Acute Renal Failure: Nursing Management & Interventions Pt 2

Part one of our discussions on acute renal failure nursing management, we focused on two interventions – Kayexalate and Dopamine. These two belong to the four nursing processes that are required to manage acute renal failure. To easily remember, you can think of the acronym – HDTV. H stands for hyperkalemia while D stands for dopamine.

In this lecture, we will tackle the remaining two processes – T and V.

Before discussing the remaining two interventions, we’ll quickly go through the first two.

Kayexalate for Hyperkalemia

Kayexalate is the first thing that is given to acute renal failure clients due to the presence of hyperkalemia. Hyperkalemia is just one of the complications of having acute renal failure, and the only way to get it out of the body is through the potty which involves urination and fecal excretion. If urine is not being produced due to acute renal failure, potassium will be expelled through the anus with the help of Kayexalate.

Dopamine

Dopamine helps in renal vasodilation and at the same time, vasoconstricting the peripheral body, causing an increase in pressure. Low blood pressure is one of the main causes of acute renal failure; therefore, dopamine will help in the hyperperfusion of the kidneys.

The T and V

Now, the last two types of intervention are a bit difficult to comprehend because both are concerned with volume.

So, the main goal is to push volume through the kidney which can be referred to as, “tickling the kidney.” Tickling the kidney simply means increasing the perfusion which will lead to increased blood volume and oxygen. By doing so, we’re trying to get the client from the oliguric phase to the diuretic phase in the hopes that the condition will eventually lead to the recovery phase.

After giving dopamine to dilate the blood vessels in the kidneys, fluid is then pushed into the diuretic phase. This is where the T and V come in.

Total Volume

Giving total volume or a bolus of IV fluid means giving more fluid to the client; much like pouring fluid with the use of IV normal saline.

The kidneys are similar to washer machines. Imagine if these washer machines have too much accumulation of mud and are broken. By dilating the renal arteries and pushing more volume, we are restarting the organ and are getting rid of the mud inside the washer machines.

Volume Depletion

Diuretics are given to make sure that the kidneys are receiving sufficient volume. This is what we refer to as the volume depletion stage. Since the primary goal is to get fluid going into the kidneys and have it restarted, diuretics will push the volume through the kidneys. Lasix (Furosemide), the most popular loop diuretic, is a potassium-depleting medication given to acute renal failure clients.

A Summary

In retrospective, when a client in an oliguric phase, the kidneys are not working, and the basic goal is to achieve a diuretic phase. This is done by increasing the amount of perfusion in the kidneys through an IV bolus. Diuretics are given to make sure that there is enough volume that is being pushed inside the kidney to have it restarted and enter the diuretic phase. Once the client’s kidneys are rebooted, the next goal is to achieve the recovery phase.

In our next lecture, we will talk about creatinine clearance tests and how it is connected to clients with renal failure.

Illustration Provided By Injury Map

Causes and Manifestations of Acute Kidney Injury

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What does acute renal failure (ARF) or acute kidney injury mean?

To get a better understanding of what’s really happening when you have acute kidney injury, we’ll go into details about its causes and manifestations. We’ll go into the three stages of acute kidney injury, its manifestations, and how to fix them with the acronym, H-D-T-V. We’ll also discuss the three causes of acute renal failure and how to tell difference between intrarenal and prerenal failure.

Let’s get into it.

The Basics

The kidneys filter three things – hydrogen ions, blood urea nitrogen, and creatinine. These elements are filtered inside the nephrons, and inside the nephrons are glomeruli. Normal glomeruli filtration rate (GFR) is between 85 – 105 ml of blood per minute. If this filtration rate drops to 65 ml/min, it means that the kidneys are in trouble and a diagnosis of acute kidney failure ensues.

Signs and Symptoms

There are three main manifestations of acute kidney injury – oliguric, diuretic, and recovery. What happens during these phases?

