Unusual intravenous catheter sites in small animals (2023)

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VSufficient access is essential for the care of veterinary patients, as it provides a route for the administration of fluids, medications and blood products, as well as a source of blood for sample collection. The most common site for intravenous (IV) access in small animal patients is the cephalic vein. However, what if this vein is not available? Why might we need to choose another site for IV access and what other sites can we choose? This article reviews sites other than the cephalic vein that can be used for intravenous catheter placement in small animals (TABLA 1).

General indications for the use of alternative intravenous catheter sites

Many factors affect the size and availability of blood vessels (TABLE 1). For example, patients who are hypotensive, hypothermic, or both will experience vasoconstriction. Newborns and small exotic domestic mammals often have extremely small blood vessels, making intravenous access difficult.¹Physical limitations to venous access include tumors (eg, lipomas, mast cell tumors, skin tags), skin infections, and edema at the site. Other challenges to intravenous access include conformational changes in the animals, such as angular limb deformities or amputated limbs. Certain catheterization sites may be chosen over others to reduce bleeding around the insertion site in patients with thrombocytopenia or other bleeding disorders. The number of intravenous access sites will also be reduced due to extremity trauma (eg, fractures, open wounds).

Other considerations include the mobility of the patient and the possibility of chewing or scraping the catheter. The possibility of dirtying the catheter due to frequent diarrhea, urination or urinary incontinence.and general stress while holding the patient by the catheteraccommodation in a certain area. The drugs alone can cause phlebitis, which should prompt consideration of other intravenous catheter options for patients possibly receiving high concentrations of potassium chloride (KCl) (80 mEq/L or higher), dextrose (7% or higher ), mannitol, or chemotherapy agents. .

General catheter placement and maintenance

Sterile placement of the intravenous catheter is necessary. Hands must be washed properly, examination gloves or sterile gloves (depending on location) must be worn, and aseptic technique must be followed. To ensure the site is as clean and secure as possible and to avoid discomfort when the tape is removed, the site should be incised approximately 2 inches above and below the point where the catheter will be placed and to the ends. peripherals. The area should be cleansed with a sterile 0.9% sodium chloride solution (normal saline) combined with a chlorhexidine lavage to achieve a 0.5% to 2% concentration.^2,3After placement, the catheter should be flushed with sterile saline to confirm patency.it is then secured with sterile dressing material.³remove the catheter,regardless of location, it should be rewrapped daily and the insertion site should be assessed twice daily for signs of sloughing, swelling, infection (red or yellow discolored skin around the insertion site or pus-like discharge), or pain and sensitivity.^2,3For lower extremity catheters, the nail and tip of the third and fourth toes should remain visible outside of the bandage to allow monitoring for signs of swelling. Elizabethan collars will prevent licking or chewing on the spot. The dressing material should be checked regularly to make sure it is dry and free of water, food, urine, or feces. Catheters not used for continuous intravenous fluids should be kept open by flushing them with saline every 2 to 4 hours.^2-4

Alternative websites

IV jugular vein

Place:The left and right external jugular veins are located on the ventral side of the neck, off the midline on either side of the trachea. (FIGURE 1A).⁵On each side, the jugular vein branches into the subclavian vein, which extends to the cranial vena cava.⁵The jugular veins lie superficial to the brachiocephalic, sternocephalic, and sternothyroid muscles and are innervated by cranial nerve XI (accessory nerve) and segmental nerves.⁵

Indications:When used as a central line, a jugular catheter is a large-bore catheter that is placed into the jugular vein.^4,6It can be a normal catheter with 1 port or a multiport catheter that allows up to 3 ports to be used at the same time. The choice of which type to use is based on access to supplies and whether more fluids will be given or blood samples taken.⁶

Installation / Maintenance:To reduce the risk of infection, the catheter site should be prepared as aseptically as possible.^4,6,7After catheter placement, drapes above and below the insertion site will help maintain sterility and protect the catheter from slipping out. Jugular catheters must be sutured to prolong their useful life and maintain proper position. The probe should be sewn to the base, tip, and both sides of the butterfly's wings. If the patient is monitoring central venous pressure, the catheter should be measured from the third to fifth ribs to ensure that the catheter tip is cranial to the right atrium.⁷A lateral chest x-ray should be taken to confirm that the catheter has not entered the heart (FIGURE 1B).⁷Otherwise, the anatomical location of the midline is not as important as long as blood samples can be obtained.⁷If the catheter is a standard 18 to 22 gauge peripheral catheter, a placement x-ray is not required.

IV head vein component

Location (FIGURE 2):An additional cephalic vein branches from the cephalic vein in the proximal medial part of the carpal joint. It is located in front of the metacarpal bone and is shaped like a "Y" as it crosses the wrist.⁵The accessory cephalic vein is superficial to the extensor carpi radialis, flexor digitorum superficialis, and flexor carpi radialis.⁵These muscles innervate the distal radial, median, and ulnar nerves.⁵The position of this vein often makes it easier to see than the cephalic vein.

