Lessons / Medical & Fluid Math / Giving fluids under the skin
🧮 Medical & Fluid Math · 6 min
Giving fluids under the skin
Why this matters
Subcutaneous injection is not difficult, but poor technique or lack of knowledge can kill your animal. Learn it hands-on before you use it.
By the end of this lesson you will be able to
- Select needle gauge by patient size
- Choose appropriate injection sites in mammals and birds
- Carry out the SQ injection sequence, including checking placement
Before you give a subcutaneous injection you must be shown how by a licensed veterinarian or a technician. What follows is supplemental material, not a substitute for being taught.
Needle gauge
Gauge runs backwards: a larger gauge number means a smaller needle. A needle that is too large causes unnecessary pain and tissue damage.
| Gauge | Size | Typical use |
|---|---|---|
| 30 | Tiny | Insulin needles; small songbird fluids or IM/IV injections |
| 27 | Very small | Small birds or small mammals |
| 25 | Small | Birds or small mammals |
| 22 | Medium | Large raptors or medium sized mammals |
| 20 | Large | Adult mammals |
| 18 | Quite large | Only large adult mammals, or filling syringes |
Sites
- Mammals: between the shoulder blades, or along the upper part of a limb. These areas have loose skin that holds fluid.
- Birds: the loose skin around the thigh. No more than 5 to 10 mL per site, which may mean giving fluids more often in smaller volumes.
The sequence
- Clean the area with alcohol-soaked cotton.
- Pinch the skin and lift it slightly.
- Slide the needle under the skin, bevel facing up, almost parallel to the animal's body.
- Draw back on the plunger. Blood means you are in a blood vessel. Air means you have gone all the way through the skin. Either way, withdraw and start over.
- If no blood and no air, inject.
- A bleb (a bubble under the skin) should appear.
- Place a sterile gauze pad over the site and withdraw the needle.
This lesson is part of the NY Wildlife Rehabilitator Exam course. Open it in the course to answer the retrieval checks that go with it, track what you have read, and quiz the whole unit. Lessons, quizzes and the glossary are free.