Breathing Filters


Breathing filters help eliminate the risk of cross-infection by preventing the transfer of bacteria and viruses to and from the patient. Electrostatic filters retain micro-organisms through the static electric charge in the medium. The tightly packed layers of mixed fibre strands in pleated paper filters, also known as mechanical filters, physically prevent bacteria and viruses from passing through.

Properties of Filters and HMEF's

When considering filters a number of important properties should be taken into account:

Filtration Efficiency

In Critical Care as many as 10-15% of invasively ventilated patients develop pneumonia at a rate of 1-3% per day of intubation. These infections may prolong hospital stays by 4-9 days and contribute to as many as 15% of all hospital deaths.

From this, it is evident that filtration efficiency is paramount to protect the patients and ventilators from cross contamination. Flexicare filters maintain protection against bacteria and viruses at a very high level of efficiency, confirmed by independent testing by the Health Protection Agency at Porton Down, Salisbury, UK. Flexicare filters maintain their high level of efficiency during the recommended period of use.

Minimal Dead Space and Minimal Pressure Drop

The filter housing must present the smallest dead space possible whilst at the same time allowing high gas flow with minimal resistance (pressure drop) through the filter media. Flexicare Filters and HMEF's  incorporate a balance between these critical requirements to create a filter with minimal resistance to flow combined with a low dead space.

Lightweight and Ergonomically Shaped

The rounded ergonomic shape of Flexicare Filters and HMEF's prevent pressure marks or discomfort for the patient. The lightweight design reduces drag on breathing systems and the clear material permits visual examination for potential occlusion or accumulation of secretions.

Humidification Abilities

The passive humidification provided by the use of an HMEF helps counteract the risk of actelectasis, epithelial damage and impairment of the mucocilary transport system in intubated patients, resisting the onset Ventilator Associated Pneumonia.

It is recommended1 that HMEF humidification levels should be at least 30mg/L H2O at an inspired air temperature of 30oC. Independent testing by the Medical Devices Agency (MDA) verifies that Flexicare HMEF's exceed this minimum moisture output performance.

1AARC Clinical Practice Guideline: Humidification During Invasive and Noninvasive Mechanical Ventilation: 2012.