Hemodialysis is a life-saving medical procedure for the treatment of patients with end-stage renal disease. In acute cases, hemodialysis provides instant relief and rapid correction of fluid and electrolyte imbalances that pose a direct threat to the patient’s health. In chronic renal failure, this procedure causes a significant reversal of uremic symptoms, such as fatigue, muscle weakness, malaise, and headache. Hemodialysis, in general, can improve the patient’s functional status and increase patient survival. However, in order to achieve favorable treatment outcomes, the hemodialysis prescription should ensure that the right amount of dialysis is delivered to the patient. The dialysis technician is also expected to perform his duty, providing direct patient care. A lot of studies have proven the correlation between the delivered dose of hemodialysis and patient death. Because of this, the delivered dose should be measured and monitored routinely by the dialysis technician to guarantee that the patient receiving the optimal amount of dialysis. Numerous factors contribute to the amount of dialysis delivered. Each of these factors are specified on the hemodialysis prescription.
The Parts of a Hemodialysis Prescription
1. The Kind of Dialyzer Being Used
The dialyzer is a plastic tube approximately 30 centimeters long that contains extremely fine clustered fibers, known as capillaries. In hemodialysis, this device actually functions as an artificial kidney and replaces the vital roles of a healthy organ. The capillaries of a dialyzer are ideally made of a combination of special plastics with special filtering and blood-compatibility characteristics. The tiny pores in the capillaries filter metabolic wastes and excess fluids from the blood and flush them out of the body with dialysis fluid. Blood cells and important proteins remain in the blood. Dialyzers can either be high-flux or low-flux. The dialysis technician should make sure that only prescribed type will be used. Nowadays, most dialysis units are using high-flux dialyzers in order to improve middle-molecular clearance. The pores in the membranes of high-flux dialyzers are two-and-a-half times larger than those in low-flux dialyzers. Because their greater permeability, high-flux dialyzers have a more efficient removal of metabolic toxin molecules from the blood. This makes the quick removal of large amounts of fluids and toxins from the body possible.
2. The Duration on Dialysis
In general, the time on dialysis ranges anywhere between two and a half to four and a half hours. However, there are patients who will need more or less dialysis than this amount of time. Increasing or decreasing the time on dialysis is probably the single-most significant change that can be made in order to increase the efficiency of dialysis. Only the doctor can prescribe the time on dialysis, which the dialysis technician should strictly follow. A dialysis technician should be aware that the time needed for dialysis will depend on:
• How well the patient’s kidneys work
• How much fluid weight the patient gain’s between treatments
• How much waste the patient has in his body
• How big the patient is
• The type of dialyzer used – high-flux dialyzers tend to have better clearance than low-flux ones.
Dialysate is one of the two fluids involved in dialysis. The other fluid being blood. Dialysate is discarded along with removed toxic substances after leaving the dialyzer. Before initiating dialysis, it is very important that the patient’s electrolytes have been screened and the treatment prescription have been adjusted accordingly by the healthcare team. A dialysis technician is normally taught the “Rule of 7s.” This informal rule states that the patient’s potassium (K+) level plus the dialysate potassium should equal approximately 7. For instance, if K+ is between 4.5-5.0mEq/L the dialysis technician should use a K+ 2 bath. If K+ is <4.5 use a K+ 3 bath. If K+ is greater than 5.0mEq/L use a K+ 1 bath. The dialysis technician really has no reason to use anything higher than a 4K bath. Potassium concentration is one of the most important parts of a prescription since any alteration can result in arrhythmias, or abnormal heart rhythm.
Aside from keeping our bones and teeth strong, calcium’s other functions include clotting blood, sending and receiving nerve signals, and squeezing and relaxing muscles. Calcium also has the capability of releasing hormones and other chemicals that maintain a normal heartbeat. In order to determine the concentration of calcium in the dialysate, the pre-dialysis calcium levels will need to be taken by the dialysis technician and reviewed by the doctor. Lately, it has been a common practice to use a Ca bath which is slightly lower than physiologic concentrations, 2.5 mEq/l. This is done mainly to prevent the buildup of calcium particles in the veins which is thought to accelerate heart disease. Patients with high calcium levels may be placed on a Calcium bath of 2. Meanwhile, patients who recently had a surgical operation done on the parathyroid should be placed on a Ca bath of 3 or 3.5 to avoid a symptomatic presence of low serum calcium levels in the blood from “hungry bone syndrome.”
