TY - JOUR
T1 - Perfusing the Cold Brain
T2 - Optimal Neuroprotection for Aortic Surgery
AU - Halstead, James C.
AU - Etz, Christian
AU - Meier, D. Matthias
AU - Zhang, Ning
AU - Spielvogel, David
AU - Weisz, Donald
AU - Bodian, Carol
AU - Griepp, Randall B.
PY - 2007/9
Y1 - 2007/9
N2 - Background: Selective cerebral perfusion (SCP) may enhance the neuroprotective benefits of hypothermia during aortic surgery. However, despite its widespread adoption, there is no consensus regarding optimal implementation of SCP. We used a survival porcine model to explore the physiologic characteristics and behavioral benefits of various protocols involving hypothermic circulatory arrest (HCA) and SCP. Methods: Thirty pigs (26.3 ± 1.4 kg), cooled to 15°C on cardiopulmonary bypass, using alpha-stat pH management (mean hematocrit 30%), were randomly allocated to differing brain protection strategies: 90 minutes of HCA (group A); 30 minutes of HCA, then 60 minutes of SCP (group B); or 90 minutes of SCP (group C). Using fluorescent microspheres and sagittal sinus sampling, cerebral blood flow (CBF [mL · 100g-1 · min-1]) and cerebral metabolic rate for oxygen (CMRO2 [mL · 100g-1 · min-1]) were assessed at baseline, after cooling, during SCP (where applicable), and for 2 hours after cardiopulmonary bypass. Neurobehavioral scores were assessed blindly from standardized videotaped sessions for 7 days postoperatively. Results: Cerebral blood flow was significantly higher (p = 0.0001) during SCP (60 and 90 minutes) if preceded by HCA. The CMRO2 was also significantly higher in group B versus group C (p = 0.016) at 60 minutes. The CMRO2 in all three groups rebounded promptly toward baseline after weaning from cardiopulmonary bypass. Postoperative neurobehavioral scores were significantly worse in group A. Conclusions: Continuous SCP provides the best brain protection overall. However, an initial period of HCA does not seem to impair late outcome; perhaps the elevated CBF and CMRO2 observed reflect a beneficial cerebral response to a recoverable insult. Clearly, 90 minutes of HCA induces permanent brain injury, even in this carefully controlled setting.
AB - Background: Selective cerebral perfusion (SCP) may enhance the neuroprotective benefits of hypothermia during aortic surgery. However, despite its widespread adoption, there is no consensus regarding optimal implementation of SCP. We used a survival porcine model to explore the physiologic characteristics and behavioral benefits of various protocols involving hypothermic circulatory arrest (HCA) and SCP. Methods: Thirty pigs (26.3 ± 1.4 kg), cooled to 15°C on cardiopulmonary bypass, using alpha-stat pH management (mean hematocrit 30%), were randomly allocated to differing brain protection strategies: 90 minutes of HCA (group A); 30 minutes of HCA, then 60 minutes of SCP (group B); or 90 minutes of SCP (group C). Using fluorescent microspheres and sagittal sinus sampling, cerebral blood flow (CBF [mL · 100g-1 · min-1]) and cerebral metabolic rate for oxygen (CMRO2 [mL · 100g-1 · min-1]) were assessed at baseline, after cooling, during SCP (where applicable), and for 2 hours after cardiopulmonary bypass. Neurobehavioral scores were assessed blindly from standardized videotaped sessions for 7 days postoperatively. Results: Cerebral blood flow was significantly higher (p = 0.0001) during SCP (60 and 90 minutes) if preceded by HCA. The CMRO2 was also significantly higher in group B versus group C (p = 0.016) at 60 minutes. The CMRO2 in all three groups rebounded promptly toward baseline after weaning from cardiopulmonary bypass. Postoperative neurobehavioral scores were significantly worse in group A. Conclusions: Continuous SCP provides the best brain protection overall. However, an initial period of HCA does not seem to impair late outcome; perhaps the elevated CBF and CMRO2 observed reflect a beneficial cerebral response to a recoverable insult. Clearly, 90 minutes of HCA induces permanent brain injury, even in this carefully controlled setting.
UR - http://www.scopus.com/inward/record.url?scp=34548009318&partnerID=8YFLogxK
U2 - 10.1016/j.athoracsur.2007.04.051
DO - 10.1016/j.athoracsur.2007.04.051
M3 - Article
C2 - 17720373
AN - SCOPUS:34548009318
SN - 0003-4975
VL - 84
SP - 768
EP - 774
JO - Annals of Thoracic Surgery
JF - Annals of Thoracic Surgery
IS - 3
ER -