Wellington, Oct 9 NZPA - New Zealand and Australian hospitals experienced a 1500 percent jump in demand for beds in intensive care units (ICUs) when swine flu struck in the seasonal flu season.
Swine flu had a profound effect on ICUs over the winter from June through August, the New England Journal of Medicine reported today.
Doctors from the Australian and New Zealand Intensive Care Society analysed the 722 H1N1 swine flu cases admitted to ICUs in the two countries, from June 1 through August 31.
The H1N1 patients were among 856 with type-A influenza admitted to ICUs.
The 722 patients had the swine flu strain confirmed with laboratory tests, Royal Perth Hospital's Steven Webb said.
In each of the previous four years, the hospitals had admitted an average of 57 patients with lung inflammation, as result of flu.
This year, swine flu patients took up a total of 8815 bed days and of the patients where data was available, 64.6 percent were on mechanical ventilation for a median period of eight days.
By September 7, 14.3 percent of the patients had died and 15.8 percent were still in hospital.
The toll was similar to a normal seasonal flu epidemic, but the study did not give a breakdown of deaths by age -- doctors have said swine flu infected more young people than seasonal flu did.
Children and teens accounted for nearly half of the hospital cases: a third of total patients were young or middle-aged adults who were neither pregnant, nor had a known co-existing condition.
Admissions for viral lung inflammation were highest especially among pregnant women, the obese and people with chronic lung disease, the study found.
Pregnant women, about 1 percent of the population on both sides of the Tasman, were responsible for 9.1 percent of the intensive care cases.
Obese patients were responsible for almost 30 percent of admissions, even though they only made up 5.3 percent of the population in 2003.
Asthmatics and other patients with chronic lung conditions made up just 13 percent of the population -- but 33 percent of the severe cases.
During the peak of severe illness, patients with the new flu strain filled between nine and 20 percent of all intensive care hospital beds in Australia and New Zealand.
In some hospitals, the pandemic filled all available beds in intensive care. New Zealand hospitals postponed non-essential surgery in July.
The greatest effect on ICU resources in a given region occurred about five to six weeks after the first confirmed winter admission.
The journal published the research as swine flu rates fell in the Southern Hemisphere, and the virus spread in most American states.
Indigenous groups were over-represented in the study: Maori (13.6 percent of the population) were 25 percent of the patients on this side of the Tasman.
Almost half of all patients (48.8 percent) had acute respiratory distress syndrome or viral pneumonitis, and 20.3 percent were diagnosed with bacterial pneumonia.
