Pressure reactivity index correlates with metabolic dysfunction in a porcine model of intracerebral hemorrhage.
OBJECTIVE
We correlated oxygen, flow, and pressure indices of cerebrovascular reactivity (CR) with extracellular cerebral metabolite concentrations in a porcine model of intracerebral hemorrhage (ICH).


METHODS
Continuous advanced multimodal monitoring including microdialysis, cerebral blood flow and P(br)O(2) probes were placed 1 cm in front of the coronal suture in the grey/white matter junction. Following a period of 1 h of monitoring, an autologous arterial ICH with defined volumes (3 mL) was induced. Pressure-, oxygen-, and flow-related autoregulation indices (PRx, ORx, and FRx) were simultaneously calculated and correlated hourly with extracellular cerebral metabolites, including glucose, lactate, pyruvate, and glutamate.


RESULTS
Seventeen swine were monitored on average 12 continuous hours per animal. FRx correlated highly with ORx (0.96, P = <0.001), but values of both FRx and ORx > 0.2 did not correlate with any microdialysis metabolite. Values of PRx > 0.2 correlated highly (0.65, P < 0.001) with the lactate/pyruvate ratio, values of PRx > 0.3 correlated with glutamate (0.67, P < 0.05), the lactate/pyruvate ratio (0.60, P < 0.01), and P(br)O(2) (-0.65, P < 0.01).


CONCLUSIONS
We found evidence for impaired CR in a porcine model of ICH. The findings suggest that, among other parameters of CR, positive PRx coefficients have the highest significance and could be associated with microdialysis alterations during hypoxic events.
Department of Neurosurgery, University of Heidelberg, Heidelberg, Germany. edgar.santos@med.uni-heidelberg.de
Edgar
E
Santos
Berk
B
Orakcioglu
Modar M
MM
Kentar
Jennifer
J
Diedler
Yoichi
Y
Uozumi
Michael
M
Schöll
Andreas
A
Unterberg
Oliver W
OW
Sakowitz
D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D002543:Cerebral Hemorrhage / Q000150:complications*; D002560:Cerebrovascular Circulation; D004195:Disease Models, Animal; D005947:Glucose / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D006706:Homeostasis; D007427:Intracranial Pressure / Q000502:physiology*; D019344:Lactic Acid / Q000378:metabolism; D008659:Metabolic Diseases / Q000209:etiology*; D010100:Oxygen; D019289:Pyruvic Acid / Q000378:metabolism; D013223:Statistics as Topic; D013552:Swine
D019344:Lactic Acid; D018698:Glutamic Acid; D019289:Pyruvic Acid; D005947:Glucose; D010100:Oxygen