title: Cerebral blood flow, oxidative metabolism and cerebrovascular carbon dioxide reactivity in patients with acute bacterial meningitis.
abstract: BACKGROUND
  The optimal arterial carbon dioxide tension (P(a)CO(2)) in patients with acute bacterial meningitis (ABM) is unknown and controversial. The objective of this study was to measure global cerebral blood flow (CBF), cerebrovascular CO(2) reactivity (CO(2)R), and cerebral metabolic rates (CMR) of oxygen (O(2)), glucose (glu), and lactate (lac), in patients with ABM and compare the results to those obtained in healthy volunteers.
  
  
  METHODS
  We studied 19 patients (17 of whom were sedated) with ABM and eight healthy volunteers (controls). CBF was measured during baseline ventilation and hyperventilation with single-photon emission computed tomography (SPECT) (14 patients) and/or the Kety-Schmidt technique (KS) (11 patients and all controls). In KS studies, CMR was measured by multiplying the arterial to jugular venous concentration difference (a-v D) by CBF.
  
  
  RESULTS
  CBF did not differ significantly among groups, although a larger variation was seen in patients than in controls. CO(2)R was not significantly different among groups. At baseline, patients had significantly lower a-v DO(2), CMR(O(2)), CMR(glu), and CMR(lac) than controls. CMR(O(2)) did not change between hyperventilation compared to baseline ventilation, whereas CMR(glu) increased.
  
  
  CONCLUSIONS
  In patients with acute bacterial meningitis, we found variable levels of CBF and cerebrovascular CO(2) reactivity, a low a-v DO(2), low cerebral metabolic rates of oxygen and glucose, and a cerebral lactate efflux. In these patients, a ventilation strategy guided by jugular bulb oximetry and/or repeated CBF measurements may be more optimal in terms of cerebral oxygenation than a strategy aiming at identical levels of P(a)CO(2) for all patients.
authors.affiliation: Department of Infectious Diseases, University Hospital Rigshospitalet, Copenhagen, Denmark. kirsten.moller@dadlnet.dk
authors.forename: K
authors.initials: K
authors.lastname: Møller
authors.forename: G I
authors.initials: GI
authors.lastname: Strauss
authors.forename: G
authors.initials: G
authors.lastname: Thomsen
authors.forename: F S
authors.initials: FS
authors.lastname: Larsen
authors.forename: S
authors.initials: S
authors.lastname: Holm
authors.forename: B K
authors.initials: BK
authors.lastname: Sperling
authors.forename: P
authors.initials: P
authors.lastname: Skinhøj
authors.forename: G M
authors.initials: GM
authors.lastname: Knudsen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001786:Blood Glucose / Q000378:metabolism; D001923:Brain Chemistry / Q000502:physiology; D002245:Carbon Dioxide / Q000097:blood*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D016920:Meningitis, Bacterial / Q000097:blood* / Q000503:physiopathology*; D008875:Middle Aged; D010084:Oxidation-Reduction; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D011446:Prospective Studies; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D001786:Blood Glucose; D002245:Carbon Dioxide; D019344:Lactic Acid; D010100:Oxygen