Bubble Humidifiers: How They Increase Air Humidity

Bubble humidifiers are high-humidity delivery devices commonly used in medical oxygen therapy.

Mechanism: Oxygen (or air) flows through a water reservoir. The gas forms bubbles that rise and burst at the water surface, releasing water vapor into the gas stream. This saturated gas then travels to the patient via tubing.

Key Features:

• Delivers near-100% relative humidity at room temperature.
• Simple, passive, no external power needed.
• Used with nasal cannulas or masks for flows up to 6–10 L/min (higher flows may cause aerosolization and rainout).
• Requires sterile/distilled water; regular cleaning prevents bacterial colonization (e.g., Pseudomonas).

Clinical Use: Prevents mucosal drying, secretion thickening, and epistaxis during prolonged oxygen therapy. Heated humidifiers (active) are preferred for high flows, mechanical ventilation, or hypothermia risk.