title: Changes in Therapeutic Intensity Level Following Airway Pressure Release Ventilation in Severe Traumatic Brain Injury.
abstract: OBJECTIVE
  Airway pressure release ventilation (APRV) utilizes high levels of airway pressure coupled with brief expiratory release to facilitate open lung ventilation. The aim of our study was to evaluate the effects of APRV-induced elevated airway pressure mean in patients with severe traumatic brain injury.
  
  
  METHODS
  This was a retrospective cohort study at a 424-bed Level I trauma center. Linear mixed effects models were developed to assess the difference in therapeutic intensity level (TIL), intracranial pressure (ICP), and cerebral perfusion pressure (CPP) over time following the application of APRV.
  
  
  RESULTS
  The study included 21 epochs of APRV in 21 patients. In the 6-hour epoch following the application of APRV, the TIL was significantly increased ( P = .002) and the ICP significantly decreased ( P = .041) compared to that before 6 hours. There was no significant change in CPP ( P = .42) over time. The baseline static compliance and time interaction was not significant for TIL (χ2= 0.2 [ df 1], P = .655), CPP (χ2= 0 [ df 1], P = 1), or ICP (χ2= 0.1 [ df 1], P = .752).
  
  
  CONCLUSIONS
  Application of APRV in patients with severe traumatic brain injury was associated with significantly, but not clinically meaningful, increased TIL and decreased ICP. No significant change in CPP was observed. No difference was observed based on the baseline pulmonary static compliance.
authors.affiliation: 1 Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA.|2 Bronson Neuroscience Center, Bronson Methodist Hospital, Kalamazoo, MI, USA.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Fletcher
authors.affiliation: 1 Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Wilson
authors.affiliation: 1 Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA.|3 Department of Neurology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Venkatakrishna
authors.initials: V
authors.lastname: Rajajee
authors.affiliation: 4 Trauma, Burn, and Surgical Critical Care Program, Bronson Methodist Hospital, Kalamazoo, MI, USA.
authors.forename: Scott B
authors.initials: SB
authors.lastname: Davidson
authors.affiliation: 4 Trauma, Burn, and Surgical Critical Care Program, Bronson Methodist Hospital, Kalamazoo, MI, USA.
authors.forename: Jon C
authors.initials: JC
authors.lastname: Walsh
mesh_terms: D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D002560:Cerebrovascular Circulation / Q000502:physiology; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D005260:Female; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D012189:Retrospective Studies
keywords: brain injuries; cerebral perfusion pressure; intracranial pressure; mechanical ventilation; positive pressure respiration