Antivenom serotherapy and volume resuscitation partially improve peripheral organ ischemia in dogs injected with scorpion venom

We tested the hypothesis that fluid resuscitation combined with antivenom serotherapy given after injection of scorpion venom may increase cardiac output (CO) and blood pressure (BP) and prevent the decline in bicarbonate, pH and gastric perfusion. Seventeen anesthetized, mechanically ventilated dogs were given 0.1 mg/kg IV venom of the scorpion Leiurus quinquestriatus. The dogs were randomized into three groups: six dogs were given venom alone; three dogs were given 6 ml of antivenom 1minute before venom injection; eight dogs were given 6 ml of antivenom and 20 ml/kg of synthetic colloid solution, 20 min after venom injection. Parameters reflecting respiratory and circulatory functions were determined at baseline and 120 min after venom injection. Scorpion venom caused a decrease in CO, BP, pH and HCO₃^-. Gastric mucosal perfusion was severely affected as assessed by mucosal pH (pHi) and the gradient between mucosal and arterial pCO₂ (ΔpCO₂). Antivenom given before venom injection prevented all the effects induced by the venom. Antivenom and fluid given 20 min after venom injection caused a marked increase in CO and BP, but had no effect on pH and HCO₃^- decline (compared with venom alone). Gastric perfusion slightly improved as the increase in ΔpCO₂ was attenuated. The combination therapy of antivenom and fluid in this dog model is superior to the therapy of each of them alone. The marked and long-standing improvement of CO is promising and may suggest improvement in HCO₃^- and pH with time.