Mp. Anstadt et al., PULSATILE VERSUS NONPULSATILE REPERFUSION IMPROVES CEREBRAL BLOOD-FLOW AFTER CARDIAC-ARREST, The Annals of thoracic surgery, 56(3), 1993, pp. 453-461
Cardiopulmonary bypass using nonpulsatile flow (NF) is currently advoc
ated for treating refractory cardiac arrest. Although the heart can be
revived using cardiopulmonary bypass support, the brain must recover
if such therapy is to be considered successful. Previous studies have
demonstrated that pulsatile flow (PF) reperfusion can improve neurolog
ic outcome compared with NF reperfusion after cardiac arrest. The purp
ose of this study was to assess cerebral perfusion and oxygen consumpt
ion during either PF or NF reperfusion after cardiac arrest. Dogs (n =
22) underwent a 15-minute cardiac arrest followed by 1 hour of either
PF or NF reperfusion. Microsphere techniques were used to assess cere
bral perfusion and oxygen consumption at 3, 15, and 60 minutes of repe
rfusion. Mean arteriovenous gradients and total brain flows were simil
ar in both groups. However, cerebral oxygen consumption was significan
tly improved at 3 minutes of reperfusion with PF versus NF (1.8 +/- 0.
3 versus 0.9 +/- 0.3 mL O2 . dL-1 - min-1, respectively; p < 0.05). Th
ese results were coincident with improved gray-to-white flow ratios at
3 minutes of PF versus NF reperfusion (5.2 +/- 1.0 versus 2.0 +/- 0.3
, respectively; p < 0.05). There were no statistically significant dif
ferences ir, brain perfusion variables by 15 minutes of reperfusion. H
owever, a relative hyperemia was exhibited at 15 minutes of NF versus
PF reperfusion, which suggests nutrient flow was insufficient during e
arly NF versus PF reperfusion. In conclusion, PF reperfusion can bette
r restore cerebral blood flow and oxygen consumption than can NF reper
fusion. These findings provide a mechanism that explains how PF versus
NF reperfusion may have improved neurologic outcome after cardiac arr
est in previous studies.