Performance of Different Active Humidification Systems in High-Flow Oxygen Therapy

Area of Science:

• Respiratory Therapy
• Medical Device Performance
• Pulmonary Medicine

Background:

• High-flow oxygen therapy (HFOT) requires effective humidification for patient comfort and safety.
• Different heated humidifiers (HH) and circuits may offer varying performance levels.
• Evaluating HH performance across conventional and unconventional flow rates is essential.

Purpose of the Study:

• To assess the absolute humidity (AH), relative humidity (RH), and temperature output of various heated humidifiers (HH) and circuits.
• To compare HH performance during high-flow oxygen therapy at flow rates ranging from 30-100 L/min.

Main Methods:

• Prospective, observational study utilizing an electronic thermohygrometer for measurements.
• Mechanical ventilator as the source for high-flow nasal cannula oxygen therapy.
• Testing included a standard HH with a water trap circuit, 3 servo-controlled HH, and 7 heated-wire circuits across 8 flow rates (30-100 L/min).

Main Results:

• Significant differences in average absolute humidity (AH) were observed between devices across all flows (P < .005).
• The Fisher & Paykel MR850 with the Medtronic-DAR circuit yielded the highest AH (40.8 mg/L at 50 L/min).
• The Flexicare FL9000 with its circuit showed the lowest AH (11.4 mg/L at 100 L/min).
• Fisher & Paykel MR850 demonstrated superior AH performance at flows > 50 L/min, irrespective of the circuit.

Conclusions:

• Heated humidifiers exhibit diverse performance during high-flow oxygen therapy, often failing to provide adequate humidification.
• Inefficiency in humidification can occur even at conventional flow rates.
• Careful selection of HH devices and flow settings is recommended for optimal high-flow nasal cannula oxygen therapy implementation.