  1. Oliguric Phase

In this phase, the kidneys are “insulted” by nephrotoxic medications or components, namely:

  • Vancomycin
  • Gentamicin
  • IV contrast

The oliguric phase can be characterized by:

  • No urine output
  • If there is urine, it would be very little and is very brown
  • High urine specific gravity

What you need to understand is that the kidneys are expected to filter out as much as what you’re consuming or drinking. Therefore, if you drink a gallon of water for a day, it is expected that the kidneys usually are filtering and excreting at least a gallon of water within that day. Which is why, clients who are drinking a gallon of water and are only peeing 100 ml/day, or taking in 135 ounces but excreting only three ounces are already suffering from oliguria.

  1. Diuretic Phase

The second phase of acute kidney injury known as the diuretic phase is when the kidneys are compensating. When injured, the body will try to compensate by getting rid of as much fluid as it can. So, in this phase, you can expect the following:

  • Low specific gravity
  • Very clear urine
  • The body is getting enough fluid and is properly flushing the toxins
  1. Recovery Phase

The last phase of acute kidney injury is referred to as the recovery phase which technically means that the kidneys are adequately producing urine and recovering from the trauma. However, this does not mean that the kidneys are 100% in perfect condition. The recovery phase mainly implies that the kidneys are properly compensating and the glomerular filtration rate is around 30 ml/hour.

Other Causes of Acute Kidney Injury

Other than vancomycin, gentamicin, and IV contrast, there are also diabetic drugs like metformin that can cause acute renal failure. These drugs are very toxic to the kidneys due to their half-life. It takes quite some time for these drugs to be excreted by the kidneys.

Therefore, if your client is taking metformin, it should be discontinued two days before or after the IV contrast so as not to increase insult to the kidneys and prevent acute kidney injury.

For the other causes of acute renal failure, mainly the three Hs, drop by SimpleNursing.com.

See you there!

Acute Renal Failure (ARF): BUN and Creatinine Interpretation

In our previous articles, we already discussed the phases of acute renal failure, namely:

  • Phase 1 – Oliguric
  • Phase 2 – Diuretic
  • Phase 3 – Recovery

We also talked about the three main causes of acute renal failure which are:

  • Low blood pressure
  • Low volume
  • Low oxygen

The mentioned causes are mainly due to low perfusion and low mean arterial pressure (MAP) that will cause the body to break down. So now, we’re going to assess how severe the acute renal failure is by determining your laboratory values.

Think of it this way: You’re driving your friend’s car, and you got into a car accident. The first thing that your friend is going to ask you once you break the news is, “How bad is it?” or “What’s the damage?” With acute renal failure, there are levels to determine the progression of the condition.                      

How to Diagnose ARF

To determine the severity of acute renal failure, doctors will request for specific tests for verification. Some of these tests may include:

  • Urine specific gravity
  • Blood urea nitrogen (BUN) and creatinine
  • Glomerular filtration rate – function test

Technically, this is breaking down the pathophysiology of kidney function, and we want to have a more vivid picture of the status of the condition, or how much of the kidney is no longer working or how much of it is still working.

Urine specific gravity

Urine specific gravity is going to show the concentration of the urine. If the test result indicates 1.030 or higher, you can expect very concentrated, dark, and stinky urine due to lack of water inside the body.

You will notice this with clients who are fond of drinking alcohol and soda but drink minimal water. Blood becomes concentrated, and it is turned into very dark urine output. In the phases of ARF, this is called as the oliguric phase.

BUN and Creatinine

As what was mentioned before, if BUN increases but the creatinine level is normal, the main reason is dehydration and NOT acute renal failure. Now, if the BUN and creatinine are both elevated, this means that you have a kidney problem.

Glomerular Filtration Rate

Glomerular filtration rate measures the creatinine in the blood. Having a GFR test result of below 65 is a sign of ARF. So remember the magic number – 65. Anything below 65 is a serious kidney issue, and anything above 65 is passing. The number that has to show on the GFR result should be above 85 to become normal.

