Should lower respiratory tract secretions from intensive care patients be systematically screened for influenza virus during the influenza season?
Crit Care. 2012 Jun 14;16(3):R104
Authors: Giannella M, Rodriguez-Sanchez B, Lopez Roa P, Catalan P, Munoz P, Garcia Viedma D, Bouza E, Gang GM
ABSTRACT: INTRODUCTION: Influenza is easily overlooked in intensive care units (ICU), particularly in patients with alternative causes of respiratory failure or in those who acquire influenza during their ICU stay. METHODS: We performed a prospective study of patients admitted to 3 adult ICUs of our hospital from December 2010 to February 2011. All tracheal aspirate (TA) samples sent to the microbiology department were systematically screened for influenza. We defined influenza as unsuspected if testing was not requested and the patient was not on empirical antiviral therapy after sample collection. RESULTS: We received TA samples from 105 patients. Influenza was detected in 31 patients and was classified as unsuspected in 15 patients (48.4%) and as hospital-acquired in 13 (42%) patients. Suspected and unsuspected cases were compared, and significant differences were found for age (53 vs. 69 median years), severe respiratory failure (68.8% vs. 20%), surgery (6.3% vs. 60%), median days of ICU stay before diagnosis (1 vs. 4), nosocomial infection (18.8% vs. 66.7%), cough (93.8% vs. 53.3%), localized infiltrate on chest x-ray (6.3% vs. 40%), median days to antiviral treatment (2 vs. 9), pneumonia (93.8% vs. 53.3%), and acute respiratory distress syndrome (75% vs. 26.7%). Multivariate analysis showed admission to the surgical ICU (OR 37.1, 95%CI 2.1 - 666.6, p=0.01) and localized infiltrate on chest x-ray (OR 27.8, 95%CI 1.3-584.1, p=0.03) to be independent risk factors for unsuspected influenza. Overall mortality at 30 days was 29%. ICU admission for severe respiratory failure was an independent risk factor for poor outcome. CONCLUSION: During the influenza season, almost one-third of critical patients with suspected lower respiratory tract infection had influenza, and in 48.4% the influenza was unsuspected. Lower respiratory samples from adult ICUs should be systematically screened for influenza during seasonal epidemics.
PMID: 22697813 [PubMed - as supplied by publisher]