"Intravenous" means the
fluids are given into a vein.
As with humans, this
treatment is usually only used in a hospital setting.
Intravenous
fluids are therefore normally reserved for acute situations. In the case
of a CKD cat, this would often be when a cat is severely dehydrated
("crashing").
They may also
be used for cats with pancreatitis, or kidney stones or kidney infections, or before and
during surgery.
What are Intravenous Fluids?
Intravenous (IV) fluids are a form of fluid therapy whereby the fluid is
administered via a drip feeding into a vein (intravenous). If you've ever
been a patient in hospital, you were probably on intravenous fluids, which
are sometimes referred to as "a drip."
The fluid used is not merely water because you cannot simply inject
ordinary water into the body, you need to use a fluid that is compatible. One commonly used fluid type is
lactated ringers solution (LRS), which is isotonic, i.e. it has the
same sodium concentration as body tissues.
Fluid therapy for critically ill dogs and cats
(2005) Schaer M Presentation to the 30th World Small Animal Veterinary
Association World Congress discusses the use of IV fluids. This is a
rather technical presentation for the layperson.
This is a
skilled form of treatment, and great care needs to be taken to ensure the
rate of fluid flow is correct for the cat. Too fast a flow can be
dangerous (it can overtax the heart), but too slow a flow may not rehydrate
the cat quickly enough.
Because of
this, IV fluids are usually only given at the vet's office, where the cat
can be carefully monitored. If you are giving fluids at home, you are
probably giving
subcutaneous fluids, not IV fluids.
When to Use Intravenous Fluid Therapy
IV fluids are used to support cats who are sick for a variety of reasons.
Introduction to fluid therapy
(2008)
DiBartola SP Idexx Laboratories FAQ states "The intravenous route is preferred when the patient is very
ill, when fluid loss is severe, or when fluid loss is acute."
Critically Ill Cats
As explained on the
Fluid Therapy
page, intravenous fluids are often used to treat acute problems e.g. to
stabilise a critically ill animal who has lost a life-threatening amount of
body fluids, perhaps following a road traffic accident, or a cat who has been
poisoned.
They are also used to treat cats who are critically ill for other reasons,
such as our George on the left who was extremely ill at this time with
liver disease.
CKD Cats
IV fluids are commonly used for severely dehydrated cats. Since CKD cats are
prone to dehydration because of their increased urination, which may be
compounded by the cat not eating and/or drinking enough, it is not
uncommon for CKD cats to become dehydrated enough to require IV fluids. This
is sometimes referred to as crashing, and may well be the first sign that your cat has CKD.
In most cases, cats in this situation will have high bloodwork with creatinine
over 6-7 mg/dl (US) or 550-650 µmol/l (international). The IV fluids are
employed as a flushing through of the kidneys to correct an acute crisis
situation of severe dehydration and any resulting electrolyte imbalances, and
to remove toxins from the blood. Increasing urine production in this way is known as diuresis.
IV fluids are also used for cats who have suffered an
acute insult to the kidneys (acute
kidney injury), such as a
kidney infection or
kidney stones.
In some cases, IV fluids may succeed in flushing out kidney
stones.
Cats with Other Ilnesses or Concerns
IV fluids may also be used for cats who need additional support
for some other reason. Cats with
pancreatitis
often require IV fluids when first diagnosed. Cats with severe
diarrhoea or vomiting may become dehydrated and need IV treatment,
as may cats who are not eating or drinking for some reason other
than CKD.
Cats Receiving Anaesthesia
Cats who are undergoing anaesthesia are often also placed on IV fluids. Anaesthesia can reduce blood flow through the kidneys
and cause falls in blood pressure, which may damage the kidneys, but giving IV fluids to the cat during
the procedure reduces this risk.
CKD cats
should definitely be placed on intravenous fluids for a few hours before, during
and after any surgery. Most vets will place cats on IV fluids during and
sometimes after surgery, but not every vet wishes to place a CKD cat on IV
fluids before anaesthesia. However, this is very important for your cat's
safety. In
Chronic kidney disease
(2007) Polzin DJ
Delaware Valley Academy of Veterinary Medicine,
Dr Polzin (a kidney specialist) states "It appears that the medical
prophylaxis most likely to be effective is related to pre-intervention
fluid support. Pre-loading patients with fluids before potential ischemic
or nephrotoxic interventions has thus far been shown to be the most
effective therapy. Other options that have been investigated include
diuretics, vasodilators, and some forms of metabolic support. However,
none have thus far proven to be superior to support with a saline-based
fluid. Usually, fluids should be administered in sufficient volume to
induce diuresis."
