Dialysis Nursing Basics You Need to Know
When you think of dialysis, you probably think of patients who have chronic renal failure who go to the dialysis center three days a week, sit there for a few hours, then go home. But wait…there’s more! In this post we’ll cover the main types of dialysis, indications for urgent dialysis and the nursing care of these often-complex patients.
Overview of Dialysis
The process of dialyzing a patient removes waste and excess fluid from the blood when the kidneys are not able to do so adequately. There are two main types of dialysis: hemodialysis and peritoneal dialysis.
Hemodialysis or “HD” as the cool kids call it, is what you think of when you think of those patients who get dialyzed on their regular three-day-a-week schedule. Blood is removed from the patient, pumped through a dialyzer which contains a specialized filter that utilizes osmosis, filtration and diffusion to essentially “clean the blood” of waste products (namely urea and uric acid). Hemodialysis will also balance electrolytes and remove excess fluid.
In the acute care setting, you will undoubtedly know if you are taking care of a chronic dialysis patient. Either they are in the hospital for a complication of their renal failure or it will be pretty obvious they receive dialysis when you see/feel/hear their HD access site (most often this will be an arteriovenous fistula or an arteriovenous graft). Some patients will have catheters in place, so if you see really large bore catheters in the patients subclavian or femoral vein, this is probably a dialysis catheter. Don’t use it for medication or fluid administration!
If you receive report on a chronic HD patient, see if you can find out their “regular” dialysis schedule (it is typically Mon-Wed-Fri or Tues-Thurs-Sat). Find out when they last went to dialysis and if they’ve missed any appointments. Make sure the attending MD on the case knows that you are taking care of a dialysis patient so they can get a renal consult. The nephrologist will write orders for the patient’s dialysis while they are in the hospital. A dialysis nurse will either come to the room to perform HD (if the patient is in ICU), or the patient might go down to a dialysis center in the hospital to receive their treatment.
Some patients are so sick that require daily hemodialysis or, at least, daily evaluation for dialysis. The nephrologist will review their labs, fluid balance and current clinical situation to decide if the patient needs dialysis more frequently than three days a week.
How hemodialysis works (in very simple terms!)
In hemodialysis, blood is removed from the patient and passed through a machine called a dialyzer. Within the dialyzer are a specialized filter and dialysate solution, which typically contains potassium, calcium, chloride, magnesium, glucose and sodium bicarbonate in varying amounts (depending on what the patient needs).
The electrolytes in the dialysate solution will be at a lower concentration than what you’ll find in the patient’s blood. This creates a concentration gradient where the electrolytes will flow from the higher level of concentration (the patient’s blood) down to the lower level (the dialysate solution), thereby effectively removing it from the patient.
On the other hand, the dialysate solution will contain HIGHER levels of sodium bicarbonate and glucose than what you’d find in the patient’s blood. So the glucose and sodium bicarb will diffuse INTO the patient’s blood, thereby correcting acidosis while preventing hypoglycemia.
Modes of Hemodialysis
Hemodialysis can take many forms, and which mode is used depends on what your patient needs AND what they can tolerate. For example, if their electrolytes are fine but they are simply fluid overloaded, they’ll get one type of HD. If their blood pressure can’t a traditional dialysis treatment, they may need slower therapy.
- Intermittent Hemodialysis (IHD): This is your typical 3-days/week dialysis. Each session takes about 3-4 hours and is great for rapidly removing fluid, balancing electrolytes and removing toxins. Toxins and electrolytes are balanced through diffusion and volume is removed through ultrafiltration. The main disadvantage is that the rapid removal of fluid and re-balancing of electrolytes can cause hypotension and potentially increase cerebral edema (it is typically not used in patients with head injury for this reason). Though IHD is usually done three times per week, the nephrologist may choose instead to perform IHD daily if the patient’s status requires it.
- Sustained low-efficiency dialysis (SLED): This mode of dialysis is used in patients who can’t tolerate the drastic drops in blood pressure that occur with IHD. Each treatment takes 6-12 hours and typically occurs daily.
- Continuous renal replacement therapy (CRRT): If your patient is very sick and hemodynamically unstable, they will not be able to tolerate IHD or even SLED. So, they will receive continuous dialysis at a very slow rate. CRRT is done only in the ICU and administered by a critical care RN (typically not the dialysis RN, though the dialysis RN may come and set up the machine initially, depending on each individual hospital policy).
