Heated humidification versus heat and moisture exchangers for ventilated adults and children

Abstract

There is little evidence of an overall difference between HMEs and HHs. However, hydrophobic HMEs may reduce the risk of pneumonia and the use of an HME may increase artificial airway occlusion in certain subgroups of patients. Therefore, HMEs may not be suitable for patients with limited respiratory reserve or prone to airway blockage. Further research is needed relating to hydrophobic versus hygroscopic HMEs and the use of HMEs in the paediatric and neonatal populations. As the design of HMEs evolves, evaluation of new generation HMEs will also need to be undertaken.

Active versus passive humidification for self-ventilating tracheostomy and laryngectomy patients: A systematic review of the literature

“…1,2 Therefore, it is necessary to provide artificial humidification to incoming cold, inspired environmental air to prevent serious complications including disruption to respiratory tract ciliary function, mucous plugging and atelectasis as highlighted by multiple previous studies, especially in the immediate post-operative period and in the context of critical care. [2][3][4] Tracheostomy is a common procedure in intensive care units, which is related to significant morbidity and mortality if managed suboptimally. The NCEPOD study estimates that the figure is around 12 000 overall for adult procedures performed in both critical care (70%) and theatres (30%), in England, Wales and Northern Ireland.…”

“…Alternatively, passive humidification can be achieved with a HME, which recycles the patient expired heat and moisture, returning it to the patient during the next cycle of inspiration. 1,2 Both methods of humidification are known to result in complications such as infections, due to water acting as a reservoir for bacterial growth, inadequate humidification, risk of aspiration and overheating, the latter two more common in active humidification. 5 A number of previous laboratory studies have focused and comparing the efficacy using measurements of absolute humidity, water and temperature gradients between both active and passive humidification techniques; 6-9 however, direct comparisons are difficult to make due to varying assessment and evaluation measures used in separate studies.…”

“…3,10,11 The use of humidification has been well described in the literature for mechanically ventilated adult and paediatric patients by a recent review. 2 However, optimal humidification in long-term, self-ventilating neck breathers is not known and seems to vary according to local clinical practice and clinical situation. 3 Published guidelines evidenced from clinical practice demonstrate than stable adult patients with adequate systemic hydration often tolerate little or no supplemental humidity or heat.…”

A modification to the Maquet Flow-i anaesthesia machine for ICU ventilation

“…Reduced humidification risks drying patient mucosa, ciliary damage, thickened secretions, atelectasis (Branson, 2009), risks of poorer outcomes (Misset et al, 1991), and a higher incidence of artificial airway blockage. While a Cochrane review of the available literature suggests there is not a major difference in ICU outcomes between HME and active humidification, it did so with the caveat "HMEs may not be suitable for patients with limited respiratory reserve or prone to airway blockage" (Kelly et al, 2010), something which certainly pertains in the COVID-19 ARDS cohort of patients. Our ICU uses Fisher & Paykel (F&P) active humidification for patients ventilated for longer than 24 hours, so the HME alone option was considered undesirable.…”

Humidification and heating of inhaled gas in patients with artificial airway. A narrative review

“…Taking into account the humidification capacity and the advantages and disadvantages, both passive and active humidifiers are suitable for the conditioning of inhaled gas ( Table 2 ). ( 48 , 49 ) Although there are some data that favor the use of HMEF (or HCHF) over active humidifiers for the prevention of pneumonia associated with mechanical ventilation, the choice of the device should not be based only on infection control. ( 9 ) An algorithm for the selection of the humidification device is proposed in figure 7 .…”