[Verse 1] Fifty mils per hundred grams, that's the global rate Gray matter drinking deeper, white matter can wait Drop below eighteen and the neurons go quiet Eight to ten — membranes collapse, no stopping that riot Between those thresholds lives the penumbra zone Salvageable tissue, still warm but alone Perfusion pressure equals MAP minus ICP CPP targets sixty to seventy, that's the decree [Chorus] Autoregulate from fifty up to one-fifty MAP Rightward shift in hypertension — chronic pressure gap P1 percussion, P2 compliance, P3 closes out When P2 overtops P1, the brain is running out PRx positive means the vessels lost their grip CMRO₂ drops with cold, but seizures crack the whip Penumbra, compliance, CPP — hold the line Sodium, herniation, waveform — read the sign [Verse 2] Cushing's triad: bradycardia, pressure climbing high Irregular breathing tells you herniation is nigh Uncal shifts the third nerve, pupil blown and fixed Kernohan's notch fools you — ipsilateral signs mixed Central syndrome tracks the rostrocaudal fall Tonsillar kills breathing when the tonsils hit the wall Subfalcine traps the ACA beneath the fold Transcalvarial bulges where the bone can't hold [Chorus] Autoregulate from fifty up to one-fifty MAP Rightward shift in hypertension — chronic pressure gap P1 percussion, P2 compliance, P3 closes out When P2 overtops P1, the brain is running out PRx positive means the vessels lost their grip CMRO₂ drops with cold, but seizures crack the whip Penumbra, compliance, CPP — hold the line Sodium, herniation, waveform — read the sign [Bridge] Vasogenic edema — barrier cracked, steroids work Cytotoxic — cells are swelling, osmotherapy's the quirk Interstitial flows from ventricles when CSF backs up Osmotic shifts when sodium corrects too fast — stop SIADH retains the water, sodium sinks low Cerebral salt wasting dumps both — urine tells you so DI floods the output, hypernatremia creeps Correct too quick and myelin weeps Excitotoxic glutamate floods the NMDA gate Calcium cascade triggered — spreading depolarization's weight The ischemic spiral, energy failure starts the fall Barbiturates suppress metabolism, quieting it all BBB tight junctions broken by tumor and by trauma Contrast enhancement marks the gap — diagnostic panorama [Chorus] Autoregulate from fifty up to one-fifty MAP Rightward shift in hypertension — chronic pressure gap P1 percussion, P2 compliance, P3 closes out When P2 overtops P1, the brain is running out PRx positive means the vessels lost their grip CMRO₂ drops with cold, but seizures crack the whip Penumbra, compliance, CPP — hold the line Sodium, herniation, waveform — read the sign [Outro] CO₂ dilates, low O₂ dilates, neurovascular coupling binds Levetiracetam seven days — the evidence reminds Beyond that, prophylaxis fades, the data turns away ICP, MAP, PbtO₂ — escalate today
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