Diaphragmatic function in advanced Duchenne muscular dystrophy.
The aim of this study was to assess diaphragm electrical activation and diaphragm strength in patients with advanced Duchenne muscular dystrophy during resting conditions. Eight patients with advanced Duchenne muscular dystrophy (age of 25 +/- 2 years) were studied during tidal breathing, maximal inspiratory capacity, maximal sniff inhalations, and magnetic stimulation of the phrenic nerves. Six patients were prescribed home mechanical ventilation (five non-invasive and one tracheotomy). Transdiaphragmatic pressure and diaphragm electrical activation were measured using an esophageal catheter. During tidal breathing (tidal volume 198 +/- 83 ml, breathing frequency 25 +/- 7), inspiratory diaphragm electrical activation was clearly detectable in seven out of eight patients and was 12 +/- 7 times above the noise level, and represented 45 +/- 19% of the maximum diaphragm electrical activation. Mean inspiratory transdiaphragmatic pressure during tidal breathing was 1.5 +/- 1.2 cmH2O, and during maximal sniff was 7.6 +/- 3.6 cmH2O. Twitch transdiaphragmatic pressure deflections could not be detected. This study shows that despite near complete loss of diaphragm strength in advanced Duchenne muscular dystrophy, diaphragm electrical activation measured with an esophageal electrode array remains clearly detectable in all but one patient.
Department of Newborn and Developmental Pediatrics, Sunnybrook and Women's College Health Sciences Center, Women's College Compus, No. 440-76 Grenville Street, Toronto, Ont., Canada M5S 1B2. jennifer.beck@sw.ca
Jennifer
J
Beck
Jan
J
Weinberg
Carl-Hugo
CH
Hamnegård
Jadranka
J
Spahija
Jan
J
Olofson
Gunnar
G
Grimby
Christer
C
Sinderby
D000200:Action Potentials / Q000502:physiology / Q000528:radiation effects; D000328:Adult; D003964:Diaphragm / Q000503:physiopathology*; D055590:Electromagnetic Phenomena / Q000379:methods; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology; D020388:Muscular Dystrophy, Duchenne / Q000473:pathology / Q000503:physiopathology*; D010791:Phrenic Nerve / Q000503:physiopathology / Q000528:radiation effects; D012119:Respiration; D012129:Respiratory Function Tests / Q000379:methods; D012132:Respiratory Muscles / Q000503:physiopathology; D013997:Time Factors; D014109:Total Lung Capacity / Q000502:physiology / Q000528:radiation effects