“Appropriate humidification of inspired air is one of the components of the high impact interventions for mechanically ventilated patients”, according to the Department of Health (Department of Health 2007). High impact interventions are part of the care bundle approach that aims to prevent ventilator-associated pneumonia (NICE 2008). Humidification must be artificially supplemented to assist normal function and facilitate secretion removal. Higginson, Parry and Williams (2016) suggest this is due to the bypassing of the protective elements of the upper airway, such as filtering and humidification of the air. Failure to adequately humidify the oxygen could result in tube becoming blocked due to the secretions becoming dry and viscous around the tracheostomy.
The most common way to deliver adequate humidification is by using a heat moisture exchanger (Swedish nose or HME). However, these filters increase the dead space (the volume of gas that does not participate in gas exchange) and airway resistance thereby increasing the work of breathing for the patient (Goldsmith and Shannon 2009). Some studies recommend changing the HME after three days (Davis et al 2000), while other researchers recommend changing them after several days (Dodek et al 2004). Although using a HME is the most common was to deliver humidification Gosh (2012) states that the healthcare professional looking after Jane must administer humidity via bottled water and elephant tubing continuously for the first week of her tracheostomy insertion. This is because HME will not offer enough humidity in the first instance thus leading to an increased risk of Jane having thick secretions and the trache becoming blocked.Heated systems are very efficient as the temperature can be controlled at recommended humidity levels.
Delivery of inspired air at 37ºC and 100% relative humidity maintains the body’s normal defence mechanisms. Ryan et al (2002) add on to this by saying inspired gas that is conditioned to the core body temperature (37?C) and has 100% relative humidity is important for an optimal clearance of mucus from the respiratory tract. However, heated systems are prone to causing lots of condensation to collect in the tubing when water vapour (distilled water and saline) cools the reservoirs in the humidification systems have been shown to be a source of infection as the aspiration of contaminated oropharyngeal secretions and fluids such as ventilator tubing condensate can lead to ventilator-associated pneumonia (Centers for Disease Control and Prevention 2005).NHS Quilty Improvement Scotland (NHSQIS, 2008) believe that nebulisers tend to be are safe and efficient, however, nebulisers can be given when they are too cool and they require a gas flow generator and tubing. This tubing can either form part of the ventilation circuit or be attached directly to the tracheostomy tube making them inconvenient for a child of Janes age.