Thoracoabdominal pattern of breathing in neuromuscular disorders.
OBJECTIVE
To assess abnormalities in thoracoabdominal pattern of breathing (TAPB) in neuromuscular disorders during spontaneous breathing, intermittent positive pressure ventilation (IPPV) with and without abdominal (AB) binder, and immediately after IPPV.


METHODS
Repeated measures design: Pre-IPPV spontaneous breathing, IPPV, IPPV with AB binder, and post-IPPV spontaneous breathing. In protocol 1, ventilator pressure was held constant at the individual value habitually adopted in sessions of IPPV. In protocol 2, it was increased stepwise from 5 to 30 cm H2O.


METHODS
University hospital, Department of Pediatrics, Intensive Care, and Neuro-Ventilatory Rehabilitation.


METHODS
Thirty-one patients with spinal muscular atrophy (SMA) and 19 patients with myopathy, mean age (+/- SD) 9.7 +/- 3 years.


METHODS
Tidal volume (VT), percent thoracic contribution to VT (%RC), the phase angle between the thoracic and the AB volume changes and the labored breathing index, which is an index of asynchrony taking into account both the phase relationships and relative volumes of rib cage and AB compartments.


RESULTS
We observed marked abnormalities in TAPB during spontaneous breathing, especially in the SMA group. %RC, labored breathing index, and phase angle displayed nearly normal values during IPPV. IPPV pressures of 25 to 30 cm H2O were necessary to increase %RC above 80%. AB binding decreased VT, but led to larger thoracic volumes, especially in patients with SMA. Thoracic contribution to VT and thoracic volume after IPPV were higher than baseline levels.


CONCLUSIONS
The quantitative assessment of TAPB enhances the ability to estimate pulmonary function in neuromuscular disorders, and the efficiency of mechanical ventilation.
Perez
A
A
Department of Pediatrics, Hôpital Raymond-Poincaré, Garches, France.
Mulot
R
R
Vardon
G
G
Barois
A
A
Gallego
J
J
D000005:Abdomen / Q000502:physiology; D002648:Child; D005260:Female; D006801:Humans; D007385:Intermittent Positive-Pressure Ventilation; D008297:Male; D009135:Muscular Diseases / Q000503:physiopathology*; D012119:Respiration / Q000502:physiology*; D014897:Spinal Muscular Atrophies of Childhood / Q000503:physiopathology*; D013909:Thorax / Q000502:physiology; D013990:Tidal Volume; D014797:Vital Capacity