Indications:Indications for use of this vein include easier access due to its prominence, limitations on the proximal side of the limb (eg, growths, edema, scar tissue), or the need to avoid use of the hindlimbs because they cannot be kept clean and dry. .

Installation / Maintenance:After inserting the catheter, make sure you have a good pad under the center of the catheter. For bandages that cover the entire foot up to the toes, the nail and the tip of the third and fourth toes must remain visible for control. Due to the position of the accessory cephalic vein, the catheter will extend medially. When this vein is used, make sure other veterinary staff know so they do not confuse the catheter with the cephalic vein catheter, which is twisted to one side and needs to be adjusted.

IV vein of the auricle

Place:The ear veins are located at the ends of the ear (middle auricular vein) and at the tail (lateral auricular vein).⁵These veins are adjacent to the spinal and caudal auricular nerves, which branch into the otolobulillar and facial nerves.⁵

Indications/contraindications:This position can be used for anesthetized patients when below-field catheter positions are not available or no longer work, or for patients who have large ears (eg,^8,9Vasoconstriction makes the ear vein a poor choice for patients with hypothermia or inadequate perfusion. The veins of the ear are extremely superficial and care must be taken not to perforate the pinna.

Installation / Maintenance (FIGURE 3):Venous catheters can be difficult to secure in place and should not be considered the first choice for a patient who requires significant volumes of fluid. In general, make sure the probe is securely attached to the ear with the tape. Suturing the tape to the ear may provide more stability, especially in patients who tend to nod. Probe integrity can be maintained by constructing an ear splint from a small cup or tongue depressor. If the patient must wear an Elizabethan collar, careful monitoring is required to ensure that the collar does not rub against the ear or dislodge the catheter.

Lateral saphenous vein IV

Location (FIGURE 4):The lateral saphenous vein runs along the lateral side of the distal tibia, immediately proximal to the tibiotarsal (tibia) joint and superficial to the flexor digitalis superficialis, flexor digitalis longus, and gastrocnemius muscles.⁵The muscles surrounding this vein are innervated by the tibial and peroneal nerves.⁵In dogs, this vein is larger in diameter than the great saphenous vein.⁸

Indications:The lateral saphenous vein can be used for a regular peripheral catheter or as the insertion site for a peripherally inserted central catheter (via PICC).⁶A PICC line is a large, long catheter, 18 gauge or larger, with one or more lumens. It can be inserted into a vein to help deliver large volumes of fluid, peripheral parenteral nutrition, or multiple medications through multiple ports (additional lumen ports keep medications separate).^8,10PICC lines can help maintain vein longevity and integrity.⁸In a 2008 study, PICC lines successfully remained in patients for an average of 16.2 days.¹⁰There were no complications during catheterization (eg, venous thrombosis, sepsis, extravasation). Bandaging the catheter after placement can be difficult due to the proximity of the tibial joint. For a typical peripheral catheter, the tape should be tight enough to hold the catheter in place, but should allow enough room for the skin, muscle, and tendon to fluctuate in size after fluid resuscitation. Tape that is too tight can lead to swelling of the feet and toes. The possibility of swelling can be minimized by starting the bandage on the distal side of the foot and working proximally. The third and fourth digits must remain exposed for tracking. The bandage should be close to the catheter insertion site (usually the proximal tibia).

Internal saphenous vein IV

Location (FIGURE 5):The great saphenous vein lies on the medial to distal side of the proximal femur, superficial to the gastrocnemius and sartorius muscles.⁵The nerves that surround this vein are the femoral nerve and its distal branch (saphenous nerve).⁵

Indications:The great saphenous vein is a good site for the catheter in patients who cannot walk and have no other open or accessible veins. In cats, the great saphenous vein is larger andit is easier to catheterize than the lateral saphenous vein.⁸

Installation / Maintenance:To place this catheter, the patient should be on the same side as the desired vessel (ie, in the right lateral position to access the right great saphenous vein) and the person supporting the patient should hold the contralateral end of the pelvis in abduction. After the catheter is placed, tape should be placed around the center of the catheter and wrapped around the patient's thigh. Care must be taken to keep the tape loose enough to prevent swelling of the distal end. The pads can be placed between the patient's legs (eg, if the patient is very mobile, the catheter could easily move).

Common dorsal digital vein (dorsal pedal vein) IV

Location (FIGURE 6):The dorsal pedal vein is located on the dorsal side of the leg, superficial to the extensor digitorum longus and the extensor retinaculum. It is innervated by the common nerve.⁵The vein begins to branch out in the shape of the letter "Y" in the middle of the metatarsal bones. either the left or right branch can be used.⁵The lack of excess fat or skin in the area often makes this vein more visible than most.

Installation / Maintenance:Once the catheter is inserted, tape should be placed around the center to secure it to the leg. When wrapping the catheter, start on the distal side of the extremity and extend the wrap near or above the ankle joint for added security.

