الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Hemodialysis is a medical procedure designed to remove wastes, toxins and fluids from the blood when the kidneys have failed. It is the most common treatment for end-stage renal disease (ESRD), more commonly known as kidney failure. During the procedure, fluids and waste products are removed from the blood before being returned to the body. The blood is cleaned by a part of the hemodialysis machine known as an artificial kidney or dialyzer, which filters the blood after it has entered the machine.
In the present work, a portable home hemodialysis machine (more frequent hemodialysis) for treating of renal failures was designed and constructed. Short daily and long nocturnal home hemodialysis is available in the constructed machine. More frequent hemodialysis lessens the amount of fluid that gathers in the body between treatments. Therefore, less fluid needs to be removed during the next treatment. This usually decreases symptoms often experienced both during and after conventional hemodialysis treatments, such as headache, nausea and vomiting, cramping, hypotension and post-dialysis fatigue.
Hemodialysis machine delivery system designed in the present work delivers dialysate, pumps blood through the dialyzer, and monitors various dialysis parameters to ensure a safe treatment. Machine delivery system monitor patient and machine safety parameters. These include blood flow, dialysate flow, dialysate temperature, conductivity, blood in dialysate leaks and air bubbles. The delivery system is two major subsystems: the dialysate delivery system and the extracorporeal blood circuit. The hemodialysis (HD) machine pumps the dialysate as well as the patient’s blood through a dialyzer. The blood and dialysate are separated from each other by a semipermeable membrane permitting solute and water transfer as governed by laws of physics. The blood circuit consists of the following components:
- Blood tubing;
- Blood pump;
- Air leak detector; and
- Clamps.
The delivery of safe dialysate involves careful regulation of its temperature, concentration, flow, pressure, as well as its proper disinfection and/or cleaning. The key components/processes of this circuit include:
- Heating;
- Deaeration; and
- Monitoring;
Different parameters effecting blood flow, dialysate flow, dialysate temperature, conductivity, pressure regulation, blood leakage detector signal and air bubble detector signal were measured and fed to the microcontroller.
Relation between flow pump speed and flow rate was studied. The amount of fluid passing in one minute was measured at different pump speeds for blood and dialysate solution. Temperature sensor depends on thermistor resistance, the value of thermistor resistance changes according to temperature change. Changing in the resistance causes changes in the potential differences. Conductivity is measured by applying an alternating electrical current (I) to two electrodes immersed in a solution and measuring the resulting voltage (V). Blood leak detector consists of a light source and light sensor. Light Emitted Diode (LED) is placed on one side of the dialysate tube and a photo-resistance (Light Dependant Resistor (LDR)) is placed on the front side of the LED on the other side of the dialysate tube. Blood leak causes increasing in the light absorbance causing change in the electric signal of the LDR.
Calibration results showed that:
• Increasing the main pump speed with increasing the input DC voltage.
• Increasing the blood pump speed with increasing the input DC voltage.
• Increasing the dialysate temperature with decreasing the resistance of the temperature sensor of the heater.
• Increasing the reading of the conductivity sensor due to increasing in the solution concentration.
• The resistance of Light Dependent Resistor (LDR) of the blood leak detector increases with the changes of the solution colour.
from the data of this work, it can be concluded that:
• The preparation of the solution is successfully done manually outside the machine and tested by a single conductivity meter inside it.
• The machine can operate with short daily or long nightly sessions by increasing or decreasing the main pump speed.
• The machine is controlled by microcontroller that no other components are needed, because all necessary peripherals are already built into it.
• The machine plugs into a standard electrical outlet, requires no special infrastructure to operate and is easy to use by trained patients accompanied by their trained partners and is portable enough to travel.