Medical Research Council Scale Predicts Spontaneous Breathing Trial Failure and Difficult or Prolonged Weaning of Critically Ill Individuals.

BACKGROUND: Handgrip strength is an alternative measure to assess peripheral muscle strength and is correlated with the Medical Research Council (MRC) scale, with promising values for diagnosing ICU-acquired weakness (ICUAW). Because ICUAW has been associated with delayed weaning from mechanical ventilation, we hypothesized that ICUAW evaluated with both the MRC scale score and handgrip strength are associated with failure of a spontaneous breathing trial (SBT) and duration of mechanical ventilation weaning. METHODS: We conducted a prospective observational study in 3 general ICUs with a total of 54 beds at 2 academic hospitals. Adult subjects with > 48 h of mechanical ventilation who were eligible for weaning were included in the study. RESULTS: In the evaluation before the first SBT, the MRC score (P < .001) and handgrip strength (P < .001) were significantly different between subjects extubated after a successful first SBT (simple weaning) and those extubated any time after a failed first SBT (difficult weaning). Only the MRC score discriminated between first SBT success or failure (P < .001); in multivariate analysis, the MRC score was significantly associated with first SBT failure (odds ratio 0.91, 95% CI 0.88-0.97, P < .001) and difficult weaning (odds ratio 0.91, 95% CI 0.87-0.96, P < .001). Handgrip strength exhibited good accuracy in identifying ICUAW. CONCLUSIONS: MRC score was independently associated with SBT failure and difficult or prolonged weaning.

Comparison of motor strength and function in patients with Duchenne muscular dystrophy with or without steroid therapy / Comparação da força e função motora em pacientes com distrofia muscular de Duchenne com ou sem corticoterapia

OBJECTIVE: To compare muscle strength (MS) and motor function in patients with Duchenne muscular dystrophy (DMD) receiving steroids for different times against the natural evolution of DMD described by Scott et al. METHOD: 90 patients with DMD (aged 5- 12 years), receiving steroids for one to seven years, were evaluated by Medical Research Council Scale (MRC) and Hammersmith motor ability score. The relation between MS and motor abilities measurement from our data and Scott's ones were ascertained statistically. RESULTS: The relation between patient's age and Hammersmith scores revealed decrease of 0.76 point per year for age against decrease of 2.23 points on Scott's study. The relation between MRC scale and patient's age showed decrease of 0.80 point per year of age against decrease of 3.65 points on Scott's study. CONCLUSION: In patients with DMD aged five to 12 years the progression of the disease is delayed by steroids and the motor function is less reduced than muscular strength.

OBJETIVO: Comparar força muscular e função motora de pacientes com distrofia muscular de Duchenne (DMD) em corticoterapia com a evolução natural da doença descrita por Scott et al. MÉTODO: Noventa pacientes, entre 5 e 12 anos de idade, em corticoterapia por um até sete anos, foram avaliados quanto à força muscular (FM) (escala MRC) e função motora (Hammersmith motor ability score). A relação entre idade, FM e função motora e a comparação com o estudo de Scott et al foram determinadas estatisticamente. RESULTADOS: a relação idade/escore Hammersmith diminuiu 0,76 pontos a cada ano de aumento da idade (2,23 pontos na história natural). A relação idade/MRC decresceu 0,80 pontos a cada ano de aumento da idade (3,65 pontos na história natural). CONCLUSÃO: Nos pacientes em corticoterapia, a progressão da doença é mais lenta que na evolução natural em todas as faixas etárias avaliadas, sendo a FM mais comprometida que a função motora.