PT - JOURNAL ARTICLE AU - Pierantonio Laveneziana AU - Gilles Garcia AU - Marc Humbert AU - Christian Straus AU - Thomas Similowski TI - Exertional dyspnoea, dynamic hyperinflation and respiratory muscle function in idiopathic pulmonary arterial hypertension (PAHi) DP - 2014 Sep 01 TA - European Respiratory Journal PG - P4890 VI - 44 IP - Suppl 58 4099 - http://erj.ersjournals.com/content/44/Suppl_58/P4890.short 4100 - http://erj.ersjournals.com/content/44/Suppl_58/P4890.full SO - Eur Respir J2014 Sep 01; 44 AB - Despite the absence of spirometric obstruction, PAHi patients may exhibit a reduction in inspiratory capacity (IC) during exercise which could contribute to increased exertional dyspnoea. Whether the reduced IC is related to reduced expiratory flows in tidal operating range or to overt inspiratory muscle dysfunction is unknown. The aim of the current study was to examine the relationships between inspiratory muscle function, change in IC and the intensity of dyspnoea in PAHi patients during symptom-limited incremental cardiopulmonary cycle exercise test (CPET).Maximal inspiratory sniff pressure (Poessniff), Poes changes during IC manoeuvers (PoesIC), IC and dyspnoea intensity (Borg scale) were obtained during CPET in 10 non-smokers PAHi patients.IC decreased progressively throughout CPET in 5 PAHi (average 0.50L, PAH-hyperinflators), whereas it increased in the remainder (average 0.40L, PAHi-non-hyperinflators). No differences in anthropometric and spirometric variables were found between the two groups.Poessniff was not significantly different before and after CPET or between the two groups. PoesIC did not change significantly during exercise within and between the two groups. Despite similarities in Poes-derived measurements, dyspnoea intensity was greater in PAHi-hyperinflators during exercise compared with PAHi-non-hyperinflators.Inspiratory muscle function was similar and preserved in both groups despite greater changes (reduction) in IC during exercise in PAHi-hyperinflators. The reduction of IC during exercise was independent of inspiratory muscle function and contributed to the greater exertional dyspnoea intensity in PAHi-hyperinflators.