MedWire News: Results of a study conducted in Australia and New Zealand show that 722 patients infected with the H1N1 influenza (swine flu) were admitted to intensive care units (ICUs) during the 2009 winter flu season, and these patients occupied up to nearly 20% of ICU beds when the epidemic was at its peak.
The findings, published in the New England Journal of Medicine, may help countries in the northern hemisphere prepare for the coming winter flu season, say Steven Webb (Royal Perth Hospital, Western Australia) and team.
The researchers studied data from all 187 ICUs in Australia and New Zealand for the winter period between June 1 and August 31 2009.
Analysis revealed that a total of 722 patients (28.7 per one million inhabitants) with confirmed swine flu were admitted to 109 ICUs during the study period, of whom 92.7% were under the age of 65 years.
The researchers also found that, although pregnant women represent approximately 1% of the general population of Australia and New Zealand, 9.1% of patients admitted to ICUs with swine flu were pregnant women.
Furthermore, although 5.3% of the general population of Australia and New Zealand have a body mass index greater than 35 kg/m2, 28.6% of 601 swine patients with available data admitted to ICUs had a BMI greater than this.
The median duration of treatment in the ICU was 7.0 days, but 456 (64.6%) of 706 patients with available data underwent mechanical ventilation for a median of 8 days.
Over the 3-month study period, 5.2% of ICU bed-days were accounted for by patients with swine flu, and the peak percentage of ICU beds occupied by infected patients ranged from 8.9% to 19.0%.
A total of 103 (14.3%) swine flu patients had died by September 7, and 114 (15.8%) were still in hospital at this time.
"Unlike previous 'seasonal' influenza strains, which impact heavily on elderly people and people with severe coexisting medical conditions, the H1N1 virus affected a different profile. Critical illness due to swine flu was most common in infants and middle-aged people; with pregnant patients, the overweight, and indigenous patients particularly affected,” commented Webb.
He added: “Overall, about one-third of patients admitted to an ICU because of swine flu had no underlying health problems."
The researchers conclude: “The 2009 H1N1 virus had a substantial effect on ICUs during the winter in Australia and New Zealand.
“Our data can assist planning for the treatment of patients during the winter in the northern hemisphere.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2009
Free full text
