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PFT & COVID-19: filter numbers only tell part of the story

05/28/2020

In an effort to protect patients, staff and equipment, everyone is looking for an edge to combat COVID-19. With the reopening of pulmonary function labs, an important protection against the COVID-19 virus is the bacterial/viral filter used during testing. Is it enough?

The specifications for some filters boast a 99.99% filtration efficiency based on a Nelson Labs report. An essential piece of information to know is that Nelson Labs tests filters only at 30 L/min (0.5 L/sec). This is about the maximum exhalation flow rate during normal tidal breathing. During pulmonary function testing, flow rates over 600 L/min (10 L/sec) are often achieved.  What they don’t tell you is that filtration efficiency at this higher flow rate can drop as low as 97%.

So, what does this mean? This means that regardless of the claims of 99.9999% calculated efficiency in preventing cross-contamination, the patient circuit/block in which the patient exhales into during testing could still become contaminated. In this sense, cross-contamination means whether or not the patient can inhale a contaminant from an infected device. MGC Diagnostics’ preVent® pulmonary function filter has also been calculated to show a Patient Cross-Contamination Prevention Efficiency of greater than 99.999% against Viral and greater than 99.9999% against Bacterial Bioburden based on Nelson Labs testing.

But...this is only part of the story.

The reason companies are focusing on cross-contamination rather than filter efficiency is because of the systems themselves. Most systems cannot be easily broken down, disinfected and put back together. This process can be time consuming AND you have to wait for warm-up and recalibration of the system. The MGC Diagnostics advantage allows you to have a clean/disinfected flow sensor and patient circuit with each patient. The preVent® flow sensor and Breathpath™ patient circuit can easily be changed between patients in less than 60 seconds. You do not have to wait for the system to warm up, nor do you need to recalibrate the system after changing these components. Once the testing components are removed, you can choose to disinfect them and reuse, or simply throw them away. You’ll have the peace of mind that the system is safe and you have done the most for your patients.

With filtration efficiency down to 97%, do you want your next patient to inhale on a system that is potentially contaminated? Do you want to perform your next biologic quality control test knowing that your system’s circuit/block may contain bacteria and viruses? Are you 100% sure that the last patient you tested did not have an active infectious disease? If you answered no to any of these questions, then simply changing the filter alone may not be the solution for you. The MGC Diagnostics advantage gives you the added protection and control during these times of uncertain infection control.

To learn more about the MGC Diagnostics advantage, go to our website www.mgcdiagnostics.com.

MGC Diagnostics continues to monitor the COVID-19 pandemic. We are dedicated to providing cardiorespiratory diagnostic health solutions. If you have any questions or need more information, please call us at 1.800.950.5597.

This article was provided by Ralph Cook, RRT, RPFT, Global Product Manager, MGC Diagnostics.

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