Jugular venous bulb oxygen saturation depends on blood pressure during cardiopulmonary bypass.
BACKGROUND
Central nervous system dysfunction after cardiopulmonary bypass is frequent and can be caused by inadequate cerebral perfusion and oxygenation.


METHODS
To test the effectiveness of cerebral autoregulation during cardiopulmonary bypass, we induced changes in the cerebral perfusion pressure by administering phenylephrine during moderate (29 degrees C) hypothermia. Using the Fick principle, we calculated relative changes in cerebral blood flow from changes in the jugular venous bulb oxygen saturation.


RESULTS
Increasing the cerebral perfusion pressure (from 47 +/- 8.2 to 93 +/- 16 mm Hg) induced increases in the jugular venous bulb oxygen saturation by 4.9% and a calculated increase in the cerebral blood flow by 19.9%, strongly suggesting impaired cerebral autoregulation.


CONCLUSIONS
Because cerebral autoregulation is impaired during cardiopulmonary bypass, phenylephrine is effective in increasing the cerebral blood flow and may contribute to the prevention of postoperative neurologic dysfunction, especially in patients who have a low jugular venous bulb oxygen saturation.
Grubhofer
G
G
Department of Cardiothoracic and Vascular Anesthesia and Intensive Care, University Clinic, Vienna, Austria. georg.grubhofer@univie.ac.at
Lassnigg
A M
AM
Schneider
B
B
Rajek
M A
MA
Pernerstorfer
T
T
Hiesmayr
M J
MJ
D001794:Blood Pressure; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D002534:Hypoxia, Brain / Q000209:etiology / Q000517:prevention & control; D007601:Jugular Veins / Q000502:physiology*; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010656:Phenylephrine / Q000494:pharmacology
D010656:Phenylephrine; D010100:Oxygen