Lung Failure in H1N1 Cases Spurs Life-Support Demand
By Jason Gale
Oct. 13 (Bloomberg) -- Dozens of swine flu patients were saved from respiratory failure when doctors in Australia and New Zealand turned to machines that pump blood through an artificial lung, resulting in a 17-fold increase in the uncommon procedure.
The finding, published in the Journal of the American Medical Association yesterday, is based on the first population- wide study of lung-bypass equipment made by companies such as Getinge AB and Medtronic Inc. to treat H1N1 patients. The study suggests the life-saving technique might be used on about 800 cases in the U.S. this winter and 1,300 in the European Union.
Sixty-eight patients whose damaged lungs rendered them unable to breathe had the procedure, the authors said. One out of five died and almost half were able to walk out of the hospital after suffering acute respiratory distress syndrome, a condition fatal in up to 48 percent of cases.
“We have a gut feeling that these patients would have died more frequently and that we did improve the likelihood of their survival,” said Andrew Davies, deputy director of intensive care at Melbourne’s Alfred Hospital and the study’s lead author.
An additional 133 flu patients received mechanical ventilation in which air is blown into the lungs, but not the lung-bypass procedure known as extracorporeal membrane oxygenation or ECMO. The study didn’t include a case-controlled comparison of patient outcomes in both groups, Davies said.
From June 1 to Aug. 31, the procedure was used in New Zealand and Australia on patients with confirmed or suspected swine flu at a rate of more than 2.6 per million people. In comparison, only four patients with acute respiratory distress syndrome or ARDS received ECMO in the same ICUs the previous winter, an incidence of 0.15 cases per million people.
ARDS, a complication of viral pneumonia and other causes of lung injury, is fatal in 30 percent to 48 percent of patients, the authors said.
The average age of patients with the new H1N1 strain who received ECMO at 15 intensive care sites in Australia and New Zealand was 34.4 years, the doctors said. At least half of them were overweight or obese, a third suffered from chronic lung disease, 16 percent were pregnant or had recently given birth, and a similar proportion suffered type-2 diabetes, they said.
“They were dreadfully sick as a bunch when we put them on ECMO, and you would have thought that group of patients would have had a higher mortality,” Davies said in a telephone interview today.
As of Sept. 7, 48 of the 68 ECMO patients had been discharged from the intensive care unit, of whom 32 had been discharged from the hospital and 16 were still hospitalized. Fourteen patients had died and six remained in the ICU, two of whom were still receiving ECMO, according to the study.
Intensive care specialists in Australia and New Zealand, where swine flu cases peaked in July and August, ordered ECMO systems from companies including Maquet Cardiopulmonary AG, a subsidiary of Sweden’s Getinge, and Minneapolis-based Medtronic to meet additional pandemic-driven demand.
The number of patients treated concurrently with ECMO in Australia and New Zealand peaked eight weeks after the first patient was treated and then decreased during the next four weeks, the authors said. At the peak, 23 patients across both countries were on ECMO on three consecutive days in early August.
ECMO allows the lungs to recover while a machine takes over gas exchange. The units cost as much as 60,000 euros ($89,000) each, Josef Bogenschuetz, Maquet’s chief executive officer, said in an interview in July. In Australia and New Zealand, patients on ECMO received the treatment for an average of 10 days.
A study last month in the Lancet, a U.K. medical journal, found average health-care costs were more than twice as high per patient for those selected for ECMO than for patients sent for mechanical ventilation. The average cost for those on ventilators was 33,435 pounds ($53,000) while the average ECMO treatment cost was 73,979 pounds.
While doctors have favored so-called positive end-pressure ventilators for helping patients overcome severe breathing difficulties since the polio epidemic in the 1950s, ECMO emerged as a treatment option in the 1980s. About 2,000 adult respiratory patients had been given ECMO, researchers from the Washington University School of Medicine said in a 2008 study.
“It’s been a therapy used for heart and lung transplant patients or patients with fairly severe heart failure,” Davies said. Improvements in the technology over the past decade have lowered the risk of hemorrhage and blood clots, making it a more viable option for lung-failure patients, he said.
Even still, bleeding complications occurred in 54 percent of the flu patients on lung bypass, mostly at the point where ECMO tubes are inserted into veins in the groin or neck, the authors said.
To contact the reporter on this story: Jason Gale in Singapore at firstname.lastname@example.org
Last Updated: October 13, 2009 05:46 EDT