Subcutaneous Fluids Tips

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Overview

• The very idea of giving subcutaneous fluids to your cat be pretty scary at first, but there are ways to make it easier for both you and your cat.
• The type of fluid and type of needle that you use can make a lot of difference to your cat’s comfort levels. This page explains more about the different types of fluids that are available and the best type of needles (Terumo).
• I also explain how to prepare and calm your cat and what to expect both during and after the session.

Key Tips

Giving sub-Qs for the first time is scary! Fortunately there are ways to make the process go more smoothly, however, not all vets are aware of these tips, so they may not tell you about them. If you follow these tips, you and your cat still may not necessarily enjoy the process (although some cats realise that sub-Qs make them feel better and actually remind their human if they are late giving them!), but it should make it tolerable for you both.

Remember, you’re doing this to help your cat. Sub-Qs do help!

The key tips:

1. Warm the fluids. Cold fluids can be very uncomfortable.
2. Use Terumo UTW (ultra thin walled needles) if possible. These can make an incredible difference to your cat’s comfort level yet few vets use them. 
3. You don’t have to only use the scruff of the neck. You can use the area that would be covered by a saddle.
4. Try to get into a routine. Most cats like routine. Even if your cat never grows to like sub-Qs, if s/he knows you always do them at 6 p.m., s/he will remain relaxed around you the rest of the time (yes, of course cats can tell the time!).

What You Will Need

You will need several items in order to give your cat sub-Qs. Vets can normally supply these items, and it is worth obtaining them from your vet the first time or two and being shown how to give sub-Qs by your vet or vet tech.

Most people do eventually start sourcing their own supplies in order to save money. See the Obtaining Supplies Cheaply section for information on where to buy fluids, needles and administration sets:

Essential Supplies When Using the Giving Set Method

This is the most common way of giving fluids in the USA.

• Fluid bags
• Most people use a type of fluid called lactated ringers solution (LRS) but sometimes other types of fluid are appropriate. See below for more on this.
• Needles
• You have to insert the needle into your cat to allow the fluids to flow into him or her. Ideally you want Terumo ultra thin wall needles.
• Fluid administration set (giving set or venoset)
• This enables you to attach the bag of fluid to the needle. The fluid flows from the bag through the administration set and into the needle and then into your cat.

Optional Supplies When Using the Giving Set Method

• IV pole
• Some people find these helpful to speed up the process.
• Weighing scales
• These can be helpful for measuring the amount of fluid you are giving.
• Burette or buretrol
• These items are used by some people to measure accurately how much fluid they are giving.
• Calming or restraint method
• Some cats do better when these are used. See below for options.
• Baby food or other treats
• Some people use these to distract their cats during fluids, others use them as a reward afterwards.

Essential Supplies When Using the Syringe Method

This is the most common way of giving fluids in the UK and is also used by some people in the USA.

• Fluid bags Most people use a type of fluid called lactated ringers solution (LRS) but sometimes other types of fluid are appropriate. See below for more on this.
• Syringes You use these to measure out the fluid which you are going to inject into your cat.
• Needles You use these to draw the fluid out of the fluid bag into the syringe, ready to give to your cat.
• Winged infusion setsThese are used to inject the fluid into your cat.

Optional Supplies When Using the Syringe Method

• Calming or restraint methodSome cats do better when these are used. See below for options.
• Baby food or other treatsSome people use these to distract their cats during fluids, others use them as a reward afterwards.

Choosing a Fluid

There are several different classes of fluid, with differing sodium content:

• isotonic – have the same sodium concentration as body tissues.
• hypotonic – have a lower salt concentration than that in body tissues.
• hypertonic – have a higher salt concentration than that in body tissues.

All the fluids discussed below (apart from dextrose, which is not recommended) are isotonic. However, ISFM consensus guidelines on the diagnosis and management of feline chronic kidney disease (2016) Sparkes AH, Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I, Langston C, Lefebvre H, White J & Quimby J Journal of Feline Medicine & Surgery 18 pp219-239 state “although a balanced electrolyte solution such as lactated Ringer’s solution is often used, a hypotonic solution (half-strength lactated Ringer’s or 0.45% saline, with added potassium as needed) may be preferable to reduce the sodium load.”

Despite this observation, from what I have seen the fluid most commonly used for CKD cats continues to be Lactated Ringers Solution (LRS), although occasionally other fluid types are prescribed, usually because of other issues that need addressing. If your vet gives you another type of fluid, do check this is necessary because some other types can sting, plus some of them are more expensive than LRS. Please also always check the bag of fluid before you start to use it in case you have been given the wrong type: mistakes can happen.

International WIN shows the contents of commonly used fluids.

Introduction to fluid therapy (2008) DiBartola S has information about different fluid types and explains why LRS is generally the best choice for sub-Qs for cats.

The DEHP Issue

The plastic of some fluid bags contain a chemical called diethylhexyl phthalate (DEHP), which softens the bags. Some people prefer not to use bags containing DEHP because they are concerned that some of the DEHP may leach into the fluids themselves, especially if the bag is warmed before use.

The Australian Government Department of Health mentions that studies into the effect of DEHP on mice and rats found that they developed liver tumours, but this was after they were fed DEHP in high doses. I am not aware of any studies into the effect of DEHP on cats.

The US Food & Drug Administration has concluded that “there is little or no risk posed by patient exposure to the amount of DEHP released from PVC IV bags during the infusion of crystalloid fluids (e.g., normal saline, D5W, Ringer’s Lactate)”.

EU Scientific Committee on Emerging and Newly Identified Health Risks states “there is no conclusive scientific evidence that DEHP exposure via medical treatments has harmful effects in humans.”

RTI International nevertheless reports that California has banned the use of DEHP from 2030.

I would probably avoid DEHP bags myself if I could find an alternative. Some brands do offer DEHP-free bags which usually cost more, but these days I think that in light of the fluids shortage in the USA, just finding fluid bags is an achievement and finding DEHP-free ones is a bonus. Personally, if I couldn’t find or afford DEHP-free bags, it is not something I would lose any sleep over because in my opinion, it is more important that a cat who needs fluids receives them.