Complications of hemodialysis
Patients undergoing hemodialysis can have a whole host of acute complications, including:
- hypotension (this is the main one)
- headaches, dizziness, fatigue
- muscle cramps
Chronic complications include bone loss (due to altered calcium metabolism), cardiovascular disease, stroke and even gastric ulcers.
Peritoneal dialysis also removes toxins and excess fluid from the blood by utilizing the patient’s own peritoneal membrane as a semipermeable dialyzing membrane. It’s genius!
In peritoneal dialysis, the patient has a catheter placed into their abdomen. The patient will infuse a dialysate solution through this catheter into their peritoneal space. Through the process of diffusion, waste products and excess electrolytes in the blood move across the peritoneal membrane and into the solution. And let’s not forget osmosis…excess water will move across the membrane as well in order to achieve fluid balance.
Many patients will perform peritoneal dialysis at home while continuing on with their daily activities as usual. The solution typically needs to dwell for 2-6 hours (depending on various factors and the patient’s needs), and some people utilize a machine so they can perform their dialysis at night while they sleep.
Complications of peritoneal dialysis
- abdominal pain and cramping (often due to cold dialysate solution)
- respiratory compromise due to increased pressure in abdomen
- peritonitis (this is a big concern, so keep the process sterile!)
- infection at the insertion site or dislodgment of the catheter
Dialysis nursing assessments and interventions
Now here’s where I am going to keep it super simple. When you have patients in chronic renal failure, you are essentially watching for a handful of KEY things:
- fluid overload
- electrolyte imbalances
Of course, there’s more…like infection at the access site, peritonitis (if using peritoneal dialysis)…but those three things are the biggies. To assess for fluid overload, you’ll monitor daily weights, edema and lung sounds. Patients who are fluid volume overloaded with renal disease are often VERY hypertensive. I remember one patient who would come in with a BP of 220-240…scary as heck! He’d get dialyzed and the BP would come down…even being on a cardene gtt didn’t really help his BP. It was nerve-wracking!
What about electrolyte imbalances? What are you going to do about those? Typically, imbalances are dealt with via dialysis…you’re not going to replace K or Mag in a dialysis patient. And, for instance, if potassium is elevated it’s not like they’re going to excrete it in the urine (so lasix is out UNLESS some kidney function remains). You could give something like kayexalate which causes K to bind to it in the GI tract, and the patient essentially “poops out” their excess levels of potassium.
For the most part, the problems your patient is having are typically dealt with by dialyzing them. See? Super simple 😉
Medications and dietary adjustments for patients on dialysis
If you haven’t already noticed, your chronic renal failure patients take a lot of meds. Here are the main ones:
- Medications for anemia such as erythropoietin and iron supplements
- Vitamin D
- Diuretics (if some kidney function remains)
- Potassium binders (such as Kayexalate)
- Phos binders (either with or without calcium…calcium carbonate and sevelamer are common)
As for the renal diet, it’s a tough one to adhere to. It’s low in salt, phosphorus and protein (in some cases low in K and Ca as well). Some would also argue that it’s low on taste, but there are plenty of resources out there for adjusting to a renal diet (and chronic renal failure lifestyle). The emphasis is on high-quality protein and your patient may also have to limit fluids, which can be tough! Encourage the use of salt-free herbal/spice blends to enhance the taste of food and be sure to ask your patients what their favorite foods are so you can consult with the dietician about modifying them for the many renal diet restrictions.
When emergent dialysis is needed
Sometimes, emergent dialysis is needed…either in patients with chronic renal failure or patients with acute renal failure or overwhelming toxic overdose. So how do you know it’s time to call a nephrologist in the middle of the night? All you have to know are your vowels!
Acidosis: Metabolic acidosis is a big problem in patients with renal failure because the kidneys have lost their ability to manufacture bicarbonate which is a main buffer in the body. If your kidney failure patient becomes altered or has decreased LOC, you would be wise to get an ABG and check their pH.
Electrolytes: Dangerously high potassium levels are the typical cause for emergent dialysis. Get your patient on the monitor and keep an eye out for ectopy, dysrhythmias, bradycardia and tall T-waves.
Intoxicants: If your patient has overdosed on something and you need to get it out NOW, then dialysis could be the way to go. Some blood thinners, for instance, have no antidote…you can either wait it out and replenish blood as you go, or dialyze it out.
Overload: Fluid overload that is compromise cardiac and respiratory status needs to be dealt with ASAP! Dialysis to the rescue!
Uremia: A toxic buildup of uremia (waste products) in the blood causes a whole host of problems. Signs include hypertension, fatigue, confusion and nausea.
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