Goals of Intravenous Fluid Therapy for CKD Cats
In terms of CKD patients, the primary aim of IV fluids is usually to
rehydrate a severely dehydrated cat. Dehydration is very unpleasant and
can make cats look and feel very ill, but they usually look and act much
better once the dehydration is under control.
As a side effect, the cat's kidney bloodwork should improve. The goal is
not to lower the bloodwork values as such, but this usually will happen,
because the dehydration is making the bloodwork look artificially
elevated.
Other goals may include flushing out kidney stones (which may or may not
be successful), or supporting the kidneys during anaesthesia.
Speed and Length of Intravenous Fluid Therapy
How much intravenous fluid to give each day and the drip rate (how fast the fluid
flows into your cat) is a complex calculation, based on various factors
such as your cat's weight and the degree of dehydration. Your vet is
trained to do this.
Most CKD cats need to stay on IV fluids for 2-4 days. For a severely dehydrated
cat, the first 2-4 hours are used to rehydrate the cat i.e. the severe
dehydration is quickly corrected. This is known as the replacement phase. Cats stay on IV for longer than this
though, usually for several days: this is the maintenance phase which is
designed to give the cat a chance to stabilise. The different phases are
discussed on the
Fluid Therapy
page.
IV fluids should not be stopped suddenly, but should be reduced gradually
in order to give the cat's kidneys time to adapt. If IV fluids are being
given to a severely dehydrated CKD cat, most vets will start this
weaning process once there are no longer any improvements in the cat's bloodwork.
This tends to be measured over 1-2 days, so if a cat's creatinine level is
unchanged on Day 3 from Day 2, that is when the vet would start gradually
reducing fluids with a view to discharge probably on Day 4 if the cat
remains stable.
Managing fluid and electrolyte disorders in renal
failure (2008) Langston C
Veterinary Clinics Small Animal Practice38 pp677–697
says "When serum creatinine
concentration reaches a baseline value (ie, when it no longer decreases
despite IV fluid therapy), fluids should be tapered in preparation for
patient discharge. After a period of intensive diuresis, fluid
administration should be tapered gradually over approximately 2 to 3
days."
One day on IV fluids is unlikely to be sufficient for most CKD cats to restore hydration
and some degree of balance; so I am concerned by the number of
vets I hear about who offer just one day on IV, say the cat's numbers
have not improved sufficiently after that short stint, and recommend euthanasia. In most
cases this is inappropriate in my opinion (and is not what Dr Langston
recommends in the previous paragraph). Yes, not every CKD cat can be saved;
but euthanasia is an irrevocable decision so you need to be very sure, and for
most people that means giving their cat every chance. For a severely ill cat,
one or two days on IV are simply not going to be long enough, so I would
recommend that you make sure that your cat is given a reasonable stint on IV
of 3-4 days if you can afford it.
Conservative medical management of chronic renal failure in cats
(2012) DiBartola SP Metropolitan New Jersey Veterinary Medical
Association says "Don't pass
judgement on a lethargic dehydrated cat with markedly
abnormal laboratory results. 2 to 3 days of conscientious intravenous fluid therapy can produce
remarkable results." If your cat's bloodwork is still improving, your
cat may stay on IV even longer, occasionally cats are on IV for as long as a
week.
IV catheters can usually remain in place for 72 hours before there is any risk
of infection; after this, a catheter can be placed in the other paw if
necessary.
Nutritional Support for Cats on
Intravenous Fluids
It is essential that your cat is fed during hospitalisation.
Enteral and parenteral nutrition in the intensive
care unit (2021) Chan DL
Clinician's BriefOct 2021 pp10-14 states "Inadequate food
intake, GI dysfunction, and metabolic changes can cause malnourishment in
hospitalized patients not supported with nutritional interventions." Dr
Chan also says "Patients with obvious signs of malnutrition, >10% body
weight loss, ≥3 days poor food intake, and prolonged illness should be
given urgent nutritional support."