Lactated Ringers Solution (LRS)

Human patients with kidney disease are given fluids containing a buffer such as lactate, and this is also the most common choice for CKD cats. The lactate is important for CKD cats because lactate is metabolised by the liver where it is converted to bicarbonate, and this aids in the correction of mild acidosis.

In the USA fluids with lactate as a buffer are known as Lactated Ringers Solution (LRS). Ringer’s Lactate (2020) Singh S, Kerndt CC & Davis D StatPearls explains more about LRS.

There are a number of different brands available with different national drug codes (see Local Sources for Fluids for the relevant codes).

The nearest British equivalent is called Aqupharm No 11 Hartmann’s Sulution, although you may also be offered Vetivex 11. These fluids may vary slightly, and there may also be small differences between human and veterinary formulations, but they are all broadly the same:

Fluid	Sodium	Potassium	Chloride	Calcium*	pH	Calories per litre	Lactate
LRS         mEq/l	130	4	109	3	6.5	9	28
Aqupharm 11  mmol/l	131	5	111	2	6.5	9	29
Vetivex 11 mmol/l	131	5	111	2	6.5	9	29

MEq/l and mmol/L values are the same for the above ions apart from for calcium ions, where the mmol/L measurement is half that of the mEq/l measurement, so the Aqupharm and Vetivex fluids each have an mEq/l value of 4

Introduction to fluid therapy (2008) DiBartola S states (penultimate question) that LRS is the best choice for most cats on sub-Qs. He states “”I am unaware of clinical situations in which small animal patients have been harmed by lactated Ringer’s solution.”

ISFM consensus guidelines on the diagnosis and management of feline chronic kidney disease (2016) Sparkes AH, Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I, Langston C, Lefebvre H, White J & Quimby J Journal of Feline Medicine & Surgery 18 pp219-239 state “although a balanced electrolyte solution such as lactated Ringer’s solution is often used, a hypotonic solution (half-strength lactated Ringer’s or 0.45% saline, with added potassium as needed) may be preferable to reduce the sodium load.”

The more recent 2024 AAHA fluid therapy guidelines for dogs and cats (2024) Pardo M, Spencer E, Odunayo A, Ramirez ML, Rudloff E, Shafford H, Weil  & Wolff E Journal of the American Animal Hospital Association 60(4) pp131-163 recommend “Lactated Ringer’s, Plasma-Lyte, or Normosol R” for sub-Qs.

Most people do seem to continue to use LRS. It is what I would choose to use at the present time, because I am familiar with it and have never heard of it causing any problems.

Normosol-R/Plasma-Lyte A/Isolyte-S

This is a type of fluid which is sometimes used instead of Lactated Ringers when a cat has high calcium levels, liver problems or lymphoma (a form of cancer).

Normosol-R is the most commonly prescribed fluid in this category, but you may also be offered PlasmaLyte A, or occasionally Isolyte-S. They are all basically the same type of fluid, but different manufacturers use different trade names.

There is also a Normosol-M, but this is not usually suitable since it contains dextrose (see below).

There are two versions of Normosol-R, one with a pH of 6.6 (similar to LRS, which has a pH of 6.5) and one with a pH of 7.4. Plasma-Lyte A also has a pH of 7.4. For cats with high calcium levels, the more alkaline varieties (pH of 7.4) may be a better choice.

Fluid	Sodium	Potassium	Chloride	Magnesium	pH	Calories per litre	Buffer
Normosol- R	140	5	98	3	6.6	18	Acetate 27 Gluconate 23
Normosol- R	140	5	98	3	7.4	18	Acetate 27 Gluconate 23
Plasma-Lyte A	131	5	98	3	7.4	18	Acetate 27 Gluconate 23
Isolyte S	141	5	98	3	7.4	18	Acetate 27 Gluconate 23

These products contain magnesium, so may not be suitable if your cat has high magnesium levels.

This type of fluid also seems to sting some cats or make them twitch when the fluids are administered (see Symptoms for other possible causes of more frequent twitching), so cats may resist being given this type of fluid. A lot of vets don’t seem to be aware of this possibility but Managing fluid and electrolyte disorders in renal failure (2008) Langston CE Veterinary Clinics Small Animal Practice 38 pp677-697 states (page 11) “Plasmalyte is reported to sting when administered SC.” Introduction to fluid therapy (2008) DiBartola S states “The low pH and high acetate content of some Plasmalyte products and Normosol R may contribute to pain on subcutaneous injection.”

There have also been quite a few reports of cats vomiting after being given this type of fluid. All of these products are also more expensive than Lactated Ringers and may be harder to find. I therefore recommend that, if at all possible, you should use lactated ringers instead.

Saline Solution (Sodium Chloride or NaCl) 0.9%

Saline solution (sometimes referred to in human medicine as “normal saline”) is composed of the following:

Fluid	Sodium	Chloride	pH	Buffer
Sodium Chloride 0.9%	154	154	4.5 – 7.0	None

This type of fluid may be suggested by some vets, but it tends not to be the best choice for a CKD cat because:

• it is usually too acidic
• it lacks the buffer contained in lactated ringers
• it does not have added potassium, which many CKD cats need.
• the higher sodium load is additional work for already damaged kidneys to process
• it is not usually suitable for cats with hypertension or liver problems.
• it can sting when injected subcutaneously, which may make the cat resist sub-Qs

However, it is sometimes appropriate for:

• cats with high calcium levels (though Normosol-R may be a better choice); or
• cats with hyperkalaemia (high levels of potassium in the blood), who may initially be placed on intravenous sodium chloride in hospital

2024 AAHA fluid therapy guidelines for dogs and cats (2024) Pardo M, Spencer E, Odunayo A, Ramirez ML, Rudloff E, Shafford H, Weil  & Wolff E Journal of the American Animal Hospital Association 60(4) pp131-163 state “0.9% NaCl has a low pH and may be painful. Avoid SC use.”

