Nov. 6 (Bloomberg) -- Swine flu sufferers who developed life-threatening complications during the pandemic’s initial wave in Ireland occupied intensive-care beds for weeks, pointing to a potential area of strain from any winter surge in cases.

Nineteen patients with the new H1N1 virus admitted to intensive care units from April 28 to Oct. 3 stayed an average of 25 days, Irish health officials said in a study yesterday. More than half were still in ICU on Oct. 13, when the study was being prepared, marking one patient’s 62nd day of critical care.

The findings show how H1N1 is stretching medical services even as the majority of patients recover within days and the number of deaths has so far been a fraction of the seasonal-flu toll. In Australia and New Zealand, where epidemics peaked in July and August, the virus drove a 15-fold increase in intensive care admissions for viral lung inflammation, especially among pregnant women, the obese and people with chronic lung disease.

“Some patients have an extremely protracted ICU stay, with a number of current patients in ICU in excess of 60 days,” wrote Jennifer Martin, a doctor with the Health Protection Surveillance Centre in Dublin, and colleagues in the study, which was published in the journal Eurosurveillance.

From late April to early October, 205 confirmed H1N1 patients were hospitalized in Ireland, with 9 percent admitted to an intensive-care unit, the authors said. Four of the hospitalized patients died.

Chronic respiratory disease was the most common risk factor in ICU admissions, followed by chronic neurological disease, asthma and severe obesity, they said.

Long stays in ICU may reflect a lack in smaller hospitals of so-called high-dependency units, or HDUs, where patients who no longer require intensive care are monitored more closely than in regular wards, the authors said.

“This will impact on ICU and HDU resources as the pandemic progresses,” they said.

To contact the reporter on this story: Jason Gale in Singapore at j.gale@bloomberg.net

Last Updated: November 5, 2009 23:01 EST