Pandemic and post-pandemic Influenza A (H1N1) infection in critically ill patients

Martin-Loeches et al. Critical Care Pandemic and post-pandemic Influenza A (H1N1) infection in critically ill patients Ignacio Martin-Loeches 0 2 4 Emili Daz 2 Loreto Vidaur 1 Antoni Torres 8 Cesar Laborda 7 Rosa Granada 6 Juan Bonastre 5 Mar Martn 10 Josu Insausti 9 Angel Arenzana 3 Jose Eugenio Guerrero 13 Ines Navarrete 14 Jesus Bermejo-Martin 11 David Suarez 12 Alejandro Rodriguez 2 for the H 0 4 N 0 4 SEMICYUC/REIPI/CIBERES Working group 0 Critical Care Center, Parc Tauli Hospital-Sabadell, CIBERes , Sabadell , Spain 1 Critical Care Department, Hospital Donostia/CIBERES - San Sebastian , Spain 2 Critical Care Department, Hospital Joan XXIII/CIBERES/IISPV/URV- Tarragona , Spain 3 Critical Care Department, Hospital V. de la Macarena/CIBERES - Sevilla , Spain 4 Critical Care Center, Parc Tauli Hospital-Sabadell, CIBERes , Sabadell , Spain 5 Critical Care Department, Hospital La Fe -Valencia , Spain 6 Critical Care Department, Hospital de Bellvitge/CIBERES - Barcelona , Spain 7 Critical Care Department. Hospital Vall d'Hebron/CIBERES/IRVH - Barcelona , Spain 8 Pneumology Department, Hospital Clinic of Barcelona, IDIBAPS, Centro de Investigacion Biomedica en Red-Enfermedades Respiratorias (CIBERES, CB06/06/0028), University of Barcelona , Barcelona , Spain 9 Critical Care Department, Hospital de Navarra - Pamplona , Spain 10 Critical Care Department, Hospital La Candelaria - Tenerife , Spain 11 Infection and Immunity Unit, Hospital Clinico Universitario-IECSCYL , Valladolid , Spain 12 Epidemiology and Assessment Unit, Fundacio Parc Tauli, Universitat Autonoma de Barcelona , Sabadell , Spain 13 Critical Care Department, Hospital G.Maranon/CIBERES - Madrid , Spain 14 Critical Care Department, Hospital V. de las Nieves - Granada , Spain Background: There is a vast amount of information published regarding the impact of 2009 pandemic Influenza A (pH1N1) virus infection. However, a comparison of risk factors and outcome during the 2010-2011 post-pandemic period has not been described. Methods: A prospective, observational, multi-center study was carried out to evaluate the clinical characteristics and demographics of patients with positive RT-PCR for H1N1 admitted to 148 Spanish intensive care units (ICUs). Data were obtained from the 2009 pandemic and compared to the 2010-2011 post-pandemic period. Results: Nine hundred and ninety-seven patients with confirmed An/H1N1 infection were included. Six hundred and forty-eight patients affected by 2009 (pH1N1) virus infection and 349 patients affected by the post-pandemic Influenza (H1N1)v infection period were analyzed. Patients during the post-pandemic period were older, had more chronic comorbid conditions and presented with higher severity scores (Acute Physiology And Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA)) on ICU admission. Patients from the post-pandemic Influenza (H1N1)v infection period received empiric antiviral treatment less frequently and with delayed administration. Mortality was significantly higher in the post-pandemic period. Multivariate analysis confirmed that haematological disease, invasive mechanical ventilation and continuous renal replacement therapy were factors independently associated with worse outcome in the two periods. HIV was the only new variable independently associated with higher ICU mortality during the post-pandemic Influenza (H1N1)v infection period. Conclusion: Patients from the post-pandemic Influenza (H1N1)v infection period had an unexpectedly higher mortality rate and showed a trend towards affecting a more vulnerable population, in keeping with more typical seasonal viral infection. - Introduction There is a vast amount of information published regarding the impact of the 2009 pandemic Influenza A (H1N1)v infection [1,2]. The pandemic represented a challenge for physicians worldwide, manifesting with the acute onset of respiratory failure in a patient population often young, with few comorbid conditions. Several recommendations have been considered, taking into account the literature published during this time. The early use of oseltamivir showed a survival benefit [3,4], while the use of systemic corticosteroids did not [5,6]. Identification of risk factors, such as the presence of community acquired respiratory co-infection (CARC) [7], obesity [8] and the development of acute kidney injury, have helped physicians gain a better understanding of the illness [9]. Health authorities warned that clinical suspicion should be maintained following the initial pandemic, with a post-pandemic period predicted for the 20102011 winter as a result of the former A/H1N1 2009 pandemic virus, currently called new A/H1N1 virus (An/H1N1) [10]. The aim of the present study was to compare risk factors, clinical features and outcomes in pandemic influenza An/H1N1 patients with those observed in the immediate post-pandemic influenza period. Material and methods This prospective, observation (...truncated)