New sensors for dialysis equipment and home-health devices
TE Connectivity (TE) introduces sensors for dialysis equipment to develop home-health monitoring devices that enable patients to live healthier, more mobile lives.
Dialysis is a therapy that filters waste, removes extra fluid and balances electrolytes (sodium, potassium, bicarbonate, chloride, calcium, magnesium and phosphate). The kidneys play an important role in maintaining health. When healthy, the kidneys maintain the body’s internal equilibrium of water and minerals (sodium, potassium, chloride, calcium, phosphorus, magnesium, and sulfate). Some acidic metabolism end-products are also excreted through the kidneys. The kidneys function as a part of the endocrine system, producing erythropoietin and calcitriol. Erythropoietin is involved in the production of red blood cells and calcitriol plays a role in bone formation.
While healthy kidneys have several functions in the body, the most well-known job is to produce urine. When kidney function goes down, kidneys are no longer able to filter the blood and make urine. This causes toxins to build up in the body along with excess fluid. One type of renal replacement therapy – meaning a treatment that replaces kidney function – is dialysis.
Temperature is a critical property in dialysis equipment. Improper temperature can cause discomfort for the patient; more importantly, blood proteins can only keep alive and remain healthy in certain temperatures. Temperature of the blood is controlled by the dialysate water in the process. NTC (negative thermal coefficient) thermistor temperature sensors installed in the housing can measure the water temperature to provide data to make adjustments to optimize performance.
The normal pressure in the vein is from 0 to 200 mmHg, but for dialysis machines, because of the pump, the reverse rotation might cause the pressure to drop below zero. Board mountable pressure sensors can measure the pressure in vacuum and positive pressure states. It is critical to monitor the blood pressure of both arterial and venous to allow detection of blood blockages in the extracorporeal blood circuit; meanwhile, blood pressure difference might cause the uncomfortableness.
The pressure in the dialysate delivery system controls the rate of convection and the clearance rate of dialysis procedure. Blood is filtered across a semipermeable membrane at a constant pressure. Media isolated pressure sensors such as the 85BSD series use a stainless steel diaphragm to convert the pressure into a 14 bit digital output signal for accurate control of the fluid pressure.
Air Bubble Detection
In order to prevent air from getting into the vein of the patient, air bubbles need to be detected in the extracorporeal blood circuit. TE manufactures standard and custom air bubble detectors for dialysis equipment. Standard designs are offered to measure bubbles in 4mm and 6mm diameter tubing.