LHSC's negative pressure room ready to handle worst outbreaks

Spring 2017

Imagine an infectious disease such as avian “bird” flu or Ebola emerging in the community.  How do hospitals care for patients with deadly infectious diseases? How do hospitals protect other patients who are vulnerable due to their illnesses?

As the regional acute care hospital, London Health Sciences Centre (LHSC) remains prepared for an infectious disease threat with a detailed readiness plan, ongoing staff training and personal protective gear. Another protective measure is the negative pressure room.

“If there was ever an outbreak of an airborne infectious disease, including any kind of new infection where we didn’t really understand the mode of transition, then we would put the individuals in a negative pressure room,” says Dr. Michael John, Co-Medical Director, Infection Prevention and Control.

Indeed, during the recent infectious disease threat of Ebola virus, LHSC was one of 10 designated referral centres in Ontario.

A negative pressure room has a ventilation system that generates negative pressure to allow air to flow into the isolation room but not escape from the room.

Air flows naturally from areas with higher pressure into areas with lower pressure, preventing contaminated air from escaping the room. Air is then ventilated to the outdoors though a high-efficiency particulate arrestance (HEPA) filter system to ensure the air is cleaned before it is ventilated to the outdoors.

LHSC has more than 63 negative pressure rooms to prevent cross contamination from room to room. These rooms are found throughout the hospital including the emergency department and the intensive care units for patients with an airborne infectious disease such as tuberculosis, chicken pox or measles.

In addition, last fall LHSC renovated a 12-bed inpatient unit at Victoria Hospital that can be converted to a fully functioning negative pressure unit when there is threat of a deadly infectious disease outbreak.

The negative pressure unit is a respirology unit where patients with cystic fibrosis, lung cancer, COPD and other respiratory diseases are treated, says Lori Hunt, Clinical Educator on the unit.

“The unit has a special ventilation system along with double doors to create a vestibule. A room adjoining the vestibule can be transformed into an anteroom that staff and physicians would then use for donning and doffing personal protective equipment,” says Hunt.

All unit staff and physicians are trained in the lockdown protocol. Unit lockdown is required to change the unit into a negative pressure area.

A detailed toolkit is handy on the unit for staff in the event they need to initiate the lockdown. The kit includes everything from signage to the device which controls the ventilation system.

It takes about 10 minutes for the ventilation system on the unit to switch from positive to negative pressure and be fully functioning.

Preparing the unit for an airborne infectious disease outbreak, involves many throughout the organization.

“It would include transferring patients, preparing the units, bringing in supplies, and restricting entry for patient, family, staff and volunteer safety,” says Hunt.

To ensure the negative pressure system is always ready to function, a “tissue test” is conducted per manufacturer recommendations on every shift. Tissue is taped to the edge of the ventilation, and if the paper is sucked up, then the air is moving in the right direction.

A monthly smoke test is also conducted. A tube containing smoke is held outside the bottom of a negative pressure room door, and a small amount of smoke is released. If the room or unit is under negative pressure, then the smoke will travel under the door and into the room or unit.

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