Intravenous Catheters: Which, Where, Why, and How?

Kara Magneheim, BAS, CVT, VTS (ECC) | BluePearl Specialty + Emergency Pet Hospital | Published: Issue 1 2024

Tags:

Editor's Pick

As veterinary technicians, one of the most common procedures that we perform is placement and maintenance of intravenous catheters. They are often thought of as a benign intervention but can be a potential source of infection and require special care. In addition, utilization of different catheter types can be beneficial for different patients.

Use of different catheter types can be used for long-term catheterization, administration of hypertonic solutions, and administration of multiple non-compatible solutions. Knowing how to select, place, utilize, and maintain various types of catheters can be beneficial for patient care and ultimately result in less stress for the patient.

Peripheral Intravenous Catheters

Peripheral intravenous catheters (pIVCs) are likely the most commonly utilized catheters in veterinary medicine. These are short (between ¾ – 2”) and made of Teflon, polypropylene, or polyvinyl chloride. These catheters are usually single lumen and are inserted into a peripheral vein. The cephalic, lateral saphenous, and medial saphenous are the most commonly utilized sites. 

Alternatively, the lateral aural vein, dorsal pedal vein, or any other vein may be catheterized. It is important to select a site that is free from trauma, has adequate blood flow proximal to the insertion site, and is free from any defect such as local infection.

Proper hand hygiene is the best place to start for reducing incidence of catheter-based infection. Before placement of pIVC, the veterinary technician should wash their hands thoroughly with soap and water or use hand sanitizer. The next step is hair removal from the proposed insertion site. 

There are varying opinions about hair removal prior to catheterization. While antiseptics are effective in the hair coat, removal of hair allows for better visualization of the vessel and less trauma as a whole. Removal of fur or hair by clipping is also associated with higher risks of infection due to skin trauma; however, with proper care these risks can be minimized.

After shaving, an appropriate antiseptic solution is used for cleansing the skin. Preferences for antiseptic will vary from hospital to hospital and include 70% alcohol, chlorhexidine gluconate, and povidone iodine. Any of these choices are acceptable as long as the manufacturer’s directions are followed carefully. Iodine has longer-lasting antimicrobial activity, but may be more irritating to skin, while chlorhexidine may be more effective at preventing catheter-based infections.

Once the vessel is localized, the catheter with stylet is advanced into the vein at a 45-degree angle until a flash of blood is seen in the catheter hub. Using the index finger, the catheter is advanced into the vessel, the stylet is removed, and an injection cap or T-port is placed on the end. The catheter is then taped or secured in place.

Photo showing appropriate route of peripheral Intravenous central catheter (blue) and sampling catheter (red) in a dog.

The maintenance of pIVCs is straightforward. If the patient is not on IV fluids, the catheter should be flushed and the site evaluated at least every 12 hours. If the patient is on IV fluids, the site should be inspected at least every six hours. Inspection of the site does not have to involve completely unwrapping the catheter. 

Ideally, the limb should be easy to visualize above and below the catheter bandaging. The limb is inspected for swelling, pain, phlebitis (a hard or rope- like vein), and the bandage is inspected for dirt or contamination. The bandage should only be unwrapped and replaced if clinically indicated. Studies have shown no reduction in instances of catheter-based infections with regularly scheduled replacement of pIVCs, so the catheter should only be replaced if clinically indicated. This saves the patient from unnecessary trauma and preserves the vessels for future use.

Peripheral Sampling Line/Intracath

Peripheral sampling lines, or Intracaths, are long (4-6”) catheters, usually single lumen, which are intended for long-term usage. These catheters are longer, terminate near the central venous supply, and are less likely to be affected by thrombus formation from the initial puncture site. That makes these catheters ideal for frequent blood sampling and administration of fluids with a higher hypertonicity. Intracaths are usually inserted in the lateral or medial saphenous vein. Site selection and preparation is the same as described above for pIVCs. Sterile gloves may be used since this catheter will be inserted further into the patient’s vessel than a pIVC.

There are two methods of placing peripheral sampling lines. Since Intracaths are sold as through-the-needle catheters, they may be placed that way. This means that the included needle is inserted into the vessel at a 45-degree angle and the catheter is advanced into the vessel using the included guidewire until only two inches remain outside of the vein. The needle is then withdrawn from the skin, and the included needle guard is snapped into place.

The guidewire is removed from the catheter, then an injection port or T-set is put into place, the catheter is secured with suture or tape, and a light bandage is placed to keep the catheter secure. This method is quick and requires few extra materials.

A second method of placing peripheral sampling lines involves the use of a pIVC two sizes larger than the selected line size. The pIVC is placed into the lateral or medial saphenous vein, and the stylet is discarded. The included needle is removed from the Intracath. Using the pIVC, the guidewire and catheter of the Intracath are inserted into the vessel. Once the hub of the Intracath is inserted into the hub of the pIVC, the guidewire is removed, and an injection cap or T-port is placed on the end of the Intracath. 

