5 ways to help you give better care to your renal patients
I’m not proud to admit this, but…
Before I moved into referral, I thought there was one way to manage CKD - because whenever we had a CKD patient in the hospital, we did this:
Assessed their renal values
Administered high rates of fluid therapy
Provided supportive care
Reassessed their renal values 3 days later and (hopefully) discharged them
Sound familiar?
Well, the reality is there is a lot more to think about when treating and nursing renal patients. And because we see them so commonly in practice, they give us so many opportunities to use new nursing skills, and improve the care we give!
In the final post in our ‘Up Your Medical Nursing Skills’ series, I’m sharing 5 skills that will help you manage your renal patients in the hospital. Whether they have chronic kidney disease, acute kidney injury or a bit of both, these skills will allow you to more closely measure renal function, get accurate diagnostics and plan even better nursing care.
Don’t forget that this week is the final week of our challenge - so if you want this week’s case study, you’ve got until Friday to get on the VIP list! Sign up here if you haven’t already.
#1: How to assess renal function
Regular assessment of renal function is vital when managing renal patients in the hospital. We can do this in several ways:
Creatinine levels
This is going to be the most common test used to assess renal function. We prefer to assess kidney function with creatinine levels over urea/BUN levels because creatinine is more specific for renal function than BUN.
BUN levels are affected by other factors, including:
Liver function (BUN is often lower in patients with hepatic dysfunction)
Gastrointestinal disease (BUN increases in patients with gastrointestinal haemorrhage)
Fluid balance (relative increases in BUN can be seen in patients who are behind on fluids)
Creatinine, on the other hand, is an indirect indicator of glomerular filtration rate (GFR) - the rate at which blood is filtered through the kidney.
GFR is the gold-standard measurement for renal function but is challenging to measure without performing complicated or more invasive tests such as the iohexol clearance test.
In comparison, creatinine is a quick, simple indicator of renal function.
Urine SG
Specific gravity (the concentration of our urine) is another indicator of renal function. It’s important to assess this on a urine sample taken before any IV fluids are administered, to get a true representation of how well the kidneys can concentrate the urine.
Renal concentrating ability reduces when approximately 66% of renal function has been lost. A specific gravity of above 1.030 in dogs and 1.040 in cats is considered adequate; below this could indicate renal dysfunction.
Urine output
Urine output is another important indicator of renal function, and should be monitored closely in patients with acute kidney injury specifically, since these patients are at a higher risk of oliguria or anuria.
Normal UOP: 20-40ml/kg/day
Polyuria: UOP >40-50ml/kg/day
Oliguria: UOP <0.5-1ml/kg/hour
Anuria: A lack of urine production
Patients with decreasing urine output are at a higher risk of fluid overload. For this reason, the administration of high rates of fluids to renal patients should be avoided if there are concerns about urine output.
The safest method of monitoring this in at-risk patients is to place a urinary catheter (see tip 4!) and measure and compare the patient’s fluids in and fluids out (see tip 5).
Other tests
There are many other parameters we look at in patients with renal disease - not necessarily as direct indicators of renal function in all cases, but because we often see other abnormalities in these patients. These tests include:
Electrolytes
Phosphate levels
Ionised calcium levels
SDMA levels (in early renal disease where creatinine is normal)
#2: How to measure blood pressure accurately
Getting an accurate blood pressure measurement is vital when monitoring renal patients, especially those with CKD who are at risk of systemic hypertension.
This is also a skill that really plays to our strengths as nurses - since we can dedicate time to these patients, take the measurement process slowly, and give them some acclimatisation time before the procedure. We can also spend time working out what their preferred site for measurement is, what distraction techniques work, and generally how to perform the procedure in a way that minimises stress.
Why is this important? Because we know we see ‘white-coat hypertension’ really commonly, especially in our feline patients. By doing whatever we can to get a more accurate reading, we’ll ensure reliable results, and therefore the correct treatment for our patients.
So what do we need to think about?
There are many key factors we need to consider to get an accurate blood pressure reading. These include:⠀
The measurement method⠀
The site used⠀
The patient's environment⠀
The cuff position and size⠀
The number of readings⠀
Record-keeping and consistency⠀
Method ⠀
Are you going to use Doppler, oscillometric or high-definition oscillometry (HDO) for your patient?
Consider the species, temperament and indication for measurement. Are they a cat, a hypovolaemic or a very wriggly patient? If so, Doppler may be better. Are they very stressed or showing signs of aggression? If so, you may prefer oscillometric, as they have more freedom and can be away from the team during measurement.
Do you need more information than systolic measurement alone? If so, you might want to opt for oscillometric or HDO.⠀
Environment ⠀
Making the patient's environment as stress-free as possible is vital in preventing white-coat hypertension.
Select an area of the hospital which works best for the individual patient (this may be in their kennel, in a carrier, or exploring a consult room!)
Let the patient acclimatise to their new surroundings for at least 10-15 minutes before measurement, and use fear-free tools like pheromones and comfortable bedding throughout.⠀
Site⠀
Select an appropriate monitoring site for the individual patient. Do they have an injury affecting a specific limb?
