Comparison of norepinephrine and dopamine in the management of septic shock using impedance cardiography

Abstract

Objective: Vasoconstrictors are one of the therapeutic modalities in\nthe treatment of septic shock. In the present study, we have compared\nthe effects of dopamine and norepinephrine in the treatment of septic\nshock with pre-defined end-points and continuous non-invasive cardiac\noutput monitoring using impedance cardiography. Design: Randomized\ncontrolled trial. Settings: Sixteen-bedded mixed intensive care unit of\na tertiary care teaching institution. Materials and Methods: The study\nincluded 50 consecutive patients presenting with septic shock and\ndivided randomly into two groups with 25 patients in each group. Group\nI patients were treated with dopamine and those in Group II were\ntreated with norepinephrine. They were optimized with fluid\nresuscitation upto CVP>10 cm of H 2 O, packed red cells transfusion\nupto hematocrit> 30, oxygenation and ventilation upto PaO 2 >60\nmmHg before the inotropes were started. The goal of therapy was to\nachieve and maintain for six hours, all of the following: (1) SBP>\n90 mm Hg, (2) SVRI> 1100 dynes.s/cm 5 m 2 , (3) Cardiac Index>\n4.0L/min/m 2 , (4) IDO 2 > 550 ml/min/m 2 and (5) IVO 2 > 150\nml/min/m 2 . Measurements: The demographic data, baseline parameters\nand post-treatment parameters were statistically analyzed by using\nt-test. Results: The post-treatment parameters were statistically\nsignificant showing the superiority of norepinephrine over dopamine in\noptimization of hemodynamics and patient survival. Significant\nimprovement in systolic blood pressure, heart rate, cardiac index,\nSVRI, IVO 2 and urine output were found in norepinephrine group than\nthe dopamine group. Dopamine showed a response in 10 out of 25 patients\nup to a maximum dose of 25 mcg/kg/min while with norepinephrine, 19\npatients responded up to a maximum dose of 2.5 mcg/kg/min The\nhemodynamic parameters were preserved in norepinephrine group with\nbetter preservation of organ perfusion and oxygen utilization with\nmaintenance of splanchnic and renal blood flow as evidenced by\nsignificant increase in O2 uptake and urine flow. Conclusion:\nNorepinephrine was more useful in reversing the hemodynamic and\nmetabolic abnormalities of septic shock compared to dopamine at the\ndoses tested.