How to Administer Subcutaneous Fluids

When a dog or cat is dehydrated or at risk of dehydration, there are a few ways to maintain or recover normal hydration. These methods include oral fluid administration (drinking or syringe-feeding), intravenous fluid administration (fluids that flow through an IV into the vein), or subcutaneous fluid administration. 
Subcutaneous fluids are given with a needle and deposited under the skin. When given in this way, fluids are absorbed slowly over several hours. This can be done in both cats and dogs and may be recommended by your veterinarian as a form of treatment to be done at home.
How to Administer Subcutaneous Fluids
 
Background
When a dog or cat is dehydrated or at risk of dehydration, there are a few ways to maintain or recover normal hydration. These methods include oral fluid administration (drinking or syringe-feeding), intravenous fluid administration (fluids that flow through an IV into the vein), or subcutaneous fluid administration. Subcutaneous fluids are given with a needle and deposited under the skin. When given in this way, fluids are absorbed slowly over several hours. This can be done in both cats and dogs and may be recommended by your veterinarian as a form of treatment to be done at home.
Getting Started
In order to give subcutaneous fluids at home, you will need the following supplies provided to you by your veterinary hospital:
Sterile needles
A sterile fluid line
A sterile bag of fluids
A receptacle for used needles. Needles should be stored safely away from children and pets. Used needles can often be returned to your veterinary hospital for disposal.
To assemble the fluid bag, fluid line, and needle:
Start by removing the bag of fluids from its outer wrapper if one is present, and hanging the bag of fluids at a level higher than where your pet will be receiving them. For example, the bag can be hung by its loop (at the top of the bag) off the handle of a kitchen cabinet door. You will know the top from the bottom of the fluid bag because the print on the bag should be upright when the bag is positioned properly.
Next, identify the bottom of the bag, which usually has two ports (short tubes) protruding from the end. One of these has a removable cover, which is typically a plastic tab or sleeve that can be peeled back and off the bag. You should do this, revealing a tube that is the entry port for the fluid line connector. Note: the inside of this tube (the entry port) is sterile, so be sure you only touch the outside of it, and don’t reach inside it with anything.
Remove the fluid line from its wrapper. This is the coiled clear plastic tubing. One or more flat plastic tabs—often blue or green—will be entrapped in the tubing of the fluid line. These are sliding clamps, and they have keyhole-shaped slits that allow you to close off the flow in the tubing. You should slide one of these clamps (any one) into the closed position now: a firm slide such that the tubing moves from the wide to the narrow slot in the clamp’s keyhole, and the tubing is pinched shut. The whole line of tubing is likely coiled and secured by a paper tie that you can easily tear off. Both ends of the tubing are capped; the end you are interested in is the large end, with the clear plastic tubular chamber. Remove the cap from this end, revealing a plastic spike-shaped tip. Do not touch it, as it is sterile, and contact from your skin to the spike could allow bacteria from your fingers to wind up in your pet’s tissues. Insert this spiked end into the entry port of the fluid bag. Using a moderate amount of pressure and a twisting back-and-forth motion, advance the spike until it is fully seated into the port: for right-handed people, the transparent chamber of the spike end of the tubing is held in the right hand, and the port of the fluid bag is held in the left. The spike will puncture a membrane in the port and allow fluid to flow out of the bag. The spike is far enough in the bag when a few drops of fluid are seen to drip into the transparent chamber in your right hand. Now the fluids are ready to flow out the bag.
With the open end of the tubing over a sink or bowl, remove the cap, and be sure to avoid touching the open end with your finger or anything else. Only the cap or a new needle should ever contact the tip; this preserves its sterility. Open all clamps on the fluid line, including a roller valve (small wheel in a rectangular plastic box) if one is present, and allow fluid to run out the line. Be sure to allow the flow to continue for several seconds to remove all the air, including large bubbles, throughout the length of the tubing, then close one clamp to stop flow. A few small (rice grain–size) bubbles are not a problem, but air that fills more than an inch or two (few centimeters) of the tubing should be purged by reopening the clamp and allowing more fluid to flow.
Examine the clear plastic cylinder again, near the fluid bag. It should be approximately half filled with fluid and half with air. This way, you will be able to see dripping of fluid from the bag into the cylinder when the fluids are being administered. If this chamber is completely filled with fluid, turn it and the bag upside down and squeeze the chamber, forcing some fluid back into the bag and some air back into the chamber.
Attach a covered needle to the opposite end of the fluid line. The system is now ready to deliver fluids. The process you just performed only has to be done once for each new bag of fluids, not with every treatment.
It is helpful to set up one area in your house for administering fluids. This way, the fluid bag can be hung up, and materials will be within easy reach, leaving both your hands free to handle the pet and the fluid line.
Troubleshooting Beforehand
Remember that the fluids and the fluid line must remain absolutely sterile on their inside surfaces. This means not touching the end of the fluid line or leaving it uncapped. When not in use, the fluid line should be clamped and the end capped with a new needle.
Do not use fluids that are cloudy. This is most commonly a sign that the fluids have been contaminated; a new fluid bag is necessary.
