CHAPTER 2 HUMIDITY AND AEROSOL
PRETEST QUESTIONS
1. Secretions tend to become thicker if the inspired air has which of the following characteristics?
2. A patient receiving 38 mg H2O per liter of gas from a nebulizer has a humidity deficit of which of the following?
3. After connecting a nasal cannula to the humidifier outlet, you kink the tubing and hear a whistling noise coming from the humidifier. Which of the following most likely has caused this?
4. You notice that the patient’s secretions have become thicker and more difficult to suction since replacing the ventilator humidifier with a heat moisture exchanger. The respiratory therapist should recommend which of the following?
5. Which of the following are indications for bland aerosol therapy?
6. You notice that very little mist is being produced by a nebulizer attached to an aerosol mask. Which of the following could be responsible for this?
REVIEW
Note: Questions regarding humidity therapy appear on the CRT exam only.
CRT Exam Content Matrix: IIA3, IIIB8, IIIF2, IIIF2g2
The objective of humidity therapy is to make up for water loss that occurs when dry gas is delivered or when the upper airway is bypassed.
EXAMPLE:
The amount of moisture in a given volume of gas at 31° C is 24 mg H2O per liter of gas. Calculate the relative humidity. (Note: At 31°C, air can hold 32.01 mg H2O per liter.)
EXAMPLE:
A gas at 22°C has a relative humidity of 54%. Calculate the absolute humidity. (Note: At 22°C, air can hold 19.42 mg H2O per liter.)
EXAMPLE:
If the gas that the patient is inspiring contains 21 mg of H2O per liter of gas, what is the body humidity?
or when expressed as a percent:
EXAMPLE:
A patient using T-tube flow-by is inspiring air from an Ohio nebulizer that contains 18 mg H2O per liter of air. What is this patient’s humidity deficit?