Respiratory muscle strength and cough capacity in patients with Duchenne muscular dystrophy.
The function of inspiratory muscles is crucial for effective cough as well as expiratory muscles in patients with Duchenne muscular dystrophy (DMD). However, there is no report on the correlation between cough and inspiratory muscle strength. To investigate the relationships of voluntary cough capacity, assisted cough techniques, and inspiratory muscle strength as well as expiratory muscle strength in patients with DMD (n= 32). The vital capacity (VC), maximum insufflation capacity (MIC), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) were measured. Unassisted peak cough flow (UPCF) and three different techniques of assisted PCF were evaluated. The mean value of MICs (1918 +/- 586 mL) was higher than that of VCs (1474 +/- 632 mL) (p < 0.001). All three assisted cough methods showed significantly higher value than unassisted method (212 +/- 52 L/min) (F = 66.13, p < 0.001). Combined assisted cough technique (both manual and volume assisted PCF; 286 +/- 41 L/min) significantly exceeded manual assisted PCF (MPCF; 246 +/- 49 L/ min) and volume assisted PCF (VPCF; 252 +/- 45 L/min) (F = 66.13, p < 0.001). MIP (34 +/- 13 cmH2O) correlated significantly with both UPCF and all three assisted PCFs as well as MEP (27 +/- 10 cmH2O) (p < 0.001). Both MEP and MIP, which are the markers of respiratory muscle weakness, should be taken into account in the study of cough effectiveness.
Kang
Seong-Woong
SW
Department of Physical Medicine and Rehabilitation, Yongdong Severance Hospital, Yonsei University College of Medicine, 146-92 Dogok-dong, Kangnam-gu, Seoul 135-720, Korea. kswoong@yumc.yonsei.ac.kr
Kang
Yeoun-Seung
YS
Sohn
Hong-Seok
HS
Park
Jung-Hyun
JH
Moon
Jae-Ho
JH
D000293:Adolescent; D000328:Adult; D001706:Biopsy; D003371:Cough; D006801:Humans; D007320:Inspiratory Capacity; D008297:Male; D015233:Models, Statistical; D018908:Muscle Weakness / Q000473:pathology; D009132:Muscles / Q000473:pathology; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics*; D010101:Oxygen Consumption; D011312:Pressure; D012132:Respiratory Muscles / Q000473:pathology*