The hub of the pIVC and the hub of the Intracath should be secured together with a piece of tape to prevent them from separating. The pIVC may be sutured in place and a light bandage, as would be used for a pIVC, should be placed to secure the catheter. This method allows for changing of the peripheral sampling line by simply changing the Intracath by removing the old one and inserting the new catheter into the pIVC.

The peripheral sampling line should be maintained as outlined with pIVCs above. In addition, the peripheral sampling line should be flushed with heparinized saline every twelve hours. Blood samples can be obtained utilizing the three-syringe technique. Using the first syringe, 0.5 – 1mL of heparinized saline should be drawn up (enough to flush the line), the second syringe should be empty, and the third syringe should have 1-3mL of heparinized saline drawn up to flush the line. 

Using the first syringe, the saline should be flushed in, and 2-3mL of blood should be obtained from the patient, enough to clear the line, plus a little extra. This syringe is kept sterile and set to the side; it is the ‘waste sample’. Next, the second syringe should be used to obtain only as much blood as is needed for the required testing. The waste sample should be inspected for any evidence of clotting; if none is found, it is returned to the patient via the sampling line. If any evidence of clotting is found, the sample is disposed of. After the sample is returned to the patient, or wasted, the line is flushed with the third syringe containing heparinized saline.

Photo showing appropriate route of central venous catheter in a dog

In addition to the normal risks of infection, phlebitis, and extravasation, peripheral sampling lines can carry the risk of interrupting the blood supply of the limb that they are in. This can cause swelling distally to the catheter, and the limb should be inspected and massaged frequently. If the digits become cold, the catheter should be removed. These catheters should not be used for monitoring blood glucose if they have been used for administration of dextrose as dextrose binds to plastic and will artificially elevate the blood glucose.

Central Venous Line/Peripherally Inserted Central Catheter

The central venous line (CVL) and peripherally inserted central catheter (PICC) are both utilized in the same fashion. The CVL is placed in the jugular vein and terminates in the cranial vena cava, while the PICC is placed in the lateral or medial saphenous vein and terminates in the caudal vena cava. Since these catheters enter the central blood supply, they are inserted sterilely. 

These catheters are long, between 5 and 20 inches. They are made of a soft silicone material, which is more rigid at room temperature but softens at body temperature. They have one or more lumens (most commonly three to five) and can be used for central venous pressures, blood sampling, administration of hypertonic solutions, and concurrent administration of solutions, which are incompatible. These catheters are designed for long term usage.

The site should be measured from the insertion site to the central venous supply, from the jugular vein to the 3 – 4th intercostal space, or just caudal to the scapula. The patient should be connected to an ECG during central line placement and may require sedation. The PICC should be measured from the insertion site, around the hind end of the patient, to the caudal vena cava, or midway along the spine. The insertion site is shaved and aseptically prepared.

Ideally, the patient is draped with quarter drapes or a fenestrated drape. The primary person placing the line, as well as an assistant, wear sterile gloves. A full cut down, or just a facilitator hole, may be required for catheterization. The vessel is localized, and a pIVC is placed in the manner outlined above. The vessel is occluded in between steps to minimize blood loss and keep the site clean. 

A guidewire is inserted into the IVC while the ECG is monitored. Any evidence of arrhythmia should not be ignored, and the guidewire should be backed out slightly to correct the arrhythmia. Once the guidewire is in place, the IVC is removed from the patient and taken off the guidewire. Either the primary person placing the line, or the sterile assistant, should have a hold of the guidewire at all times; if the guidewire is dropped, it could migrate into the patient. 

Next, a dilator is placed along the guidewire and into the vessel. It is often helpful to lift the skin and twist the dilator slightly while inserting. Once the dilator has been inserted, it is removed from the patient and off of the guidewire. There are often multiple dilators included in a kit, and they may all need to be utilized before the actual catheter can be placed. Once the final dilator is removed from the guidewire, the catheter is inserted along the guidewire. It will come out of the distal port. It should be sutured in place, and any cut-down site should be sutured closed.

Each port should be suctioned back until blood is obtained and flushed through with heparinized saline. Radiographs should be taken after placement to confirm appropriate anatomical positioning. After placement is confirmed, a soft padded bandage should be placed to protect the catheter and site.

Care of the CVL or PICC is the same as the care outlined for the peripheral sampling catheter. The individual ports should be labeled for their individual uses and all lines should be handled in an aseptic manner. As with the peripheral sampling, catheter lines used for administration of dextrose should not be used for blood glucose sampling. Since this catheter is covered with a soft padded bandage, the bulk of the bandage should be removed daily and the site visually inspected.

