A current view of cerebral protection in aortic arch repair.

The major objective in arch surgery is to supply the basic metabolic eeds of the brain during the anastomosis. Many advances have een introduced into aortic arch surgery since Griepp et al1 used he DHCA technique. Svensson et al2 reported the safe DHCA eriod as 40 minutes. However, Ergin et al3 reported this duration s 30 minutes. The safe DHCA period also was reported to be 30 inutes under 15 °C and 40 minutes under 10°C.4 Michenfelder et al5 reported that the complete arrest of the erebral circulation for as long as 30 minutes at 18°C would ot result in any permanent neurologic injury, and they rovided evidence indicating that periods of DHCA as long s 60 minutes should be safe. Neuropsychologic tests after HCA showed that DHCA duration of more than 25 minutes nd advanced age were significant predictors of poor perormance in examinations of memory and fine-motor funcion.6 Ueda et al7,8 described an RCP technique through the supeior vena cava cannula under DHCA. RCP may accomplish europrotection by flushing embolic material from the cerebral irculation,9 providing cerebral flow sufficient to support cereral metabolism,10 and maintaining cerebral hypothermia.11 lthough RCP was reported to expel air emboli, it is now well nown that the pressure necessary for this causes brain edea.12 Another point is that the blood returning to the aortic arch as less than 5% of the amount given through the retrograde erfusion cannula. ACP was reported to afford the best cerebral rotection, but RCP was reported to provide clear improvement ompared to DHCA.13 RCP, especially at high pressures, although successful in emoving some emboli, may aggravate cerebral injury.14 Beides, it was not able to decrease the incidence of stroke.15 ecently, RCP has lost its popularity because it did not suffiiently prolong the safe period of DHCA. Less than 60 minutes f RCP was reported to be tolerated with a minimal risk of rain complication.16 DHCA also has been found to be associted with excellent organ protection with an RCP time less than 5 minutes.17 t