Objectives: To document the effects of dobutamine on
standard hemodynamics and right ventricular (RV) performance in
patients exhibiting pulmonary edema following severe scorpion
envenomation, and to characterize the tissue oxygenation profile in
patients sustaining scorpion envenomation-related shock.
Design: Prospective cohort study.
An ICU in a university hospital.
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 μg/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 the 10
patients with peripheral shock. The clinical signs of tissue
hypoperfusion improved, and optimal hemodynamic parameters were
achieved at a mean ± SD dobutamine dosage of 17 ± 7μ
g/kg/min. Dobutamine infusion evoked statistically
significant increases in cardiac index, from 2.3 ± 0.6 to
3.6 ± 0.7 L/min/m2; stroke volume index, from 18 ± 5
to 31 ± 10 mL/m2; and systemic arterial pressure, from
64 ± 12 to 78 ± 14 mm Hg. Pulmonary artery occlusion pressure
(PAOP) and venous admixture decreased significantly: from 23 ± 4 to
15 ± 6 mm Hg and from 29 ± 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 profile was consistent with cardiogenic
shock, showing increased oxygen extraction as a consequence of a
striking depression in oxygen delivery (Do2).
After dobutamine infusion, Do2 improved
significantly, from 386 ± 104 to 676 ± 156 mL/min/m2,
with a significant decrease in oxygen extraction, from 34 ± 8% to
24 ± 6%.
Conclusions: In severe scorpion
envenomation, dobutamine infusion improves impaired heart function. The
effects involve both left ventricular and RV dysfunction. Impaired
tissue oxygenation is also improved.