Bomba sangüínea espiral: Concepção, desenvolvimento e aplicação clínica de projeto original

Abstract

Introduction: This paper addresses an original project that encompasses the concept, development, and clinical application of a helical bypass pump using the association of the centrifuge and axial propulsion forces based on the Archimedes principle, referred to as Spiral Pump. This project has obtained Brazilian Patent and a Preliminary International Report defining it as an invention. Methods: We seek to evaluate the homodynamic capacity and the impact of its application to the blood cells by means of experimental "in vitro" tests, such as Hydrodynamic Efficiency, Normalized Hemolytic, and Flow Visualization. The "in vivo" experimental tests were carried-out in lambs submitted to bypass for 6 hours and in 43 patients undergoing bypass heart surgery using the Spiral Pump. Results: When the rotor - plastic carcass gap was 1.5 mm, the generated flow was nearly 9 L/min; pressure above 400 mmHg at 1500 rpm, normalized hemolytic indexes not superior to 0.0375 g/1001 under high-flow and pressure conditions, and by the flow visualization at the entrance and exit of the pump, as well as the extremity of the spindles. At the "in vivo" tests in the lambs, the pump was capable of maintaining adequate pressure and the Free Hemoglobin ranged between 16.36 mg% and 44.90 mg%. Evaluating the results of the 43 patients using this pump in bypass heart operations we observed that the Free Hemoglobin ranged from 9.34 mg% to 44.16 mg% before and after surgery, respectively; the Serum Fibrinogen from 236.65 mg% to 547.26 mg%; Platelet Blood Count from 152.465 to 98.139; and the Lactic Dehydrogenase from 238.12 mg% to 547.26 mg%. The Activated Coagulation Time was near 800 seconds during the bypass. Conclusion: The Spiral Pump was very effective in generating adequate flow and pressure, causing no excessive harm to the blood cells.