One possible compromise would be to use half strength (0.45%) sodium chloride fluids. ISFM consensus guidelines on the diagnosis and management of feline chronic kidney disease (2016) Sparkes AH, Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I, Langston C, Lefebvre H, White J & Quimby J Journal of Feline Medicine & Surgery 18 pp219-239 state “although a balanced electrolyte solution such as lactated Ringer’s solution is often used, a hypotonic solution (half-strength lactated Ringer’s or 0.45% saline, with added potassium as needed) may be preferable to reduce the sodium load.”

Dextrose

These fluids contain dextrose, a form of sugar. Therefore they do contain a few calories, though not enough to be of any real benefit (8.5 calories per 100ml of fluid). These fluids are sometimes used when appropriate as intravenous fluids in a hospital setting but they are not usually appropriate for home use because:

• the sugar means that bacteria can easily grow in the fluid and cause infection at the injection site.
• fluids containing dextrose may sting when administered via sub-Qs.
• fluids containing dextrose also have a shorter lifespan than non-dextrose fluids.

Occasionally vets may dispense this sort of fluid in the form of 2.5% dextrose added to either 0.45% sodium chloride or to LRS, as a way to reduce the amount of sodium your cat is receiving. I don’t really see much benefit from adding dextrose, which has few advantages for CKD cats.

Pet Place discusses the need to avoid giving sub-Qs with added dextrose.

Introduction to fluid therapy (2008) DiBartola S discusses why fluids containing dextrose are best avoided for sub-Qs for cats.

Managing fluid and electrolyte disorders in renal failure (2008) Langston CE Veterinary Clinics Small Animal Practice 38 pp677-697 states (page 11) “Dextrose-containing fluids increase the risk of abscess formation… when administered SC.”

Preparation for Sub-Qs

Preparation is the key with sub-Qs. You want to have the best equipment possible, and you want to have a system in place to increase your chances of success. It is fine to buy a few supplies from your vet to tide you over until you’ve read through this page and the Obtaining Supplies Cheaply page and sorted out your plans for which supplies to use and where to obtain them.

The first thing to do is to practise giving sub-Qs — on an orange. The feel of a needle going into an orange is similar to that of a needle going into a cat, so give it a go and see how it feels. Just use the needle, don’t bother with the fluids. You just want to feel the sensation. You can also practice on a piece of raw chicken with skin. Try to inject the needle between the skin and the muscle.

If you don’t have to start sub-Qs urgently, you can also get your cat used to the idea of injections. Training your cat to love injections without ruining your relationship (2011) is a helpful article with photos from Dr Sophia Yin.

If you give your first sub-Q to your cat at the vet’s, you may well find your cat behaves better there, but don’t be surprised if your cat is less co-operative at home, where s/he does not expect this sort of treatment and is probably less fearful and therefore less afraid of letting you know what s/he thinks! You may also find that your first few sessions at home go well, but then your cat starts to object. This is also normal.

Most people do find that their cat eventually accepts sub-Qs at home. If you don’t succeed, don’t beat yourself up but instead look into alternatives, such as having a vet nurse/tech come to your home to help you, or taking your cat to the vet for treatment.

Fluid Preparation

Fluid Storage and Lifespan

Fluid bags have an expiration date on them. Do not use them beyond this date.

Once you have opened a bag of fluids, you should ideally use it for no longer than ten days. If you are giving 100ml of fluid every day, this is not a problem, but if you are only giving fluids every other day or small amounts at one time, this means you will probably have to discard a 1 litre bag before you have finished it. It is possible to buy 500ml bags of fluid, but these tend to work out more expensive than buying 1 litre bags and discarding what you don’t use. See Obtaining Supplies Cheaply for fluid purchasing options.

Some people do use opened bags for longer than ten days without problems. Determining expiration date for substances used in research animals University of Wisconsin-Madison says “Fluids for subcutaneous (SQ) administration may be kept for up to two weeks once a line is attached to the bag.”

In fact, Assessment of sterility of fluid bags maintained for chronic use (2011) Matthews KA & Taylor DK Journal of the American Association for Laboratory Animal Science 50(5) pp708–712 found that “fluid bags used chronically can be maintained in a sterile condition for a maximum of 30 days” but that study was using syringes to remove the fluid from the bags (see How to Give Subcutaneous Fluids: Syringe Method) rather than using giving sets. Personally, I would err on the side of caution because CKD cats are immune-compromised, but if you do decide (with your vet’s approval) to keep an opened fluid bag for longer than ten days, I would not keep it beyond thirty days, and ideally not beyond fourteen days.

Fluids may be kept in the fridge and removed shortly before use, but if you are going to use up the bag  within ten days of opening it, it is usually not necessary to do this; fluid bags are not usually refrigerated in hospitals.

The US National Library of Medicine mentions that fluids should be stored at room temperature of 25° C (about 65° F). We stopped refrigerating our fluids and had no problems.

Regardless of how long each opened bag lasts, always check the bag before each use. In order to avoid any possible problems with infection or contamination, never use a bag of fluids if the contents look cloudy. Often the bag itself will look a bit misty with condensation, particularly if you have just removed it from the fridge, but if the contents themselves look cloudy, that is a red flag.

I am sometimes contacted by people whose fluids have been left outside by delivery people in extreme temperatures, and they are concerned about the viability of the fluids.

If the fluids are left outside in warm weather, they may still be safe to use, depending upon how long they were outside and how hot it was. Hospira says “Store at 20 to 25°C (68 to 77°F).” It also says “Exposure to temperatures above 25°C/77°F during transport and storage will lead to minor losses in moisture content. Higher temperatures lead to greater losses. It is unlikely that these minor losses will lead to clinically significant changes within the expiration period.”

