Baseline hemodynamic state and response to hemodilution in patients with acute cerebral ischemia

Abstract

Hemodynamic data were obtained in 9 patients (mean age 65 yrs) with carotid territory cerebral infarct within the preceding 24 hours (mean 14 +/- 8) as part of a pilot study testing the feasibility and safety of hypervolemic hemodilution. Pulmonary arterial catheters (PACs) were placed without complication in all patients, and after baseline measurements were obtained, up to 1500 cc of 6% hetastarch in 0.9% sodium chloride was administered the first day and up to 1000 cc per day the second and third days. Pulmonary wedge pressure (PWP) rose from 6.3 +/- 3.5 to 14.4 +/- 3.4 mm Hg (p less than 0.001) without development of congestive heart failure in any patient. This was accompanied by a drop in hematocrit (Hct) from 40.3 +/- 3.4 to 32.9 +/- 2.0 (p less than 0.001) and rise in cardiac output (CO) from 4.3 +/- 1.0 to 5.3 +/- 0.6 (p less than 0.05). Phlebotomy of 250 cc was performed in 2 patients and 500 cc in one in order to reduce Hct to desired levels. The volume of fluid needed to raise PWP to 15 was unpredictable (2361 +/- 1106 cc) and therefore PACs were necessary to monitor the rate and volume of fluid administration. The data show that PWP is sufficiently low and Hct sufficiently high following stroke in most patients that hemodilution by volume expansion with phlebotomy added if necessary can be undertaken safely with appropriate monitoring of hemodynamic function, and that this therapy results in optimal reduction of Hct and increased CO without risk of hypotension.