CHAPTER 1
Vascular Access Techniques

INTRODUCTION

A variety of methods can be used for placement of peripheral, central venous, and arterial catheters. If a peripheral or central catheter cannot be placed due to small patient size, severe hypovolemia or dehydration, or hypotension, intraosseous catheters can be placed in the femur, humerus, or wing of the ileum. This chapter will discuss indications, contraindications, and methodologies listed above.

Through-the-needle or over-the-wire central venous catheters can be placed in the jugular, medial saphenous, or lateral saphenous veins. The indications and contraindications for central venous catheter placement, irrespective of type, are similar.

The restraint for placement of peripheral and central venous catheters is the same, although local anesthesia is advised when entrance holes are made in the skin for placement of central venous catheters. Catheters should not be placed into the jugular vein in cases of increased intraocular or increased intracranial pressure or if there is thrombosis of the contralateral jugular vein.

The following series of images display the anatomic location of the jugular, cephalic, lateral saphenous, and medial saphenous veins.

Fig. 1.1. Restraint for jugular catheterization. Place the patient in lateral recumbency and have an assistant restrain the head and the rear limbs. A second assistant may be required to restrain the forelimbs.

Fig. 1.2. Restraint for cephalic catheterization. Place the patient in sternal recumbency. Have an assistant hold the neck and head while pushing caudal to the elbow.

Fig. 1.3. Restraint for lateral saphenous vascular catheterization. Place the patient in lateral recumbency with the proposed site of catheter placement up. Have an assistant restrain the patient's head and neck. A second assistant can restrain the rear limbs and occlude the lateral saphenous vein proximally, caudal to the stifle.

Fig. 1.4. Restraint for medial saphenous catheterization. Place the patient in lateral recumbency with the proposed site of catheter placement down. Have an assistant restrain the patient's head and neck while occluding the medial saphenous vein proximally, close to the inguinal region.

PERIPHERAL CATHETERIZATION

Introduction

Peripheral venous catheters are the most common type of intravenous catheters placed in small animal patients. Peripheral catheters are easy to place and simple to maintain, and have minimal risks to the patient. Peripheral catheters can be used for infusion of crystalloid and colloid fluids, blood products, intravenous drugs, and anesthetic agents. In large breeds, larger-bore (16 to 18 gauge) catheters can sometimes be used for blood sample collection.

Supplies Needed

½- and 1-inch white adhesive tape to secure and wrap the catheter

Kling

Antimicrobial scrub solution

T-port or male adapter

Heparinized flush solution in a 3-mL syringe

• 1000 units of unfractionated heparin/250 to 500 mL of 0.9% NaCl; bags of unused heparinized flush should be discarded after 24 hours.

Electric clipper and blades

Intravenous catheter

Indications

Infusion of crystalloid and colloid fluids

Infusion of blood products

Infusion of intravenous drugs

Induction of general anesthesia

Maintenance of total intravenous anesthesia

Blood sample collection

Contraindications

Burn, abrasion, or pyoderma over the catheter site

Thrombosis of vein selected for catheterization

Infusion of hyperosmolar solutions (parenteral nutrition, concentrated dextrose, and concentrated vasopressors such as norepinephrine)

Fig. 1.5. Restraint for cephalic catheterization. The animal is positioned in sternal recumbency, and the assistant draws one arm under the animal's neck, pulling the head toward the assistant's body, and then pushes the forelimb cranially while occluding the vessel at the elbow.

Fig. 1.6. Supplies needed for peripheral catheterization.

Fig. 1.7. Have an assistant restrain and clip the antebrachium circumferentially in between the elbow and carpus, and then aseptically scrub the clipped area.

Fig. 1.8. If the skin is very tough, or if the animal is very dehydrated, make a small nick incision through the skin with the bevel of an 18-gauge needle. This technique is called "percutaneous facilitation," and will make the task of catheter insertion easier, as it prevents the catheter from becoming burred as it goes through the thickened or dehydrated skin and underlying tissue.

Helpful hint: Use care to avoid lacerating the underlying vessel when performing percutaneous facilitation.

Fig. 1.9a. Have an assistant occlude the vessel. Wearing gloves (nonsterile), insert the catheter needle through the skin at a 15° angle. Bluntly but gently penetrate the skin.

Fig. 1.9b. Watch for a flash of blood, the push the catheter off of the stylette into the vessel. Note: A gauze 4 x 4 square is placed distal to the proposed catheter insertion site to help prevent the catheter from being dragged through fur. It also helps prevent blood from wetting the skin and fur, which would prevent the tape from adhering and properly securing the catheter in place.

Fig. 1.10a. Have an assistant occlude the vessel just over the point of catheter insertion, and then remove the stylette.

Fig. 1.10b. Have an assistant occlude the catheter to prevent backflow of blood into your field.

Fig. 1.11. Tape the catheter around the hub and limb with a half-inch length of white adhesive tape.

Helpful hint: Make sure that the catheter hub and skin are completely dry, so that the tape will securely attach itself to the catheter hub and the catheter hub will not spin around, or else the catheter will not remain in place and will pull out of the vessel.

Fig. 1.12. Finish taping the catheter in place with layers of 1-inch white adhesive tape, Kling, Elasticon®, or VetrapT.

Fig. 1.13. Place a T-port flushed with heparinized saline and flush the catheter.

CENTRAL VENOUS CATHETER PLACEMENT

Central venous catheters can be placed into the jugular, lateral saphenous, and medial saphenous veins. Central catheters can be used for infusion of crystalloid and colloid fluids, infusion of continuous or intermittent drugs, or infusion of hyperosmolar solutions including parenteral nutrition. An additional benefit of indwelling central venous catheters is ease of repeated blood sample collection without the need for repeated venipuncture. Many companies supply single- and multi-lumen over-the-wire products. Multi-lumen catheters are beneficial when multiple products are being infused into a patient simultaneously. The added ports allow vascular access without the needle for placement of multiple single-lumen central or peripheral catheters.

Supplies Needed

Sterile gloves

Antimicrobial scrub and solution

Central venous catheter(s)

Cotton roll gauze

Electric clipper and blades

Gauze 4 x 4 inch squares

Heparinized 0.9% saline flush solution

Kling bandaging material

T-port

1-inch white tape

VetrapT

Indications

Crystalloid or colloid infusion

Continuous drug infusion

Infusion of parenteral nutrition or other hyperosmolar substances

Repeated blood sample collection

Contraindications

Coagulopathies

• Thrombocytopenia
• Thrombocytopathia
• Vitamin K antagonist rodenticide intoxication

Hypercoagulable states

• Hyperadrenocorticism
• Disseminated intravascular coagulation
• Protein losing enteropathy
• Protein losing nephropathy

Catheters should not be placed into the jugular vein in cases of increased intraocular or increased intracranial pressure or if there is thrombosis of the contralateral jugular vein.

The following series of images display the anatomic location of the jugular, cephalic, lateral saphenous, and medial saphenous veins.

OVER-THE-WIRE CATHETERS (SELDINGER TECHNIQUE)

Supplies Needed

Sterile gloves

Antimicrobial scrub solution

Number 11 scalpel blade

Lidocaine 2%

3-mL syringe with 24-gauge needle

Electric clipper and blades

1-inch white tape

3-0 nonabsorbable...