[Vasopressin for treatment of shock]

Vasodilatory refractory shock is common in patients with severe burns. It is defined by resistance to high doses of volume and vasopressor therapy.

Our objective was to investigate effects of vasopressin therapy in severe burn patients with vasodilatory refractory shock.

We carried out an open, prospective study in 15 patients with severe burns with vasodilatory refractary shock. Patients were monitored with arterial line, pulmonary artery catheter, transtoracic echocardiography, arterial and central venous gases, gastric-arterial CO2 gradient, serum and urinary osmolality, urinary electrolytes, dieresis, and trooping T and CPK-MB levels. All patients were cultivated. Vasopressin was used in continuous infusion at 0.04 IU/min for 72 h. Measurements of hemodynamic and metabolic parameters were recorded at 2, 4, 8, 12, 24, 48, 72 and 96 h. During treatment with vasopressin, therapy with pressor amines was determined and reduced by hemodynamic evolution. At the end of 72-h infusion, vasopressin was slowly tapered in 24 h.

After administration of vasopressin, systemic vascular resistance index (SVRI) and pre-arrest morbidity (PAM) were significantly increased (p < 0.05). We observed a significant decrease in dopamine and norepinephrine requirements (p < 0.005). Norepinephrine was discontinued at 72 h and dopamine infusion was continued at low dose. Urine output, urinary sodium, and serum bicarbonate were significantly increased. deltaCO2 was increased and this finding was associated to decrease in norepinephrine and dopamine requirements; this effect translated in to better splachnic perfusion. Left ventricular function indexes were normal. Patients did not develop evidence of myocardial, splachnic, or limb ischemia during vasopressin infusion. In all patients vasopressin was weaned at 24 h and removed. In five patients, it was necessary to reinitiate vasopressin infusion for another 96 h without complications. Low-dose vasopressin infusions (0.04 IU/min), are a useful therapy to severely burned patients with vasodilatory refractary shock and who are devoid of adverse effects.