NONINVASIVE QUANTIFICATION OF DIAPHRAGM KINETICS USING M-MODE SONOGRAPHY

Purpose: The standard conditions of spirometry (i.e., wearing a nosecl ip and breathing through a mouthpiece and a pneumotachograph) are like ly to alter the ventilatory pattern, We used ''time-motion'' mode (M-m ode) sonography to assess the changes in diaphragm kinetics induced by spirometry during quiet breathing, Methods: An M-mode sonographic stu dy of the right diaphragm was performed before and during standard spi rometry 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), whe reas the diaphragmatic inspiratory time (T-1 diaph) increased from 1.2 7 +/- 0.15 to 1.53 +/- 0.23 sec, (P = 0.015), without change in diaphr agmatic total time interval (Ttot diaph). Therefore, the diaphragm dut y cycle (T-1 diaph/Ttot diaph) increased from 38% +/- 1% to 44% +/- 4% (P = 0.023). The diaphragm inspiratory (DIV) and expiratory (DEV) mot ion velocity increased (P = 0.007), Conclusion: M-mode sonography enab led us to demonstrate that the wearing of a nose clip and breathing th rough a mouthpiece and a pneumotachograph induce measurable changes in diaphragm kinetics.