Sensitivity and responsiveness of the medical research council dyspnoea scale to the presence and treatment of adult laryngotracheal stenosis

Objectives: To assess the sensitivity and responsiveness of the Medical Research Council (MRC) scale, a psychophysical dyspnoea assessment instrument to the presence and treatment of adult laryngotracheal stenosis. Design: Prospective observational study. Settings: Tertiary/National referral airway reconstruction centre. Participants: Fourty tracheostomy-free patients undergoing endoscopic airway examination/laryngotracheoplasty. Main outcome measures: Demographic and clinical information, obtained from patient records, lesion severity, which was recorded intraoperatively, standard spirometry, which was measured preoperatively, and the MRC dyspnoea scale, which was administered preoperatively and at the first outpatient visit 4-6 weeks later. Results: There were 16 males and 24 females. Mean age at presentation was 44 +/- 14 years (+/- SD). Postintubation stenosis was the commonest aetiology (73%) followed by idiopathic subglottic stenosis and Wegener's Granulomatosis. Six patients were examined post-treatment and had minimal residual stenosis and the remaining patients had glottic stenosis (n = 11) or Myer-Cotton Grade I (n = 8), II (n = 7) or III (n = 8) tracheal stenoses. Pre-treatment MRC dyspnoea scores and the degree of change in the MRC score following treatment strongly correlated with pre-treatment stenosis severity (r = 0.75 and r = -0.71 respectively; P < .001). Moreover statistically significant correlations existed between preoperative peak expiratory flow and forced expiratory volume in 1 s and preoperative MRC dyspnoea scores (r = -0.34 and r = -0.35 respectively; P < 0.05). Discussion: Exertional dyspnoea is the hallmark symptom of laryngotracheal stenosis and for many patients it is the primary cause of disability. These findings confirm that the MRC dyspnoea scale is an appropriate outcome instrument for assessing dyspnoea associated with this condition.