Freezing temperatures are more of a concern. Hospira says “Protect from freezing.” If you live in a cold location, try to order fluids locally, but if they are being shipped, try to order them early in the week so they are delivered to you before the weekend.

You can often make a claim for fluids that are not delivered properly, and that is probably the wisest move if it is an option.

Fluid Warming

When used straight from the fridge or even at room temperature, many cats find the fluids uncomfortable and may twitch (room temperature is after all a lot lower than a cat’s body temperature). Therefore you should warm the fluids before use. Place the bag of fluids and the giving set (keep the port openings out) in a bowl full of hot water, ensuring that the entrance to the bag (where the marker is) is not immersed, and leave to warm for ten minutes.

Some people have found that filling a cooler box with hot water or using a styrofoam container to insulate the bowl works well. Alternatively, you could use a heatpad to warm the fluids.

One person who used the syringe method liked to keep the syringes wrapped in a tea towel soaked in hot water and then wrung out so the fluid in the syringes did not cool down before they were used.

When you connect the fluid bag to the fluid administration set, run a little fluid through the line before you give it to your cat to ensure your cat does not receive cold fluid remaining in the administration set.

Make sure the fluids are not so hot that they will burn your cat! You can buy an infrared digital thermometer to check the temperature – I bought one from Radio Shack which cost about US$10.

Amazon sells an infrared thermometer for US$18,95.

Warming fluids in the microwave is not recommended because it is hard to get the right temperature so you may find the fluids are too hot in places.

A small number of cats do prefer the fluids at room temperature so experiment to see what works best for you both.

If you take your cat to the vet for fluids, you may find they do not warm them. Discuss with them whether it would be possible to do so if you think it would make your cat more comfortable.

All About Needles

In order to give your cat sub-Q fluids, you will need hypodermic needles. All needles are universal, i.e. they will fit any administration set. Needles are widely available from a number of different manufacturers and are single use only (see below to understand why). If you don’t insert the needle into your cat correctly the first time, throw it away and use a new one.

A needle is sterile and should be kept that way until use, so after you’ve given your cat fluids, remove the needle from the end of the line and place a new needle complete with cover on, ready for your next session. Only remove the protective covering or cap from the needle when you are about to use it.

Hands up, those with a needle phobia. Join the club! I did master the art of giving sub-Qs despite my own needle phobia. In twenty five years of running this site, I’ve only heard of one person who did not master giving sub-Qs herself because of a needle phobia (she never even tried). Please give it a try. It’s much cheaper for you and less stressful for your cat if you learn to give sub-Qs yourself at home.

Choosing Needles: Terumos

Many vets routinely stock Monoject needles or other brands. Some people use these without any problem, and many people use them initially when they have not yet had time to shop around for supplies. However, the best needles for CKD cats are widely considered to be those made by Terumo.

Why are Terumo needles so good?

1. They are extremely fine but still very sharp. Terumo states that its Sur-Vet veterinary needles have been shown to be the sharpest on average among brands tested (10% sharper than BD needles and 16% sharper than Covidien needles). Other needles are referred to as “kitty harpoons” on Tanya’s CKD Support Group, but Terumos slide in like a sharp knife through soft butter.
2. The diameter of the inside bore of some Terumo needles (see below for information on needle sizes) is larger than another manufacturer’s needle of equivalent size, allowing greater flow rate. Terumo Europe has a photo of how this works. This feature means it takes less time to give your cat sub-Qs.

If you haven’t yet used Terumo needles, give them a try if you can. I regularly hear from people who cannot believe the difference they make to their cat’s comfort levels and their own stress levels! I even heard from a professor at the University of California at Davis College of Veterinary Medicine who told me he had been unaware of Terumo needles until he read about them here, but he was now using them all the time because he found them so much better.

Some people find it can be hard to take the covers off Terumo needles. There are various ways to do it, but one way that seems to work is to attach the needle to the IV tubing, then twist and tug the cover quickly. Alternatively you can rock the cap to and fro to loosen it, then pull up quickly. Terumo now makes a new style of needle with a guard which is easier to open, but most needles with this feature are not thin wall (see below).

How to change the IV needle is a short video that some people find helpful.

Terumos in USA and Canada

Terumo needles used to be marketed as Ultra Thin Wall (UTW) but this is no longer the case, apparently because of an FDA regulation. I have asked Terumo for more information about this but they never respond to me, which is a bit rich when you think how much custom they must get via this website!

Terumo needles are now available as Regular or Thin Wall (TW) and you definitely want their Thin Wall needles, which some sources say are the same as the old Ultra Thin Wall needles. Certainly everyone I hear from is happy with Terumo TW needles.

Nipro make an ultra thin walled needle called Flomax. I have heard from a few people who have tried Nipro needles and while they don’t find them as sharp as Terumo and think they do not flow as fast, overall they are satisfied with them.

You can obtain details of mail order suppliers for needles in Obtaining Supplies Cheaply. You can expect to pay around US$10 for 100 needles.

Terumos in UK and Europe

Terumo Europe sells needles under the name of Neolus and they are described as having triple faceting. I note they have the same codes as the North American thin wall needles.

Terumo also sells needles branded as Agani, and one seller, MediSupplies, states that these needles were formerly known as Neolus but then adds “unique double bevel design.” So it is not clear whether they are really triple faceted Neolus or not; I think probably not. They do appear to be all that is now available in the UK from Terumo.

If you are giving sub-Qs with a syringe, you will normally need winged infusion sets. These help you when inserting the needle and give you something to hold when you are switching syringes over. Terumo Europe sells these under the Surflo name. .

Choosing Needles: Size and Speed

The size of needle used can make a tremendous difference to your cat’s (and your) comfort and stress levels. On the packet it will say something like 21G x 5/8″. The first number with the G is the gauge, i.e. the needle size. The second number is the length of the needle in inches, so this needle is 5/8 inches long.

The higher the number (gauge) of the needle, the finer—smaller—the needle. If you choose a needle below size 18, it can be rather big and uncomfortable for the cat (size 16, for example, is often used on goats and sheep). On the other hand, a needle above size 23 can mean it takes too long to give subcutaneous fluids.

