title: Analysis of the hydrodynamic profile in different roller pumps models used in cardiopulmonary bypass.
abstract: OBJECTIVE
  Among the equipments used in cardiopulmonary bypass the roller pumps have great importance with various models available from several manufacturers. The calibration is an important factor in hemolysis rates and its potential is different in each. Researchers do not always approach details on the pump bed profiles assuming that the standardized calibration settings ensure equal and comparable values for all models of roller pumps. We have mainly two methods for calibration of pumps which also interferes on the hemolytic potential. In both of them, the characteristics of fluid impulsion defined by the pump bed design are not considered. The aim of this study is to compare the hydrodynamic profile of three models of roller pumps available in the Brazilian market.
  
  
  METHODS
  The rollers occlusion was performed by measures of drop and dynamic calibration. Two different silicone diameter tubes were used (3/8 x 1/16 and 1/2 x 3/32 inches).
  
  
  RESULTS
  The profiles showed differences in their variances, P<0.01 for drop rate measures and P<0.0001 for dynamic calibration. Different changes in pressure were found between the pumps analyzed (P<0.002).
  
  
  CONCLUSIONS
  The measures of occlusion are dependent on the design of the pump bed and comparisons involving roller pumps should be performed with caution. Blood tests should be performed to verify the influence of changes in hemolysis pressure.
authors.affiliation: Nucleus of Medicine and ExperimentalSurgery of the School of Medical Sciences, State University ofCampinas (UNICAMP) - São Paulo, Brazil. fubaldo@terra.com.br
authors.forename: Francisco Ubaldo
authors.initials: FU
authors.lastname: Vieira
authors.forename: Reinaldo Wilson
authors.initials: RW
authors.lastname: Vieira
authors.forename: Nilson
authors.initials: N
authors.lastname: Antunes
authors.forename: Orlando
authors.initials: O
authors.lastname: Petrucci
authors.forename: Pedro Paulo de
authors.initials: PP
authors.lastname: Oliveira
authors.forename: Márcia Milena Pivatto
authors.initials: MM
authors.lastname: Serra
authors.forename: Karlos Alexandre de Sousa
authors.initials: KA
authors.lastname: Vilarinho
authors.forename: Marcio Roberto do
authors.initials: MR
authors.lastname: Carmo
mesh_terms: D000704:Analysis of Variance; D001938:Brazil; D002138:Calibration; D002315:Cardiopulmonary Bypass / Q000295:instrumentation*; D004867:Equipment Design; D016014:Linear Models; D011673:Pulsatile Flow / Q000502:physiology*