Background: The effects of moderate-dose vasopressin on gastric mucosal perfusion and its relation to global and hepatosplanchnic hemodynamic and oxygen transport variables were investigated in patients with severe sepsis.
Methods: Vasopressin was administered at a dose of 0.04 IU · kg⁻¹ · h⁻¹ over 4 h in 12 patients with severe sepsis who were receiving norepinephrine. During the study period, the norepinephrine infusion rate was reduced to keep mean arterial blood pressure constant. Hepatosplanchnic blood flow, oxygen delivery, and oxygen consumption (via hepatic venous catheterization using the Fick principle and continuous indocyanine green infusion technique), global hemodynamics (transpulmonary thermodilution method), and the difference between the gastric mucosal and arterial carbon dioxide tension (Pco₂-gap) were measured at baseline and 4 h after the start of the vasopressin infusion.
Results: The administration of 0.04 IU · kg⁻¹ · h⁻¹ vasopressin over 4 h was associated with minimal changes in global hemodynamics. Heart rate decreased slightly from 99 [81-115] (median [interquartile range]) to 96 [74-109] beats/min (P = 0.016) and cardiac index from 3.7 [2.8-4.7] to 3.5 [2.7-3.6] L · min⁻¹ · m⁻² (P = 0.003). Global oxygen delivery index decreased significantly from 461 [375-637] to 419 [352-551] ml · min⁻¹ · m⁻² (P = 0.002), whereas hepatosplanchnic blood flow and oxygen uptake remained unchanged. Gastric mucosal Pco₂-gap increased significantly from 13.3 [8.0-16.7] to 17.1 [10.3-28.7] mmHg (P = 0.002), suggesting that blood flow may have been redistributed away from the gut mucosa.
Conclusions: Vasopressin at a dosage of 0.04 IU · kg⁻¹ · h⁻¹ may impair gastric mucosal perfusion with minimal global hemodynamic effects.