Our Previous Work
BME has discovered that during hemodialysis, blood circulates at high velocity and turbulence inside the circuit of tubes and needles, and that the high velocity and the vortices and eddies of the turbulent flow cause frequent and forceful contacts of the cells with each other or against the walls of the circuit, which causes high shear stress (which is parallel or tangencial friction) and high normal stress (which is perpendicular impact) on the circulating red cells, platelets and white cells membranes. And the high shear forces cause the “activation” of the circulating white cells which is the up-regulation and expression of genes to produce and release pro-inflammatory humoral factors, such as cytokines and others. Any increase in the velocity of the flow causes an exponential increase of the friction and impact of cells, shear forces, and number of cells activated. In a turbulent blood flow, each blood cells behaves like a missile flowing at high velocity in chaotic directions and impacting with the millions of other cells in circulations or with the walls.
During one hemodialysis treatment, each blood cell circulates 15-30 times through the dialysis circuit and gets exposed to multiple frictions and impacts when traveling through the approximately 14-16 feet long circuit. Thus,in one dialysis, most if not all the white cells in circulation could be activated, produce and release proinflammatory humoral factors causing a transient state of inflammation. Repetitive hemodialysis like in patients receiving long-term dialysis contributes to cause a state of permanent or chronic inflammation. This may explain why many of these patients experience fatigue after dialysis, failure to thrive, anemia, high serum phosphorus and inflammation biomarkers, low serum albumin, muscle waste, and accelerated atherosclersois, etc.
This problem is exacerbated at present because in order to obtain higher efficiency of dialysis, that is, the removal of more solutes from the blood in a same period of time, the blood flow rate has been increased up to 400, even 500mL/min instead of the 200-250mL/min which was used initially, 60 years ago and higher than the 250-300ml/min used until a few years ago. Higher blood flow rates shorten the duration of a dialysis treatment but the high blood flow rate causes higher velocity, an exponential increase of the turbulence, friction and impact of cells and production and release of pro-inflammatory humoral factors.
The BME’s innovative dialysis needle ameliorated many of the problems caused by the high velocity and turbulence of the flow because it decreases the velocity, turbulence and release of proinflammatory humoral factors.
BME’s findings also help to explain why there are clinical differences between a short hemodialysis of 4 hrs at high blood flow rate, which is the current standard prescription, and a long hemodialysis of 8 hrs at low blood flow rate which has immensily better outcomes. Both, the short and long duration hemodialysis remove about equal amount of solutes from the blood. The only difference is that in a short dialysis with high blood flow rate, the velocity of the blood is higher and so is the turbulence, activation of white cells and amount of pro-inflammatory humoral factors released, whereas in a long dialysis with low blood flow rate, the velocity of the blood, turbulence, activation of white cells and release of humoral factors is lower. This may explain why patients receiving long duration dialysis with low flow rate have exceptionally superior outcomes in quality of life, severity of illness, wellbeing, and mortality than patients receiving the current standard 4 hrs, short dialysis.
Thus, BME’s findings provided the scientific basis to choose dialysis of longer duration, which should become the standard of care, and not dialysis of shorter duration These findings are of great benefit to patients and the dialysis provider industry and contributed to settle the question about which is the proper dialysis prescription, a question whose answer has been elusive for over 60 years.
Future studies should expand the knowledge of this once overlooked problem.