invasive ventilation

The necessity to heat and humidify the respiratory gas during invasive ventilation (i.e. ventilation via tracheal tube or tracheal cannula, bypassing the natural nasal, pharyn-geal, and laryngeal spaces) is undisputed ([1], [2]). Even a short period of ventilation using suboptimal conditioned (humidified/warmed) gas will induce significant physi-cal damage and functional impairment to the mucosal membranes (i.e. decreased mucus production and mucus transport). This will favour the settlement of patho-gens, consecutively leading to pneumonia with severe impairment of gas transport and gas exchange ([3], [4]).

[1] Chalon J, Loew DAY, Malebranche J. Effects of dry anaesthetic gases on tracheobronchial ciliated epithelium. Anaesthesiology 1972; 37: 338-343

[2] Tsuda T, Noguchi H, Takumi Y, Aochi O. Optimum humidification of air administered to a tracheotomy in dogs. Br J Anaesth 1977; 49: 965-977.

[3] Wilson R, Roberts D, Cole P. Effect of bacterial products on human ciliary
function in vitro. Thorax 1985; 40: 125-131.

[4] Estes R, Meduri G. The Pathogenesis of Ventilator-Associated Pneumonia: 1. Mechanisms of bacterial transcolonization and airway innoculation. Int Care Med 1995; 21:365-383