Fluid management in the neurosurgical patient

The goal of fluid administration in neuroanesthesia and neurocritical care is to avoid dehydration, to maintain an effective circulating volume, and to prevent inadequate tissue perfusion. Management of the neurosurgical patient requires careful attention to fluid and electrolyte balance over all the perioperative periods [1]. These patients can receive diuretics (e.g., mannitol, furosemide) to treat cerebral edema and to reduce intracranial pressure (ICP); at the same time, they may require large volumes of either fluid or blood as part of an initial resuscitation, treatment of cerebral vasospasm, correction of preoperative dehydration, or maintenance of hemodynamic stability.1 . Movement of water between the normal brain and the intravascular space depends on osmotic gradients, particularly serum sodium concentration. 2 . In the setting of fluid therapy, reducing serum osmolality induces brain edema and increases ICP. Therefore, the goal of fluid management in neurosurgery is to avoid the reduction of serum osmolality. Reduction of COP, with careful maintenance of osmolality, does not increase edema in the injured brain. 3 . Hypertonic solutions, mannitol and hypertonic saline, decrease brain water content in the normal brain and are commonly used to reduce ICP. 4 . Glucose-containing solutions should not be used in patients who have brain pathology, and should be avoided in patients at risk for cerebral ischemia. 5 . Fluid restriction minimally affects cerebral edema and can lead to hemodynamic instability