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

Abstract

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 8 min 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.

Clamping of the Aortic Arch Vessels During Normothermic Regional Perfusion Does Not Negatively Affect Donor Cardiac Function in Donation After Circulatory Death

“…5 We confirmed restoration of brain activity in a study of cerebral perfusion and activity following DCD and NRP in the animals from the present study. 7 We found that cerebral reperfusion restored some kind of cerebral activity in all animals in the nonclamp group. Ethics mandate to uphold the permanence of death by AAV clamping when performing TA-NRP‚ and we have now shown no negative cardiac or inflammatory effects of AAV clamping during NRP.…”

“…Controversially, reperfusion of the brain has shown to restore some brain activity in pigs. 7 Following this finding, we have demonstrated that clamping of the aortic arch vessels (AAVs) sufficiently prevents restoration of cerebral blood flow and electrical activity. 7 However, little is known about the hemodynamic and inflammatory effects following clamping of the AAV in relation to DCD donation.…”

Ensuring the Permanent Cessation of Brain Function During Normothermic Regional Perfusion

“…In the current issue, Dalsgaard et al 9 demonstrate that clamping of aortic arch vessels in a pig model of NRP is sufficient to prevent resumption of cortical blood flow, cortical electrical activity, and brain stem function during NRP. The authors prospectively randomized 16 female pigs to clamping of aortic arch vessels versus sham surgery during NRP.…”

Cold but not too cold: advances in hypothermic and normothermic organ perfusion

“…These techniques have been extensively discussed by a number of expert groups in the UK, Canada, and other countries [ 63 ]. After confirmation of death in DCD and before starting normothermic regional perfusion (NRP), it is considered appropriate to perform surgery to ligate or divide the aortic arch vessels for cases with thoracic NRP or to occlude the descending aorta for abdominal NRP [ 65 ]. Opening the vessels of the supra-aortic arch to the atmosphere ensures that there is no reperfusion to the brain.…”