Aim: We treated 24 patients suffering from an acute ischemic stroke of the middle cerebral artery, with a hypervolemic hemodilution combined with dopamine/dobutamine. Method: The influence of blood pressure and cardiac output on the blood flow velocity in the middle cerebral artery was measured using transcranial Doppler sonography (TCD). Results: Under the hypervolemic hemodilution supported with dopamine/dobutamine, a dosage-dependent increase of 12% in blood pressure and a 53% increase in cardiac output was observed. In the affected hemisphere, flow velocity was one fourth lower (significance p < 0.05) than in the unaffected hemisphere. With therapy, the systolic flow velocity was increased in the unaffected hemisphere by 27%, on the side of the lesion only by 11%. Mean flow velocity remained nearly constant. The pulsatility index (PI) increased simultaneously by 46% in the affected and 47% in the unaffected hemisphere. Conclusion: Similar effects on TCD-flow velocity and PI under comparable slight increases in blood pressure are not known. The increase in cerebrovascular resistance can be ascribed to a counter-regulation of the cerebral autoregulation, triggered by an increase of cardiac output.

AIM:We treated 24 patients suffering from an acute ischemic stroke of the middle cerebral artery, with a hypervolemic hemodilution combined with dopamine/dobutamine. METHOD:The influence of blood pressure and cardiac output on the blood flow velocity in the middle cerebral artery was measured using transcranial Doppler sonography (TCD). RESULTS:Under the hypervolemic hemodilution supported with dopamine/dobutamine a dosage-dependent increase of 12% in blood pressure and a 53% increase in cardiac output was observed. In the affected hemisphere, flow velocity was one fourth lower (significance p < 0.05) than in the unaffected hemisphere. With therapy, the systolic flow velocity was increased in the unaffected hemisphere by 27%, on the side of the lesion only 11%. Mean flow velocity remained nearly constant. The pulsatility index (PI) increased simultaneously by 46% in the affected and 47% in the unaffected hemisphere. CONCLUSION:Similar effects on TCD-flow velocity and PI under comparable slight increases in blood pressure are not known. The increase in cerebrovascular resistance can be ascribed to a counter-regulation of the cerebral autoregulation, triggered by an increase of cardiac output.

Patients suffering from acute ischemic stroke have impaired cerebral autoregulation. For this reason, the perfusion of the penumbra depends directly on BP and CO. The CO can be increased by hypervolemic hemodilution and administration of positive inotropic drugs. In the present study, we examined the effect of different therapy protocols on hemodynamics in three patient groups. In patients with no manifest cardiac insufficiency, suffering from nonacute cerebrovascular diseases (group 1, n=6) we carried out a hypervolemic hemodilution with an initial loading dose. In a second group of patients (group 2, n=6), suffering from an acute stroke and limited cardiac capacity, we combined hypervolemic hemodilution with administration of digitalis. In a third group of patients, suffering from an acute stroke, without manifest cardiac insufficiency, we combined hypervolemic hemodilution with the administration of sympathomimetics (group 3, n=6). Group 1 showed a rapid, 15% increase in CO that lasted approximately 3 hours. Group 2 showed a slow improvement in CO, which became apparent during the course of the therapy. Group 3 showed a rapid and lasting increase in CO of more than 30% which correlated closely with the administered dopamine/dobutamine dose. Hypervolemic hemodilution alone does not result in a rapid and longlasting increase of CO, particularly not in patients with myocardial insufficiency. To improve the hemodynamic status of acute stroke patients, the administration of positive inotropic substances is a viable alternative.

Although the dependence of cerebral perfusion on blood pressure has been well studied, little data is available about the effect cardiac output has on cerebral flow velocity and autoregulation, particularly during acute stroke. To improve cerebral perfusion, we treated 10 patients who suffered from an acute ischemic stroke of the middle cerebral artery with a hypervolemic hemodilution combined with dopamine‐dobutamine. The influence of blood pressure and cardiac output on the blood flow velocity in the middle cerebral artery was measured using transcranial doppler sonography (TCD). Under the therapy, a dosage‐dependent increase of 12% in blood pressure (BP) and 53% increase in cardiac output was observed. There was a significant ( p > 0.01) correlation between TCD‐mean flow velocity ( V m ) and cardiac output ( r = 0.33) as well as between V m and blood pressure ( r = 0.52) on the affected side. The unaffected side showed no correlation between V m and cardiac output ( r = 0.01), or between V m and blood pressure ( r = 0.03). Systolic flow velocity increased significantly in both hemispheres. As an expression of increasing cerebral vascular resistance, the pulsating index (PI) increased significantly ( p > 0.01) in the affected hemisphere as well as in the unaffected hemisphere. This suggests that during acute stroke blood flow velocity and autoregulation in the affected vascular region depend not only on cerebral perfusion pressure but also on CO levels.