Arterial Catheter

Arterial catheters are usually regular pIVCs that are placed into an artery rather than a vein. Most commonly used is the dorsal pedal artery, though any artery can be used including the radial, femoral, coccygeal, or auricular. These catheters are not used for drug or fluid administration but can be used for blood sampling and central venous pressures.

The site is shaved and aseptically prepared as outlined above. The artery is localized and the ideal position for insertion will be the most distal place that the artery can be palpated. Administration of a small amount of lidocaine can help to prevent arterial spasms. The catheter with stylet is inserted at a 10–20-degree angle until blood is noted, and the catheter is slowly advanced off of the stylet. If the catheterization was successful, pulsatile blood flow should be noted. The catheter is flushed with heparinized saline, capped with an injection cap or T-port, and secured in place with either suture or tape or both.

Radiograph showing appropriate positioning of central venous catheter and nasocastric tube.

The site is shaved and aseptically prepared as outlined above. The artery is localized and the ideal position for insertion will be the most distal place that the artery can be palpated. Administration of a small amount of lidocaine can help to prevent arterial spasms. The catheter with stylet is inserted at a 10–20-degree angle until blood is noted, and the catheter is slowly advanced off of the stylet. If the catheterization was successful, pulsatile blood flow should be noted. The catheter is flushed with heparinized saline, capped with an injection cap or T-port, and secured in place with either suture or tape or both.

Blood should be obtained using the three-syringe technique outlined above. Common issues from arterial catheter placement include hemorrhage, thrombus formation, and sepsis.

Intraosseous Catheter

Intraosseous catheters are often steel-needle catheters and may be inserted by hand or with the use of an EZ IO device. Spinal needles or large bore needles may be used for intraosseous catheters. They are frequently used as temporary venous access or primary venous access in small animals. Intraosseous catheters can be placed quickly in a patient who is in cardiac arrest and may be the first choice for intravenous access. The trochanteric fossa of the femur, iliac wing, proximal humerus, or tibial tuberosity are all good access sites. Any pneumatic bones should be avoided in birds.

The skin above the site is aseptically prepared as outlined above. The bone is localized, and the needle is inserted in a twisting motion. A small amount of lidocaine may be inserted into the muscle before the needle is inserted, or a sedative may need to be utilized. A gentle popping will be felt as the needle enters into the cortex of the bone; once in place, the needle will move as the leg moves. Radiographs are the gold standard to confirm placement; however, aspirating the catheter and obtaining bone marrow, or flushing the catheter, can be utilized as alternative methods.

References

  1. Tan R, Dart A, Dowling B. Catheters: a review of the selection, utilisation and complications of catheters for peripheral venous access. Australian veterinary journal. 2003;81(3):136- 139.
  2. Coolman B, Marretta S, Kakoma I, Wallig M, Coolman S, Paul A. Cutaneous antimicrobial preparation prior to intravenous catheterization in healthy dogs: clinical, microbiological, and histopathological evaluation. The Canadian Veterinary Journal. 1998;39(12):757.
  3. Dez H, Beal MW. Emergency vascular access. Veterinary Clinics of North America: Small Animal Practice. 2000;30(3):491-507.
  4. Marsh-Ng ML, Burney DP, Garcia J. Surveillance of infections associated with intravenous catheters in dogs and cats in an intensive care unit. Journal of the American Animal Hospital Association. 2007;43(1):13-20.
  5. Ueda Y, Odunayo A, Mann F. Comparison of heparinized saline and 0.9\% sodium chloride for maintaining peripheral intravenous catheter patency in dogs. Journal of Veterinary Emergency and Critical Care. 2013;23(5):517-522.
  6. Elliott K, Fleeman L, Rand J. Using 20-gauge percutaneous peripheral catheters to reliably collect serial 4-mL blood samples from conscious dogs. Australian veterinary journal. 2010;88(6):215-221.
  7. O’Grady NP, Alexander M, Burns LA, et al. Guidelines for the prevention of intravascular catheter-related infections. Clin Infect Dis. 2011;52(9):e162-93. doi:10.1093/cid/cir257.
  8. Johnson JA. Nosocomial infections. Veterinary Clinics of North America: Small Animal Practice. 2002;32(5):1101-1126.

 

About the Author

Kara Magneheim, BAS, CVT, VTS (ECC)

Kara grew up in Sarasota, Florida. She graduated with her Bachelor of Applied Science in Veterinary Technology (Clinical) from St. Petersburg College and is certified with the FVTA and the FVMA. About a year into working in veterinary medicine, Kara learned that emergency and critical care was the right place for her. She truly enjoys working with critically ill patients and making a difference in their lives and the lives of their owners. She loves all aspects of nursing care and particularly enjoys the fact that she gets to learn something new every day at work. Kara also enjoys the challenge of anesthesia, especially in emergency cases or unstable patients.

Become a member to receive articles in our quarterly publication!