Optimal Perfusion Pressure For Experimental Retrograde Cerebral Perfusion

Abstract

We evaluated cerebral metabolism during retrograde cerebral perfusion (RCP) and circulatory arrest during profound hypothermia, and also investigated the effects of perfusion pressure on RCP. Twenty-four adult mongrel dogs were placed on cardiopulmonary bypass and cooled to a nasopharyngeal temperature of 20 degrees C. At this temperature, hypothermic circulatory arrest (HCA; n = 6), and RCP with a perfusion pressure of 10 mmHg (RCP10; n = 6), 20 mmHg (RCP20; n = 6), and 30 mmHg (RCP30; n = 6) were carried out for 60 minutes. RCP was performed with oxygenated blood via the bilateral maxillary veins, and the retrograde flow rate was regulated to maintain a mean perfusion pressure of 10, 20, or 30 mmHg in the external jugular vein. At 60 minutes of RCP, we measured nasopharyngeal temperature; regional cerebral blood flow (rCBF); cerebral oxygen consumption, carbon dioxide excretion, and excess lactate; cerebral tissue adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and energy charge; and cerebral tissue water content. In the RCP10 group, there was excess cerebral lactate, and ATP and energy charge were low. In the RCP30 group, the water content of cerebral tissue was significantly higher than in other groups. In the RCP20 group, temperature was maintained in a narrow range, oxygen consumption and carbon dioxide excretion could be observed, there was no excess lactate, and ATP and energy charge were significantly higher than in the HCA group. In conclusion, RCP can provide adequate metabolic support for the brain during circulatory arrest, and a perfusion pressure of 20 mmHg is most appropriate for RCP.

Postoperative brain complications following retrograde cerebral perfusion

“…On the other hand, the water content volume of cerebral tissues after RCP was higher at 30 mmHg than at 10 and 20 mmHg. 15 Another experimental study revealed that cerebral blood flow, oxygen consumption, and the removal of carbon dioxide reached maximum values at a perfusion pressure of 25 mmHg, while a pressure of over 25 mmHg may induce brain edema. 16 Venous valves in the internal jugular vein are present at the venous angle, namely, the jugular-subclavian junction, in 80%-90% of humans.…”

Optimal brain temperature for retrograde cerebral perfusion in dogs

“…However, transient or permanent neurological complications in patients who underwent an operation with the RCP technique have been reported in some cases [2,7,8], and the effective time range of application for cerebral protection using this method remains uncertain. In previous experimental studies, the efficacy and optimal conditions of this technique were reported [9][10][11][12]. The perfusion pressure of 20-25 mmHg is considered more advantageous than a pressure of 20 mmHg or lower with respect to cerebral blood flow, oxygen consumption, carbon dioxide removal, and energy charge of cerebral tissues.…”

Retrograde cerebral perfusion: clinical and experimental aspects

“…Raising venous pressure above this did not augment flow despite a rise in cerebrospinal fluid pressure. Also in dogs, Nojima et al 30 found that retrograde flow increased with venous pressures up to 30 mmHg, but at 30 mmHg, significant cerebral oedema occurred. Additionally, no significant increase in oxygen consumption or carbon dioxide excretion was found above an RCP pressure of 20 mmHg.…”

“…Nojima et al have investigated the optimal perfusion pressure during RCP in 24 mongrel dogs. 30 True cerebral blood flow increased with perfusion pressure, but cerebral oedema developed when RCP perfusion pressure was increased to 30 mmHg. The maximum pressure that cerebral capillaries are subjected to in normal life is approximately 30 mmHg with the mean about 22 mmHg.…”