title: S(+)-ketamine/propofol maintain dynamic cerebrovascular autoregulation in humans.
abstract: OBJECTIVE
  This study investigates the effects of S(+)-ketamine and propofol in comparison to sevoflurane on dynamic cerebrovascular autoregulation in humans.
  
  
  METHODS
  Twenty-four patients were randomly assigned to one of the following anesthetic protocols: group I (n=12): 2.5 mg.kg(-1)*hr(-1) S(+)-ketamine, 1.5-2.5 microg*mL(-1) propofol-target plasma concentration; group II (n=12): 2.0 MAC (4.0 %) sevoflurane. Patients were intubated and ventilated with O(2)/air (PaO(2)=0.33). Following 40 min of equilibration dynamic cerebrovascular autoregulation was measured and expressed as the autoregulatory index (ARI), describing the duration of cerebral hemodynamic recovery in relation to changes in mean arterial blood pressure.
  
  
  METHODS
  Mann-Whitney U test (statistical significance was assumed when P <0.05).
  
  
  RESULTS
  Dynamic cerebrovascular autoregulation was intact in all patients with S(+)-ketamine/propofol anesthesia as indicated by an ARI of 5.4 +/- 1.1. In contrast, dynamic cerebrovascular autoregulation was significantly delayed with 2.0 MAC sevoflurane (ARI=2.6 +/- 0.7) CONCLUSION: Dynamic cerebrovascular autoregulation is maintained with S(+)-ketamine/propofol-based total iv anesthesia. In contrast, 2.0 MAC sevoflurane delayed dynamic cerebrovascular autoregulation. This supports the use of S(+)-ketamine in combination with propofol in neurosurgical patients based on its neuroprotective potential along with maintained cerebrovascular physiology.
authors.affiliation: Klinik für Anaesthesiologie der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany. k.engelhard@lrz.tu-muenchen.de
authors.forename: K
authors.initials: K
authors.lastname: Engelhard
authors.forename: C
authors.initials: C
authors.lastname: Werner
authors.forename: O
authors.initials: O
authors.lastname: Möllenberg
authors.forename: E
authors.initials: E
authors.lastname: Kochs
mesh_terms: D000328:Adult; D000368:Aged; D000777:Anesthetics / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D005260:Female; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D015742:Propofol / Q000494:pharmacology*
chemical_list: D000777:Anesthetics; D007649:Ketamine; D015742:Propofol