Mechanical Volume Management in Acute Stroke: A First-Principles Biophysical Derivation (Preprint)

BACKGROUND Current acute stroke management guidelines focus primarily on time-based imaging windows and the pharmacological suppression of acute hypertension. This paper proposes an alternative paradigm based on a first-principles theoretical derivation of hydraulic states. OBJECTIVE The primary goal of this framework is to establish the physiological feasibility of a "Stability Corridor" for Cerebral Perfusion Pressure (CPP) to maximize neuronal salvage. METHODS The methodology utilizes a first-principles biophysical derivation incorporating the Monro-Kellie Doctrine and Laplace's Law. It modifies the Cushing Reflex sequence, framing the terminal rise in intracranial pressure (ICP) as a result of a systemic blood pressure spike driven by ischaemic vasoparalysis. RESULTS The derivation identifies two phases of hydraulic failure: a "Masked Influx" where the 0.05 alpha extracellular space (ECS) buffer is exhausted, followed by a "Terminal Spike" in ICP. It establishes a "Stability Corridor" by identifying the Ischaemic Floor for collateral flow and the Elastic Limit to prevent vascular tearing. CONCLUSIONS By modulating ICP to keep CPP within the Stability Corridor and using GFAP biomarkers as proxies for hydraulic integrity, clinicians can theoretically maintain cerebral perfusion and prevent the "Hydraulic Breach" of macro-haemorrhage. CLINICALTRIAL N/A (Theoretical Paper)