What is respiratory humidification?
Respiratory gas humidification is a method of artificial warming and humidifying of respiratory gas for the patient during mechanical ventilation.

When is respiratory humidification affected?
When a patient is requiring mechanical ventilation over a longer period of time, it is imperative to take measures to compensate the losses of heat and moisture in order to avoid the aforesaid complications.

Respiratory humidification during non-invasive ventilation
In case of non-invasive respiration (e.g. respiratory masks) a continuous positive flow is administered (e.g. CPAP). Thereby caused increased oral breathing may elicit undesirable accompanying symptoms. In the long run the upper respiratory tracts dry out through the permanent supply with cool respiratory gases of positive pressure. The consequences are painfully inflamed nasal and oral mucous membranes as well as blockages of the air passages and congestion of secretion in the respiratory apparatus. Particularly leakages at the respiratory mask may promote drying out of the nasal mucous membranes. A continuous supply of warm respiratory gases materially contributes to the abatement of this clinical picture.

Respiratory humidification during invasive humidification
In case of invasive respiration (intubation or tracheotomy) the upper respiratory tracts are bypassed, thus prevented form exercising their natural function. In that case respiratory gas conditioning is dislocated solely to the trachea, which however cannot effect the necessary humidifying, warming and clearing performance solely by itself. Artificial respiration with cold and dry respiratory gases causes within short time mucus on the respiratory epithelium to become more viscous, impairing the functionality of the cilia. That may have severe consequences:

• Impairment of the ciliary function by viscous mucus and swelling mucous membranes
• Increasing flow resistance of the respiratory passages and decrease of compliance through increasing congestion of secretion as well as incrustations
• Risk of atelectases formation because of reduced surfactant activity
• Aggravation of the gas exchange in the lung
• Increased susceptibility to pulmonic infections

Atemgasbefeuchtung bei Frühchen
Premature infants are particularly endangered by such complications. Though they are survivable from the 24th week of pregnancy, their lungs and mucociliary clearance however are still extremely underdeveloped. Furthermore at the same time they must immediately adjust to a cooler and dryer ambience. Even after birth the ontogenetic development is not yet completed. In order to obviate drying out or hardening of the lung, optimum respiratory gas humidification is absolutely mandatory for mechanical ventilated premature infants and neonates.

Our solution for you
The WILAmed respiratory humidifier PMH5000 with its accessory (breathing tube systems, humidifying chambers and clamps) is an effective solution for ideal humidification of ventilated patients. The natural cleaning function of the lung, the mucociliary clearance, is supported by optimum warming up and humidification of the respiratory gas. The risk of pulmonic infections or damaging of lung tissues is so effectively reduced.

Literature to this topic

• W. Oczenski, H. Andel und A. Werba: Atmen - Atemhilfen. Thieme, Stut tgar t 2003: 274, ISBN 3-13-137696-1.
• A. Wanner, M. Salathé, T.G. O‘riordan: Mucociliary Clearance in the Airways. In: American journal of respiratory and critical care medicine, 1996, 154 (1), no6: 1868-1902, ISSN 1535-4970.
• N. Cauna, K.H. Hinderer: Fine structure of blood vessels of the human nasal respiratory mucosa. In: Ann Otol Rhinol Laryngol, 1969; 78(4) :865-79, ISSN 0003-4894.
  
• J. Rathgeber, K. Züchner, H. Burchardi: Conditioning of Air in Mechanically Ventilated Patients. In: Vincent JL. Yearbook of Intensive Care and Emergency Medicine, 1996: 501-519, ISSN 0942-5381.
  
• M.P. Shelly, G.M. Lloyd, G.R. Park: A review of the mechanism and methods of humidification of inspired gases. In: Intens Care Med. 1988; 14:1, ISSN 0342-4642.
  
• M.A. Sleigh, J.R. Blake, N. Liron: The Propulsion of Mucus by Cilia. In: Am. Rev. Respir., Dis. 1988; 137: 726-41, ISSN 0003-0805.
• R. Williams, N. Rankin, T. Smith, et al. Ralationship between humidity and temperature of inspired gas and the function of the airway mucosa. In: Crit. Care Med, 1996, Vol. 24, no11: 1920-1929, ISSN 0090-3493.
  
• R. Estes, G. Meduri : The Pathogenesis of Ventilator-Associated Pneumonia: 1. Mechnisms of Bacterial Transcolonization and Airway Innoculation. In: Intensive Care Medicine. 1995; 21: 365-383, ISSN 0340-0964.
  
• H. Schif fmann: Humidification of Respired Gases in Neonates and Infants. In: Respir Care Clin. 2006;12:321-336, ISSN 1078-5337.
  
• S. Schäfer, F. Kirsch, G. Scheuermann und R. Wagner: Fachpflege Beatmung. Elsevier, München 2005, S. 145-146, ISBN 3-437-25182-1
  
• M.T. Mar tins de Araújo, S.V. Vieira, E.C. Vasquez, et al. Heated Humidification or Face Mask To Prevent Upper Airway Dryness During Continuous Positive Airway Pressure Threapy. In: Chest. 2000; 117: 142-147, ISSN 0012-3692.