29.4. The effects of vasopressor agents on the systemic and regional hemodynamics and metabolism

Public examination of a doctoral dissertation in the field of anaesthesiology and intensive care

Doctoral candidate: Lic Med Tero Martikainen

Time and venue: 29.04.2011 at 12 noon, Kuopio University Hospital, Auditorium 2

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.

The doctoral dissertation of Licenciate of Medicine Tero Martikainen, entitled The effects of vasopressor agents on the systemic and regional hemodynamics and metabolism will be examined at the Faculty of Health Sciences. The opponent in the public examination will be Professor Juha Perttilä of the University of Turku and the custos will be Professor Esko Ruokonen of the University of Eastern Finland.

Photo available for download at http://www.uef.fi/vaitoskuvat  

Contact: Tero Martikainen, tel. +358 44 089 1610, tero.martikainen@kuh.fi

Publishing year: 2011

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