Innovation in Ventilation for Healthcare

By: Martha Vockley

June 10, 2021

Categories: AAMI News, HTM Professionals, Medical Device Manufacturers


Living through a pandemic has made everyone hyper-aware that the air we breathe can be dangerous. Nowhere is this truer than in enclosed healthcare settings, including surgical suites, emergency departments, intensive care units (ICUs), and patient rooms.

Viral respiratory outbreaks like COVID-19 continue to pose pandemic threats—and the time between outbreaks is shorter. “So far in the U.S., we have seen more than 3,600 healthcare workers dying from COVID-19,” said Peter Hojerback, CEO of Avidicare AB, at a Wednesday education session at AAMI Exchange REWIRED. “That inability to protect our own staff is supposed to be something that we cannot tolerate.”

Airborne transmission has been observed in enclosed spaces, with prolonged exposure to respiratory particles, and where ventilation is inadequate. “Airborne contaminants are not only contributing to respiratory or other kinds of viral diseases,” Hojerback said. “They’re also contributing to healthcare-acquired infections and, especially, the most deadly and most expensive of all—surgical-site infections.”

Hojerback cited evidence to back this point:

  • Approximately one-third of all healthcare-acquired infections involve transmission by airborne pathogens.

  • More than 60 years of peer-reviewed evidence supports the relationship between airborne transmission and surgical-site infections. Implants, including total hip and total knee replacements, are particularly prone to be associated with infections.

“As we get older, many of us will need hip or knee replacements because we want to remain active,” Hojerback said. “Infections are the primary reason for revisions of total joint arthroplasty. By 2030, surgical-site revisions for total hip replacement are projected to increase by 142%, and by 190% for total knee replacement. Power tools, hammers, and other surgical instruments used in orthopedic surgery can spread airborne particles and contaminate surgical wounds and implanted devices. Bacteria shed by healthcare workers’ skin can cause infections as well. 

The Shortcomings of Standard Ventilation

Inadequate ventilation in high-risk areas is a contributing factor to the spread of diseases and infections. Currently in the U.S., the standard ventilation method in emergency departments and ICUs is turbulent mixed airflow. Based on the dilution principle, filtered air is streamed into a space and mixed with contaminated air, which eventually exits the space. But air moves unpredictably, based on pressure and temperature differences.

“It’s like there’s a lot of people in a room that needs to be evacuated, but nobody knows where the exit is,” Hojerback said. It’s an inefficient system that keeps airborne contaminants in the air, which doesn’t meet the medical, scientific definition of “ultraclean.”

In operating rooms, laminar airflow is the standard method of ventilation in the U.S. This method, which relies on air direction and velocity, does not result in ultraclean rooms either. The strong downward flow of air creates vortexes of contaminated air. Laminar airflow is no longer recommended by the Centers for Disease Control and Prevention, World Health Organization (WHO), or International Consensus Group on Perisprosthetic Joint Infection, Hojerback said.

A New Solution to Inadequate Ventilation

Temperature-controlled Air Flow Technology (TcAF) is a novel ventilation alternative that is in use in 250 healthcare facilities in Europe. Designed for the modern operating room and other high-risk healthcare settings, it is a validated technology that achieves ultraclean conditions throughout the entire space, improves comfort for surgical teams, and optimizes energy use, Hojerback said. This solution also meets or exceeds ANSI/ASHRAE/ASHE Standard 170 – Ventilation of Health Care Facilities. Hojerback encouraged healthcare systems that are building or renovating facilities to design them for tomorrow with TcAF.

TcAF works by slowly releasing cool air from the ceiling. “It’s about three degrees Fahrenheit cooler than room temperature,” Hojerback said. “This air is heavier, so it falls down itself by gravity. This counteracts all the warm air that rises from people, instruments, and other equipment and heat sources in the room. On the periphery, air is supplied to push the air to the exhaust.” Room temperature and humidity can be adjusted to the needs of the patient and comfort of the staff. Monitoring and analytics enhance reliability and support compliance with environment of care standards.

Hojerback also pointed out that, unlike emerging European Union and WHO standards, U.S. standards are silent on what constitutes an acceptable level of microbial contamination in an operating room. In addition, there are no requirements for testing of airborne microbial bioburden. Development of such standards would require leadership by a recognized standards development organization, such as AAMI.

“Current AAMI standards address instrumentation and water. Should air be next?” Hojerback asked.