Vasopressors Do Not Influence Cerebral Critical Closing Pressure During Systemic Inflammation Evoked by Experimental Endotoxemia and Sepsis in Humans

Abstract

Experimental human endotoxemia results in a decreased CrCP due to a loss of vascular resistance of the arterial bed. Vasopressors did not prevent this decrease in CrCP. Findings in patients with sepsis are comparable to those found in subjects after LPS administration.Patients with sepsis, despite treatment with vasopressors, have a risk for low cerebral blood flow and ischemia.

Dynamic Cerebral Autoregulation and Critical Closing Pressure in Experimental Human Endotoxemia and Sepsis Patients

“…This indicates that a cerebrovascular adaptation process has been switched on, also during experimental endotoxemia with intact cerebral autoregulation. These results are analogous to our previous observations of a decreased CrCP in human endotoxemia (2 ng/kg bolus) and sepsis [20]. This decreased CrCP operates as a protection for the brain against ischemia, and is mainly caused by a decrease in the time constant (Tau) of the cerebral arterial bed (Tau = Ca × CVR).…”

“…The first limitation pertains the small groups of subjects enrolled and the fact that sex and age where different between the endotoxemia and the sepsis groups. As described in a previous study, we enrolled only young healthy male people in the experimental human endotoxemia study to confine intersubject variability [20]. A second limitation is the measurement of MAP through a arterial catheter in the radial artery.…”

“…Finally, we cannot rule out the consequences of alterations in carbon dioxide on CBFV MCA and modification, because of an increase in respiratory rate and temperature after infusion of LPS [20].…”

“…Recordings were performed at 60 min before (baseline, T = BL), and at 150, Some clinical data (ABP, heart rate, temperature), CBFV and CrCP of the 8 endotoxemia subjects who received a bolus administration of LPS and of the 10 sepsis patients were previously reported [20].…”

“…In the present study, we investigated dynamic cerebral autoregulation and CrCP in healthy volunteers following continuous or bolus administration of LPS, and compared these responses to those observed in sepsis patients. Some clinical data (ABP, heart rate, temperature), cerebral blood flow velocity (CBFV) and CrCP of the 8 endotoxemia subjects who received a bolus administration of LPS and of the 10 sepsis patients were previously reported [20]. So in this study we also investigated dynamic cerebral autoregulation and CrCP following continuous (and higher total dose) administration of LPS to observe if this dose regime better resembles the situation in sepsis.…”