Long-term Outcome and Lung Capacity in Survivors of ARDS Due to Influenza A (H1N1) v2009 The RESPIFLU Study
Condition: Influenza; Pneumonia, Viral; Pulmonary Fibrosis; Quality of Life; Stress Disorders, Post Traumatic
MeSH terms: Influenza, Human; Pneumonia, Viral; Pulmonary Fibrosis; Stress Disorders, Post-Traumatic
Study type: Observational

Summary: 
      Influenza A (H1N1) v2009 infection was responsible throughout the world of viral pneumonia
      and severe pulmonary edema requiring rescue therapeutics such as extracorporeal oxygenation.
      To date, no data exist on the outcome of patients having developed acute respiratory distress
      syndrome (ARDS) due to influenza A (H1N1) v2009, and in particular in patients with very
      severe lung injury requiring extracorporeal oxygenation. Although data exist on long-term
      outcome of survivors of ARDS, the patients included in the observational studies were
      heterogeneous with various underlying disease. Moreover, no study compared the outcome of
      survivors of ARDS according to the need or not of extracorporeal oxygenation. We therefore
      conducted this prospective case-control study to compare the long term pulmonary and extra
      pulmonary function in 2 groups of patients, one with severe ARDS due to H1N1 requiring
      extracorporeal oxygenation (case), and the second with ARDS due to H1N1 but without need for
      extracorporeal oxygenation (control). Eighteen case patients with inclusion and without
      non-inclusion criteria were selected from our national registry, and 32 controls (with
      inclusion and exclusion criteria) were matched on age, sex, and body mass index. All 48
      patients will be contacted and asked to participate. Patients will be evaluate at least 9
      months after ICU discharge, looking for health-related quality of life, measured by the
      Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36), post traumatic
      stress disorder, assessed by the Impact of Event Scale Anxiety, and depression, assessed by
      the Hospital and Depression Score. Pulmonary function testing, including VO2 max test on a
      static bike will be performed. Muscle weakness will be clinically evaluated by the medical
      council research (MRC) test, with an additional electromyography if the result of the test
      was <48/60. A CT-scan will be performed, looking for lung abnormalities (fibrosis...).
      Albumin and prealbumin will be measured to evaluate the nutritional status.

      Primary outcome measurement is carbon monoxide diffusion capacity. The primary hypothesis is
      that patients with extracorporeal oxygenation will have a carbon monoxide diffusion capacity
      lower than patients without extracorporeal oxygenation (15% difference between groups).
      Inclusion of 13 patients in the case group and 26 patients in the control group will allow
      testing this hypothesis with a statistical power of 80% (standard deviation 15%). Secondary
      outcome measures will be the quality of life, the presence or not of post-traumatic stress
      disorders, of anxiety and/or depression, the results of pulmonary function testing, of the
      CT-scan, and of muscle testing. All results will be compared in patients with and without
      extracorporeal oxygenation.
    


Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Two groups of survivors of severe acute respiratory distress syndrome due to influenza A
        H1N1 infection will be recruited; the first required extracorporeal oxygenation at the time
        of viral infection, and the second did not require extracorporeal oxygenation at the time
        of viral infection. Patients will be recruited at least 9 months after ICU discharge.
        Eighteen case patients matching inclusion and non-inclusion criteria were selected from our
        national registry, and 32 controls (with inclusion and exclusion criteria) were matched on
        age, sex, and body mass index.