A heat and moisture exchanger has an efficiency rating of 80. ...

[hubes95]

A heat and moisture exchanger has an efficiency rating of 80. What does this mean?
 
  a. Of the exhaled water vapor, 80 returns to the patient on inspiration.
  b. The inspired temperature is 80 of the expired temperature.
  c. Of the exhaled water vapor, 20 returns to the patient on inspiration.
  d. The device provides 80 relative humidi-ty at body temperature.

Question 2

An ideal heat and moisture exchanger (HME) should have an efficiency rating of at least which of the following?
 
  a. 30
  b. 50
  c. 70
  d. 90

[manuelcastillo]

Answer to Question 1

ANS: A
These devices typically achieve approximately 70 efficiency (40 mg/L exhaled, 27 mg/L re-turned).

Answer to Question 2

ANS: C
The ideal HME should operate at 70 efficiency or better.