HUMIDIFICATION - ARTIFICIAL HUMIDIFIERS

This briefly explains the artificial humidification and different types of humidifiers available.

1. HUMIDIFICATION SHOBIYA.T M.SC.,anaesthesia technology

2. Dry oxygen therapy without humidification is harmful It may cause: Heat loss Dry mucosa Thick secretion Airway obstruction In asthmatics, hyperventilation with dry o2 can cause bronchoconstriction . HUMIDIFICATION:

3. Flow rate >4 lit/min. Invasive ventilation Neck breathers- tracheostomy or laryngectomy Bronchiectasis Cystic fibrosis Chest infection retaining secretions INDICATIONS:

4. PASSOVER HUMIDIFIERS: Mechanism: oxygen and gas passes over the surface of water bath,picking up moisture. Advantage: simple and easily available Disadvantage: water supports growth of pseudomonas aeuroginosa causing respiratory infection accidental hot water spillage and thermal burn.

5. Heated passovers : Mechanism: directs gas over a resevoir of heated water. Disadvantage: accidental hot water spillage and thermal burn. Diffuser cascade : the area for gas-water interface is increased by use of large diffusion tower.

6. Bubble through wick: Utilize a paper or cloth wick through which the mainstream flow must pass. SPECIAL CONCERNS : Water levels of humidifiers should be maintained to ensure maximum humidity output. Inspired temperature should be monitored continuously with inline thermometer. Thermometer should be as close to the patient as possible. The humidifiers should be changed every 24 hrs.

7. HEAT MOISTURE EXCHANGE(ARTIFICIAL NOSE): Mechanism: exhaled heat and moisture are collected and made available to warm and humidify the following inspiration. It should be changed every 12-24 hrs Advantage: cost effective Able to maintain physiological air conditioning even in long term ventilated patients.