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. Author manuscript; available in PMC: 2012 Jul 23.
Published in final edited form as: Ann Allergy Asthma Immunol. 2011 Jan 6;106(3):191–199. doi: 10.1016/j.anai.2010.11.011

Figure 1.

Figure 1

Components of the impulse oscillometry apparatus. A, A pressure signal generated in the loudspeaker reaching both the (terminal) resistor proximally and the pneumotachography more distally is transmitted into the airway through the mouthpiece. Pressure and flow signals from tidal breathing and pressure oscillations pass though the pneumotachograph and are measured by the transducer. B, Eight-year-old boy performing IOS. Patient is using a nose-clip, supporting the cheeks, and making a tight seal with the lips at the mouthpiece of the IOS apparatus. The results of IOS testing are graphically displayed on the computer monitor.