Monitoring cardiac function and intravascular volume in neurosurgical patients

Evaluation of cardiac function and intravascular volume has proved essential in two broad groups of neurosurgical patients: those with cerebrovascular disease and those with intracranial hypertension. For accurate assessment of cardiac function and intravascular volume, determinations were made by a dye dilution technique. This approach was used in 68 patients, in whom 215 dye dilution measurements were made. Useful parameters of left ventricle function included cardiac output, cardiac index, stroke volume, and mixing time. Important measures for the assessment of intravascular volume were mixing volume, dispersion volume, total peripheral resistance, central venous pressure, and mean pulmonary artery wedge pressure. Cardiopulmonary monitoring by this dye dilution technique has proved useful, relatively noninvasive, rapid, and easily repeatable in a wide variety of clinical situations in which cardiac function and state of hydration require accurate assessment. By adding this dye dilution technique to the more commonly used methods for evaluating intravascular volume and cardiac function, more accurate monitoring of critically ill neurosurgical patients can be carried out.