Heart, lung machines last resort in H1N1 cases

Swine flu deaths in Australia could have doubled without the use of a mechanical heart and lung treatment, a doctor says.

An Australian and New Zealand study, published in Monday's onlineedition of the Journal of the American Medical Association, found 79 per centof swine flu patients treated with extracorporeal membrane oxygenation (ECMO) survived.

Intensive care specialist Dr. Daryl Jones of Monash University in Melbourne says ECMO is an artificial heart and lung machine. It takes the blood out of the body, removes the carbon dioxide and replaces it with oxygen and then sends the blood back in and around the body, he says.

The study collected data on swine flu patients from all 15 centres that offer ECMO treatment in Australia and New Zealand.

Of the 5,000 people infected with swine flu in Australia and New Zealand that needed hospitalization, 61 required treatment with ECMO, he says.

Jones says that's a significant increase in the number of people who've required ECMO in the past.

"Last year only four patients across Australia and New Zealand required ECMO during winter."

Jones says that, unlike seasonal influenza, swine flu affected many young adults.

"A substantial number of young people became very sick with pneumonia [due to] the virus or a secondary infection," he says.

Last resort

According to Jones, when patients become very short of breath and have respiratory failure, they're put on a ventilator. If that doesn't work, ECMO treatment is the last resort.

Pediatrician Prof. Robert Booy, of the Children's Hospital at Westmead in Sydney, says patients that require ECMO are "extremely unwell and teetering on death."

Of the 61 swine flu patients treated with ECMO, 79 per centsurvived, which Booy says is "very impressive."

Without ECMO, about 90 per centof people suffering from severe influenza associated respiratory failure would have died, he says.

But Booy says the current swine flu death rate statistics in Australia are "hiding" those saved from intensive care management.

"When we say we've had just under 200 deaths, the numbers could easily have been twice that, but for the fact we've got such high-quality intensive care in Australia and New Zealand."

Booy says the study is extremely important, and demonstrates that intensive care doctors across Australia and New Zealand have a "superb" network, which allows them to publish important research quickly.

Jones admits the study was unable to determine the survival rate of those with severe respiratory failure associated with swine flu who did not receive ECMO treatment.

Warning saved lives

He says Australian clinicians were "forewarned" of what to expect before swine flue arrived in Australia, by the experiences of doctors in Mexico and the U.S.

When the outbreak of swine flu was announced in Mexico, he says, a lot of young people were presenting with severe pneumonia.

"They also reported a very high fatality rate per case of infection."

Jones hopes their study will be of similar value to the Northern Hemisphere who have yet to experience swine flu outbreaks during winter.

"Given what we learned from the Mexican experience, we felt we had an obligation to reciprocally provide advanced warning for people in the north."

An editorial also published in the latest edition of JAMA written by Dr. Douglas White and Dr. Derek Angus, both of the University of Pittsburgh, says any deaths from swine flu will be regrettable, "but those that result from insufficient planning and inadequate preparation will be especially tragic."

The same issue of the journal includes studies by doctors in Canada and Mexico describing H1N1 outbreaks in those countries.