Subjects were asked to breathe quietly, with the nose occluded, through a mouthpiece connected to the pneumotachograph
(Fleish Lausanne, Switzerland) with a two-way low- resistance breathing valve (0.9 cm[H.sub.2]Ox[L.sup.-1] s, dead space of 50 ml, model 9340 occlusion valve, Hans Rudolph inc, Kansas City, Missouri, U.S.A).
USA) that was calibrated according to the manufacturer's recommendations and a pneumotachograph
(2 to 30 L x [min.sup.-1]).
Respiratory gas exchange was sampled from a mouthpiece connected to a medium flow pneumotachograph
(Medgraphics, Minnesota, USA) and a gas analyzer (V02000, Medgraphics, Minnesota, USA), calibrated before each test with gas standards of known concentrations [oxygen ([O.sub.2]) = 12.0%; carbon dioxide (C[O.sub.2]) = 5.3%].
Sciurba, "The accuracy of pneumotachograph
measurements during mechanical ventilation," American Journal of Respiratory and Critical Care Medicine, vol.
Cough volume acceleration is difficult to measure clinically as it requires a pneumotachograph
and related equipment.
Artificial thorax chamber pressure was measured with a differential pressure transducer (Validyne DP 45-24, Validyne Engineering, Northridge, CA, USA), and airflow velocity with a pneumotachograph
tube connected to the differential pressure transducer.
Respiratory air flow was measured by a pneumotachograph
(Hans Rudolph RSS 100 0-160 L/min) attached on a facemask (Respironics Spectrum medium size).
Computerized flexiflow machine with pneumotachograph
was used to perform the dynamic PFTs.
Flow was measured with a heated pneumotachograph
(Ventrak 1550, Novametrix Company, USA) connected to a differential pressure transducer inserted between the Y-piece of the ventilator circuit and the endotracheal tube.
Breathing patterns were monitored using a Buxco mouse pneumotachograph
with a Buxco pressure transducer coupled to automated Iox 2 software (emka TECHNOLOGIES S.A.S).
the reduction of the mass of the bell and the addition of graphic and timing devices), and the Fleisch pneumotachograph
is also widely used in modern commercial analysers.
Expiratory flow-volume curves were recorded by a spirometer with a pneumotachograph
sensor (Model ST90, Fukuda Sangyo Co.