title: Effects of varying levels of positive end-expiratory pressure on intracranial pressure and cerebral perfusion pressure.
abstract: OBJECTIVE
  To determine the influence of positive end-expiratory pressure (PEEP) on intracranial pressure and cerebral perfusion pressure.
  
  
  METHODS
  Neurosurgical intensive care patients requiring intracranial pressure monitoring and mechanical ventilation were studied in a randomized, controlled study.
  
  
  METHODS
  Tertiary care, neurosurgical intensive care unit.
  
  
  METHODS
  Eighteen patients were enrolled in the study. Patients had posttraumatic head injuries (n = 9), subarachnoid hemorrhage (n = 7), obstructive hydrocephalus (n = 1), and intracerebral hemorrhage of unknown cause (n = 1).
  
  
  METHODS
  Patients had PEEP levels of 5, 10, and 15 cm H2O applied to their lungs.
  
  
  RESULTS
  Changes in intracranial pressure, mean arterial pressure, and cerebral perfusion pressure were measured. The results were analyzed separately for patients with normal and increased intracranial pressure (> 15 mm Hg). PEEP at 5 cm H2O had no effect on intracranial pressure in the group with normal intracranial pressure. However, PEEP at 10 and 15 cm H2O produced a significant (p < .05) increase in intracranial pressure (1.9 and 1.5 mm Hg, respectively). In the group with increased intracranial pressure, no significant change in intracranial pressure occurred at any of the PEEP levels used. In both groups, cerebral perfusion pressure was unchanged throughout.
  
  
  CONCLUSIONS
  In patients with normal intracranial pressure, PEEP at 5 cm H2O did not significantly alter intracranial pressure. The clinical relevance of the intracranial pressure increase at PEEP levels of 10 and 15 cm H2O is questionable because cerebral perfusion pressure did not change and remained > 60 mm Hg. In patients with increased intracranial pressure, higher levels of PEEP did not significantly change intracranial pressure or cerebral perfusion pressure.
authors.affiliation: Department of Anaesthesia, Toronto Hospital, ON, Canada.
authors.forename: G
authors.initials: G
authors.lastname: McGuire
authors.forename: D
authors.initials: D
authors.lastname: Crossley
authors.forename: J
authors.initials: J
authors.lastname: Richards
authors.forename: D
authors.initials: D
authors.lastname: Wong
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000009:adverse effects