title: Early neurovascular uncoupling in the brain during community acquired pneumonia.
abstract: BACKGROUND
  Sepsis leads to microcirculatory dysfunction and therefore a disturbed neurovascular coupling in the brain. To investigate if the dysfunction is also present in less severe inflammatory diseases we studied the neurovascular coupling in patients suffering from community acquired pneumonia.
  
  
  METHODS
  Patients were investigated in the acute phase of pneumonia and after recovery. The neurovascular coupling was investigated with a simultaneous electroencephalogram (EEG)-Doppler technique applying a visual stimulation paradigm. Resting EEG frequencies, visual evoked potentials as well as resting and stimulated hemodynamic responses were obtained. Disease severity was characterized by laboratory and cognitive parameters as well as related scoring systems. Data were compared to a control group.
  
  
  RESULTS
  Whereas visually evoked potentials (VEP) remained stable a significant slowing and therefore uncoupling of the hemodynamic responses were found in the acute phase of pneumonia (Rate time: control group: 3.6 ± 2.5 vs. acute pneumonia: 1.6 ± 2.4 s; P < 0.0005). In the initial investigation, patients who deteriorated showed a decreased hemodynamic response as compared with those who recovered (gain: recovered: 15% ± 4% vs. deteriorated: 9% ± 3%, P < 0.05; control: 14% ± 5%). After recovery the coupling normalized.
  
  
  CONCLUSIONS
  Our study underlines the role of an early microcirculatory dysfunction in inflammatory syndromes that become evident in pre-septic conditions with a gradual decline according to disease severity.
authors.affiliation: Department of Neurology, Justus-Liebig University of Giessen, Klinikstrasse 33, 35392 Giessen, Germany. bernhard.rosengarten@neuro.med.uni-giessen.de
authors.forename: Bernhard
authors.initials: B
authors.lastname: Rosengarten
authors.forename: Dennis
authors.initials: D
authors.lastname: Krekel
authors.forename: Stefan
authors.initials: S
authors.lastname: Kuhnert
authors.forename: Richard
authors.initials: R
authors.lastname: Schulz
mesh_terms: D018806:APACHE; D000465:Algorithms; D000704:Analysis of Variance; D001783:Blood Flow Velocity / Q000502:physiology; D001927:Brain Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation / Q000502:physiology*; D017714:Community-Acquired Infections / Q000503:physiopathology*; D004569:Electroencephalography; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D011014:Pneumonia / Q000503:physiopathology*; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D017585:Ultrasonography, Doppler, Transcranial