Hemodynamic monitoring in the neurological intensive care unit.

The neurointensivist needs to have a thorough understanding of hemodynamic issues and the interaction of the brain and the cardiovascular system. Before one decides to intervene and try to correct an apparent "abnormal hemodynamic parameter" one needs to think whether such an intervention is indeed warranted and what effect the intervention would have on the cerebral circulation. The neurointensivist thus needs to approach these issues differently from the approach an internist or general intensivist would take.

Sodium disturbances frequently encountered in a neurologic intensive care unit.

Most sodium disturbances in patients with CNS lesions result from disturbed water regulation. Possible systemic and iatrogenic causes must be evaluated prior to treatment. Insufficient secretion of ADH leads to hypernatremia if fluid intake is inadequate and can be treated with either fluid or hormone replacement. Care must be exercised in patients with acute diabetes insipidus because of the potentially variable and transient nature of the disturbance. Hyponatremia usually results from inappropriate secretion of ADH and should be managed aggressively in symptomatic patients with loop diuretics and hypertonic saline. However, very rapid correction or overcorrection should be avoided. Patients with SAH and hyponatremia should not be fluid restricted because of the risk of exacerbating vasospasm but treated with large volumes of isotonic or mildly hypertonic saline.