Some vets will tell you that your cat is receiving nutrients and calories
from the IV fluids, but a litre of lactated ringers solution contains only
around 10 calories, which is not enough. They may also tell you that your
cat is being fed, but they are simply placing food in front of the cat and
do not ensure that the cat actually eats the food.
2022 Consensus guidelines on management of the
inappetent hospitalised cat (2022) Taylor S, Chan
DL, Villaverde C, Ryan L, Peron F, Quimby J, O’Brien C & Chalhoub S
Journal of Feline Medicine and Surgery24 pp614-640 state that
cats need a high protein intake in particular: "protein
requirements for critically ill cats have not been established, but a
common recommendation is to provide 60-80 g/1000 kcal." The paper also has
strategies for encouraging voluntary food intake in hospitalised cats.
2022 Consensus guidelines on management of the
inappetent hospitalised cat (2022) Taylor S, Chan
DL, Villaverde C, Ryan L, Peron F, Quimby J, O’Brien C & Chalhoub S
Journal of Feline Medicine and Surgery24(7) pp614-640 state
that appetite stimulants should only be used in hospitalised cats once
nausea, pain and stress have been addressed. The guidelines contain advice
(page 623) for vets on how to ensure hospitalisation is as stress-free as
possible for cats.
If your cat does not eat voluntarily, ensure any possible causes of
inappetence (such as low potassium levels or nausea) are being treated and
if necessary consider the use of a feeding tube. See
Feeding Tubes for more
information.
Monitoring Cats on
Intravenous Fluids
Cats on IV fluids need
close monitoring to ensure they do not become overhydrated, which is a
strain on the heart. The cat should be checked once an hour, and heart and
lungs should be checked every 3-4 hours. The cat should be assessed by a
vet at least once every twelve hours and weighed regularly. The following
should be routinely monitored:
the weight of the cat
blood pressure
electrolytes,
such as potassium and sodium levels
chest sounds
fluid output (urination)
Unfortunately
many American vet offices do not have anybody present at their premises
overnight, so some of these tests cannot be performed for several hours,
which is potentially very risky.
2013 AAHA/AAFP fluid therapy guidelines for dogs and
cats (2013) Davis H, Jensen
T, Johnson A, Knowles P, Meyer R, Rucinsky R & Shafford H Journal of
the American Animal Hospital Association49(3) pp149-159 state
"Patients with a
high risk of fluid
overload include those with heart disease, renal disease, and patients
receiving fluids
via gravity flow."
I personally would not feel at all
comfortable leaving a cat on IV fluids unattended. If your vet recommends
IV fluids for your cat, but s/he would be left alone overnight, a possible
compromise is for your cat to be on IV fluids at the vet's office during
the day, but to come home (with catheter still in place) overnight. Ideally
though, your cat should be on IV fluids continuously but under
supervision.
The vet
may add treatment for
nausea to the IV fluids. Ask if this is being done
because if it is not, your cat may need oral medication instead. Depending
upon the situation, your cat may also need painkillers.
Helping Your Cat on Intravenous
Fluids
If you agree to
have your cat put on IV fluids, ask for him/her to be put in a quiet area
as far away as possible from any canine in-patients. Leave a blanket or an
old item of clothing with your smell on it in the cage to comfort your
cat.
Some people believe that they should not visit their hospitalised cat
because the cat may find it distressing. I don't agree with this, I think
it is better for both the cat and the caregiver if regular visits take
place, preferably daily. This also enables you to feed your cat yourself during your visits
if the vet's nutritional protocol permits. The
Persuading Your Cat
to Eat page has tips on getting food into your cat.
I know it can seem very lonely at home while your cat is in
hospital, but remember, you are doing this in order to help your cat. Try
to focus on the positives: your cat is receiving
professional care to give him or her the best chance possible; you can
have
a break from chasing your cat with plates of food, pilling sessions etc,
and can recharge your batteries a little. Focus on resting, reading this website and obtaining the supplies you
need, so you can offer your cat the best possible care when s/he returns
home.
If Bloodwork Does Not
Improve With Intravenous Fluids
Don't be too despondent if your cat's bloodwork does not improve after a
few days on IV fluids. In fact, sometimes the bloodwork actually worsens
after 1-3 days on IV. This can happen with BUN in particular, because BUN
can be found in other tissues as well as the bloodstream, and as the BUN
is removed from the bloodstream via diuresis, it may flow into the blood
from the other tissues, so it may still appear high.
