Humidification: ISB, INDICATION, TYPES, CONTRAINDICATIONS,

1. HUMIDIFICATION THERAPY
PREPARED BY
HINA VAISH

2. HUMIDITY
• Humidity therapy is the adding of molecular water to air
which is delivered to patient.
• Nose adds heat and humidity to inspired gas.
Absolute and Relative Humidity
• Absolute humidity: amount of water in a given volume of
air
• Relative humidity: ratio between the amount of water in a
given volume of air and capacity of the air to hold water
when totally saturated at body temperature expressed as
percentage
Fink J. (2010). Humidity and aerosol therapy. Cairo J, Pilbeam S, editors; Mosby’s respiratory equipment, 8 ed

3. ISOTHERMIC SATURATION
BOUNDARY(ISB)
• As inspired air moves into lungs, it is fully
saturated to 100% relative humidity at body
temperature. This is called as Isothermic
saturation boundary.
• Above the ISB, temperature and humidity
decrease during inspiration and increase
during exhalation.
• Below the ISB, temperature and humidity
remain constant

4. INDICATION
Primary
• Overcoming humidity deficit created when
upper airway is bypassed
• Humidifying dry medical gases
Secondary ( Heated Humidity)
• Managing hypothermia
• Treating bronchospasm caused by cold air
• Thick secretions
Secondary ( Cool Humidity)
• Upper Airway inflammation

5. TYPES OF HUMIDIFIERS
Active Humidifiers
Actively adding heat or water
or both to the device-patient
interface
• Bubble humidifiers
• Passover humidifiers
• Jet Nebuliser
Passive Humidifiers
Recycling exhaled heat and
humidity from the patient
1. Heat and moisture
exchangers (HMEs)
a) Simple condenser
b) Hydrophobic HMEs
c) Hygroscopic HMEs
Kacmarek, R., Stoller, J., Heuer, A., & Egan, D. (2013). Egan's fundamentals of respiratory care (1st ed.). St. Louis, Mo.:
Elsevier/Mosby.
American Association for Respiratory Care: Clinical practice guideline: humidification during invasive and non invasive
mechanical ventilation. Respir Care 57:5 2012

6. BUBBLE HUMIDIFIER PASS OVER HUMIFIDIFIERS
Simple reservoir
Wick units

7. JET NEBULISER HEAT MOISTURE EXCHANGER
• Artificial Nose
Simple condenser humidifiers
• High thermal conductivity
• Metallic gauze, corrugated
metal or parallel metal
tubes
• Trap approximately 50%
exhale moisture
Fink J. (2010). Humidity and aerosol therapy. Cairo J, Pilbeam S, editors; Mosby’s respiratory equipment, 8 ed

8. HME cont..
• Hydrophobic HMEs
• Hygroscopic HMEs

9. CONTRAINDICATIONS
HME is contraindicated under some circumstances.
• Bloody or thick, copious secretions
• Use of an HME is contraindicated in patients on NIV
with large mask leaks, as the patient does not exhale
enough tidal volume to replenish heat and moisture to
adequately condition the inspired gas.
• Body temperatures less than 32°C
• Patients with high minute ventilation ( greater than10
L/ min).
• In patients with acute respiratory failure, HMEs
substantially increase minute ventilation and work of
breathing.
American Association for Respiratory Care: Clinical practice guideline: humidification during invasive and non invasive
mechanical ventilation. Respir Care 57:5 2012

10. SUMMARY
• The main goal of humidification therapy is to
maintain normal physiologic conditions in
airways.
• Humidification therapy is particularly useful
for patients in whom upper airway has been
bypassed or are delivered with medical gases
• Humidification can assist clearance of
secretions