who had at least a score of 3 (movement against gravity) on the Medical Research Council scale. Three upper limb and three lower limb muscle groups were tested at the right-hand side. Patients were tested twice daily by two independent raters. Fifty-one test-retests were performed in 39 critically ill patients. Handheld dynamometry demonstrated good interobserver agreement with intraclass correlation coefficients >0.90 in four of the muscle groups tested (range, 0.91-0.96) and somewhat less for hip flexion (intraclass correlation coefficient, 0.80) and ankle dorsiflexion (intraclass correlation coefficient, 0.76). Limb muscle strength was considerably reduced in all muscle groups as shown by the median z-score (range, -1.08 to -3.48 sd units). Elbow flexors, knee extensors, and ankle dorsiflexors were the most affected muscle groups. Loss of muscle strength was comparable between men and women.
  
  
  CONCLUSIONS
  Handheld dynamometry is a tool with a very good interobserver reliability to assess limb muscle strength in awake and cooperative critically ill patients. Future studies should focus on the sensitivity of handheld dynamometry in longitudinal studies to evaluate predictive values toward patients' functional outcome.
authors.affiliation: Department of Rehabilitation Sciences, University Hospitals Leuven, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: Goele
authors.initials: G
authors.lastname: Vanpee
authors.forename: Johan
authors.initials: J
authors.lastname: Segers
authors.forename: Helena
authors.initials: H
authors.lastname: Van Mechelen
authors.forename: Pieter
authors.initials: P
authors.lastname: Wouters
authors.forename: Greet
authors.initials: G
authors.lastname: Van den Berghe
authors.forename: Greet
authors.initials: G
authors.lastname: Hermans
authors.forename: Rik
authors.initials: R
authors.lastname: Gosselink
mesh_terms: D000328:Adult; D000368:Aged; D001530:Belgium; D003422:Critical Care / Q000379:methods*; D016638:Critical Illness / Q000628:therapy; D003430:Cross-Sectional Studies; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007362:Intensive Care Units; D035002:Lower Extremity; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D018908:Muscle Weakness; D015588:Observer Variation; D018579:Patient Selection; D019095:Point-of-Care Systems; D012307:Risk Factors; D034941:Upper Extremity