Non-invasive quantification of diaphragm kinetics using m-mode sonography.
OBJECTIVE
The standard conditions of spirometry (i.e., wearing a noseclip and breathing through a mouthpiece and a pneumotachograph) are likely to alter the ventilatory pattern. We used "time motion" mode (M-mode) sonography to assess the changes in diaphragm kinetics induced by spirometry during quiet breathing.


METHODS
An M-mode sonographic study of the right diaphragm was performed before and during standard spirometry in eight patients without respiratory disease (age 34 to 68 yr).


RESULTS
During spirometry, the diaphragm inspiratory amplitude (DIA) increased from 1.34 +/- 0.18 cm to 1.80 +/- 0.18 cm (P = 0.007), whereas the diaphragmatic inspiratory (T1 diaph) increased from 1.27 +/- 0.15 to 1.53 +/- 0.23 sec, (P = 0.015, without change in diaphragmatic total time interval (Ttot diaph). Therefore, the diaphragm duty cycle (T1 diaph/Ttot diaph) increased from 38% +/- 1% to 44% +/- 4% (P = 0.023). The diaphragm inspiratory (DIV) and expiratory (DEV) motion velocity (P = 0.007).


CONCLUSIONS
M-mode sonography enabled us to demonstrate that the wearing of a nose clip and breathing through a mouthpiece and a pneumotachograph induce measurable changes in diaphragm kinetics.
Ayoub
J
J
Department of Ultrasound, Nîmes University Hospital, France. Biomed@zeus.sc.univ-montpl.fr
Cohendy
R
R
Dauzat
M
M
Targhetta
R
R
De la Coussaye
J E
JE
Bourgeois
J M
JM
Ramonatxo
M
M
Prefaut
C
C
Pourcelot
L
L
D000328:Adult; D000368:Aged; D003964:Diaphragm / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D012119:Respiration; D013147:Spirometry / Q000379:methods; D014463:Ultrasonography / Q000379:methods