Cardiotomy suction: a major source of brain lipid emboli during cardiopulmonary bypass.
BACKGROUND
Brain injury remains a significant problem in patients undergoing cardiac surgery assisted by cardiopulmonary bypass (CPB). Autopsy brain specimens of patients after cardiac operations with CPB reveal numerous acellular lipid deposits (10 to 70 microm) in the microvasculature. We hypothesize that these small capillary and arterial dilatations result from a diffuse inflammatory response to CPB or from emboli delivered by the bypass circuit. This study was undertaken to determine which aspect of CPB is most clearly associated with these dilatations.


METHODS
Thirteen dogs were studied in four groups: group I (n = 3), right-heart CPB; group II (n = 2), lower-extremity CPB; group III (n = 3), hypothermic CPB; and group IV (n = 5), hypothermic CPB with cardiotomy suction. All dogs in all groups were maintained on CPB for 60 minutes and then euthanized. Brain specimens were harvested, fixed in ethanol, embedded in celloidin, and stained with the alkaline phosphate histochemical technique so that dilatations could be counted.


RESULTS
All dogs completed the protocol. The mean density of dilatations per square centimeter for each group was as follows: group I, 1.77 +/- 0.77; group II, 4.17 +/- 1.65; group III, 4.54 +/- 1.69; and group IV, 46.5 +/- 14.5. In group IV (cardiotomy suction), dilatation density was significantly higher than in group III (hypothermic cardiopulmonary bypass) (p = 0.04) and all other groups (p = 0.04).


CONCLUSIONS
Blood aspirated from the surgical field and subsequently reinfused into dogs undergoing CPB produces a greater density of small capillary and arterial dilatations than CPB without cardiotomy suction, presumably because of lipid microembolization.
Brooker
R F
RF
Department of Anesthesia, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1088, USA.
Brown
W R
WR
Moody
D M
DM
Hammon
J W
JW
Reboussin
D M
DM
Deal
D D
DD
Ghazi-Birry
H S
HS
Stump
D A
DA
D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D001160:Arterioles / Q000473:pathology; D001804:Blood Transfusion, Autologous / Q000009:adverse effects*; D002196:Capillaries / Q000473:pathology; D002315:Cardiopulmonary Bypass / Q000009:adverse effects* / Q000379:methods; D002560:Cerebrovascular Circulation; D004108:Dilatation, Pathologic / Q000209:etiology / Q000473:pathology; D004285:Dogs; D004730:Endothelium, Vascular / Q000473:pathology; D006651:Histocytochemistry; D007036:Hypothermia, Induced; D002542:Intracranial Embolism and Thrombosis / Q000209:etiology* / Q000473:pathology; D008055:Lipids / Q000009:adverse effects*; D008833:Microcirculation / Q000473:pathology; D013396:Suction / Q000009:adverse effects*; D014657:Vasculitis / Q000209:etiology / Q000473:pathology
D008055:Lipids; D000469:Alkaline Phosphatase