Do they hate their feet being touched?
Do they have hindlimb weakness or arthritis?
Minimising any pain or fear associated with measurement is key to accuracy.⠀
Cuff
Measure the cuff to make sure it is the correct size for the patient (the width should be around 40% of the limb circumference).
Also, make sure the cuff is lined up correctly - most cuffs have a shaded zone or marked area which should be positioned over the artery.⠀
Number of Readings
At least 3-5 consistent readings should be obtained, and these used to calculate an average result. If any readings are not consistent, these should be discarded.⠀
Consistency
These patients will require regular measurements - not just during hospitalisation, but when they return for restaging of their renal disease. Keeping accurate records of how the measurement was obtained is therefore vital, so the technique can be repeated at subsequent visits.
#3: How to feed the patient with renal disease
There is a lot to think about when it comes to feeding the renal patient. And often it’s us as nurses who are responsible for creating these nutritional plans - and getting those anorexic renal patients eating!
There are two main differences in how we approach renal patients nutritionally - it depends on whether they are in the hospital (acutely unwell) or at home, having recovered from any acute illness.
Feeding renal patients in the hospital
In the hospital, my priority when creating a nutritional plan for these patients is to get them eating SOMETHING.
Not necessarily a renal diet - in fact, we ideally want to withhold this until they are at home and feeling better. The best diet in the hospital is the one they want to eat.
So perform a nutritional assessment, calculate their RER and volumes of food required, and tempt them with whatever seems appealing to them.
Alongside this, we also need to ensure we’re managing any systemic illness that could be driving their anorexia. For example, patients with CKD are often nauseous or have had vomiting. They may be painful, depending on the individual. A painful or nauseated patient is unlikely to want to eat - so get these signs under control before reaching for the food or appetite stimulants!
And of course, we wouldn’t be doing our job as nurses if we weren’t considering feeding tubes in these patients. Naso-oesophageal tubes are quick and easy to place and well tolerated, so are a good option for short-term (in-hospital) feeding. If you suspect your patient may be hyporexic or anorexic for some time, an oesophagostomy tube should also be considered.
Feeding the renal patient at home
Once the patient has gone home and is recovering from their acute period of illness/hospitalisation, it’s time to think about gradually introducing a long-term renal diet (if one is indicated).
Because the last thing we want to see is food aversion (a particular challenge with our cats!) we want to avoid introducing any new diet until they are eating consistently at home, and feeling better in themselves. Otherwise, we run the risk of the patient associating that new food with feeling unwell.
Most patients with chronic kidney disease will benefit from a therapeutic diet designed for patients with renal disease. These are formulated to slow the progression of CKD and include features such as:
Restricted phosphorus content, to slow CKD progression and prevent renal secondary hyperparathyroidism
Controlled protein restriction, to minimise uremia whilst minimising loss of lean body mass
Omega-3 fatty acid and antioxidant supplementation, to reduce oxidative damage and protect the kidneys
Neutral-to-slightly-alkalinising in pH, to counteract the metabolic acidosis often seen with kidney disease
Increased potassium and B-vitamin content, to replace those lost in the urine)
Decreased sodium content, to minimise hypertension
The degree of protein and phosphate restriction varies, with ‘early’ renal diets having less restriction, and being used for stage 1-2 chronic kidney disease. ‘Traditional’ renal diets have greater restriction, and are indicated for advancing stages of CKD.
#4: How to place and manage urinary catheters
Urinary catheters are commonly placed in patients with acute kidney injury, where we need to keep a particularly close eye on their urine output.
We also see primary urinary tract disease cause acute kidney injury - for example, patients with urethral or ureteral obstructions, causing post-renal azotaemia. These patients often have catheters placed to manage their urinary tract disease - allowing us to also assess their urine output and renal function!
How to place a urinary catheter
The first thing we need to do is prepare the site.
This is vital to minimise contamination from the patient’s skin/hair and minimise the risk of ascending urinary tract infection.
To prepare the site, excess fur from around the prepuce/vulva should be trimmed, and the area cleaned with a diluted antimicrobial skin solution.
The inside of the prepuce/vulva should also be flushed with a diluted antimicrobial skin solution before the catheter is placed.
Next up, we need to place the catheter itself - and the way we do this varies depending on species and gender.
Male Dogs
To place a urinary catheter in a male dog:
Restrain the dog in lateral recumbency and prepare the site.
Measure the catheter from the bladder neck to the prepuce.
Ask an assistant to grasp the os penis and retract the prepuce caudally.
Lubricate the catheter and insert it aseptically into the urethra.
Ask the assistant to relax their grasp on the penis once the catheter reaches the level of the os penis, to facilitate insertion.
Advance the catheter until it enters the bladder and urine emerges from the catheter hub.
If you’re placing an indwelling catheter, inflate the Foley balloon with an appropriate volume of 0.9% saline, and withdraw the catheter gradually until the balloon sits in the bladder neck.
Female Dogs
Placing urinary catheters in female dogs is a little more complex, but there’s no reason why we can’t be doing this as nurses!
