The Toll of Pandemic Influenza
The Toll of Pandemic Influenza
Kumar A, Zarychanski R, Pinto R, et al; Canadian Critical Care Trials Group H1N1 Collaborative
JAMA. 2009;302:1872-1879
The World Health Organization declared the first phase 6 global influenza pandemic of the century on June 11, 2009, as a result of 30,000 cases of novel H1N1 influenza A infection spanning 74 countries. The authors of this study aimed to describe the characteristics, treatments, and outcomes of critically ill patients with influenza A (H1N1) infection in 38 adult and pediatric intensive care units in Canada. The cohort included 168 patients with confirmed (n = 162) or probable (n = 6) community-acquired H1N1 infection. Mean patient age was 32.3 years; 67.3% were women and 29.8% were children. The median time from symptoms to hospital admission was 4 days and from hospitalization to intensive care unit admission, 1 day. Severe hypoxemia was common, with a mean arterial oxygen tension/fractional inspired oxygen ratio of 147 mm Hg. Mechanical ventilation was required by 81% of patients for an average of 12 days. Shock and nonpulmonary organ dysfunction were also common. Overall mortality was 14.3% at 28 days and 17.3% at 90 days.
The Centers for Disease Control and Prevention estimate that as of mid-January 2010, between 41 million and 84 million cases of H1N1 influenza have occurred in the United States. Estimates of H1N1-related hospitalization range from 183,000 to 378,000, and estimates of deaths number between 8330 and 17,160. In nearly all reports, most infections occurred among young adults. In addition to this study, a synchronous publication of H1N1 cases from Mexico echoed previous reports of increased rates of disease in obese patients (36% of patients in the Mexican cohort). Although chronic respiratory disease has not been a consistent risk factor for H1N1 infection, chronic comorbid medical conditions are disproportionately high in patients with H1N1 influenza. Fortunately, treatment with neuraminidase inhibitors is nearly universal and is associated with improved survival. At present, it seems that the pandemic phase of H1N1 disease may be waning, although vigilance remains important as sporadic cases continue to occur.
Critically Ill Patients With 2009 Influenza A(H1N1) Infection in Canada
Kumar A, Zarychanski R, Pinto R, et al; Canadian Critical Care Trials Group H1N1 Collaborative
JAMA. 2009;302:1872-1879
Study Summary
The World Health Organization declared the first phase 6 global influenza pandemic of the century on June 11, 2009, as a result of 30,000 cases of novel H1N1 influenza A infection spanning 74 countries. The authors of this study aimed to describe the characteristics, treatments, and outcomes of critically ill patients with influenza A (H1N1) infection in 38 adult and pediatric intensive care units in Canada. The cohort included 168 patients with confirmed (n = 162) or probable (n = 6) community-acquired H1N1 infection. Mean patient age was 32.3 years; 67.3% were women and 29.8% were children. The median time from symptoms to hospital admission was 4 days and from hospitalization to intensive care unit admission, 1 day. Severe hypoxemia was common, with a mean arterial oxygen tension/fractional inspired oxygen ratio of 147 mm Hg. Mechanical ventilation was required by 81% of patients for an average of 12 days. Shock and nonpulmonary organ dysfunction were also common. Overall mortality was 14.3% at 28 days and 17.3% at 90 days.
Viewpoint
The Centers for Disease Control and Prevention estimate that as of mid-January 2010, between 41 million and 84 million cases of H1N1 influenza have occurred in the United States. Estimates of H1N1-related hospitalization range from 183,000 to 378,000, and estimates of deaths number between 8330 and 17,160. In nearly all reports, most infections occurred among young adults. In addition to this study, a synchronous publication of H1N1 cases from Mexico echoed previous reports of increased rates of disease in obese patients (36% of patients in the Mexican cohort). Although chronic respiratory disease has not been a consistent risk factor for H1N1 infection, chronic comorbid medical conditions are disproportionately high in patients with H1N1 influenza. Fortunately, treatment with neuraminidase inhibitors is nearly universal and is associated with improved survival. At present, it seems that the pandemic phase of H1N1 disease may be waning, although vigilance remains important as sporadic cases continue to occur.
Source...