title: Critically ill children during the 2009-2010 influenza pandemic in the United States.
abstract: BACKGROUND
  The 2009 pandemic influenza A (H1N1) (pH1N1) virus continues to circulate worldwide. Determining the roles of chronic conditions and bacterial coinfection in mortality is difficult because of the limited data for children with pH1N1-related critical illness.
  
  
  METHODS
  We identified children (<21 years old) with confirmed or probable pH1N1 admitted to 35 US PICUs from April 15, 2009, through April 15, 2010. We collected data on demographics, baseline health, laboratory results, treatments, and outcomes.
  
  
  RESULTS
  Of 838 children with pH1N1 admitted to a PICU, the median age was 6 years, 58% were male, 70% had ≥1 chronic health condition, and 88.2% received oseltamivir (5.8% started before PICU admission). Most patients had respiratory failure with 564 (67.3%) receiving mechanical ventilation; 162 (19.3%) received vasopressors, and 75 (8.9%) died. Overall, 71 (8.5%) of the patients had a presumed diagnosis of early (within 72 hours after PICU admission) Staphylococcus aureus coinfection of the lung with 48% methicillin-resistant S aureus (MRSA). In multivariable analyses, preexisting neurologic conditions or immunosuppression, encephalitis (1.7% of cases), myocarditis (1.4% of cases), early presumed MRSA lung coinfection, and female gender were mortality risk factors. Among 251 previously healthy children, only early presumed MRSA coinfection of the lung (relative risk: 8 [95% confidence interval: 3.1-20.6]; P < .0001) remained a mortality risk factor.
  
  
  CONCLUSIONS
  Children with preexisting neurologic conditions and immune compromise were at increased risk of pH1N1-associated death after PICU admission. Secondary complications of pH1N1, including myocarditis, encephalitis, and clinical diagnosis of early presumed MRSA coinfection of the lung, were mortality risk factors.
authors: Children's Hospital Boston, Boston, MA 02115, USA. adrienne.randolph@childrens.harvard.edu
authors: Adrienne G
authors: AG
authors: Randolph
authors: Frances
authors: F
authors: Vaughn
authors: Ryan
authors: R
authors: Sullivan
authors: Lewis
authors: L
authors: Rubinson
authors: B Taylor
authors: BT
authors: Thompson
authors: Grace
authors: G
authors: Yoon
authors: Elizabeth
authors: E
authors: Smoot
authors: Todd W
authors: TW
authors: Rice
authors: Laura L
authors: LL
authors: Loftis
authors: Mark
authors: M
authors: Helfaer
authors: Allan
authors: A
authors: Doctor
authors: Matthew
authors: M
authors: Paden
authors: Heidi
authors: H
authors: Flori
authors: Christopher
authors: C
authors: Babbitt
authors: Ana Lia
authors: AL
authors: Graciano
authors: Rainer
authors: R
authors: Gedeit
authors: Ronald C
authors: RC
authors: Sanders
authors: John S
authors: JS
authors: Giuliano
authors: Jerry
authors: J
authors: Zimmerman
authors: Timothy M
authors: TM
authors: Uyeki
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D016638:Critical Illness; D005260:Female; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D058873:Pandemics; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology; D055815:Young Adult