There are two ways of catheterising a female dog - blindly and via visualisation:
Position your patient in lateral or dorsal recumbency with the hindlimbs extended cranially, or in sternal recumbency with the hindlimbs hanging from the end of the table (depending on your preference).
Prepare the site.
Measure the catheter from the bladder neck to the vulva.
A vaginal speculum may be used to facilitate direct visualization of the urethral orifice. If you’re using this, lubricate and insert it with the slit directed ventrally.
The external urethral orifice can be visualised along the ventral aspect of the cranial vestibule.
If you’re using the blind method, the external urethral orifice can be palpated as a small, round, firm mass around 2.5-5cm from the vulva, along the ventral aspect of the vestibule. Using your index finger, guide the catheter tip into the urethral orifice.
If you’re using the visualisation method, lubricate your urinary catheter and insert it into the urethra aseptically.
Advance the catheter until it enters the bladder and urine emerges from the catheter hub.
If you’re placing an indwelling catheter, inflate the Foley balloon with an appropriate volume of 0.9% saline, and withdraw the catheter gradually until the balloon sits in the bladder neck.
Male Cats
To place a urethral catheter in a male cat, deep sedation or general anaesthesia is typically required. Here’s how to do it:
Following sedation or anaesthetic induction, position the patient in lateral recumbency and prepare the site.
Measure the catheter from the bladder neck to the prepuce.
Use your thumb and index finger to push the prepuce cranially, exposing the glans penis.
Lubricate the catheter and advance it into the urethra aseptically.
Once the catheter is advanced into the penile urethra, grasp the prepuce and pull it caudally. This straightens the urethra, facilitating the passage of the catheter.
Advance the catheter until it enters the bladder and urine emerges from the catheter hub.
The catheter, if remaining in situ, is secured to the prepuce with sutures.
Female Cats
Though we don’t place them as frequently, urinary catheters are easier to place in female cats than we think!
Here’s how to do it:
Following sedation or anaesthetic induction, position the patient either in lateral or dorsal recumbency, depending on individual preference, and the site prepared.
Measure the catheter from the bladder neck to the vulva.
Lubricate the catheter.
Grasp the vulval lips and extend them ventrally, whilst inserting the catheter along the ventral midline of the vestibule.
The catheter should advance into the external urethral orifice (which lies on the ventral floor of the vestibule) without the need for visualisation.
Continue advancing the catheter until it enters the bladder and urine emerges from the catheter hub.
The catheter, if remaining in situ, is secured to the vulva with sutures.
Catheter Care
So now our catheter is in… we need to think about the nursing considerations for our patient!
Ascending infection via the catheter into the urinary tract is very common, and therefore performing thorough and regular catheter care is vital to minimise the risk of infection.
We can do this by:
Consider the catheter type we use - place a Foley where possible as these can be secured in place without the need for sutures, which can pull on the patient, be uncomfortable, and risk interference.
Always use a closed collection system on the end of every indwelling catheter, and never leave any open to the environment.
Wear gloves whenever handling the urinary catheter, bag and lines, in conjunction with performing hand hygiene.
Clean the prepuce/vulva, the external portion of the catheter, the collection system and all connections with a diluted antimicrobial skin solution every 4-6 hours.
Storing the collection system away from contaminated surfaces, such as the floor. Popping the urine bag in a clear ziplock bag, or a clean litter tray used only for catheter bag storage is a good alternative.
Prophylactic antibiotics should not be routinely administered to patients with indwelling urinary catheters, owing to the risk of developing a resistant UTI. Instead, in patients where the risk of UTI is considered high, a urine sample is collected via cystocentesis after the urinary catheter is removed. This sample is submitted for bacterial culture, and appropriate treatment is administered if required.
#5: How to measure fluids in and fluids out
Once our urinary catheter is placed, we need to use this to measure our patient’s urine output. We’ll compare this to the volume of fluid administered to our patient - we ideally want them to match, to ensure we’re not over or under-hydrating our patient!
Here’s how to do it:
Measure fluid output
Add together your patient’s total fluid output:
Urine output
Any other increased losses - e.g. from vomit, diarrhoea or drains
Divide this total by the number of hours you’ve been measuring them over, and then divide this by the patient’s weight.
This will give you their fluid output in ml/kg/hour.
Measure fluid intake
Add together the total fluid given to your patient:
IV fluid therapy
Liquid diet (e.g. via tube feeding)
Oral water intake
Constant rate infusions
Divide this total by the number of hours you’ve been measuring them over, and then divide this by your patient’s weight.
This gives you their fluid intake in ml/kg/hour.
You can now compare these two figures. If your ins are significantly higher than your outs, that indicates an increasing risk of fluid overload. If your ours are much higher than your ins, your patient is likely to need their fluid rate increasing!
So there you have it! 5 top tips and practical skills you can use when nursing renal patients. Don’t forget the final case study in this challenge is heading your way THIS FRIDAY (at the time of this post going live) - make sure you’re signed up to receive it here if you’re not already on the VIP list!