Measurement of tidal flow using a transit-time ultrasonic breath analyser.
The ability of the Transit-time Ultrasonic Breath Analyser (TUBA, GHG Medical Electronics GMBH, Zürich, Switzerland) to measure peak flow and tidal volume in the laboratory was tested using a variety of flow and pressure conditions, chosen to simulate the respiratory patterns of patients receiving mechanical ventilatory support. A stable zero baseline was achieved by acoustic damping of the TUBA flow sensor head. A piston pump was used to generate sinusoidal flow pattern, with a peak flow range from 0.1 to 1.51.s-1. The calculated peak flow matched the peak flow measured by the TUBA. The TUBA accurately measured tidal volumes (+/- 10%) delivered using three different flow patterns over a range of volumes from 0.25 to 11. We conclude, that once modified, the TUBA can provide an accurate measurement of peak flow and tidal volume over a range of values likely to be encountered during mechanical ventilation of the lungs.
Williams
E M
EM
Nuffield Department of Anaesthetics, University of Oxford, Radcliffe Infirmary, UK.
Burrough
S L
SL
McPeak
H
H
D001944:Breath Tests / Q000295:instrumentation*; D006801:Humans; D010366:Peak Expiratory Flow Rate; D011175:Positive-Pressure Respiration; D012121:Respiration, Artificial; D013990:Tidal Volume; D014463:Ultrasonography / Q000295:instrumentation*