Changes in cerebral oxygenation during cold (28 degrees C) and warm (34 degrees C) cardiopulmonary bypass using different blood gas strategies (alpha-stat and pH-stat) in patients undergoing coronary artery bypass graft surgery.
BACKGROUND
Impaired cerebral oxygenation, which is reflected by measuring jugular bulb oxygenation, is thought to play an important role in the development of neurological injury after cardiac operations with cardiopulmonary bypass (CPB). The effects of cardiopulmonary temperature and blood gas strategy on cerebral oxygenation are not fully appreciated.


METHODS
Sixty patients were randomly allocated into four equal groups (cold alpha-stat, cold pH-stat, warm alpha-stat and warm pH-stat) to compare the effect of these perfusion strategies on cerebral oxygenation monitored by jugular bulb oximetry [jugular bulb oxygen saturation (SjO(2)) and arterial-jugular bulb oxygen content difference (AjDO(2))]. Jugular bulb oxygen saturation and AjDO(2) were measured before CPB, after 5, 20, 40 min on CPB, at start and end of rewarming, 5 min before the end of CPB and 10 min after CPB. Two-way analysis of variance was used to model the lowest SjO(2) and highest AjDO(2) during CPB, with CPB temperature and blood gas management as contributing factors.


RESULTS
Significant changes in SjO(2) were only related to the type of blood gas management, with no significant difference between warm and cold CPB patients. In addition, during rewarming, desaturation (SjO(2) </= 50%) occurred in seven patients of 30 in the alpha-stat groups and in one patient of 30 in the pH-stat groups (P = 0.021), and in five patients of 30 in the cold groups vs. three of 30 in the warm groups (P = 0.434). However, no significant changes were found in the highest AjDO(2) between the four groups.


CONCLUSIONS
Cold CPB failed to offer any further brain protection in terms of better preservation of cerebral oxygenation than warm CPB. Therefore, warm CPB (34 degrees C) with different blood gas strategies appears to be a satisfactory alternative to cold CPB (28 degrees C).
Ali
M Shaaban
MS
Department of Anaesthetics, Assiut University Hospital, Assiut, Egypt. msali58@hotmail.com
Harmer
M
M
Vaughan
R S
RS
Dunne
J A
JA
Latto
I P
IP
Haaverstad
R
R
Kulatilake
E N P
EN
Butchart
E G
EG
D000368:Aged; D001784:Blood Gas Analysis; D001921:Brain / Q000378:metabolism*; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D013696:Temperature
D010100:Oxygen