title: Impaired cerebrovascular autoregulation in patients with severe sepsis and sepsis-associated delirium.
abstract: BACKGROUND
  Sepsis-associated delirium (SAD) increases morbidity in septic patients and, therefore, factors contributing to SAD should be further characterized. One possible mechanism might be the impairment of cerebrovascular autoregulation (AR) by sepsis, leading to cerebral hypo- or hyperperfusion in these haemodynamically unstable patients. Therefore, the present study investigates the relationship between the incidence of SAD and the status of AR during sepsis.
  
  
  METHODS
  Cerebral blood flow velocity was measured using transcranial Doppler sonography and was correlated with the invasive arterial blood pressure curve to calculate the index of AR Mx (Mx>0.3 indicates impaired AR). Mx was measured daily during the first 4 days of sepsis. Diagnosis of a SAD was performed using the confusion assessment method for ICU (CAM-ICU) and, furthermore the predominant brain electrical activity in electroencephalogram (EEG) both at day 4 after reduction of sedation to RASS >-2.
  
  
  RESULTS
  30 critically ill adult patients with severe sepsis or septic shock (APACHE II 32 ± 6) were included. AR was impaired at day 1 in 60%, day 2 in 59%, day 3 in 41% and day 4 in 46% of patients; SAD detected by CAM-ICU was present in 76 % of patients. Impaired AR at day 1 was associated with the incidence of SAD at day 4 (p = 0.035).
  
  
  CONCLUSIONS
  AR is impaired in the great majority of patients with severe sepsis during the first two days. Impaired AR is associated with SAD, suggesting that dysfunction of AR is one of the trigger mechanisms contributing to the development of SAD.
  
  
  BACKGROUND
  clinicalTrials.gov ID NCT01029080.
authors.forename: Patrick
authors.initials: P
authors.lastname: Schramm
authors.forename: Klaus Ulrich
authors.initials: KU
authors.lastname: Klein
authors.forename: Lena
authors.initials: L
authors.lastname: Falkenberg
authors.forename: Manfred
authors.initials: M
authors.lastname: Berres
authors.forename: Dorothea
authors.initials: D
authors.lastname: Closhen
authors.forename: Konrad J
authors.initials: KJ
authors.lastname: Werhahn
authors.forename: Matthias
authors.initials: M
authors.lastname: David
authors.forename: Christian
authors.initials: C
authors.lastname: Werner
authors.forename: Kristin
authors.initials: K
authors.lastname: Engelhard
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018805:Sepsis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D065166:Sepsis-Associated Encephalopathy / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods