Giving Subcutaneous Fluids to a Cat
This information is not meant to be a substitute for veterinary care.
Always follow the instructions provided by your veterinarian. 
In the photographs below, unless otherwise noted, the cat is facing to your
right.
Variations on these instructions exist.
Supplies used in giving subcutaneous fluids will vary by manufacturer and
may differ from those pictured here.
Fluid given under the skin, subcutaneously (SQ), is absorbed into the
blood stream and can be used to correct or prevent dehydration. The most
frequent disease for which fluids are given is chronic kidney failure. Cats
with chronic kidney failure pass large amounts of urine and may not feel
well enough to drink enough to prevent dehydration. The cat owner may give
subcutaneous fluids a few times a week to supplement the water the cat is
drinking in order to prevent dehydration and help flush waste products
through the kidneys.
Your veterinarian will prescribe a certain type of fluids and a volume
and frequency for administration to your cat. The most common fluid type
given to cats with chronic kidney failure is Lactated Ringers Solution
(LRS).
There are 3 general techniques used to give SQ fluids:
- with a syringe and needle
- with a syringe, needle and flexible tubing called an extension set
- from a vinyl bag using a solution drip set
Most cats tolerate being given subcutaneous fluids. You can give about
10-20 ml per kg of body weight (5 -10 ml per pound) in one spot (e.g. 50 ml
for a 10 pound cat) before you move to another location. It usually takes 6
to 8 hours for all the fluids to be absorbed. Check to see if the previously
administered fluids have been absorbed before giving more fluids. Even
though the fluids are given on the back, gravity will cause the fluids to
accumulate on the belly, so check for residual fluids on the belly before
you give more. Check with your veterinarian if the fluids are not being
fully absorbed.
Usually the skin is not cleansed before inserting the needle. If
the cat has a normal immune system, the few bacteria that are pushed under
the skin with the needle will be killed by the cat's immune system.
You can use alcohol on a cotton ball to make the hair lay flat so it is
easier to see where the hair ends and the skin starts. Alcohol takes about
30 minutes before bacteria are killed, so just swiping the hair with alcohol
is not effective in killing bacteria.
If your cat may have an abnormal immune system, for example is on anti
cancer drugs, then several patches of hair may be shaved and the injection
sites scrubbed with an antiseptic solution such as Novalsan or
Betadine
before placing the needle, to prevent pushing bacteria under the skin.
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The thickness of a needle is
measured by gauge (g), the smaller the number, the thicker the
needle. An 18 gauge needle is thicker than a 20 gauge needle.
Needles may also be different lengths, one-inch and one and
one-half-inch are most commonly used.
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The plastic hub is the wide part of the needle that attaches to the
syringe. The hub of the needle is color coded by size, although these colors
may vary by manufacturer. 18g needles have a pink hub, 20g needles have a
yellow hub. 20g needles are most commonly used to give SQ fluids although
larger needles (18g) may be used to draw fluid from the container of fluids.
Smaller needles (22g) may be recommended for cats.
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Needles are packaged in a rigid
plastic cover and wrapped in paper or plastic to keep them
sterile. Keep the needles in the original package until use. Do
not dispose of needles or syringes in the trash. Keep used
needles and syringes in a puncture-proof container and return
them to your veterinarian for disposal. |
Don't use the same needle that was placed under the skin to draw more
fluids from the container of fluids or bacteria will be introduced into the
container of sterile fluids.
If you use an 18g (pink) needle to draw from the solution container and a
20g (yellow) needle to give the fluids, it will be easier to keep track of
which needle to use. Keep the white plastic cap to place over the sharp
needle when it is not in use.
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Usually a large (60 ml) syringe is
used for fluid delivery. The syringe is often packaged in a
plastic case. If the syringe is to be used more than once, you
may want to keep the container. The plastic container is also
useful for placing used needles for disposal.
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The syringe has 2 parts, a barrel
and a plunger.
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The syringe is marked in
milliliters (ml) and ounces. The syringe is marked at 5 ml
increments (5 ml, 10 ml, 15 ml, etc.). Each line between the
numbers is 1 ml. The plunger has a domed end. The top edge of
the plunger is used to read the amount of fluid in the syringe.
This syringe contains 26 ml of fluid.
There is a small air bubble in this syringe. It is not
necessary to remove tiny air bubbles such as this one when you
are giving fluids SQ.
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Remove the needle from the
paper/plastic wrap but leave the plastic cover on the needle.
Place the hub of the needle firmly over the tip of the syringe.
Some needles and syringes have threads that screw together
(luer-lock). Remove the plastic needle cap just before use.
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Fluids are in plastic bags or
glass bottles. Bags of fluids come packaged in a plastic
wrapper. Remove the wrapper from the plastic bag just before
using. The fluid type that is most often given SQ is Lactated
Ringers Solution (LRS).
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Fluids do not contain a preservative, so ideally they should only be used
only once and then any remainder should be discarded. Most veterinarians
stock fluids in 1,000 ml bags. This volume is larger than is given to a cat
at one time. You may be given instructions to draw fluids from the same bag
for a few days. See the instructions below
for suggestions on how to prevent contamination of the bag of fluids.
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The neck of the bag of fluids has
2 ports; the injection port that is covered with a rubber
stopper and a port covered by plastic (blue) in which the spike
of a solution set is inserted (discussed below). |
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Follow your
veterinarian’s instructions for handling the fluids sterilely so
the container of fluids is not contaminated, and you may be able
to use the same container of fluids for a few days, if
recommended by your veterinarian. Clean the rubber stopper of
the injection port with an antiseptic solution such as Novalsan
(chlorhexadine) or Betadine
(povidone iodine) before inserting the needle, if more than one
puncture will be made through the stopper.
Alcohol takes about 30 minutes of contact before bacteria are
killed, so it is not a good solution to use for this purpose.
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Always use a sterile needle to draw fluids from the sterile container. Do
not use the same needle to give the fluids to the cat, and then place that
needle back into the fluid container as it will become contaminated with
bacteria from the skin.
If you use an 18g (pink) needle to draw from the solution container and a
20g (yellow) needle to give the fluids, it will be less confusing.
Never use a bag of fluids if it appears cloudy.
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Remove the plastic cap from the needle and place the tip of
the needle in the injection port.
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The needle must be inserted into
the center of the rubber stopper. The injection port itself is
held so the needle is inserted straight
into the injection port. |
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This needle is properly aligned.
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This needle is placed off-center
and is puncturing the injection port. |
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Draw back on the syringe plunger
while holding the syringe barrel steady so the needle does not
pull out of the fluid bag. Fill the syringe to the volume
prescribed by your veterinarian.
Do not fill a 60 ml syringe past 50 ml as the plunger may
accidentally be pulled out of the barrel of the syringe,
spilling the fluid.
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If you used an 18g needle to draw from the bag, replace the plastic cap,
remove from the syringe, and set aside this needle.
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Replace the 18 g needle with a 20g needle. When you have
given the first syringeful of fluids, change back to the 18g
needle to draw another syringeful. Then change back to the 20g
needle to inject the cat. Keep the plastic caps on the needles
as you exchange them. Use one new 18 g and one new 20g needle
each time you give fluids to your pet; alternating needles
between syringefuls of fluids.
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Pinch up a fold of skin anywhere
along the neck or back using your left hand if you are
right-handed. |
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Use your right hand to place the
needle into the skin fold along the long axis of the fold. |
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If you place the needle in the
opposite direction, across the skin fold, it is more likely that
the needle will go through one fold of skin and out the other
fold of skin. The needle in this picture is yellow and is
attached to a flexible piece of tubing (technique described
below). |
Before injecting the fluid, pull back on the plunger of the syringe. If
air bubbles appear in the syringe, the needle has gone through both folds of
skin and you are sucking room air into the syringe. Remove the needle from
the skin and try again.
If you get blood, the tip of the needle is in a blood vessel. Remove the
needle and try again.
