Performance data and safety-related requirements for active respiratory gas humidifiers are specified by the standard ISO 8185.
A bubble bottle is mostly used in oxygen therapy with high flow rates via a mask, nasopharyngeal catheter, or nasal cannula in order to prevent drying of the mucous membranes in the nose and mouth.
As there are significant functional differences among the various HMEs on the market, respiratory therapists should test the efficacy of each individual model.
The ideal HME has high reversible water retention capacity, small internal volume, and low flow resistance.
[citation needed] To enable the absorption of sufficient amounts of water and heat, the expiratory stream of respiratory gas must be fully filtered through the HME.
[clarification needed] Other negative effects of this technology include increased secretions (i.e. mucus) and nosebleeds, either or which may clog an HME.