What are the guidelines for using heated humidifiers (HH) in patients with respiratory conditions?

Guidelines for Using Heated Humidifiers in Respiratory Conditions

Heated humidifiers should be used according to manufacturer's instructions, with sterile water for bubbling humidifiers, and should only be changed when visibly contaminated or malfunctioning rather than on a routine schedule. 1

General Principles for Heated Humidifier Use

• Heated humidifiers are essential for providing adequate humidity to patients with respiratory conditions, especially those who are intubated 2
• Follow manufacturer's instructions for use of oxygen humidifiers unless evidence indicates modifications pose no threat to patient safety 1
• No definitive recommendation exists for preferential use of either Heat-Moisture Exchangers (HMEs) or heated humidifiers to prevent pneumonia in mechanically ventilated patients 1

Humidifier Fluid Management

• Use sterile water (not distilled or nonsterile water) to fill bubbling humidifiers to prevent contamination and reduce infection risk 1
• Periodically drain and discard any condensate that collects in ventilator tubing, taking precautions not to allow condensate to drain toward the patient 1
• Wear gloves when handling condensate fluid and decontaminate hands afterward with soap and water or alcohol-based hand rub 1

Maintenance and Replacement Guidelines

Heated Humidifier Circuits

• Do not change breathing circuits (ventilator tubing, exhalation valve, and attached humidifier) routinely based on duration of use 1
• Only change circuits when visibly soiled or mechanically malfunctioning 1
• Change humidifier-tubing (including nasal prongs or mask) when it malfunctions or becomes visibly contaminated 1

Heat-Moisture Exchangers (HMEs)

• Change an HME only when it malfunctions mechanically or becomes visibly soiled 1
• Do not routinely change HMEs more frequently than every 48 hours 1
• Do not routinely change the breathing circuit attached to an HME while in use on a patient 1

Infection Control Measures

• Between uses on different patients, change the tubing (including nasal prongs or mask) used to deliver oxygen 1
• For small-volume medication nebulizers, clean, disinfect, rinse with sterile water, and dry between treatments on the same patient 1
• Use only sterile fluid for nebulization and dispense aseptically 1
• For mist tents, replace nebulizers, reservoirs, and tubings with sterilized or high-level disinfected equipment between different patients 1

Common Pitfalls and Caveats

• Avoid using large-volume room-air humidifiers that create aerosols unless they can be sterilized or subjected to high-level disinfection daily and filled with sterile water 1
• Some research suggests that certain convection-type humidifiers do not aerosolize water and may not require sterile water 3, but this contradicts guideline recommendations which still advise sterile water for bubbling humidifiers 1
• While some studies suggest extended use of prefilled humidifiers may be safe 4, guidelines still recommend following manufacturer instructions for replacement 1
• Consider using hydrophobic filters between humidifiers and breathing circuits to reduce potential bacterial transmission, especially in sleep apnea patients using CPAP with heated humidifiers 5