Needles also come in different lengths, the most common being 5/8 inch or 1 inch. You are less likely to accidentally poke the shorter needle into your cat and out the other side, but on the other hand, it is harder to adjust the smaller needle (for example, if the fluid isn’t flowing properly and you wish to move the needle a little). The length of the needle is a personal choice, but most people seem to like the 1 inch length.

If your cat dislikes fluids, you need to decide if it is the actual sticking that bothers him/her, or if it’s the length of time it takes. If it is the sticking that is an issue, opt for size 20 or above thin wall Terumo needles.  If it’s the length of time it takes to give the fluids, opt for a size 18 or 19 which will get the job done quicker. Most Tanya’s CKD Support Group members use size 19 or 20 because these give a balance between size of needle and speed of fluid flow. Size 20 is no longer available in the veterinary range but is still available in the human range.

Rad, whose lovely cat, Purr Box, is the model in How to Give Subcutaneous Fluids: Giving Set Method, ran an experiment regarding the flow rate of various needles. Here are the results of his experiment, which he has kindly given me permission to publish here. The flow rates (all for 100ml of fluid) are in minutes and seconds.

Needle Details			Speed of Flow in Minutes and Seconds
Brand and Size	Length (inches)	Type	First Flow Test	Second Flow Test	Average Flow Rate
Terumo 18	1	TW	00:55	00:51	00:53
Monoject 19	1	n/a	01:11	01:09	01:10
Becton Dickinson 18	1	n/a	01:14	01:10	01:12
Terumo 19	1	TW	01:17	01:16	01:16
Monoject 18	1	n/a	01:15	01:18	01:17
Terumo 20	1	UTW	02:02	01:56	01:59
Becton Dickinson 20	1	n/a	02:28	02:29	02:29
Monoject 20	1	n/a	02:32	02:34	02:33
Terumo 21	1	UTW	02:39	02:37	02:38
Terumo 22	1	UTW	04:05	04:13	04:09
Terumo 21 (Sur-Vet Label)	1	TW	05:59	05:53	05:56
Monoject 22	0.75	n/a	06:04	06:12	06:08
Monoject 22	1	n/a	06:21	06:08	06:15
Terumo 23	1	UTW	07:16	07:03	07:09
Monoject 22	1.5	n/a	07:21	07:13	07:17
Terumo 25	1	UTW	13:21	13:20	13:20

TW Thin Wall

UTW Ultra Thin Wall

Freezing Needles

Some people freeze needles before using them. This is because of a study, Pain associated with injection using frozen versus room-temperature needles (2001)Denkler K Journal of the American Medical Association 286 p1578, where a plastic surgeon who froze needles before using them on his (human! — what cat needs plastic surgery?) patients found that 76.6% of the patients found the frozen needles less painful.

Freezing the needles doesn’t always seem to make a difference for cats, but it might be worth a try. If you decide to try this, do not freeze the needles for longer than a few days in case it adversely affects the sterile packaging.

IV Administration Sets (Venosets or Giving Sets)

If you are giving sub-Qs by letting the fluid drip out of the bag (giving set method), you need a venoset, also known as an IV administration set. You usually need a prescription (it depends which state you live in). As with fluid bags, you may wish to use a DEHP-free set (Hospira makes one, among others).

There are two factors to consider with administration sets, the flow rate and the length. In terms of length, these sets come in a variety of lengths but most people seem to like 72, 80 or 100 inches long sets.

In terms of flow rate, you will see a drop/ml reference, for example 10 drop/ml. 10 drop/ml means that 10 drops provide 1 ml, so if you are giving 100ml, you would be giving 1000 drops. Thus you want a 10 drop/ml or at most a 15 drop/ml administration set, because higher numbers/slower flow rate administration sets would take too long.

One thousand drops sounds like a lot, but it will only take you about 3-4 mins to give your cat fluids with this size of venoset, depending upon how much fluid you are giving and what size needle you are using. Obviously a 15 drop/ml set takes 50% longer to give the fluids than the 10 drop/ml set, but on the other hand the slower flow rate may suit some cats and mean they tolerate fluids better. You will have to experiment to see which works better for your cat. PharMerica University has a chart showing the speed of various drop/ml rates.

Some venosets have a luer lock to lock the needle in place, which most people find helpful. Some venosets have a port which you can use to add certain medications. If you do this, make sure you only use medications in a form suitable for this purpose.

Most people use the administration set for 2-3 bags of fluid, as long as the end to which the needle is attached is kept sterile. When you want to remove the needle from the administration set, it can be rather difficult. Using pliers or a pair of rubber gloves can help.

See the Obtaining Supplies Cheaply page for stockists.

Mar Vista Vet has a helpful video about preparing for giving fluids.

Animal Medical Center in NYC also has a video with useful tips.

Dr Mike Ontiveros has a video which shows how to prepare a venoset for sub-Q fluids.

IV Pole

Since giving fluids via a fluid administration set relies on gravity to deliver the fluids, many people try to hang the fluid bag high up so as to speed up the process. You can use a coathanger, but some people decide to buy an IV pole. This can be wheeled to your cat, which can be helpful if your cat copes better with fluids while sleepy.

Amazon sells an IV pole for US$35 with free shipping.

Dr C Wladis explains how the height of the fluid bag affects the speed of delivery.

Preparing Your Cat

It often helps both you and your cat if you set up a routine, ideally including set times, and stick to it. You can choose a special word or phrase that tells them you are about to give them medication and/or fluids. Your cat will soon learn what this means, and will then not be stressed when you approach him or her at other times.

Speak to your cat during the procedure and reassure him/her, but don’t overdo it or s/he may think s/he is right to be frightened. Try not to be nervous yourself or your cat will sense it; aim to be very matter-of-fact about it all. Tell him/her what you are doing and why — many people find this seems to help.

