St. Boniface Hospital LogoAccording to a latest study, serious illness among Canadian patients with 2009 influenza A (H1N1) seemed to occur quickly after hospital admission, frequently in young adults. Additionally, it may possibly be associated with severely low levels of oxygen in the blood, multi-system organ failure, a need for prolonged mechanical ventilation, and regular use of rescue therapies.

It was believed that infection with the 2009 influenza A (H1N1) virus has been reported in almost all country in the world. It was estimated that the largest number of confirmed cases occurred in North America between March and July 2009.

The World Health Organization was noted to declare the first phase six global influenza pandemic of the century on June 11, 2009. Apparently, the first phase indicated widespread human infection.

For the purpose of the study, Anand Kumar along with his colleagues and the Canadian Critical Care Trials Group H1N1 Collaborative were believed to have conducted an observational study of critically ill patients with 2009 influenza A (H1N1).

They examined nearly 38 adult and pediatric intensive care units (ICUs) in Canada between April 16 and August 12, 2009. Supposedly, the study focused on the death rate at about 28 and 90 days, in addition to the occurrence and duration of mechanical ventilation and the duration of ICU stay.

The study findings revealed that a total of 168 patients appear to have confirmed or were likely to suffer from 2009 influenza A (H1N1) infection. Moreover, they seem to become critically ill during this time period, and 24 patients i.e. about 14.3 percent died within the first 28 days from the onset of critical illness.

It was observed that five more patients died within 90 days. The average age of the patients with confirmed or probable 2009 influenza A (H1N1) seem to be 32.3 years and nearly 113 patients were female i.e. 67.3 percent and approximately 50 patients appear to be children i.e. 29.8 percent.

“Our data suggest that severe disease and mortality in the current outbreak is concentrated in relatively healthy adolescents and adults between the ages of 10 and 60 years, a pattern reminiscent of the W-shaped curve (rise and fall in the population mortality rate for the disease, corresponding to age at death) previously seen only during the 1918 H1N1 Spanish pandemic,” elucidates Anand Kumar, M.D., of the Health Sciences Centre and St. Boniface Hospital, Winnipeg, Manitoba, Canada.

Kumar further stated that, “In conclusion, we have demonstrated that 2009 influenza A(H1N1) infection-related critical illness predominantly affects young patients with few major comorbidities and is associated with severe hypoxemic respiratory failure, often requiring prolonged mechanical ventilation and rescue therapies. With such therapy, we found that most patients can be supported through their critical illness.”

The study authors also found that patients suffering from 2009 influenza A (H1N1) infection-related critical illness seemed to have experienced symptoms for a median of nearly four days before entering the hospital. However, it appears to have worsened quickly thereby requiring care in the ICU within one or two days.

Furthermore, shock and multi-system organ failure seem to be common. Approximately 136 patients i.e. 81 percent were noted to have received mechanical ventilation with the median duration being 12 days. The average ICU stay appears to be for 12 days. Evidently, lung rescue therapies included neuromuscular blockade, inhaled nitric oxide and high-frequency oscillatory ventilation.

The findings of the study have been presented at a meeting of the European Society of Intensive Care Medicine.