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If the needle is not directly
attached to the syringe, but is attached to a flexible piece of
tubing (an extension set) first, the cat can move around a bit
while the fluids are being injected. The extension set will be
packaged in a plastic/paper wrapper. Remove from wrapper, remove
the white plastic cap from one end and firmly place on the tip
of the syringe. Remove the cap on the other end and place into
the hub of the needle.
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The two ends are different, the female end fits over the tip of the
syringe. The male end fits into the hub of the needle.
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The needle attached to the extension set is inserted into the
injection port as described above for a
needle directly attached to a syringe. Draw the prescribed
amount of fluids into the syringe. Replace the 18g needle with a
20g needle and recap the 18g needle with the plastic needle cap.
Push some of the fluid through the tubing to evacuate air
from the tube, a procedure called priming.
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The syringe containing the fluids is laid on the table. The
needle is placed under the skin. Pull back on the plunger of the
syringe. If air bubbles appear in the syringe, the needle has
gone through both folds of skin and you are sucking room air
into the syringe. Remove the needle from the skin and try again.
If you get blood, the tip of the needle is in a blood vessel.
Remove the needle and try again.
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Once you have checked that the
needle is correctly placed, push the plunger to inject the
fluids. The plunger can be pushed using one hand by holding the
syringe between the index finger and middle finger and pushing
the plunger with the thumb of the same hand. If this is
difficult, hold the syringe in one hand and push the plunger
with the other. |
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If you handle the syringe with one hand, your other hand is
free to comfort or restrain the cat.
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When you are finished giving fluids, if you are instructed to
use the same syringe and extension set for more fluids later,
place a clean needle covered by its plastic cover on the end of
the extension set.
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The third method to give SQ fluids is to attach a solution
drip set to a bag of fluids.
Remove the solution set from the plastic/paper wrapper. Both
ends are covered with plastic caps. After removing the cap, the
male end fits into the hub of the needle. The white spike is
punctured into the spike port of the bag of fluids after
removing the plastic tube that covers the spike.
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The spike port on the bag of fluids is covered by a blue
plastic cover. This cover is pulled off. The cover is tightly
covering the spike port and you have to pull firmly to remove
it.
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The white spike
on the solution set is pushed into the spike port. Hold the
spike port in your left hand to guide the spike straight into
the port. If you push the spike in at an angle, it may puncture
the bag of fluids.
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Attach a needle to the other end of the solution set.
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The plastic tubing has 2 clamps
that must be opened to allow fluid to flow.
- The dark blue pinch clamp has a tapered slot, the tubing
is pushed to the widest part of the slot to open and pushed
to the narrowest part of the slot to stop fluid flow
- The light blue clamp is a roller clamp. Use your thumb
to roll the white disk up, toward the solution chamber to
open and in the opposite direction to close.
The fastest flow of fluids occurs with both clamps fully
open.
Before placing the needle in the SQ, open the clamps and let
fluid flow until the air is evacuated from the tubing (priming).
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You will see drops of fluid drop in the drip chamber when the clamps are
open. If the drip chamber fills with fluid so that you cannot see the drops
forming, turn the drip chamber upside down and squeeze some of the fluids
back into the bag.
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The skin is tented and the needle
inserted along the long axis of the fold. You cannot suck back
to check for air so watch the site at which the fluids are
entering the skin fold to make sure the hair isn't getting wet
suggesting the needle is incorrectly placed. |
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There are 2 clamps on the solution drip set that must be
opened to allow fluids to flow.
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The fluids can be dripped into
the SQ space as fast as the drip will go. The higher you hang
the bag, the faster the fluids will flow. |
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You can also roll up the bag and
squeeze the fluids out of the bag. If you are instructed to
use the same fluids and solution set for more fluids later,
place a clean needle covered by its plastic cover on the end of
the solution set.
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Complications of SQ fluid administration can include:
- development of an abscess which will be a hard, painful lump that is
warm to the touch
- edema if too much fluid is given
- if the cat is severely dehydrated, the fluids will not be absorbed
Washington State University assumes no liability for injury to you or
your pet incurred by following these descriptions or procedures.
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