There are different sizes of needles. Most commonly, a 20- or 22-gauge needle is provided. The 22-gauge needle has a smaller diameter than the 20 gauge. This means it isn’t felt as much by the pet when being pushed into the skin, but because it is smaller, the 22-gauge needle delivers fluids more slowly than a larger-diameter needle like the 20 gauge.
Expect to use the same bag of fluids, the same fluid line, but a new needle every time you administer fluids. This will ensure that the needle is both clean and sharp.
Although fluids may be safely stored at room temperature, they may actually be too cold to be comfortable for a pet. Handle the bag, and place it against your bare arm. If the bag feels cool, consider warming it slightly before administration. This can be accomplished easily by placing the fluid bag inside a watertight food storage bag and allowing it to rest in a bowl of warm water ahead of time. The microwave is not recommended. Warming the fluid bag in a microwave can quickly result in fluids that are very hot. Do not administer fluids that are too warm or hot.
Procedure for Administering Fluids
Start by bringing the pet into the prepared area. Stroke them and help them feel relaxed. A cat or small dog may be comfortable on your lap or on a table in front of you. A larger dog will do well sitting or standing on the floor. Note the amount of fluid in the bag as the starting point, and note your veterinarian’s directions about how much to give.
Then, practice “tenting” the skin on the back of the neck between the shoulder blades. This means pulling up some skin between your thumb and index finger and creating a triangular tent shape in the skin that lies behind the neck at the topmost part of the shoulders (where the front legs are). The skin in this area is strong and insensitive, so it is the preferred location for administering the fluids. Practice handling the needle with your dominant hand (for example, your right hand if you are right-handed), and handle the pet with the other hand.
Now, to give the fluids, uncap the needle that is on the end of the fluid line, and hold the needle in your dominant (e.g., right) hand the same way you would hold a pen or pencil. The needle will be directed into the empty space under the skin created by the tent (the “inside” of the tent). In the process, be sure to avoid stabbing your own fingers holding the skin tent, or any of the pet’s underlying muscles or bones. Prepare the skin tent, elevating the skin between the shoulders using your left hand. Advance the needle through the skin, in a direction that is parallel to the pet’s spine or back. Insert quickly and smoothly but without jabbing. Normally you will likely feel a small amount of resistance at the skin surface and then a soft release as the needle passes through the skin. Once the needle is placed, the skin tent can be released. Holding the needle in place may be necessary if the pet moves at all. At first this takes time, but with practice, the time from uncapping the needle to having it in place is typically less than 10 seconds.
Next, unclamp the fluid line, and allow the fluids to create a bulge under the skin. This is not painful for the pet, but petting and comforting them can help keep them still during the time necessary to deliver the amount of fluids recommended by your veterinarian. When the desired amount has been given (monitoring the level on the bag itself), reclamp the fluid line and remove the needle from the skin. Replace the needle cover, and immediately change to a new covered needle to protect the end of the fluid line until the next time fluids are delivered. Dispose of the old needle in a childproof and petproof receptacle.
Afterwards
For larger amounts of fluids or in smaller pets, it may be necessary to divide the total amount of fluid into two different areas. These areas can be side by side or one in front of the other, and your veterinarian will instruct you on this if it is necessary.
Be sure to keep used needles in a safe place away from misuse or accidents and to dispose of them in accordance with local laws governing medical waste.
Frequently Asked Questions
What if my pet runs off in the middle of the fluid administration?
If this happens, calmly clamp off the fluid line and change the needle to a new one. Simply stopping midway through the process is not harmful, but it means the full amount of fluid was not received. It may be helpful to have someone help you (especially by petting, talking to, or otherwise distracting the pet) when you administer the fluids again. If it is a recurrent problem, or if you are concerned that your pet is intolerant to the point of aggression (biting, scratching), contact your veterinarian to discuss alternatives.
Does it hurt?
No. The area of skin between the shoulder blades is very insensitive on a dog or cat’s body. With rare exceptions, such as when there is skin disease or another disorder of that area of the body, the vast majority of dogs and cats show no discomfort at all with this approach.
There is fluid leaking out of the hole in my pet’s skin where the needle just came out. Is this a problem?
A small amount of fluid leakage is common after withdrawing the needle. This can be prevented by gently rubbing the area where the needle was removed for a few seconds afterward. If leakage is occurring during the fluid administration, the needle is likely not far enough in (has slipped back out the skin) or is too far in (has emerged through the other side of the skin tent. In such cases, you should withdraw the needle and reinsert it in order to finish giving the right amount of fluids.
Fluid isn’t flowing. What is wrong?
If the bag is new, be sure the spike of the fluid line is completely inserted into the bag. Then check all the clamps. There may be several. Be sure all clamps of all types are in the open position. Examine the tubing of the fluid line. Sometimes the tube can be kinked or twisted. Pinching or untwisting a kinked section should restore the normal cylindrical shape of the tube. Examine the chamber near the end of the fluid line that is inserted into the bag. If fluid is dripping into this chamber, then fluid is flowing. If fluid is still not flowing, you may adjust the needle position by withdrawing it half an inch (1 cm) in case the needle tip was abutting against something that was blocking it.