title: Postoperative cognitive deficit after cardiopulmonary bypass with preserved cerebral oxygenation: a prospective observational pilot study.
abstract: BACKGROUND
  Neurologic deficits after cardiac surgery are common complications. Aim of this prospective observational pilot study was to investigate the incidence of postoperative cognitive deficit (POCD) after cardiac surgery, provided that relevant decrease of cerebral oxygen saturation (cSO2) is avoided during cardiopulmonary bypass.
  
  
  METHODS
  cSO2 was measured by near infrared spectroscopy in 35 patients during cardiopulmonary bypass. cSO2 was kept above 80% of baseline and above 55% during anesthesia including cardiopulmonary bypass. POCD was tested by trail making test, digit symbol substitution test, Ray's auditorial verbal learning test, digit span test and verbal fluency test the day before and 5 days after surgery. POCD was defined as a decline in test performance that exceeded - 20% from baseline in two tests or more. Correlation of POCD with lowest cSO2 and cSO2 - threshold were determined explorative.
  
  
  RESULTS
  POCD was observed in 43% of patients. Lowest cSO2 during cardiopulmonary bypass was significantly correlated with POCD (p = 0.015, r2 = 0.44, without Bonferroni correction). A threshold of 65% for cSO2 was able to predict POCD with a sensitivity of 86.7% and a specificity of 65.0% (p = 0.03, without Bonferroni correction).
  
  
  CONCLUSIONS
  Despite a relevant decrease of cerebral oxygen saturation was avoided in our pilot study during cardiopulmonary bypass, incidence of POCD was comparable to that reported in patients without monitoring. A higher threshold for cSO2 may be needed to reduce the incidence of POCD.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Schwanenweg 21, D-24105 Kiel, Germany. fudickar@anaesthesie.uni-kiel.de.
authors.forename: Axel
authors.initials: A
authors.lastname: Fudickar
authors.forename: Sönke
authors.initials: S
authors.lastname: Peters
authors.forename: Claudia
authors.initials: C
authors.lastname: Stapelfeldt
authors.forename: Götz
authors.initials: G
authors.lastname: Serocki
authors.forename: Jörn
authors.initials: J
authors.lastname: Leiendecker
authors.forename: Patrick
authors.initials: P
authors.lastname: Meybohm
authors.forename: Markus
authors.initials: M
authors.lastname: Steinfath
authors.forename: Berthold
authors.initials: B
authors.lastname: Bein