During treatment, a blood pump is adjusted to a constant speed to force your blood through the dialyzer and back to the patient’s body. The doctor ideally prescribes the blood flow rate, and the dialysis technician sees to it that this rate is maintained. It is also the role of the dialysis technician to let the patient know what his prescribed blood flow rate is. The blood flow rate is usually set between 300 and 500 mL/min (milliliters per minute). Ultimately, the rate of blood flow is limited by the size of the patient’s access, the tubing, and the needles. Fistulas and grafts normally have better blood flow rates than catheters. To compromise for a slower blood flow rate, patients with catheters may be prescribed a longer treatment and a high flux dialyzer. Higher blood flow rates result to better clearances.
6. The Dialysate Flow Rate
While this measure plays a minimal role in the determination of clearance efficiency, the rate of dialysate flow impacts the amount of cleaning that happens. Dialysate, as previously mentioned, is the fluid that surrounds the blood compartment. This means that the more dialysate used the more toxins removed from the blood. The dialysate flow rate can be controlled by the machine based on a setting maintained by the dialysis technician.
Anemia is an abnormal condition in which the body has fewer red blood cells than normal. Red blood cells transport oxygen to tissues and other vital organs throughout the body. Without oxygen, our bodies won’t be able to use energy from food. With anemia, red blood cells carry far less oxygen to the heart and brain, making them malfunction progressively. Patients who have chronic renal failure or end-stage renal disease usually have anemia. When kidneys are not working or damaged, they will not be able to make enough erythropoietin. Erythropoietin, commonly known as EPO, is a hormone that controls red blood cell production. As a result, the bone marrow makes fewer red blood cells, causing anemia in hemodialysis patients. A complete blood count is the most definitive test used to diagnose anemia. Males should have 13 grams per deciliter (g/dL) of hemoglobin and females 12 g/dL. Anything lower confirms anemia. In most cases, anemia is treated accordingly. A dialysis technician should not be surprised to encounter intravenous iron medications in a prescription. However, only nurses can administer medications. Dialysis technicians are limited to providing non-pharmacological interventions. A dialysis technician may also advise patients with kidney disease who have anemia caused by iron, vitamin B12, or folic acid deficiencies to include sources of these nutrients in their diets.
Normally, our kidneys help regulate the excretion of waste products and maintain a delicate balance of minerals in our bodies. They also secrete hormones, which impact other body systems. Unhealthy kidneys can’t excrete phosphorus, leading to an increase of phosphorus in the blood. With kidney disease, calcium is also not reabsorbed, leading to decreased serum calcium. Both increased serum phosphorus levels and decreased serum calcium levels stimulate excessive secretion of parathyroid hormone (PTH). An elevated PTH increases both the number and activity of cells that break down bone, called osteoclasts. For this reason, hemodialysis patients will usually have problems in bone metabolism. Prescriptions will ideally list interventions to address bone metabolism. This usually covers regulating the patient’s calcium, phosphorus and PTH levels with medications in the form of calcitriol, vitamin D analogues, or Cinacalcet. Bear in mind that medications can only be provided and charted by the nurse, not the dialysis technician.
If a patient’s current condition is enough to cause physical symptoms, the patient may be prescribed specific medications to control these. A good patient-specific medication is an antibiotic, used to counteract infections. People with kidney disease will usually have a weakened immunity, making them prone to infections. Generally, dialysis technicians are limited to providing non-pharmacological interventions. The administration and charting of medications are ideally done by nurses.
10. The Complications Caused by Dialysis, If There Are Any
The complications brought about by dialysis can be mild or severe, depending on the patient’s condition. Complications can arise at any second. Whether or not the patient is carefully following their dietary and fluid restrictions, a dialysis technician should possess vital knowledge about dialysis and kidney function.