Some cats tolerate sub-Qs better if they are sleepy.

Some cats feel happier if they are given fluids in a familiar place, whereas others may be more co-operative if the fluids are given in a strange place, perhaps a room they are not normally allowed to enter. Experiment and see what works best.

Here are some methods which people have found makes the process easier.

Calming Methods – Feliway or Zylkène

Feliway

Feliway is a copy of the pheromones naturally present on a cat’s face. When a cat rubs his face on something, s/he is marking it with these pheromones, which make the cat feel more relaxed.

Some people find Feliway can be helpful when giving sub-Qs. Improving the feline veterinary consultation: the usefulness of Feliway spray in reducing cats’ stress (2016) Pereira JS, Fragoso S, Beck A, Lavigne S, Varejão AS & da Graça Pereira G Journal of Feline Medicine and Surgery 18(12) pp959-964 found that caregivers in the study considered their own cats to be “easier to handle/more relaxed” when given Feliway compared to a placebo.

You can buy Feliway plug-ins and simply leave them on in the room where you usually give fluids, or you can use the spray version.

Entirely Pets sells various versions of Feliway.

Vet UK sells Feliway in the UK.

Zylkène

Zylkène is a natural product derived from casein, the protein in milk. Life Extension Magazine has an article about why bioactive milk peptides can be calming. Effect of alpha-casozepine (Zylkene) on anxiety in cats (2007) Beata C, Beaumont-Graff E, Coll V, Cordel J, Marion M, Massal N, Marlois N & Tauzin J Journal of Veterinary Behavior: Clinical Applications and Research 2(2), pp40–46 found that it seems to be effective, and it does seem to help some cats to accept sub-Qs.

Zylkène is often available from vets in Europe. In the USA you can find it on Amazon. You can open the capsule and mix its contents with food. It can take a few weeks to start working, so don’t give up too soon.

Distraction and Bribery

Training your cat to love injections without ruining your relationship (2011) has photos and a video showing how to use treats to train your cat to accept injections.

Even if you prefer not to feed your cat during the procedure, many cats feel hungry after fluids so take the opportunity to offer your cat some food afterwards — we always fed Thomas as his reward for being a good boy. 

Restraint

Some cats do better if they are restrained during sub-Qs, either by hand or by a cat restraint bag, or in a carrying basket with a top opening. However, others are more likely to co-operate if they are not restrained and feel they have some kind of control. If your cat tends not to like being held generally, s/he probably won’t like to be held during the sub-Q process either. You know your cat best so decide which would be better. 

Comfort cats in a towel wrap is a video by Dr Yin on how to handle a difficult cat simply using a couple of blankets.

Feline friendly handling and improving client compliance in the feline practice (2015) Scherk M is a helpful article on reducing stress for your cat.

Restraint Products

Four Flags in the USA makes the Cat Sack, for holding your cat while you medicate him/her or administer sub-Qs. It can help with wriggly cats, and most cats do not seem to mind it. I put this on my cat and was surprised to see that she didn’t mind it at all.

Amazon also sells the Cat Sack in various sizes at various prices (be sure to buy the correct size for your cat).

Amazon also sells the Cozy Comfort Carrier, though I don’t know of anyone who has used this type as yet so do not know for sure if it is suitable..

Getting Started

So you’ve got your supplies and your cat, and you’re all ready to go. It can be worth doing a trial run without your cat to ensure you have all the supplies that you need at the ready. But eventually it will be time to stick a needle in your cat. And you’re terrified. Don’t worry, that is completely normal. The first time might go well or it might not. Don’t worry if it’s a bit of a disaster, if you don’t get all (or even any) of the fluid in. Many people only get 30ml or so in the first time. You are going to get better at this!

Having said that, do try to think positive. Your cat will sense if you are fearful, and may react to this, creating a vicious circle. So think positive, and remember, you will both adapt, especially once you and your cat realise how much better s/he feels afterwards.

We all know cats can be good at giving you a guilt trip. Some cats make a fuss even if the needle is not in! But if it does turn into a bad session, let it go and try again later or the next day.

The website most people find most helpful when they are getting started is Sophia gets her subcutaneous fluids. You can also visit these pages with photos of giving sub-Qs to see the two different ways of giving sub-Qs:

• How to Give Subcutaneous Fluids: Giving Set Method
• How to Give Subcutaneous Fluids: Syringe Method

The Saddle Area

You do not need to restrict your injections to the neck area, in fact it is better to move around the body in order to minimise the possibility of scar tissue forming.

Roughly speaking, you can inject your cat anywhere which would be covered by a saddle (as Sophia models here; scroll to near the end of the page). Some people move around a little like on a clock, moving an inch further around each time they give fluids. Others will give fluids on the left on one day, on the right the next, moving a little away from the previous injection site each time.

Experiment a little because some cats have preferences – Thomas much preferred being injected on his right side to his left. Be careful to avoid the spine though.

Numbing or Cleaning the Area

Some people use lidocaine but it is not recommended because it can be toxic to cats. Pet Place states “Caution should be used whenever lidocaine is given to cats since they tend to be especially sensitive to the drug.” Local anesthetic toxicosis (2000) Welch LS Toxicology Brief says “Cats are sensitive to the CNS effects of lidocaine, however, so monitor them for seizures when you give lidocaine as an antiarrythmic or local anesthetic.” In Topical creams and pets: a dangerous -combination the ASPCA includes lidocaine on its watch list. In any event, if you use sharp needles, sub-Qs are really not that painful.

You also don’t need to wipe with alcohol first. It needs time to work, about 30 minutes, and since most people don’t wait that long, it’s a bit pointless. Critical Care DVM says “It is not necessary to “sterilize” the skin with alcohol prior to inserting the needle. In reality, wiping a little alcohol on the skin does not sterilize it, and the odor and feel of alcohol may aggravate your pet.” If you are keen to clean the area, ask your vet about using chlorhexidine (hibiscrub). You only need to wait 30 seconds for chlorhexidine to take effect but it should not be removed until you’ve finished giving the sub-Qs.

