Year: 2011
Type: dissertation
Abstract: Background: Vasoactive agents are frequently needed in the treatment of septic shock and in the management of brain dead organ donors.However, the effects of vasopressors on splanchnic blood perfusion and metabolism remain controversial.We wanted to evaluate the effects and differences of several vasoactive agents on systemic and splanchnic blood perfusion and metabolism in septic shock and after brain death.Materials and methods: We used experimental porcine models.Anesthetized animals were extensively instrumented for collecting blood samples and monitoring the regional hemodynamics and metabolism.Septic shock was induced with an endotoxin infusion, aiming to cause hypotensive shock.Vasopressor infusion was aimed to increase systemic blood pressure to a predetermined level for 4-14 hours.The brain death was performed with an inflatable subdural balloon.Systemic hypotension was treated with dopamine or vasopressin for five hours.Regional hemodynamics and metabolism were monitored similarly to a septic shock model.Results: 1) Dopexamine increased the systemic and superior mesenteric arterial blood flow (Qsma) but decreased the fractional celiac trunk blood flow, while the gastric mucosal pCO2 gradient incresed.2) Vasopressin decreased the systemic and Qsma blood flow and caused systemic and regional lactate release.3) Hypoperfusion and regional lactate release caused by vasopressin were reversed when combined with dobutamine.4) Epinephrine caused severe arterial lactatemia, increased the gastric venous-to-arterial CO2 content gradient and had a tendency to increase the gastric lactate gradient.5) Norepinephrine did not cause systemic or regional hypoperfusion.6) Vasopressin decreased the systemic and Qsma blood flow and oxygen delivery after brain death, while these adverse effects were not associataed with dopamine.Conclusions: Dopexamine redistributed the splanchnic perfusion by retrieving the colonic but compromising the gastric blood flow.Vasopressin caused systemic and especially mesenteric hypoperfusion, while the adverse effects of vasopressin were reversed when combined with dobutamine.Systemic arterial hyperlactatemia associated with epinephrine is not explained solely by hypoperfusion, but epinephrine did induce selective hypoperfusion to the gastric mucosa.Norepinephrine was not correlated to any harmful effect on systemic or regional blood perfusion or metabolism.Dopamine is superior to vasopressin in securing small bowel blood perfusion after brain death.
Author: Tero J. Martikainen
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: green
Funder: Pohjois-Savon Rahasto
OpenAlex ID: W3203097410