Humidification During Invasive and Noninvasive Mechanical Ventilation: 2012

Abstract

When the upper airway is bypassed during invasive mechanical ventilation, humidification is necessary to prevent hypothermia, disruption of the airway epithelium, bronchospasm, atelectasis, and airway obstruction. In severe cases, inspissation of airway secretions may cause occlusion of the endotracheal tube. 1 While there is not clear consensus on whether or not additional heat and humidity are always necessary when the upper airway is not bypassed, such as in noninvasive mechanical ventilation (NIV), active humidification is highly suggested to improve comfort. [2][3][4][5][6][7] Two systems, active humidification through a heated humidifier (HH) and passive humidification through a heat and moisture exchanger (HME), are available for warming and humidifying gases delivered to mechanically ventilated patients. There are 3 types of HME or artificial nose: hydrophobic, hygroscopic, and a filtered HME.Heated humidifiers operate actively to increase the heat and water vapor content of inspired gas. 8 HMEs operate passively by storing heat and moisture from the patient's exhaled gas and releasing it to the inhaled gas. 9 The upper airway provides 75% of the heat and moisture supplied to the alveoli. When bypassed, the humidifier needs to supply this missing heat and moisture. Since The authors have disclosed a relationship with Teleflex Medical, which manufactures humidification devices.

Stability of commonly nebulized drugs in heated and humid condition

“…Heated humidification is common method to increase temperature and water content of inhaled gas to Body Pressure Temperature Saturated (BPTS) conditions and helps prevent damage to airway mucosa from exposure to cold dry gas [1,20].…”

Anaesthesiology and intensive care Possibilities of modification of risk factors for ventilator-associated pneumonia (VAP) in cardiac surgery patients

“…The most recent guidelines, published in the USA in 2012, describe in detail the indications and contraindications for both the active and passive humidification of air exhaled by the ventilated patient [with heated humidifiers (HHs) and heat and moisture exchangers (HMEs), respectively] [19]. It should be noted that no significant difference in VAP incidence has been demonstrated between the two methods, indicating, however, that HMEs should be used in the case of mechanical ventilation lasting ≤ 96 hours and during the patient's transport, whereas HHs should be employed when the use of HMEs is contraindicated [19].…”

Normal Saline and Mucous Plugging

“…Two systems of humidifiers are routinely used in mechanical ventilation: the heated humidifier and the heat moisture exchanger. 8 The heated humidifier actively heats the inspired air and provides water vapor. The heat moisture exchanger passively provides heat and humidity by using the moisture and heat from the patient's own exhaled gas.…”

“…Heat moisture exchangers are also not recommended for use during aerosol treatments in the ventilator circuit and when using lung-protective strategies. 8 Systemic dehydration may also play a role in "drying" secretions in patients with impaired clearance of mucus. The airway epithelium and mucus interact, resulting in adhesion of concentrated mucus.…”