Some vets may recommend euthanasia if this occurs, but don't feel obliged
to agree to this, especially if you are in the USA where your cat is
probably receiving IV fluids in the ER. Vets in the ER are usually
emergency medicine specialists who are used to dealing with acute
situations; they often have a lot less experience of cats with chronic
diseases and may not realise that further improvement may occur. This may
not even necessarily occur while the cat is in hospital but may gradually
happen once you take your cat home and use sub-Q fluids.
Thomas is a good example of a cat who did not respond
dramatically to IV fluids, but they did help stabilise him, and he
continued to improve once he came home. Initially Thomas was on IV fluids for
four solid days and nights, and only began to eat a little on day 3. He
had urea of 89 µmol/L (BUN: 241 mg/dl) at diagnosis, and it did not
actually improve after four days and nights of IV fluids either. But he was
rehydrated and acting better in himself by the end of the four days, so we
took him home. He had his good and bad days, which were influenced in
particular by his severe anaemia, but with home
sub-Qs and an
ESA and other treatments over a
number of weeks he improved and began to enjoy life again. Eventually his numbers
reduced to urea 27
(BUN: 76) and creatinine 316 µmol/L (US: 3.57 mg/dl), where they stabilised for some months.
What to Expect After IV Fluid Therapy
When your cat comes home from a session on IV fluids in
hospital, don't expect him/her to bounce back immediately. Most cats are
exhausted — if you've ever been in hospital, you'll know how hard it can
be to sleep well there — so fatigue and lethargy are normal. Your cat will
probably not drink much either, because s/he will be well hydrated from the IV
fluids. Many cats hide, which indicates they are not feeling 100%. Give
them time.
Most cats need a few days at home convalescing before they
begin to act better.
Appetite may take some time to return, or your cat may
need a little help in this department, perhaps treatment for nauseaand, if that is not sufficient, possibly an
appetite stimulant.
Most CKD cats who have been on IV fluids will need sub-Q
fluids at home if they are to avoid crashing again. You probably won't
need to start sub-Qs as soon as you return home because your cat will be
nicely hydrated from the IV fluids but you will probably need to start
them
a couple of days after returning home. Bring a few basic supplies home
from the vet, and then check
Obtaining
Supplies Cheaply to find sources for obtaining the supplies you need
more cheaply.
If your vet believes IV
fluid therapy is the best treatment for your cat, you should give it very serious
consideration - it really can be lifesaving.
When Not to Use Intravenous Fluids
IV fluids are not always a benign
treatment, plus they are can be stressful for your cat and
expensive for you. Therefore they should only be used
when necessary.
I occasionally hear of vets putting
CKD cats with low or medium level numbers (creatinine around 3-3.5
mg/dl (US) or 260-300 µmol/l (international) on
IV fluids. In most cases this is unlikely to be necessary, because most cats
would not be dehydrated at this level. However, it may be
appropriate if a cat is very dehydrated despite the low bloodwork, perhaps
from vomiting or diarrhoea, or if there are other issues present, such as
a kidney
infection, kidney stones or
pancreatitis.
IV fluids are not a suitable treatment for ongoing
hydration purposes: they are too taxing on the kidneys and, since they
increase GFR (see What is
CKD?), they could accelerate the loss of kidney function if done for
too long; plus of course they entail a stay in the vet's office, which
many cats find very stressful and which is also very expensive.
TREATING YOUR CAT WITHOUT VETERINARY ADVICE CAN BE
EXTREMELY DANGEROUS.
I have
tried very hard to ensure that the information provided in this website is
accurate, but I am NOT a vet, just an ordinary person who has lived
through CKD with three cats. This website is for educational purposes
only, and is not intended to be used to diagnose or treat any cat. Before
trying any of the treatments described herein, you MUST consult a
qualified veterinarian and obtain professional advice on the correct
regimen for your cat and his or her particular requirements; and you
should only use any treatments described here with the full knowledge and
approval of your vet. No responsibility can be accepted.
If your cat
appears to be in pain or distress, do not waste time on the internet,
contact your vet immediately.
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