The Tent

One reader asked me to mention that if your cat wears a collar and you give fluids nearby, you need to make sure the collar does not become uncomfortably tight as a result.

Inserting the Needle

Before you insert the needle, look to see it is smooth and sharp; on rare occasions needles are faulty and have a little barb which makes inserting it uncomfortable. If your cat normally doesn’t flinch when you insert the needle, but suddenly does so, this might be the cause.

Another reason why your cat might flinch when you insert the needle is that you hit a muscle. Just withdraw the needle, reassure your cat, and try again in another spot (with a new needle).

Flinching only happens very rarely, but if it seems to happen regularly, you may be using a type of fluid (such as saline or Normosol) which stings, in which case you may wish to speak to your vet about changing to another type of fluid.

Occasionally I hear about cats who yelp when the needle goes in but there does not seem to be any issue with the needle. If this happens to you, do a fake injection, i.e. hold the needle near your cat’s skin and pretend to inject by simply touching your cat with your fingers. If your cat still yelps, you know you’ve got a cat who likes to give you guilt trips (-;

You need to insert the needle the right way up. The needle will look like this from the side: ______\ or this:  l____. Holding the needle parallel to your cat’s back, insert the needle smoothly into the tent you have formed.

It can be helpful not only to move the needle towards the tent, but also to raise the skin slightly to meet the needle. Ensure you have not pushed the needle through the other end of the tent. You will soon know if you have done this, because  the fluid will leak if so.

Keeping the Needle in Place

I used to simply hold the needle gently in place, but that is easy to do with a winged infusion set.

EZ IV Harness has been used by some members of Tanya’s CKD Support Group who give sub-Qs with a giving set. This can be shipped internationally. It allows the cat to wander a little, which can be better for cats who do not like restraint. It helps hold the needle in place, so you don’t need to. If you enter the code tanya, you will receive a 15% discount.

Lori demonstrates how to use the EZ IV harness in this video. She also has another helpful video.

Giving Madison sub-Qs at home shows how to use a homemade harness made from a bandage.

Idea exchange: clip fluid lines into place (2011) Chatt K Veterinary Medicine, suggests using small hair clips to hold the fluid line and needle in place.

If the needle does slip out, try again with another needle. However, I would not stick a cat more than twice in one session, so if the needle slips out more than once, I would give up and try again another time.

Multiple Needle Sticks

Some vets in the UK recommend using multiple needle sticks, e.g. only giving 20ml in one place, so a cat receiving 100ml would receive five sticks. This is completely unnecessary. International Cat Care states “Generally around 10-20 ml/kg of fluid can be given at a single SQ injection site (around 60-100 ml for an average sized cat).” See How to Give Subcutaneous Fluids: Syringe Method to see how we gave Thomas fluids with only one needle stick per session.

Trouble Inserting the Needle – Thick Skin

Sometimes the skin may feel tough so it is hard to get the needle in. There are a number of possible reasons for this. Firstly, perhaps surprisingly, it can indicate dehydration, in which case your cat definitely needs the fluids. Secondly, it may indicate scar tissue. This is actually not that common, and usually doesn’t happen for a long time (months to years) but one way to avoid it is to rotate where you give fluids (see above).

Stabbing Yourself with the Needle

At some point you will almost certainly accidentally stab yourself with a needle. This is usually nothing to worry about, it happens to virtually everyone and is not usually cause for concern. However, if you have a compromised immune system or if the area becomes red or sore, or if you are worried, seek medical advice; if you’re not up to date on your tetanus shots, you may be advised to have one.

Giving the Fluids

The actual process should only take 2-5 minutes. If it’s taking longer than this, you need to review the rest of this page to work out why.

If your cat fights the process, don’t panic, but try to find the cause. Certain types of fluid can sting, see above for more information. Not warming the fluids can be uncomfortable for some cats. Occasionally a needle can be barbed.

If your cat is calm initially but then fights you after a minute or two, it might be because you are giving too much fluid in one spot and it is becoming uncomfortable: generally speaking, you should not give more than 100ml in one spot. Also make sure you are holding the needle in place, so it does not move and irritate your cat.

Pressure Infusor

Some people with fidgety cats use a pressure infusor to help the fluids flow more quickly. A pressure infusor is a special bag into which a bag of fluid is placed, and a pump is used to squeeze the fluid out of the fluid bag more quickly. The Society of Critical Care Medicine explains more about how these work. You will need a prescription from your vet.

In principle you can give 100ml of fluids in under a minute using a pressure infusor, though you have to be careful not to make them flow so quickly that it is uncomfortable for the cat. Because the fluids flow so quickly, you also have to be very careful not to give too much fluid to your cat.

In theory the pressure infusor bags should only be used once but some people use them more than once. Be guided by your vet.

Air Life produces pressure infusors to fit various fluid bag sizes.

Measuring the Fluid

It is important to try to give fluids accurately. Giving too much in one go can be risky, especially for cats with heart conditions. There are a number of ways to measure how much fluid you are giving, as outlined below.

If you do accidentally give too much fluid once, it will probably be fine, but check in with your vet and watch for signs of overhydration.

Never give any more fluid until the previous amount has been properly absorbed.

Syringes

If you are using the syringe method, you can measure the amount you give very accurately.

Marking the Fluid Bag

In the USA, there are markings on the bag, often the numbers 1 to 9 or 10. These numbers represent 100ml, and when you hang the bag up, I am told you usually have the number 1 at the top. So, for example, if your fluid level is at 7, you have used 700ml of the bag altogether and have 300ml remaining. However, many people think the markings are not too accurate, especially when they get near the end of the bag.

Fluid bags often aren’t marked in the UK. Some people mark the bag with a permanent marker (sharpie) but this was not recommended because the ink can leach through to the fluids, though The contamination of intravenous fluids by writing on the infusion bag: fact or fiction (2014) Langston JD, Monaghan WP & Bush M International Journal of Advanced Nursing Studies 3(1) pp18-19 found that in fact this did not happen during their study.

