title: Prognostic evaluation by oxygenation with positive end-expiratory pressure in acute exacerbation of idiopathic pulmonary fibrosis: A retrospective cohort study.
abstract: BACKGROUND
  Acute exacerbation (AE) is a severe complication of idiopathic pulmonary fibrosis (IPF), which shares some common pathological features with acute respiratory distress syndrome (ARDS). The new definition of ARDS requires positive end-expiratory pressure (PEEP) to assess gas exchange and has better predictive validity for short-term mortality compared with the previous definition.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the prognostic utility of oxygenation with PEEP in AE-IPF.
  
  
  METHODS
  We performed a retrospective cohort study using the data of AE-IPF patients between 2007 and 2015. At the time of diagnosis, PaO2/FiO2was evaluated before and 30 minutes after PEEP. We evaluated the prognostic utility of PaO2/FiO2with PEEP after including other candidate prognostic factors. Considering the definition of ARDS, patients with AE-IPF were classified into a severe group (PaO2/FiO2≤ 300 with PEEP) and a non-severe group (PaO2/FiO2> 300 with PEEP).
  
  
  RESULTS
  We identified 62 consecutive patients with AE-IPF. All patients were treated with mechanical ventilation on the first day. The median PaO2/FiO2before and 30 minutes after PEEP was significantly increased (237.5-425.5, P < .001). In multivariate Cox proportional analysis, Krebs von den Lungen-6 (KL-6) (HR 1.239; 95%CI 1.050-1.461; P = .011), D-dimer (HR 1.039; 95%CI 1.015-1.064; P = .001), % neutrophils in bronchoalveolar lavage fluid (HR 1.015; 95%CI 1.003-1.027; P = .017), and being in the severe group (HR 3.233; 95%CI 1.503-6.957; P = .003) had significant impacts on survival up to 90 days.
  
  
  CONCLUSIONS
  Evaluation of oxygenation with PEEP may provide useful information for predicting short-term mortality in patients with AE-IPF.
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Aichi, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Aichi, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Taniguchi
authors.affiliation: Center for Advanced Medicine and Clinical Research, Nagoya University, Hospital, Nagoya, Aichi, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ando
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Aichi, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kondoh
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Aichi, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Aichi, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kataoka
authors.affiliation: Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Matsuda
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Aichi, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Sakamoto
authors.affiliation: Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Hasegawa
mesh_terms: D000368:Aged; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D018450:Disease Progression; D004452:Echocardiography / Q000379:methods; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000166:cytology; D010100:Oxygen / Q000378:metabolism / Q000627:therapeutic use*; D011175:Positive-Pressure Respiration / Q000295:instrumentation*; D011379:Prognosis; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012121:Respiration, Artificial / Q000379:methods; D012128:Respiratory Distress Syndrome / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D012189:Retrospective Studies
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D; D010100:Oxygen
keywords: acute exacerbation; acute respiratory distress syndrome; idiopathic pulmonary fibrosis; mechanical ventilation; positive end-expiratory pressure