Two Conditions of ARF

Now, we will determine how severe the condition is and in doing so, you have to know the two conditions of acute renal failure which are:

  • Extrarenal failure (prerenal) – 20:1 ratio for BUN/creatinine
  • Intrarenal failure – 10:1 ratio for BUN/creatinine

The difference between the two is their location. Extrarenal or prerenal failure means that the problem is outside the kidneys while intrarenal means the problem is inside the kidneys. To give you a more straightforward example, if there’s a fire (damage) and it happened outside the house (kidneys), it’s called prerenal. On the other hand, if the fire happened inside the house, it’s called intrarenal. Between the two, prerenal is more preferred than intrarenal to avoid serious damage.

Interpreting BUN and Creatinine

If your BUN is at 40, the expected creatinine will be at two; there’s enough space separating the BUN and creatinine. Since creatinine is the main factor that determines the severity of ARF, the moment it starts rising, and the numbers become closer, that’s a sign that therapeutic modality should be provided immediately.

Remember, if the “fire” is inside the kidneys, there will be depleted oxygen content and will start to suffocate the kidneys. Therefore, your kidneys need to be rebooted with treatment modalities that Mike likes to call “HDTV.”

To know more about these HDTV treatment modalities, check out our other nursing videos at simplenursing.com. See you there!

Identifying the Most Common Causes of Acute Renal Failure

Aside from pouring cement (toxins) into your washer machines (kidneys) which could automatically create massive destruction (renal failure), there are other ways that the kidneys can go into acute renal failure and these ways are broken down into three Hs.

What are the three Hs that contribute to the development of acute renal failure (ARF)?

  1. Hypotension or low blood pressure
  2. Hypovolemia or low volume
  3. Hypo-oxygenation or low perfusion

So, how does these three Hs cause ARF? Let’s go into a detailed explanation for each.

Hypotension

So, you’re wondering, “What does blood pressure have to do with kidney function?”

Well, without oxygen, the body breaks down and dies. If you don’t breathe, you die. If you put a rubber band around your finger, it will turn purplish-blue and eventually die. This is the same with your kidneys.

If there’s low blood pressure, there will be hypoperfusion. And if there’s hypoperfusion, there won’t be sufficient blood and oxygen that’s going to be delivered into the kidneys. Therefore, the primary concern in acute renal failure is how much oxygen the kidneys are receiving.

But how is oxygen delivered to the kidneys?

First, oxygen is breathed in and goes into your respiratory tract to get exchanged with carbon dioxide. Oxygen is then carried by hemoglobin that is present in your red blood cells and takes oxygen into the heart to be distributed or pumped to the different parts of the body. Basically, this is how the body receives oxygen.

If there is hypotension, there will be low blood pressure and the kidneys will receive an insufficient amount of oxygen due to the inefficient push of blood from the heart.

Hypovolemia

What happens if there is not enough blood volume to push oxygen around the body or if an accident happened and the client bled out? Is there going to be sufficient oxygen-carrying blood to transport oxygen around the body?

If there is decreased volume, there won’t be enough blood to circulate the body; thus, hypo-oxygenation will also occur.

Hypo-oxygenation (hypoperfusion)

A great example would be a client who has chronic obstructive pulmonary disease (COPD). Client with COPD has dysfunctional lungs that are unable to exchange oxygen with carbon dioxide. Without proper oxygen-carbon dioxide exchange, there won’t be enough oxygen-carrying hemoglobin to transport O2 down to the kidneys.

What Is MAP?

Low blood pressure will be equivalent to hypoperfusion and hypo-oxygenation. So the question now is, how does one measure if there’s enough blood pressure? This is where mean arterial pressure (MAP) comes in.

