Clinical course and outcomes of critically ill patients with SARS-CoV-2 pneumonia in Wuhan, China: a single-centered, retrospective, observational study.

Copyright © 2010 Massachusetts Medical Society. During the spring of 2009, a novel influenza A (H1N1) virus of swine origin caused human infection and acute respiratory illness in Mexico.1,2 After initially spreading among persons in the United States and Canada,3,4 the virus spread globally, resulting in the first influenza pandemic since 1968 with circulation outside the usual influenza season in the Northern Hemisphere (see the Supplementary Appendix, available with the full text of this article at NEJM.org). As of March 2010, almost all countries had reported cases, and more than 17,700 deaths among laboratory-confirmed cases had been reported to the World Health Organization (WHO).5 The number of laboratory-confirmed cases significantly underestimates the pandemic’s impact. In the United States, an estimated 59 million illnesses, 265,000 hospitalizations, and 12,000 deaths had been caused by the 2009 H1N1 virus as of mid-February 2010.6 This article reviews virologic, epidemiologic, and clinical data on 2009 H1N1 virus infections and summarizes key issues for clinicians worldwide.

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Clinical aspects of pandemic 2009 influenza A (H1N1) virus infection.

Critical care and the global burden of critical illness in adults

Context Early data on pandemic 2009 influenza A(H1N1) suggest pregnant women are at increased risk of hospitalization and death. Objective To describe the severity of 2009 influenza A(H1N1) illness and the association with early antiviral treatment among pregnant women in the United States. Design, Setting, and Patients Surveillance of 2009 influenza A(H1N1) in pregnant women reported to the Centers for Disease Control and Prevention (CDC) with symptom onset from April through December 2009. Main Outcome Measures Severity of illness (hospitalizations, intensive care unit [ICU] admissions, and deaths) due to 2009 influenza A(H1N1) among pregnant women, stratified by timing of antiviral treatment and pregnancy trimester at symptom onset. Results We received reports on 788 pregnant women in the United States with 2009 influenza A(H1N1) with symptom onset from April through August 2009. Among those, 30 died (5% of all reported 2009 influenza A[H1N1] influenza deaths in this period). Among 509 hospitalized women, 115 (22.6%) were admitted to an ICU. Pregnant women with treatment more than 4 days after symptom onset were more likely to be admitted to an ICU (56.9% vs 9.4%; relative risk [RR], 6.0; 95% confidence interval [CI], 3.5-10.6) than those treated within 2 days after symptom onset. Only 1 death occurred in a patient who received treatment within 2 days of symptom onset. Updating these data with the CDC's continued surveillance of ICU admissions and deaths among pregnant women with symptom onset through December 31, 2009, identified an additional 165 women for a total of 280 women who were admitted to ICUs, 56 of whom died. Among the deaths, 4 occurred in the first trimester (7.1%), 15 in the second (26.8%), and 36 in the third (64.3%); Conclusions Pregnant women had a disproportionately high risk of mortality due to 2009 influenza A(H1N1). Among pregnant women with 2009 influenza A(H1N1) influenza reported to the CDC, early antiviral treatment appeared to be associated with fewer admissions to an ICU and fewer deaths.

https://jamanetwork.com/journals/jama/articlepdf/185713/joc05037_1517_1525.pdf

Pandemic 2009 Influenza A(H1N1) Virus Illness Among Pregnant Women in the United States

Design, Setting, and Patients A cohort study in which ECMO-referred patients were defined as all patients with H1N1-related ARDS who were referred, accepted, and transferred to 1 of the 4 adult ECMO centers in the United Kingdom during the H1N1 pandemic in winter 2009-2010. The ECMO-referred patients and the non–ECMO-referred patients were matched using data from a concurrent, longitudinal cohort study (Swine Flu Triage study) of critically ill patients with suspected or confirmed H1N1. Detailed demographic, physiological, and comorbidity data were used in 3 different matching techniques (individual matching, propensity score matching, and GenMatch matching). Main Outcome Measure Survival to hospital discharge analyzed according to the intention-to-treat principle. Results Of 80 ECMO-referred patients, 69 received ECMO (86.3%) and 22 died (27.5%) prior to discharge from the hospital. From a pool of 1756 patients, there were 59 matched pairs of ECMO-referred patients and non–ECMO-referred patients identified using individual matching, 75 matched pairs identified using propensity score matching, and 75 matched pairs identified using GenMatch matching. The hospital mortality rate was 23.7% for ECMO-referred patients vs 52.5% for non–ECMO-referred patients (relative risk [RR], 0.45 [95% CI, 0.26-0.79];P=.006) when individual matching was used; 24.0% vs 46.7%, respectively (RR, 0.51 [95% CI, 0.31-0.81]; P=.008) when propensity score matching was used; and 24.0% vs 50.7%, respectively (RR, 0.47 [95% CI, 0.31-0.72]; P=.001) when GenMatch matching was used. The results were robust to sensitivity analyses, including amending the inclusion criteria and restricting the location where the non–ECMOreferred patients were treated. Conclusion For patients with H1N1-related ARDS, referral and transfer to an ECMO center was associated with lower hospital mortality compared with matched non–ECMO-referred patients.

https://jamanetwork.com/journals/jama/articlepdf/1104507/jce15004_1659_1668.pdf

Referral to an Extracorporeal Membrane Oxygenation Center and Mortality Among Patients With Severe 2009 Influenza A(H1N1)

Context In March 2009, novel 2009 influenza A(H1N1) was first reported in the southwestern United States and Mexico. The population and health care system in Mexico City experienced the first and greatest early burden of critical illness. Objective To describe baseline characteristics, treatment, and outcomes of consecutive critically ill patients in Mexico hospitals that treated the majority of such patients with confirmed, probable, or suspected 2009 influenza A(H1N1). Design, Setting, and Patients Observational study of 58 critically ill patients with 2009 influenza A(H1N1) at 6 hospitals between March 24 and June 1, 2009. Demographic data, symptoms, comorbid conditions, illness progression, treatments, and clinical outcomes were collected using a piloted case report form. Main Outcome Measures The primary outcome measure was mortality. Secondary outcomes included rate of 2009 influenza (A)H1N1−related critical illness and mechanical ventilation as well as intensive care unit (ICU) and hospital length of stay. Results Critical illness occurred in 58 of 899 patients (6.5%) admitted to the hospital with confirmed, probable, or suspected 2009 influenza (A)H1N1. Patients were young (median, 44.0 [range, 10-83] years); all presented with fever and all but 1 with respiratory symptoms. Few patients had comorbid respiratory disorders, but 21 (36%) were obese. Time from hospital to ICU admission was short (median, 1 day [interquartile range {IQR}, 0-3 days]), and all patients but 2 received mechanical ventilation for severe acute respiratory distress syndrome and refractory hypoxemia (median day 1 ratio of PaO 2 to fraction of inspired oxygen, 83 [IQR, 59-145] mm Hg). By 60 days, 24 patients had died (41.4%; 95% confidence interval, 28.9%-55.0%). Patients who died had greater initial severity of illness, worse hypoxemia, higher creatine kinase levels, higher creatinine levels, and ongoing organ dysfunction. After adjusting for a reduced opportunity of patients dying early to receive neuraminidase inhibitors, neuraminidase inhibitor treatment (vs no treatment) was associated with improved survival (odds ratio, 8.5; 95% confidence interval, 1.2-62.8). Conclusion Critical illness from 2009 influenza A(H1N1) in Mexico occurred in young individuals, was associated with severe acute respiratory distress syndrome and shock, and had a high case-fatality rate.Published online October 12, 2009 (doi:10.1001/jama.2009.1536).

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Marco A. Martinez

Papers

Critically Ill Patients With 2009 Influenza A(H1N1) in Mexico