TRANSCRANIAL DOPPLER AND SYSTEMIC HEMODYNAMIC-STUDIES IN SEPTIC SHOCK

The present study outlines the relationship between cerebral and syste mic hemodynamics in patients with septic shock. Sepsis is an immune me diated systemic disease in which the systemic vascular resistance (SVR ) often decreases as a result of a Gram negative sepsis. The result is a hyperdynamic systemic circulation with redistribution phenomena in different organ systems. In order to study the effect of sepsis on cer ebral vessels 20 patients with septic shock (12 men, 8 women, mean age 57.9 years) were subjected to both pulmonary artery catheter and tran scranial Doppler (TCD) monitoring. The data were correlated to the APA CHE II score and outcome. The study showed that cerebral mean and end- diastolic blood flow velocities (BFV) in the middle cerebral arteries significantly enhanced if the SVR-index decreases. In some patients a severely reduced SVRI (below 500 dynes.s/cm(5).m(2)) was observed in c ombination with a downstroke latent steal phenomenon. TCD abnormalitie s were strongly related to disease severity and outcome. The increased BFV are explained by a mild vasospasm of the basal cerebral arteries. TCD appears to be a valuable tool to monitor the cerebral hemodynamic s in these patients. They are particularly at risk for ischemic brain damage if they are subjected to therapeutic or spontaneous hyperventil ation, which can potentially be detected by TCD.