title: Increased systemic perfusion pressure during cardiopulmonary bypass is associated with less early postoperative cognitive dysfunction and delirium.
abstract: OBJECTIVE
  Patients undergoing cardiac surgery procedures are thought to be at risk of early neuropsychological deficits and delirium. Regional cerebral hypoperfusion may play a role in the etiology of this complication. We hypothesized that low systemic perfusion pressure during cardiopulmonary bypass (CPB) would correlate with early postoperative cognitive dysfunction in on-pump patients.
  
  
  METHODS
  In this prospective, randomized, single-center trial, we assigned 92 patients scheduled for elective or urgent coronary artery bypass grafting (CABG) to high-pressure (HP: 80-90 mm Hg, n = 44) or low-pressure (LP: 60-70 mm Hg, n = 48) perfusion groups during CPB. Patients with prior cerebrovascular or psychiatric disorders were excluded. Primary end point was the cognitive outcome as measured by Mini-Mental-Status examination before and 48 h after surgery.
  
  
  RESULTS
  Patients' pre- and intra-operative characteristics did not differ between groups. Significantly more patients in the LP group developed postoperative delirium than in the HP group (LP 13%. vs HP 0%, p = 0.017). The postoperative drop in Mini-Mental-Status scores was significantly greater in the LP group (LP 3.9 ± 6.5 vs HP 1.1 ± 1.9; p = 0.012). No group differences were detected in cerebral oxygenation measured by near-infrared spectroscopy during CPB. The LP group's postoperative arterial lactate concentration in the intensive care unit was significantly higher as compared with the HP group (LP 2.0 ± 1.1 mmol l(-1) vs HP 1.4 ± 0.6 mmol l(-1); p < 0.001). We observed no differences between the groups in any other postoperative clinical, functional, or laboratory parameters.
  
  
  CONCLUSIONS
  Maintaining perfusion pressure at physiologic levels during normothermic CPB (80-90 mm Hg) is associated with less early postoperative cognitive dysfunction and delirium. This perfusion strategy neither increases morbidity, nor does it impair organ function.
authors.affiliation: Department of Cardiovascular Surgery, University Medical Center Freiburg, Freiburg, Germany. matthias.siepe@web.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Siepe
authors.forename: Thomas
authors.initials: T
authors.lastname: Pfeiffer
authors.forename: Andreas
authors.initials: A
authors.lastname: Gieringer
authors.forename: Silke
authors.initials: S
authors.lastname: Zemann
authors.forename: Christoph
authors.initials: C
authors.lastname: Benk
authors.forename: Christian
authors.initials: C
authors.lastname: Schlensak
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Beyersdorf
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D001921:Brain / Q000098:blood supply; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000379:methods*; D003072:Cognition Disorders / Q000209:etiology / Q000517:prevention & control*; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000379:methods; D003693:Delirium / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011446:Prospective Studies; D011594:Psychometrics
chemical_list: D010100:Oxygen