Clinical characteristics and outcomes of patients with 2009 influenza A(H1N1) virus infection with respiratory failure requiring mechanical ventilation.
OBJECTIVE
The purpose of the study was to describe the clinical characteristics and outcomes of critically ill patients with 2009 influenza A(H1N1).


METHODS
An observational study of patients with confirmed or probable 2009 influenza A(H1N1) and respiratory failure requiring mechanical ventilation was performed.


RESULTS
We studied 96 patients (mean age, 45 [14] years [mean, SD]; 44% female). Shock and acute respiratory distress syndrome were diagnosed during the first 72 hours of admission in 43% and 72% of patients, respectively. Noninvasive positive pressure ventilation was used in 45% of the patients, but failed in 77% of them. Bacterial pneumonia was diagnosed in 33% of cases, 8% during the first week (due to community-acquired microorganisms) and 25% after the first week (due to gram-negative bacilli and resistant gram-positive cocci). Intensive care unit mortality was 50%. Nonsurvivors differed from survivors in the prevalence of cardiovascular, respiratory, and hematologic failure on admission and late pneumonia. Reported causes of death were refractory hypoxia, multiorgan failure, and shock (50%, 38%, and 12% of all causes of death, respectively).


CONCLUSIONS
Patients with 2009 influenza A(H1N1) and respiratory failure requiring mechanical ventilation often present with clinical criteria of acute respiratory distress syndrome and shock. Bacterial pneumonia is a frequent complication. Mortality is high and is primarily due to refractory hypoxia.
Nin
Nicolás
N
Hospital Universitario de Getafe & CIBER de Enfermedades Respiratorias, Madrid, Spain.
Soto
Luis
L
Hurtado
Javier
J
Lorente
José A
JA
Buroni
María
M
Arancibia
Francisco
F
Ugarte
Sebastian
S
Bagnulo
Homero
H
Cardinal
Pablo
P
Bugedo
Guillermo
G
Echevarría
Estrella
E
Deicas
Alberto
A
Ortega
Carlos
C
Frutos-Vivar
Fernando
F
Esteban
Andrés
A
D000328:Adult; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D000860:Hypoxia / Q000209:etiology / Q000401:mortality; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D009102:Multiple Organ Failure / Q000209:etiology / Q000401:mortality; D018410:Pneumonia, Bacterial / Q000150:complications / Q000401:mortality; D011175:Positive-Pressure Respiration; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000401:mortality*; D012720:Severity of Illness Index; D012769:Shock / Q000209:etiology / Q000401:mortality*