"Its cheaper to just clean the machine every now and again"

"I swap out my circuits between patients"

"The new pneumotachs are easier to clean"

"Filters are a waste of money"

"No one has ever proved a case of cross contamination in a lung function test"

We've heard it all before, some of these are comments that many Department Heads, Clinician's and respected Research Specialist said to us about filters only a few years ago. Now these same people are using the SureGard® filter. A study conducted by one of the Southern Hemisphere's leading Lung Function Research Laboratories compared the "real" cost of using a filter on a per patient basis and the "real" cost of cleaning a machine within standardised guidelines.

FACT 1: It took 41.5minutes to reprocess the items necessary to preform spirometry using a standard piece of Lung Function Equipment, this does not include drying time, only disassembly, cleaning and re-assembly. A cost analysis of two approaches to infection control in a lung function laboratory. Side et al, Aust NZ J Med 1999: 29.

FACT 2: Over 1000 patients required to perform spirometry, the cost per test for a barrier filter was AU$2.95 regardless of the type of test done. If no filter was included in the test and the machine required cleaning, the cheapest the cost could be brought down to, even without using a scientist (cleaners wage paid) where possible was AU$15.56 for a Spirometry test, AU$16.26 for a TLCO test (Jaeger), AU$10.89 for a TLCO test (PK Morgan) and AU$11.74 for a Plethysmograph test. A cost analysis of two approaches to infection control in a lung function laboratory. Side et al, Aust NZ J Med 1999: 29.

Question: Many patients that come through a laboratory with undiagnosed infectious respiratory diseases are not identified until many days or weeks after the patient has performed the initial respiratory tests. Following procedures what total real costs would be involved if a patients came though a Laboratory/Clinic and was at a later stage, say 3 working days found to be infected with TB or SARS? The lab does not use filters. The equipment is ok because it gets cleaned at AU$15.56 per patient, what about the scientist sitting two feet from the patient? Or the next patient that sat in exactly the same vicinity within 120seconds of the infected patient performing a manoeuver of up to 750L/min and aerosoling most of the vapourised moisture in their chest to atmosphere?

The cost of a filter looks pretty good, because the facts are that in high risk environments like Hospitals and Clinics where infected people come into higher concentrations, the real risk of cross contamination in todays world is greatly increased.