RT Journal Article
SR Electronic
T1 Muscle Impairment in Neuromuscular Disease Using an Expiratory/Inspiratory Ratio
JF Respiratory Care
FD American Association for Respiratory Care
SP respcare.03367
DO 10.4187/respcare.03367
A1 Guilherme Fregonezi
A1 Ingrid G Azevedo
A1 Vanessa R Resqueti
A1 Arméle D De Andrade
A1 Lucien P Gualdi
A1 Andrea Aliverti
A1 Mário ET Dourado-Junior
A1 Veroônica F Parreira
YR 2015
UL http://rc.rcjournal.com/content/early/2015/01/13/respcare.03367.abstract
AB BACKGROUND: Neuromuscular diseases (NMDs) lead to different weakness patterns, and most patients with NMDs develop respiratory failure. Inspiratory and expiratory muscle strength can be measured by maximum static inspiratory pressure (PImax) and maximum static expiratory pressure (PEmax), and the relationship between them has not been well described in healthy subjects and subjects with NMDs. Our aim was to assess expiratory/inspiratory muscle strength in NMDs and healthy subjects and calculate PEmax/PImax ratio for these groups. METHODS: Seventy (35 males) subjects with NMDs (amyotrophic lateral sclerosis, myasthenia gravis, and myotonic dystrophy), and 93 (47 males) healthy individuals 20 – 80 y of age were evaluated for anthropometry, pulmonary function, PImax, and PEmax, respectively. RESULTS: Healthy individuals showed greater values for PImax and PEmax when compared with subjects with NMDs. PEmax/PImax ratio for healthy subjects was 1.31 ± 0.26, and PEmax%/PImax% was 1.04 ± 0.05; for subjects with NMDs, PEmax/PImax ratio was 1.45 ± 0.65, and PEmax%/PImax% ratio was 1.42 ± 0.67. We found that PEmax%/PImax% for myotonic dystrophy was 0.93 ± 0.24, for myasthenia gravis 1.94 ± 0.6, and for amyotrophic lateral sclerosis 1.33 ± 0.62 when we analyzed them separately. All healthy individuals showed higher PEmax compared with PImax. For subjects with NMDs, the impairment of PEmax and PImax is different among the 3 pathologies studied (P < .001). CONCLUSIONS: Healthy individuals and subjects with NMDs showed higher PEmax in comparison to PImax regarding the PEmax/PImax ratio. Based on the ratio, it is possible to state that NMDs show different patterns of respiratory muscle strength loss. PEmax/PImax ratio is a useful parameter to assess the impairment of respiratory muscles in a patient and to customize rehabilitation and treatment.