Objective: Selective cerebral perfusion (SCP) is commonly applied during the correction of complex congenital cardiac defects. In this study, we assessed the impact of different flow levels of SCP on potential brain ischaemia.
Methods: Fifteen piglets (7-10 kg, age 3-4 weeks) received SCP via the right common carotid artery during cardiopulmonary bypass at 25°C for 90 min. Regular brain perfusion (1 ml/g brain weight/min), moderate hypoperfusion (0.5 ml/g/min) and extensive hypoperfusion (0.25 ml/g/min) were evaluated. Clinical parameters and tissue oxygenation index (TOI) were registered online until 3 h of reperfusion. Hematoxylin and eosin (HE) staining and immunohistological analyses for apoptosis inducing factor (AIF) and nitrotyrosine (NO-Tyr) were performed on sections of the hippocampus.
Results: Intracerebral pressure remained stable throughout the study. Haemodynamic parameters, blood gas and lactate measurements were stable until the end of the study. Extensive hypoperfusion led to a moderate reduction of TOI. NO-Tyr immuno-positive cells were 15.7% at regular cerebral perfusion, 23.9% at moderate hypoperfusion (P = n.s.) and 46.1% at extensive hypoperfusion (P < 0.05). AIF immuno-positive nuclei were present in 8.3% of the hippocampus cells after regular perfusion, in 10.8% after moderate hypoperfusion (P = n.s.) and in 17.9% after extensive hypoperfusion (P < 0.05).
Conclusions: SCP using a moderate SCP flow regime demonstrates comparable results to normal brain perfusion while after extensive hypoperfusion significant morphological brain injury could be found. Thus moderate, but not extensive, hypoperfusion might have the potential to prevent perfusion-related cerebral oedema and an increasing risk of brain injury.