Effects of elevated ICP on brain function: can the multiparametric monitoring system detect the 'Cushing Response'?
The 'Cushing Response' is a significant phenomenon associated with elevated ICP. The purpose of our study was to examine the effects of the intracranial hypertension level and duration on the cerebral tissue physiology, using a Multiprobe assembly (MPA). The parameters monitored simultaneously included ICP, CBF, mitochondrial NADH redox state, extracellular K+ and H+ levels, DC potential and ECoG, calculated CPP and blood pressure. Two groups of rats were used. In one group, ICP was elevated to 50-60 mmHg for 13-15 min and, in the second group, ICP was elevated to 20 mmHg for 30 min. The results show that ICP of 50-60 mmHg led to CPP reduction below the lower limits of autoregulation. However, ICP of 20 mmHg, even for a prolonged period of time is completely tolerated. Additionally, we found that the 'Cushing Response', developed in the moderate treatment (ICP = 20 mmHg) is beneficial, assuring high CBF levels under intracranial hypertension. Furthermore, CBF and CPP monitoring, apparently, are not sufficient for autoregulation assessment; more parameters are needed.
Barbiro-Michaely
Efrat
E
Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
Mayevsky
Avraham
A
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D001921:Brain / Q000098:blood supply / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005110:Extracellular Space / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D019586:Intracranial Hypertension / Q000503:physiopathology*; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D008991:Monitoring, Physiologic / Q000379:methods*; D009243:NAD / Q000032:analysis; D010084:Oxidation-Reduction; D011188:Potassium / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar
D009243:NAD; D011188:Potassium