title: Spiral blood pump: conception, development and clinical application of the original project.
abstract: BACKGROUND
  This paper addresses an original project that encompasses the conception, development and clinical application of a helical bypass pump called the Spiral Pump, that uses the association of centrifugal and axial propulsion forces based de the Archimedes principle. This project has obtained a Brazilian Patent and an International Preliminary Report, defining it as an invention.
  
  
  METHODS
  The aim of this work was to evaluate the hemodynamic capacity and the impact of its application on blood cells by means of experimental in vitro tests, including hydrodynamic efficiency, effect on hemolysis and flow visualization. Moreover, in vivo experimental tests were carried out on lambs that were submitted to cardiopulmonary bypass for six hours and in 43 patients submitted to heart bypass surgery using the Spiral Pump.
  
  
  RESULTS
  When the rotor-plastic casing gap was 1.5mm, the flow generated was nearly 9 L/min, the pressure was greater than 400 mmHg at 1500 rpm, and the normalized hemolytic indexes were not greater than 0.0375 g/100L in high-flow and pressure conditions. Additionally, by the flow visualization techniques, stagnation was not seen inside the pump nor was turbulence identified at the entrance or exit of the pump, or at the ends of the spindles. In the in vivo tests using cardiopulmonary bypasses for 6 hours in lambs, the pump maintained adequate pressure rates and the free hemoglobin levels ranged between 16.36 mg% and 44.90 mg%. Evaluating the results of the 43 patients who used this pump in heart bypass operations we observed that the free hemoglobin ranged from 9.34 mg% before to 44.16 mg% after surgery, the serum fibrinogen was from 236.65 mg% to 547.26mg%, platelet blood count from 152,465 to 98,139 and the lactic dehydrogenase from 238.12mg% to 547.26mg%. The Activated Coagulation Time was close to 800 seconds during the bypass.
  
  
  CONCLUSIONS
  The Spiral Pump was very effective in generating adequate flow and pressure and caused no excessive harm to the blood cells.
authors.affiliation: Bioengineering and Surgical, Division of Instituto Dante Pazzanese de Cardiologia, São Paulo, Brazil (IDPC/SP). j.dinkhuysen@uol.com.br
authors.forename: Jarbas J
authors.initials: JJ
authors.lastname: Dinkhuysen
authors.forename: Aron José Pazin
authors.initials: AJ
authors.lastname: de Andrade
authors.forename: Ricardo
authors.initials: R
authors.lastname: Manrique
authors.forename: Claudia Sanches Medina
authors.initials: CS
authors.lastname: Saito
authors.forename: Juliana
authors.initials: J
authors.lastname: Leme
authors.forename: Francisco
authors.initials: F
authors.lastname: Biscegli
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001672:Biocompatible Materials; D001783:Blood Flow Velocity; D001938:Brazil; D004867:Equipment Design; D004869:Equipment Safety; D005112:Extracorporeal Circulation / Q000295:instrumentation*; D006331:Heart Diseases / Q000601:surgery*; D006354:Heart, Artificial; D006353:Heart-Assist Devices / Q000592:standards*; D006461:Hemolysis; D006801:Humans; D008955:Models, Cardiovascular; D010330:Patents as Topic; D012756:Sheep
chemical_list: D001672:Biocompatible Materials