Humidification of the gases a patient inspires during mechanical ventilation can be passive or active. Passive Humidification involves the use health and moisture exchangers that allow for condensation from the patient’s expired air, which is later evaporated during inspiration. On the other end, active humidification is performed by heated humidifiers that allow inspired gases to pass across or through a heated water bath (Al Ashry & Modrykamien, 2014). Active humidification systems use energy and water that are outside the body of the patient to condition the gas the patient inspires (Branson, 1999). Passive Humidification depends on the difference in temperatures and humidity between the patient’s body and the external environment. Both of these systems have advantages that allow them to aid in the prevention of Ventilator Associated Pneumonia (VAP) (Al Ashry & Modrykamien, 2014).
Humidification is often provided for all patients that require mechanical ventilation. Patients with an artificial airway require the use of active humidifiers (Branson, 1999). The provision of heat and humidity when using mechanical ventilation is ideal for patients with artificial airways. However, the amount of moisture to provide is debatable (Branson, 1999). Active humidifiers have several features that make them suitable in such as case. Firstly, active humidifiers have a higher absolute humidity and provide no added dead space. Additionally, active humidifiers are likely to collude and produce decreased resistive load during the breathing process (Branson, 1999). Active humidifiers are heated. Therefore, they prevent further heat losses from the patient, which is important in neonatal situations. Active humidifiers also use little water than passive humidifiers and eliminate water losses from the patient’s respiratory tract. The active humidifiers also make it easy to monitor the temperature of the inhaled and exhaled air, which is vital for positive outcomes for the patient (Al Ashry & Modrykamien, 2014).
Nonetheless, both passive and active humidifiers have merits that make them ideal for use in mechanical ventilation. Active humidifiers have a high absolute humidity. Notably, they provide the physiological temperature of 37oC with 100 percent relative humidity (Branson, 1999). They also have no added dead space or breathing resistance. The secretion of liquefaction reduces the risk of occlusion. Active humidifiers also maintain mucociliary clearance for longer. Additionally, the active humidifiers do not provide avenues for moisture losses during extraction (Al Ashry & Modrykamien, 2014). The active humidifiers use little water and eliminate water loss from the respiratory tract of the patient. They provide easy temperature monitoring methods and can be used in neonates of less than 2500g (Branson, 1999). On the other end, passive humidifiers are affordable as they cost less than active humidifiers. They are also simpler to use than active humidifiers (Siempos, Vardakas, Kopterides, & Falagas, 2007). They provide passive humidification depending on the body of the patient. Passive humidifiers are also easily portable and eliminate the secretion of a condensate (Siempos, Vardakas, Kopterides, & Falagas, 2007).