title: Pulmonary Function and Clinical Manifestations of Patients Infected with Mild Influenza A Virus Subtype H1N1: A One-Year Follow-Up.
abstract: OBJECTIVE
  To investigate the long-term effects of mild H1N1 influenza infection on the pulmonary function of a cohort of patients.
  
  
  METHODS
  Forty-eight patients, all diagnosed with influenza A virus subtype H1N1 in 2009, were retrospectively included in this study. Each patient in the study was monitored for 11-13 months by standard pulmonary function examination. The examination included monitoring respiratory tract infection symptoms (cough, expectoration or gasping) and vital signs. Long-term changes in symptoms and changes in vital signs were correlated back to and compared with the severity of the initial H1N1 influenza infection.
  
  
  RESULTS
  One year post discharge, mild to moderate pulmonary dysfunction was observed in the majority of patients. Further, 54.2% of patients had signs of severe abnormal pulmonary function, including diffusion disorder (33.3%) and small airway dysfunction (33.3%). Fourteen patients presented with respiratory tract infection symptoms; 12 with abnormal pulmonary function and two with normal pulmonary function. Our results indicated that the change in pulmonary function at one year post discharge was not significantly correlated with the severity of H1N1 influenza.
  
  
  CONCLUSIONS
  Signs and symptoms of abnormal pulmonary function accompanied by respiratory tract infection symptoms remain for some patients after one year following discharge from the hospital for mild influenza A virus subtype H1N1 infection. These patients should continue to be monitored for any changes in condition and symptoms and rehabilitation treatment should be provided when necessary.
authors.affiliation: Department of Respiratory Medicine, First Hospital, Jilin University, Changchun, 130021, Jilin Province, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Respiratory Medicine, First Hospital, Jilin University, Changchun, 130021, Jilin Province, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Peng
authors.affiliation: Department of Respiratory Medicine, First Hospital, Jilin University, Changchun, 130021, Jilin Province, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Respiratory Medicine, First Hospital, Jilin University, Changchun, 130021, Jilin Province, China.
authors.forename: Shucheng
authors.initials: S
authors.lastname: Hua
mesh_terms: D000328:Adult; D003371:Cough / Q000188:drug therapy / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000472:pathogenicity*; D007251:Influenza, Human / Q000503:physiopathology* / Q000821:virology; D008297:Male; D012129:Respiratory Function Tests; D012143:Respiratory Physiological Phenomena