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Dec 07, 2020

Traditional O.R. ventilation systems are not enough

Yet another study confirms need for better operating room ventilation 

In a meta-analysis published in Cambridge University Press, researchers analyzed 14 scientific studies comparing two OR ventilation system technologies, laminar airflow (LAF) and traditional mixing ventilation. The researchers found no significant difference in terms of better outcomes in the form of fewer Surgical Site Infections. The conclusion is that the additional cost of LAF ventilation systems cannot be justified and recommended.

Apparently, the two classical ventilation systems are difficult to distinguish when it comes to better outcomes. To do nothing means a status quo that is both is deadly and expensive. At the same time the need for surgery is increasing, especially infection-sensitive orthopedic procedures for new hips or knees that many will need as we are getting older and still want to remain active. Just treating such infections with antibiotics is neither a good option since antibiotics are losing their effectiveness due to increasing antimicrobial resistance. We are in great need of innovation!

How can it be that current systems fail in showing better outcomes?

There is widespread discussion on statistical methods, yet one reason is surely also that LAF was created for cleanrooms in industry, where the objective is to protect a certain small area and where staff is moving slowly dressed in sterile tight clothing also called “space suits”. An OR demands a more robust system, with a large working area and tolerances for comfortable clothing and normal disturbances such as movement of staff, door openings and obstacles in the downflow in the form of surgeons’ heads, lamps, and medical devices. 

In order to actually decrease the risk of surgical site infections, the key is to reduce the level of airborne bacteria. Less bacteria in the air means less risk of infections, and earlier studies indeed show fewer infections when the OR is ultra-clean (J Charnley, Lidwell et al). Research shows that this is impossible with mixing ventilation unless you bring in lots of air while also dressing the staff in very tight clothes that are notoriously uncomfortable and expensive.

Are any new studies showing better outcomes?

Reliable studies of outcomes are rare given that many things have an impact on infections. Additionally, with infection rates of some percent, really large numbers of patients are required to get valid results. Still, a recent such study has been done in an OR where only the ventilation system was changed and all else remained the same, including patient characteristics.

The study involved 2.000 patients who underwent total arthroplasty. Before installing new ventilation 1.000 operations were performed in an OR with mixing ventilation.The ventilation was then replaced with Temperature-controlled Air Flow technology (TcAF, Opragon by Avidicare) and another 1.000 operations were performed. TcAF cut down SSI rates from 3% to 1% by reducing airborne bacteria levels. This aligns very well with earlier research. You can find the full article on our website.

A superior healthcare ventilation system

Temperature-controlled air flow technology was invented due to the limitations of both existing operating room ventilation technologies. We developed the technology by combining a cooled unidirectional airflow in the center of the room with mixed/sedimenting ventilation in the periphery. Downflow is created by controlling the temperature of the center and keeping it 2 C cooler than room temperature. As colder air is heavier than warm, it will fall to the floor driven by gravity.

The periphery is supplied with air that has a temperature appropriate for delivering the required room temperature set by the staff. This ensures comfortable working conditions and the safety of the patient. Any temperature can quickly be achieved given that the whole room is covered with air inlets.


With this patented combination TcAF creates a more robust and energy efficient ventilation system than a laminar airflow ceiling, which requires higher air flows to push the air down over the staff and instruments. Compared to traditional mixing ventilation systems, Opragon needs less air to maintain ultra-clean conditions, while also allowing more comfortable operating clothes.

Read more about TcAF technology on our website.

An innovation that works

In summary with Opragon you get the whole operating room as your useful working area without the ultra-tight clothes required if you had chosen mixing ventilation. And neither do you need to adapt to the limited working area or high airspeeds of LAF. The staff can instead focus on the patient and everything else is automatic.

With the first installation already in 2007 and with more than 250 installations, we are ready to take on many new projects. We will help you create a larger ultra-clean operating zone and reduce airborne contaminants and, in this way, reduce the risk of Surgical Site Infections. It will also protect staff since they will work in a room with a constant downflow minimizing the risk of infectious transmissions.

Join us Towards Zero Infections, contact us today for free design support!

 Read the article here