Counting the Drops

If you are using a fluid administration set, these are measured in drops per ml. Most people use either 10 drop/ml or 15 drop/ml sets. If you want to give 100 ml and you are using a 10 drop/ml set, then 1000 drops would equal 100ml. If you want to give 100 ml and you are using a 15 drop/ml set, then 1500 drops would equal 100ml.

Obviously counting this many drops would be very tedious, but you could consider timing how long it takes to give, say, 100 drops using a 10 drop/ml set, and then multiply this by ten. So if, for example, it takes 30 seconds for 100 drops to drip into the chamber, then it would take five minutes (30 seconds times ten) to give 1000 drops or 100ml.

Again, this is not a massively accurate way of measuring how much fluid you are giving.

Weighing the Fluid Bag

Hanging scales can help you work out how much fluid you have given if you are using a fluid administration set. 100ml of fluid weighs 100g, so it is not too difficult to do. Hanging scales are usually the best choice.

Pesola is a popular brand of hanging scale but is quite expensive.

American Weigh Scales is another popular brand.

Wayfair sells an American Weigh Scales hanging scale for US$24.99.

Amazon sells an American Weigh Scales hanging scales for US£24.99.

Amazon UK also has scales which are not hanging scales but one member of  Tanya’s CKD Support Group has used these scales successfully.

Buretrol/Burette

These terms are often used interchangeably. As far as I’ve been able to work out, a burette is a chamber which allows you to measure precise amounts of fluid. A buretrol is a device containing a burette which essentially does the same thing when you are giving fluids or other medications. Baxter has photos of buretrols.

Buretrols can be useful for measuring the amount of fluid you are giving to your cat, though bear in mind that some of them come with an attached fluid administration set, which means that the speed of that set controls how quickly you can give fluids to your cat. Since buretrols are usually used for intravenous fluids, where a slow flow is normal, some of them are 60 drops/ml, which is too slow for giving fluids to a CKD cat (see above for more on drop speeds). Therefore most people use an add-on buretrol, as shown by The ABCs of IVs, which means the speed is determined as usual by your administration set drip rate and the size of your needle.

You attach the spike (pointy bit) on the end of your fluid administration set into the bottom of the cylinder. You then attach the spike on the end of the buretrol to the end of your fluid bag.

Another advantage of a buretrol is that you can simply warm the amount of fluid you are giving that day, rather than having to warm a bag multiple times.

Some buretrols stop automatically once empty.

See Obtaining Supplies Cheaply for where to buy buretrols.

After Sub-Qs

Most cats feel better after receiving fluids, and are often more active, with a better appetite. If your cat becomes lethargic after receiving fluids, or loses appetite, this may be a sign of overhydration or heart problems. If your cat vomits, it may be because of the type of fluid you are using (see above). Speak to your vet about this.

Leaking Fluid

You may sometimes see a bit of fluid leaking out on to your cat’s fur after you remove the needle; this is normal. If you pinch or massage the injection area for a minute or so, as my husband is doing for Thomas in the photo, this will minimise the possibility of fluids leaking.

Seeing Blood

Occasionally you may see a little blood when you withdraw the needle. This usually means you have simply nicked a small vein, and is not normally anything to worry about.

The Fluid Pouch

After a little while the pouch of fluid which you have injected will move around the cat’s body. It may go down one of the front legs or just hang on the stomach. This is normal and is nothing to worry about — think of it like a camel’s hump, to keep your cat hydrated. It should be absorbed gradually over 6-8 hours.

Still, it is better to avoid injecting in an area where the fluid consistently moves down to a front leg because this can be uncomfortable for the cat (try to move back slightly); and you should never give more fluid until the fluid in the pouch has been absorbed.

Crackling Noise Under the Skin (Subcutaneous Crepitus)

Occasionally you may hear a “crackling” noise under your cat’s skin after giving sub-Qs and/or the cat may seem “squishy”. This simply means that a little air has got under the skin (this is known as subcutaneous crepitus), and should go away on its own in a couple of days.

It is not usually anything to worry about unless it happens regularly. If it does, I would recommend that you discuss it with your vet because it may mean that your cat is overhydrated, in which case you need to reduce the amount of fluid which you are giving; or you may need to refine your technique so as to allow less air under the skin.

Here is a picture of air bubbles in the line.

The Nurse Path Blog has some information about how to reduce the chances of getting air bubbles in the line.

Re-Using Supplies

Re-using Venosets (IV Sets)

Most people change the venoset every time they change the fluid bag, though some people use them for two fluid bags. If you use the venoset for two bags, switch the line to the new bag as soon as you’ve finished the first bag, making sure not to contaminate it.

Re-using Needles

This is not recommended, because using a needle just once blunts and distorts the needle which means using it again makes it more painful for the cat. Children with Diabetes  shows photographs of how a used needle looks — scary! Re-using a needle also increases the risk of infection, not a good idea with an immune-compromised cat.

You can obtain needles cheaply (around US$10 for 100 online, see Obtaining Supplies Cheaply) so it’s really best to use each needle only once.

Needle Disposal

Some vets may allow you to return used needles to them for free, which is what I used to do.

If your vet does not permit this, you need to find another way of disposing of needles. You can usually buy a sharps disposal unit from your vet or local pharmacy for a few dollars or pounds, and you can then return it to them when it is full (which may incur a small additional charge).

Some people place needles in a rigid plastic container (such as a liquid washing powder container), screw the lid on tightly and label it “needles” or “sharps” before placing it in the bin, and this is perfectly legal in some locations.

Most countries have laws about putting used needles in the trash, so you need to check the legal restrictions for hazardous waste disposal in your area.

Safe Needle Disposal has information about safe needle disposal and allows you to search for disposal locations in the USA.

This page last updated: 05 July 2025

Links on this page last checked:18 June 2025