Vasopressin Receptor Agonists in Septic Shock: Effects on Microcirculation

60 septic shock patients requiring norepinephrine to maintain mean arterial pressure between 65 and 75 mmHg despite adequate volume resuscitation will be enrolled in the study. After an initial hemodynamic resuscitation aimed at achieve a mean arterial pressure between 65 and 75 mmHg and normovolemia, patients will be randomly allocated to be treated with either a) intravenous administration of terlipressin 1 µg∙kg-1∙h-1 for 6 hrs, b) intravenous administration of arginine vasopressin 0.04 UI∙min-1 for 6 hrs, c) intravenous administration of terlipressin bolus dose of 0.5 mg (each n = 20). In all groups open label norepinephrine will be additionally administered to maintain a mean arterial pressure (MAP) between 65 and 75 mmHg, if necessary. Data from right heart catheterization and sublingual microvascular network will be obtained just before randomization (baseline) and then after 6 hours in the vasopressin, terlipressin infusion and terlipressin bolus groups.

The sublingual microvascular network will be studied using the sidestream dark field (SDF)imaging. The device will be applied on the lateral side of the tongue, in an area approximately 2-4 cm from the tip of the tongue. Sequences of 10 secs from eight adjacent areas will be recorded on disk using a personal computer. These sequences will be later analyzed by an investigator blinded to the patient's diagnosis and therapy.