UPDATE: Legionella found in UW heart surgery device

SEATTLE — Special pieces of equipment used in heart surgery have been linked to the deadly Legionnaires' outbreak at the UW Medical Center.

Four cases have been reported, with two people dying of the disease.

UW has pulled the “heating-cooling” devices used to cool and heat blood during surgery out of use. The process is done using water, and Legionella bacteria was found in the water of the three machines.

However, the water never comes in contact with the blood. This is the main reason UW’s medical director believes it is highly unlikely the machines are the source of the outbreak.

Heater-coolers were linked to deadly infections in Pennsylvania last year. But those were from a different company and the cases involved a different bacteria.

“The manufacturer and type of machine that we have, there's no evidence that there have ever been infections linked to this type of machine,” said Dr. Thomas Staiger, UW medical director.

But Lawrence Muscarella, who studies the safety of heater-coolers and other hospital equipment, contends there is always a risk the water in any equipment could become infected and leak or spray into the air.

He hopes finding Legionella serves as a wake-up call for hospitals to take a closer look at all heater-coolers.

UW maintains it is far more likely that either the faucets or water fountains in the Cascade Tower are to blame for this outbreak.

Monday night highly chlorinated water was pumped through the plumbing of the tower to make sure any remnants of the deadly bacteria are killed.