A screen pneumotachograph is: a. built with metal struts. c. ...

[lindiwe]

A screen pneumotachograph is:
 
  a. built with metal struts. c. bidirectional and very accurate.
  b. expensive and non-disposable. d. heated to prevent condensation.

Question 2

The best method for accurately measuring the thoracic gas volume of a patient with emphysema is:
 
  a. helium dilution. c. pressure plethys-mography.
  b. nitrogen washout. d. chemiluminescence monitoring.

[LVPMS]

Answer to Question 1

ANS: D
The screen pneumotachograph is similar to Fleisch-type devices in that a heating element is in-corporated to prevent water condensation on the metal screens.

Answer to Question 2

ANS: C
Inert gas techniques, such as helium dilution and nitrogen washout, can measure gas volumes on-ly in communicating airways. Body plethysmography measures all of the volume in the thorax. Therefore, inert gas measurements of functional residual capacity (FRC) for a patient with chronic obstructive pulmonary disease and severe air trapping will be lower than functional re-sidual capacity measurements obtained during body plethysmography.