Filters

Filters

It is widely recognised that respiratory testing equipment is not sterile and that exposure to normal levels of environmental organisms during testing poses no greater risk than being in other public areas. We presuppose that anyone may be ‘potentially’ infectious irrespective of clinical information provided therefore we apply standard precautions in all instances.
Direct Contact: There is the potential for transmission of upper respiratory disease, enteric infections, and blood-borne infections through direct contact. Although hepatitis and HIV transmission are unlikely via saliva, disease transmission is a possibility when there are open sores on the oral mucosa, bleeding gums, or hemoptysis. The most likely surfaces for contact are mouthpieces and the immediate proximal surfaces of valves or tubing.
In our Lab we adhere to a set of disease-prevention precautions including proper hand-washing techniques. Filters, nose clips, and any other equipment coming into direct contact with mucosal surfaces are disinfected, sterilized and disposable single use items are discarded after each use. Any equipment surface showing visible condensation from expired air is disinfected or sterilized before reuse whenever the potential for cross contamination exists.
Indirect Contact: Lung function tests that involve both expiratory and inspiratory
manoeuvres have been proposed as a potential source of cross-infection between
patients and it is well known that contamination of respiratory apparatus during
expiration has been recognised since 1965 as a source of nosocomial infections.
The use of single use bacterial/viral disposable filters placed between the patient and the apparatus are designed to prevent such contamination and are a viable method to reduce possible risk to patients.
Many studies have been performed which measure the efficiencies of the filters calculated by determining the airborne concentration of viable micro-organisms upstream and downstream of the filter using suitable aerosol sampling techniques and microbial assay methods which demonstrate that pathogenic bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus could pass onto equipment if filters are not used and the figures for viral transmission is obviously going to be much more damming.

Vanessa