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October 12, 2009JAMA news releases are made available to the public after 3 pm US Central time on the first 4 Tuesdays of each month. The Archives of Journals news releases are made available to the public after 3 pm Central time on Mondays. We also provide a list of previous news releases. THIS WEEK'S CONTENTS
JAMA NEWS RELEASES
(Embargoed for Early Release: 9 a.m. CT Monday, October 12, 2009)
INFORMATION CONTAINED IN THESE NEWS RELEASES IS PROTECTED BY COPYRIGHT. JOURNAL ATTRIBUTION IS REQUIRED. JOURNALISTS CAN NOW ACCESS EMBARGOED JAMA/ARCHIVES STUDIES ON-LINE. Go to www.jamamedia.org for more information and to apply for access. Please Note: The FOR THE MEDIA website now has a search feature to enable media to find previous JAMA/Archives news releases on specific medical topics. This search feature link is located on the home page at www.jamamedia.org EMBARGOED FOR RELEASE UNTIL 9 A.M. (CT), Monday, October 12, 2009
H1N1 Critical Illness Can Occur Rapidly; Predominantly Affects Young Patients
CHICAGO—Critical illness among Canadian patients with 2009 influenza A(H1N1) occurred rapidly after hospital admission, often in young adults, and was associated with severely low levels of oxygen in the blood, multi-system organ failure, a need for prolonged mechanical ventilation, and frequent use of rescue therapies, according to a study to appear in the November 4 issue of JAMA. This study is being published early online to coincide with its presentation at a meeting of the European Society of Intensive Care Medicine. Infection with the 2009 influenza A(H1N1) virus has been reported in virtually every country in the world. The World Health Organization declared the first phase six (phase indicating widespread human infection) global influenza pandemic of the century on June 11, 2009. The largest number of confirmed cases occurred in North America between March and July 2009, according to background information in the article. Anand Kumar, M.D., of the Health Sciences Centre and St. Boniface Hospital, Winnipeg, Manitoba, Canada, and colleagues with the Canadian Critical Care Trials Group H1N1 Collaborative conducted an observational study of critically ill patients with 2009 influenza A(H1N1) in 38 adult and pediatric intensive care units (ICUs) in Canada between April 16 and August 12, 2009. The study focused on the death rate at 28 and 90 days, as well as the frequency and duration of mechanical ventilation and the duration of ICU stay. The researchers found that a total of 168 patients had confirmed or probable 2009 influenza A(H1N1) infection and became critically ill during this time period, and 24 (14.3 percent) died within the first 28 days from the onset of critical illness. Five more patients died within 90 days. The average age of the patients with confirmed or probable 2009 influenza A(H1N1) was 32.3 years, 113 were female (67.3 percent), and 50 were children (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," the authors write. Patients with 2009 influenza A(H1N1) infection-related critical illness experienced symptoms for a median (midpoint) of four days before entering the hospital, but worsened rapidly and required care in the ICU within one or two days. Shock and multi-system organ failure were common, and 136 patients (81 percent) received mechanical ventilation, with the median duration being 12 days. The average ICU stay was 12 days. Lung rescue therapies included neuromuscular blockade, inhaled nitric oxide and high-frequency oscillatory ventilation.
"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," the authors write. "With such therapy, we found that most patients can be supported through their critical illness."
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. Editorial: Preparing for the Sickest Patients With 2009 Influenza A(H1N1)
In an accompanying editorial, Douglas B. White, M.D., M.A.S., and JAMA Contributing Editor Derek C. Angus, M.D., M.P.H., of the University of Pittsburgh School of Medicine, write that many U.S. hospitals may not have adequate numbers of physicians or staffing structures to facilitate timely treatment of the most seriously ill patients with 2009 influenza A(H1N1).
"Hospitals must develop explicit policies to equitably determine who will and will not receive life support should absolute scarcity occur," they write. "Any deaths from 2009 influenza A(H1N1) will be regrettable, but those that result from insufficient planning and inadequate preparation will be especially tragic," they conclude.
Editor's Note: Please see the article for additional information, including financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org. EMBARGOED FOR RELEASE UNTIL 9 A.M. (CT), Monday, October 12, 2009
Critical Illness From 2009 H1N1 in Mexico Associated With High Fatality Rate
CHICAGO—Critical illness from 2009 influenza A(H1N1) in Mexico occurred among young patients, was associated with severe acute respiratory distress syndrome and shock, and had a fatality rate of about 40 percent, according to a study to appear in the November 4 issue of JAMA. This study is being published early online to coincide with its presentation at a meeting of the European Society of Intensive Care Medicine. Novel 2009 influenza A(H1N1) was first reported in the southwestern United States and Mexico in March 2009. Between March 18 and June 1, 2009, 5,029 cases and 97 documented deaths occurred in Mexico. The population and health care system in Mexico City experienced the first and greatest early burden of critical illness, according to background information in the article. Guillermo Domínguez-Cherit, M.D. of Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán," Mexico City, and colleagues conducted an observational study of critically ill patients at six hospitals in Mexico that treated the majority of such patients with confirmed, probable, or suspected 2009 influenza A(H1N1) between March 24 and June 1, 2009. The study focused on the death rate, rate of critical illness and mechanical ventilation, and length of stay in the hospital and the intensive care unit. Among 899 patients admitted to hospitals with confirmed, probable, or suspected 2009 influenza A(H1N1), 58 became critically ill. The critically ill patients had a median (midpoint) age of 44 years. Most were treated with antibiotics, and 45 patients were treated with anti-influenza drugs known as neuraminidase inhibitors, including oseltamivir and zanamivir. Fifty-four patients required mechanical ventilation. "Our analysis of critically ill patients with 2009 influenza A(H1N1) reveals that this disease affected a young patient group," the authors write. "Fever and respiratory symptoms were harbingers of disease in almost all cases. There was a relatively long period of illness prior to presentation to the hospital, followed by a short period of acute and severe respiratory deterioration." By 60 days, 24 of the critically ill patients (41.4 percent) died. Nineteen patients died within the first two weeks after becoming critically ill. "Patients who died had greater initial severity of illness, worse hypoxemia [abnormally low levels of oxygen in the blood], higher creatinine kinase levels, higher creatinine levels, and ongoing organ dysfunction," the authors report.
"Early recognition of disease by the consistent symptoms of fever and a respiratory illness during times of outbreak, with prompt medical attention including neuraminidase inhibitors and aggressive support of oxygenation failure and subsequent organ dysfunction, may provide opportunities to mitigate the progression of illness and mortality observed in Mexico," they conclude.
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org. EMBARGOED FOR RELEASE UNTIL 9 A.M. (CT), Monday, October 12, 2009
Most H1N1 Patients With Respiratory Failure Treated With Oxygenating System Survive Illness
CHICAGO—Despite the severity of disease and the intensity of treatment, most patients in Australia and New Zealand who experienced respiratory failure as a result of 2009 influenza A(H1N1) and were treated with a system that adds oxygen to the patient's blood survived the disease, according to a study to appear in the November 4 issue of JAMA. This study is being published early online because of its public health importance. The influenza A(H1N1) pandemic affected Australia and New Zealand during the 2009 southern hemisphere winter, causing an epidemic of critical illness. Some patients developed severe acute respiratory distress syndrome (ARDS) and were treated with extracorporeal membrane oxygenation (ECMO), according to background information in the article. ARDS is a lung condition that leads to respiratory failure due to the rapid accumulation of fluid in the lungs. ECMO is a type of life support that circulates blood through a system that adds oxygen. ECMO was used for the patients in this study because they developed very low blood oxygen levels that developed rapidly despite standard ventilator (or respirator) settings. ECMO is generally used for a limited time because of the risks of bleeding, clotting, infection, and organ failure. The Australia and New Zealand Extracorporeal Membrane Oxygenation (ANZ ECMO) Influenza Investigators in collaboration with the Australian and New Zealand Intensive Care Research Centre at Monash University in Melbourne, conducted an observational study of patients with 2009 influenza A(H1N1)-associated ARDS treated with ECMO in 15 intensive care units (ICUs) in Australia and New Zealand between June 1 and August 31, 2009. The researchers looked at incidence, clinical features, the degree of lung dysfunction, technical characteristics, the duration of ECMO, complications, and survival. The study found that 68 patients with severe influenza-associated ARDS were treated with ECMO, including 53 with confirmed 2009 influenza A(H1N1). An additional 133 patients with influenza A received mechanical ventilation, but not ECMO, in the same ICUs. The 68 patients who received ECMO had a median (midpoint) age of 34.4 years and half were men. "Affected patients were often young adults, pregnant or postpartum, obese, had severe respiratory failure before ECMO, and received prolonged mechanical ventilation and ECMO support," the authors write. The median duration of ECMO support was ten days. At the time of reporting, 54 of the 68 patients had survived and 14 (21 percent) had died. Six patients remained in ICU, including two who were still receiving ECMO. Sixteen patients were still hospitalized, but out of ICU, and 32 had been discharged from the hospital.
"Despite their illness severity and the prolonged use of life support, most of these patients survived," the authors conclude. "This information should facilitate health care planning and clinical management for these complex patients during the ongoing pandemic."
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org. |
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