Dobutamine in severe scorpion envenomation - Effects on standard hemodynamics, right ventricular performance, and tissue oxygenation

Objectives: To document the effects of dobutamine on standard hemodynamics and right ventricular (RV) performance in patients exhibiting pullmonary edema following ser ere scorpion envenomation, and to characterize the tissue oxygenation profile in patients sustaining scorpion envenomation-related shock. Design: Prospective cohort study. Setting: An ICU in a university hospital. Patients: Nineteen consecutive patients were admitted to the ICU for severe scorpion envenomation; all 19 patients exhibited,hemodynamic pulmonary edema, and 10 patients had peripheral shock. Interventions: All patients underwent a hemodynamic study with a Swan-Ganz catheter. In 8 of 19 patients, the thermodilution catheter was equipped with a fast-response thermistor. Measurements and results: Standard hemodynamic parameters were recorded on admission and following the infusion of dobutamine in all patients at a dosage, from 7 to 20 mu g/kg/min, intended to achieve the best hemodynamic and tissue oxygenation compromise. RV ejection fraction (RVEF) and RV volumes were simultaneously recorded in 8 patients, and tissue oxygenation parameters were assessed in die 10 patients with peripheral shock. The clinical signs of tissue hypoperfusion implored, and optimal hemodynamic parameters were achieved at a mean + SD dobutamine dosage of 17 +/- 7 mu g/kg/min. Dobutamine infusion evoked statistically significant increases in cal dine index;, from 2.3 +/- 0.6 to 3.6 0.7 L/min/m(2); stroke volume index, from 18 +/- 5 to 31 +/- 10 mL/m(2); and systemic alterial pressure, from 64 +/- 12 to 78 +/- iii mmHg. Pulmonary artery occlusion pressure e (PAOP) and venous admixture decreased significantly: from 23 +/- 4 to 15 +/- 6 mm E-Ig and from 20 +/- 7% to 20 +/- 5%, respectively , With respect to RV function, dobutamine infusion significantly increased the RVEF, from 24 +/- 7% to 42 +/- 9%, without significantly changing the RV end-diastolic volume index, reflecting an enhanced RV contractility. In patients with peripheral circulatory failure, the baseline tissue oxygenation pl of the was consistent with cardiogenic shock, showing increased oxygen extraction as a consequence of a striking depression in oxygen delivery (Do(2)). After dobutamine infusion, Do(2) improved significantly;, from 386 +/- 101 to 676 a 156 mL/min/m(2), with a significant decrease in oxygen extraction, from 34 +/-: 8% to 24 +/- 6%. Conclusions: In severe scorpion envenomation, dobutamine infusion improves impaired cd heart function. The effects involve both left ventricular and RV dysfunction. Impaired: tissue oxygenation is also improved.