title: Evaluation of noninvasive positive pressure ventilation after extubation from moderate positive end-expiratory pressure level in patients undergoing cardiovascular surgery: a prospective observational study.
abstract: BACKGROUND
  It remains to be clarified if the application of noninvasive positive pressure ventilation (NPPV) is effective after extubation in patients with hypoxemic respiratory failure who require the sufficient level of positive end-expiratory pressure (PEEP). This study was aimed at examining the effect and the safety of NPPV application following extubation in patients requiring moderate PEEP level for sufficient oxygenation after cardiovascular surgery.
  
  
  METHODS
  With institutional ethic committee approval, the patients ventilated invasively for over 48 h after cardiovascular surgery were enrolled in this study. The patients who failed the first spontaneous breathing trial (SBT) at 5 cmH2O of PEEP, but passed the second SBT at 8 cmH2O of PEEP, received NPPV immediately after extubation following our weaning protocol. Respiratory parameters (partial pressure of arterial oxygen tension to inspiratory oxygen fraction ratio: P/F ratio, respiratory ratio, and partial pressure of arterial carbon dioxide: PaCO2) 2 h after extubation were evaluated with those just before extubation as the primary outcome. The rate of re-intubation, the frequency of respiratory failure and intolerance of NPPV, the duration of NPPV, and the length of intensive care unit (ICU) stay were also recorded.
  
  
  RESULTS
  While 51 postcardiovascular surgery patients were screened, 6 patients who met the criteria received NPPV after extubation. P/F ratio was increased significantly after extubation compared with that before extubation (325 ± 85 versus 245 ± 55 mmHg, p < 0.05). The other respiratory parameters did not change significantly. Re-intubation, respiratory failure, and intolerance of NPPV never occurred. The duration of NPPV and the length of ICU stay were 2.7 ± 0.7 (SD) and 7.5 (6 to 10) (interquartile range) days, respectively.
  
  
  CONCLUSIONS
  While further investigation should be warranted, NPPV could be applied effectively and safely after extubation in patients requiring the moderate PEEP level after cardiovascular surgery.
authors.affiliation: Department of Anesthesiology and General Intensive Care Unit, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Anesthesia, Kawasaki Municipal Hospital, 12-1 Shinkawadori, Kawasaki-ku, Kawasaki-shi, Kanagawa 210-0013 Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kurazumi
authors.affiliation: Department of Anesthesia, Kawasaki Municipal Hospital, 12-1 Shinkawadori, Kawasaki-ku, Kawasaki-shi, Kanagawa 210-0013 Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Toyonaga
authors.affiliation: Department of Anesthesia, Kawasaki Municipal Hospital, 12-1 Shinkawadori, Kawasaki-ku, Kawasaki-shi, Kanagawa 210-0013 Japan.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Masuda
authors.affiliation: Department of Anesthesia, Kawasaki Municipal Hospital, 12-1 Shinkawadori, Kawasaki-ku, Kawasaki-shi, Kanagawa 210-0013 Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Morita
authors.affiliation: Department of Anesthesia, Kawasaki Municipal Hospital, 12-1 Shinkawadori, Kawasaki-ku, Kawasaki-shi, Kanagawa 210-0013 Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Masuda
authors.affiliation: Department of Anesthesiology and General Intensive Care Unit, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 Japan.
authors.forename: Shizuko
authors.initials: S
authors.lastname: Kosugi
authors.affiliation: Department of Anesthesiology and General Intensive Care Unit, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Katori
authors.affiliation: Department of Anesthesiology and General Intensive Care Unit, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morisaki
keywords: Cardiovascular surgery; Invasive mechanical ventilation; Moderate PEEP level; Noninvasive positive pressure ventilation; Weaning