In this study we have done the following steps:
- We analyzed the autotransfusion process duration theoretical dependence on initial blood concentration (Hct percentage), bowl size and wash flow rate.
- We figured out a test specification that would be able to identify the issue, i.e. a method to verify the relationship between wash flow speed and the fluid volume variations of the bowl circuit (TEST 1, chapter 3.2).
- From that tests we have demonstrated that, if a "critical" inlet wash flow rate is exceeded (600 ml/min), a by-pass flow issue occurs
- It has been found that standard US welded bowls have better performances than the pasted ones.
- Analyzing the two types of standard bowls, we can state that rotation eccentricity is a key factor about by-pass flow issue.
Another important difference between pasted and US welded bowls is the bottom protrusion.
- Through a fluid dynamical study and a computational fluid dynamic (CFD) analysis through Fluent® program, 16 modified prototypes have been designed and built up based on the standard US welded bowls.
- Best of all, the ultrasounds welded bowl with dome shaped collector (changing R) gives high improvements at every wash flow rates (87% at 750 ml/min, 75% at 800 ml/min..) and delays the by-pass at 800 ml/min.