Osmotherapy

Abstract

Reducing the volume of the intracranial content, decreasing ICP, and increasing CPP by drawing water out of the brain into the vascular compartment along an osmotic gradient is a cornerstone in the medical treatment of elevated ICP. Solutions of mannitol and hypertonic saline are effective and used frequently in clinical practice (White et al. 2006; Bhardwaj 2007). Both solutions exert an early effect on ICP due to optimising of rheological properties of the blood resulting in decreased blood viscosity and haematocrit, increasing cerebral blood flow (CBF) and oxygen delivery, and resulting in reflex autoregulatory vasoconstriction of cerebral arterioles that reduces CBV and ICP. This is followed by an osmotic shrinkage of brain cells that peaks after 15–30 min (Ziai et al. 2007).