Cannula

A cannula is a thin tube that can be inserted into the body, often for the delivery or removal of fluids. In veterinary medicine, cannulas are used for various purposes, including intravenous (IV) therapy, fluid administration, blood sampling, and providing medications. Here’s a detailed overview of the use of cannulas in animals:

Types of Cannulas

1. Intravenous Cannulas:
   • Peripheral IV Cannulas: These are the most common types used in veterinary practice. They are inserted into a peripheral vein, usually in the leg or ear of the animal.
   • Central IV Cannulas: Inserted into a large central vein, often used in more critical cases where long-term access or larger volumes of fluids are needed.
2. Intranasal Cannulas:
   • Used to deliver oxygen or medications directly into the nasal passages of the animal. Commonly used in respiratory distress cases.
3. Subcutaneous Cannulas:
   • Used for the administration of fluids or medications under the skin. This is less invasive and often used for long-term fluid therapy in animals like cats and small dogs.
4. Intraosseous Cannulas:
   • Inserted into the bone marrow cavity to provide emergency vascular access, particularly in small animals, neonates, or when peripheral access is difficult.

Uses of Cannulas

1. Fluid Therapy:
   • Cannulas are essential for rehydration and administering IV fluids in dehydrated or critically ill animals.
2. Medication Administration:
   • Used to deliver medications directly into the bloodstream, ensuring quick and efficient drug action.
3. Blood Sampling:
   • Facilitate easy and repeated access for blood sampling, especially in research settings or for monitoring critically ill patients.
4. Nutritional Support:
   • Provide parenteral nutrition to animals that cannot eat or absorb nutrients orally.

Application of Cannulas

1. Preparation:
   • Selection: Choose the appropriate size and type of cannula based on the animal’s size, species, and the intended use.
   • Sterilization: Ensure all equipment is sterile to prevent infections.
   • Restraint: Properly restrain the animal to minimize stress and movement during the procedure.
2. Insertion:
   • Peripheral IV Cannula:
     • Shave and clean the insertion site with an antiseptic solution.
     • Insert the cannula into the vein at a shallow angle.
     • Once blood is seen in the flash chamber, advance the cannula slightly and then remove the needle, leaving the cannula in place.
     • Secure the cannula with adhesive tape or a bandage.
   • Intraosseous Cannula:
     • Typically used in an emergency; the insertion site is usually the tibia, humerus, or femur.
     • Clean the site, and insert the cannula directly into the bone marrow using a specialized needle.
3. Maintenance:
   • Regularly check the cannula site for signs of infection, swelling, or displacement.
   • Ensure the cannula remains patent (open) by flushing with saline solution as needed.
   • Change the site if any complications arise.