Pesek M, Kibler K, Easley RB, Mytar J, Rhee C, Andropolous D, Brady K. The Upper Limit of Cerebral Blood Flow Autoregulation Is Decreased with Elevations in Intracranial Pressure.
Acta Neurochir Suppl 2016;
122:229-31. [PMID:
27165912 DOI:
10.1007/978-3-319-22533-3_46]
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Abstract
BACKGROUND
The upper limit of cerebrovascular pressure autoregulation (ULA) is inadequately characterized. We sought to delineate the ULA in a neonatal swine model.
METHODS
Neonatal piglets with sham surgery (n = 9), interventricular fluid infusion (INF; n = 10), controlled cortical impact (CCI; n = 10), or impact + infusion (CCI + INF; n = 11) had intracranial pressure monitoring and bilateral cortical laser-Doppler flux recordings during arterial hypertension until lethality. An increase in red cell flux as a function of cerebral perfusion pressure was determined by piecewise linear regression and static rates of autoregulation (SRoRs) were determined above and below this inflection.
RESULTS
When identified, the ULA (median [interquartile range]) was as follows: sham group: 102 mmHg (97-109), INF group: 75 mmHg (52-84), CCI group: 81 mmHg (69-101), and CCI + INF group: 61 mmHg (52-57; p = 0.01). Both groups with interventricular infusion had significantly lower ULA compared with the sham group.
CONCLUSION
Neonatal piglets without intracranial pathological conditions tolerated acute hypertension, with minimal perturbation of cerebral blood flow. Piglets with acutely elevated intracranial pressure, with or without trauma, demonstrated loss of autoregulation when subjected to arterial hypertension.
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