Impact of hypothermic selective cerebral perfusion compared with hypothermic cardiopulmonary bypass on cerebral hemodynamics and metabolism.
OBJECTIVE
Hypothermic selective cerebral perfusion (SCP) is widely used for cerebral protection during aortic arch surgery, but the effect of the absence of systemic perfusion on cerebrovascular dynamics it has never been established. This study explored the physiology of prolonged SCP compared to hypothermic cardiopulmonary bypass (HCPB) in pigs.


METHODS
In this blinded protocol, 29 juvenile pigs (20-23 kg) were randomized after cooling on cardiopulmonary bypass (CPB) to 20 degrees C. Group I pigs (n=14) underwent 90 min of SCP, while group II (HCPB, n=15) underwent total body perfusion. Fluorescent microspheres were injected during perfusion and recovery, enabling calculation of total and regional cerebral blood flow (CBF). Cerebrovascular resistance (CVR), oxygen consumption and intracranial pressure (ICP) were also monitored.


RESULTS
CBF decreased significantly (P=0.0001) during cooling, but remained at significantly higher levels with SCP than with HCPB throughout perfusion and recovery (P<0.0001). CVR was significantly lower with SCP than with HCPB throughout perfusion (P=0.04). Oxygen consumption fell significantly with cooling (P=0.0001), remained low during perfusion, and rebounded promptly with rewarming; with SCP it was significantly higher than with HCPB throughout the perfusion interval (P=0.03), and remained higher thereafter. ICP rose significantly less with SCP than with HCPB (P=0.02).


CONCLUSIONS
We conclude that, compared with HCPB, SCP results in beneficial cerebral vasodilatation, as evidenced by significantly higher CBF and oxygen consumption during SCP, by prompt recovery of oxygen consumption after rewarming, and by significantly lower ICP during perfusion and in the post-bypass period.
Department of Cardiothoracic Surgery, Mount Sinai School of Medicine/New York University, One Gustave L. Levy Place, P.O. Box 1028, New York, NY 10029, USA. ju.strauch@gmx.de
Justus T
JT
Strauch
David
D
Spielvogel
Peter L
PL
Haldenwang
Ning
N
Zhang
Donald
D
Weisz
Carol A
CA
Bodian
Randall B
RB
Griepp
D000818:Animals; D001013:Aorta, Thoracic / Q000601:surgery; D001921:Brain / Q000378:metabolism; D002315:Cardiopulmonary Bypass / Q000379:methods*; D002560:Cerebrovascular Circulation; D004195:Disease Models, Animal; D005260:Female; D006439:Hemodynamics; D007036:Hypothermia, Induced / Q000379:methods*; D007427:Intracranial Pressure; D007430:Intraoperative Care / Q000379:methods*; D008863:Microspheres; D010101:Oxygen Consumption; D010477:Perfusion / Q000379:methods; D013552:Swine; D014655:Vascular Resistance