July 7, 2022 admin
Hemodialysis Procedure and Machines:
Hemodialysis is a procedure in which blood is cleaned using a dialysis machine and a special filter known as dialyzer (artificial kidney). To get blood into the dialyzer, the doctor must gain access to, the blood vessels. This is accomplished through minor surgery, usually on arm.
Blood is cleaned using HD machines by passing it through the dialyzer. A clear plastic cylinder filled with hair-thin hollow fibres serves as the “artificial kidney.” Dialysate fluid bathes the outside of the fibres while blood flows through the insides. Wastes and excess water from the blood are flushed away through tiny pores in the fibres and into the dialysate. Blood becomes cleaner with each pass, through the dialyzer.
Doctor will perform surgery to create an entrance point (vascular access) into blood vessels so that blood can flow to the artificial kidney. There are three types of entry points: 1. Fistula arteriovenous (AV). This type connects two arteries and veins. It is the preferred choice. 2. Graft of the AV. A looped tube is one of these. 3. Catheter for vascular access, this is likely to be inserted into a large vein in neck.
The AV fistula and graft are both intended for long-term dialysis treatments. Two to three months after surgery, patients with AV fistulas are healed and ready to begin hemodialysis. Patients who receive AV grafts recover in two to three weeks. Catheters are intended to be used only temporarily.
How does dialysis machine work?
A hemodialysis machines facilitate the filtering of blood by the dialyzer. The dialysis machine has built-in safety checks to ensure the process is safe and effective. The machine also monitor the blood flow rate (QB) and the dialysate flow rate (QD) to ensure optimum filtration, clearance of uremic toxins and maintenance of effective fluid balance in the body.
What is dialysate?
Dialysate is a liquid composed of water, electrolytes, and salts. Dialysate cleans blood inside the dialyzer by removing waste products and balancing electrolytes. Nephrologist will prescribe the appropriate dialysate for body’s needs. The typical average dialysate concentration is 35mmol/l, obtained from proportioning dialysis stations that mix bicarbonate from solution or dry powder to water and a ‘acid’ compartment containing sodium, potassium, calcium, and magnesium.
What is the function of a dialyzer (artificial kidney)?
A dialyzer is the part of the hemodialysis machine that filters blood.
• The dialyzer’s core is made up of thousands of tiny mesh tubes.
• Blood flows through each tube, while the dialysate remains on the outside.
• Small pores in the tubes allow waste and excess fluids from blood to pass into the dialysate.
• Cleaned blood is then expelled from the dialyzer and returned to the body.
What happens if the power goes out during dialysis?
If the power goes out during dialysis, it will close all the lines. The information about session will be saved by the machine using a backup battery. If the power is restored soon, the stored information allows the machine to continue the session, if not the machine will return the blood to the patient and the dialysis is continued after the power is restored.
Power Source and Battery Management:
All dialysis equipment is AC-line powered due to the lengthy duration of the dialysis process. Standard AC-DC converters that meet medical safety requirements are used. A variety of voltage rails at various power levels are required due to the variety of components requiring power. For noise-sensitive precision circuits, a power system with multiple-output switching regulators and a significant amount of linear regulation at the load is required.
switching regulators and a significant amount of linear regulation at the load is required. Power-supply self-monitoring for voltage, temperature, and current flow is required by safety regulations. Detectors for overvoltage and undervoltage are common. Because of the higher power levels, active cooling using fans and temperature sensors in a variety of locations is required.
Water sterilisation capabilities are included in home-use machines, which may require more power than a standard 15A wall outlet. As a result, the power supply must be capable of limiting the current drawn from the alternating current line while also adding parallel power from a battery (or ultracapacitor).
As previously discussed, home-use dialysis machines require batteries (or ultracapacitors) to supplement the output power of the power supply when heating water for sterilisation. These must be charged whenever possible and fuel gauged to indicate when there is enough capacity to continue with the water sterilisation process.