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Critical illness in children with influenza A/pH1N1 2009 infection in Canada
Philippe Jouvet1, Jamie Hutchison, Ruxandra Pinto
1Department of Pediatrics, University of Montreal, Montreal, Quebec, Canada. philippe.jouvet@umontreal.ca
Insights
Critically ill children with pandemic influenza A (pH1N1) often had chronic conditions. While severe respiratory illness and prolonged ventilation were common, mortality was similar to seasonal influenza.
Area of Science:
- Pediatric critical care
- Infectious diseases
- Epidemiology
Background:
- The 2009 pandemic influenza A (pH1N1) virus presented a novel challenge to pediatric populations.
- Understanding the characteristics and outcomes of critically ill children is crucial for public health preparedness.
Purpose of the Study:
- To describe the clinical characteristics, treatment interventions, and outcomes of children with influenza A/pH1N1 infection admitted to Canadian pediatric intensive care units (PICUs).
Main Methods:
- An observational study was conducted in nine Canadian PICUs, analyzing data from 57 critically ill children with confirmed influenza A/pH1N1 infection between April and August 2009.
- Patient characteristics, including comorbidities and ethnicity, were recorded.
- Outcomes such as mechanical ventilation, acute lung injury, and mortality were assessed and compared with national surveillance data.
Main Results:
- 70.2% of critically ill children had at least one chronic comorbidity, and 24.6% were of aboriginal ethnicity.
- Mechanical ventilation was required in 68% of patients, with a median duration of 6 days.
- The PICU mortality rate was 7%, and critically ill children were more likely to have chronic medical conditions than those hospitalized but not in the ICU.
Conclusions:
- During the initial pH1N1 outbreak, severe illness disproportionately affected children with underlying chronic conditions and aboriginal children.
- Influenza A/pH1N1 infection in critically ill children was frequently associated with severe hypoxemic respiratory failure and extended mechanical ventilation.
- Despite the severity, the mortality rate for pH1N1-related critical illness in children did not exceed that of seasonal influenza.
Objective:
To describe characteristics, treatment, and outcomes of critically ill children with influenza A/pandemic influenza A virus (pH1N1) infection in Canada.
Design:
An observational study of critically ill children with influenza A/pH1N1 infection in pediatric intensive care units (PICUs).
Setting:
Nine Canadian PICUs.
Patients:
A total of 57 patients admitted to PICUs between April 16, 2009 and August 15, 2009.
Interventions:
None.
Measurements And Main Results:
Characteristics of critically ill children with influenza A/pH1N1 infection were recorded. Confirmed intensive care unit cases were compared with a national surveillance database containing all hospitalized pediatric patients with influenza A/pH1N1 infection. Risk factors were assessed with a Cox proportional hazard model. The PICU cohort and national surveillance data were compared, using chi-square tests. Fifty-seven children were admitted to the PICU for community-acquired influenza A/pH1N1 infection. One or more chronic comorbid illnesses were observed in 70.2% of patients, and 24.6% of patients were aboriginal. Mechanical ventilation was used in 68% of children, 20 children (35.1%) had acute lung injury on the first day of admission, and the median duration of ventilation was 6 days (range, 0-67 days). The PICU mortality rate was 7% (4 of 57 patients). When compared with nonintensive care unit hospitalized children, PICU children were more likely to have a chronic medical condition (relative risk, 1.73); aboriginal ethnicity was not a risk factor of intensive care unit admission.
Conclusions:
During the first outbreak of influenza A/pH1N1 infection, when the population was naïve to this novel virus, severe illness was common among children with underlying chronic conditions and aboriginal children. Influenza A/pH1N1-related critical illness in children was associated with severe hypoxemic respiratory failure and prolonged mechanical ventilation. However, this higher rate and severity of respiratory illness did not result in an increased mortality when compared with seasonal influenza.
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