Clamping of the Aortic Arch Vessels During Normothermic Regional Perfusion After Circulatory Death Prevents the Return of Brain Activity in a Porcine Model

Background. The cerebral effect of clamping following normothermic regional perfusion (NRP) in donation after circulatory death (DCD) remains unknown. We investigated the effect of cerebral reperfusion during NRP and the preventive effect of clamping on brain function in a porcine model. Methods. In 16 pigs, intracranial physiological parameters were recorded, including pressure, cerebral blood perfusion (CBF), temperature, and oxygen. Additionally, electroencephalography (EEG) and somatosensory evoked potentials (SSEPs) were used to assess brain function. The animals were cannulated for the heart-lung machine, and baseline measurements were performed before withdrawal from life support. After 8min of mechanical asystole, the animals were randomly allocated to clamp (n = 8) or nonclamp (n = 8) of the aortic arch vessels. After 30 min of NRP, the animals were monitored for 3 h after weaning (AW). Results. Intracranial measurements of CBF, oxygen, and temperature indicated successful occlusion of the arch vessels following NRP and AW in the clamp group versus the nonclamp group. In the clamp group, EEG was isoelectric and SSEPs were absent AW in all pigs. In the nonclamp group, EEG activity was observed in all 8 pigs, whereas SSEPs were observed in 6 of 8 pigs. Additionally, agonal respiratory movements in the form of gasping were observed in 6 of 8 pigs in the nonclamp group. Conclusions. Reperfusion of the brain during NRP led to a return of brain activity. Conversely, clamping of the arch vessels halted cerebral circulation, ensuring the permanent cessation of brain function and maintaining the determination of death in DCD.