Mean arterial pressure directly correlates with the amount of blood that carries oxygen the kidneys are receiving. The magic number of your MAP is 65. If the MAP drops below 65, this means that your kidneys are not getting enough perfusion and your client is probably going into the oliguric phase or is currently in the oliguric phase.

ARF in Geriatric Clients

When you think about geriatric clients, they are dehydrated with decreased muscle mass. Reduced muscle mass means decreased fluid retention. Geriatric clients also have loss of appetite leading to hypovolemia.

Now, if geriatric clients are taking blood pressure medications and the kidneys are not getting enough blood volume to filter the drugs, this will cause toxicity and directly leads to decreased MAP.

Furthermore, if the geriatric client is a chronic smoker and develops COPD like emphysema and chronic bronchitis, this will also cause acute renal failure that is caused by hypo-oxygenation. With the geriatric community, this is called as the synergistic effect.

So remember, the three Hs of acute renal failure are: hypotension, hypovolemia, hypo-oxygenation that all lead to one major issue – perfusion.

Acute Renal Failure: Nursing Management and Interventions

Before discussing the therapeutic modalities of acute renal failure, we’ll be tackling a bit about your prerenal and intrarenal.

So, this is basically a quick review of your prerenal and intrarenal BUN level with regards to your creatinine. You just have to remember the following:

  • Prerenal = big BUNs = BUN-creatinine ratio is 20:1
  • Intrarenal = small BUNs = BUN-creatinine ratio is 10:1

When talking about nursing interventions of your kidneys, regarding acute renal failure, which do you think is more serious – prerenal or intrarenal?

Prerenal Acute Kidney Failure

Mike has stated that prerenal acute kidney failure is when the fire is outside the house, which means that the fire is not inside the kidneys nor is it affecting the nephrons just yet. Therefore, in prerenal, urine is still being created so there will still be urine output.

Even if the specific gravity of the urine would be very concentrated, brown, and stinky, there would still be some urine being excreted by the body.

Intrarenal Acute Kidney Failure

On the other hand, intrarenal acute kidney failure presents no pee-pee (urine output) because the “fire” is inside the kidneys affecting the structures within and mainly causing damaging effects to the kidneys.

So, that’s basically how you can easily distinguish prerenal from intrarenal acute kidney failure.

Nursing Intervention – HDTV

Regardless of what you’re thinking, HDTV does not stand for high definition television. Instead, HDTV here stands for:

  • H – Hyperkalemia
  • D – Dopamine
  • T – Total volume (increased)
  • V – Volume excess (decreased)

What does this mean in terms of your nursing process?

Hyperkalemia

During your oliguric phase, urine is not created, or if urine is being created, the body is not getting rid of it. Therefore, potassium must be increased. However, since potassium is a potent electrolyte, increased potassium can cause increased contraction that may result to dysrhythmias. Thus, hyperkalemia happens.

In providing nursing interventions, one must always remember that the first thing that needs to be addressed is what’s detrimental to your client. And since increased potassium can severely affect the client’s heart, it should first be managed.

You have to give attention to hyperkalemia first by bringing down the potassium level using Kayexalate. Kayexalate helps in getting rid of excess potassium from the body.

Since the body is unable to urinate, potassium will exit the body through the feces. So one side effect that you have to watch-out-for when giving Kayexalate is episodes of diarrhea.

Hyperkalemia > Kayexalate > Gets rid of excess potassium > poo-poo (feces) > diarrhea

Dopamine

Dopamine is used to dilate the renal arteries to get more blood down to the kidneys, causing:

  • More perfusion
  • More pressure
  • More oxygen
  • Increased blood flow to heart, lungs, and kidneys

Technically, when you give dopamine to your client, you wanted to increase the mean arterial pressure (MAP) to cause increased perfusion, thus also increasing the oxygen level.

On part two of our discussion, we will be talking about the T (total volume) and the V (excess volume). It’s just as simple as increasing the total volume while decreasing the excess volume.

Drop by simplenursing.com for the continuation of this discussion.

See you there!