Background: In critical care, dopamine is administered by infusion at lowdoses (/=5 microg/kg/min) for assessment of hemodynamics. Thepresent study was conducted to explore the effects of dopamine infusion on the vast microvascular networkof skeletal muscle in the early phases of sepsis. Material/Methods: An observational study was performedwhich included twelve critically ill patients. Patients' response to dopamine infusion (3 microg/kg/min)was studied within 24 hours from admission to the ICU. The forearm blood flow (FBF) and vascular resistance(FVR) were measured by near-infrared spectroscopy (NIRS). Results: Dopamine did not ameliorate forearmregional oxygenation. The infusion of dopamine caused an increase in MAP, while FBF decreased with theresistance increase (p>0.05). Conclusions: NIRS was suitable to measure bedside the vascular resistanceand to test the effects of low doses of dopamine on forearm blood flow. A dopamine infusion of 3.0 microg/kg/mincaused a reduction in forearm blood flow and an increase in vascular resistance in our patients.

Keywords: Vascular Resistance - drug effects, Sepsis - physiopathology, Regional Blood Flow - drug effects, Muscle, Skeletal - blood supply, Microcirculation - physiopathology, Infusions, Intravenous, Aged, 80 and over, Hemodynamics - drug effects, Forearm - blood supply, Dopamine - pharmacology, Critical Illness, Critical Care