Chapter 39 Egans Flashcards
Absolute Humidity
Amount of water in a given volume of gas
Relative Humidity
Amount of water vapor in a volume of gas
What is HME?
(Heat and moisture exchange)
Primary function of upper respiratory tract
What are the normal BTPS conditions?
37 degrees Celsius, 100&RH-
How far below the carina is the isothermic saturation boundary (ISB)
5cm
What is the temp, RH and AH at mouth?
Temp: 22 degrees Celsius
RH: 50% AH: 10mg/L
What are the temp, RH, and AH in the throat?
Temp: 30 degrees Celsius
RH: 95% AH: 30mg/L
What is the temp, RH, and AH, at ISB?
Temp: 37 degrees Celsius
RH: 100% AH: 43.9mg/L
What is the temp at inspiration?
28.5 degrees Celsius
What is the temp at expiration?
30.2 degrees Celsius
What factors affect a humidifier?
Temp, Surface Area, Time of contact, thermal mass
What are the 4 active humidifiers?
Bubble, pass-over, nebulizers, and bland aerosols, vaporizers
What is a passive humidifier?
Heat and moisture exchangers
What are the 3 pass over humidifiers?
Simple reservoir, wick type, membrane type
International Organization for Standardization (ISO)
Design and performance standards for HME’s
What are the 5 types of heated elements?
1) hotplate element at base of humidifier
2) wraparound type that surrounds humidifier chambers
3) yoke (collar) element that sits between the water reservoir and gas outlet
4) immersion- type (place in water)
5) Heated wire in limb
6) thin-film high-surface area broiler
What is the minimum level of humidity for intubated patients?
30mg/L
3 common problems with humidification
Condensation, Cross-Contamination, ensuring proper conditioning of inspired gas
What is bland aerosol?
liquid particles suspended in gas
aerosol mask/ face tent
upper airways
T-tube
orally/nasally intubated, or tracheostomy
How to affect appropriate therapy?
1) gas flow
2) presence/ absence of artificial airway
3) character of pulmonary secretions
4) need for and expected duration of mechanical ventilation
5) contraindications to using an HME unit
what is sputum induction?
High-density hypertonic saline aerosols applied to airway to help mobilize pulmonary secretions
Primary goal of humidification
Maintain normal physiologic conditions in the lower airways
What are the 3 HME’s
-Simple condenser humidifier
-Hydroscopic condenser humidifier
-Hydrophobic condenser humidifier
What is normal minute ventilation?
5-7L/min
When should a concha be used? (high flow)
over 15L/min
