Analysis of the hydrodynamic profile in different roller pumps models used in cardiopulmonary bypass.
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.
Vieira
Francisco Ubaldo
FU
Nucleus of Medicine and ExperimentalSurgery of the School of Medical Sciences, State University ofCampinas (UNICAMP) - São Paulo, Brazil. fubaldo@terra.com.br
Vieira
Reinaldo Wilson
RW
Antunes
Nilson
N
Petrucci
Orlando
O
Oliveira
Pedro Paulo de
PP
Serra
Márcia Milena Pivatto
MM
Vilarinho
Karlos Alexandre de Sousa
KA
Carmo
Marcio Roberto do
MR
D000704:Analysis of Variance; D001938:Brazil; D002138:Calibration; D002315:Cardiopulmonary Bypass / Q000295:instrumentation*; D004867:Equipment Design; D016014:Linear Models; D011673:Pulsatile Flow / Q000502:physiology*