Vena sublingual IV

Location (FIGURE 7):The sublingual vein originates from the dorsal part of the tongue and courses caudally to the myloid muscle.⁵

footprints: The sublingual vein can be used for a short time in anesthetized patients. If peripheral intravenous access is lost while the animal is under anesthesia, catheterization of the sublingual vein may be attempted because the tongue is often still easily accessible.Typically, a sublingual catheter is used for intravenous drug administration to maintain anesthesia until a new peripheral catheter is placed.

Installation / Maintenance:When placing a sublingual catheter, first clean the tongue as aseptically as possible with a solution of chlorhexidine and saline (0.13% solution). However, before cleaning, make sure the endotracheal tube cuff is inflated to prevent passage of cleaning solution or chlorhexidine fluid into the trachea. After cleaning the catheter site, rinse your mouth with sterile water or saline to prevent the corrosive effects of prolonged chlorhexidine exposure to the tongue. Tongue depressors can be used to create a splint to add rigidity to the tongue and make it easier to hold the catheter in place.

corpus cavernosum IV

Location (FIGURE 8):The corpus cavernosum consists of 2 columns of spongy tissue on the shaft of the penis.⁵This tissue is full of blood vessels that enlarge during an erection.⁵The corpus cavernosum is located on the lateral side of the penis, caudal to the penile opening.⁵

Indications:Although not widely used, corporal catheterization is a short-term option to administer resuscitative fluids or drugs untilthe second IV access route is achieved.^11,12Experimentalmodels showed catheters placed in the bodyCavernosum can support adequate flow rates to resuscitate hypovolemic animals and can be used to perform cardiac arrest.medications (such as epinephrine, atropine).¹¹Although the administration of other emergency medications by this route has not been studied, complications have not been reported after the administration of blood products and intravenous phenobarbital to some patients through the corpora cavernosa.¹²

Installation / Maintenance:A large diameter catheter (18 or 19 gauge) was inserted into the lateral skin of the penis at a 45° angle caudal to the opening of the penis into the corpus cavernosum.¹²The catheter can be glued and sewn to the dorsal side of the penis.

Vena umbilical IV

Place:The umbilical vein is found in the navel of newborns.

Indications/contraindications:The umbilical vein is accessible immediately after birth, as long as the vein is not ligated after a cesarean section.¹²Because the umbilical cord begins to dry out, harden, and fall off within 24 to 72 hours of birth, this vein may no longer be a viable option after 24 hours.

Installation / Maintenance:Accessing this vein can be difficult and time consuming if not practiced regularly. Therefore, a better option for intravenous access in the newborn might be an intraosseous catheter. To access the umbilical vein, the base of the umbilicus must be wrapped with umbilical tape tight enough to prevent bleeding.¹²To avoid infection and possible sepsis in the newborn, the sterility of the site preparation should be similar to that of a central line or PICC.¹²The catheter should not advance more than a few centimeters above the point where the flash of blood appears. Further progress could result in the insertion of a catheter into the portal vein system. An x-ray is necessary to make sure it is well seated.¹²

Intraosealni IV

Location (FIGURE 9):The 3 most common sites for intraosseous catheter placement are the medullary cavities of the greater tubercle of the proximal humerus, the intertrochanteric fossa of the proximal femur, and the tibial ganglion.^{12-14 (screen, others).}Other sites include the ilium and ilium in small mammals and the distal ulna and proximal tibia in birds.^1,12,13

Indications/contraindications:Intraosseous catheters may be used when a venous catheter cannot be placed. Most drugs that can be given intravenously can also be given intraosseously.¹²The exceptions are drugs that are toxic to the bone marrow (eg, sodium bicarbonate, chemotherapy agents, large amounts of hypertonic saline).^12,13If the catheter is moved into the spongy part of the bone that has a network of blood vessels and capillaries, a blood sample can be taken.intraosseous catheter.¹⁵in a studyof 12 dogswhat was compared0.5 mL of blood was collected from the jugular vein opposite the proximal tibia, samples were analyzed for blood urea nitrogen (BUN), glucose, packed cell volume (PCV), total plasma protein, lactate, potassium, sodium and chloride. The authors found statistically significant differences between blood collected at the 2 sites for BUN, potassium, sodium, and chloride, and a large but not statistically significant difference for PCV.¹⁵However, it turns out that there are differences.blood from intraosseous catheter and without clinical significanceit can be used as a method to estimate parameters, excluding potassium and PCV, in healthy dogs. Further studies in critically ill patients are needed to determine if this pathway is reliable for other blood values.

Installation / Maintenance:Since the placement of any intraosseous catheter involves passage through superficial and underlying tissues and muscles, there is always a risk of muscle trauma and nerve damage. For example, the intertrochanteric fossa of the proximal femur is adjacent to the sciatic nerve, which innervates the biceps femoris muscle (among others).⁵Other associated muscles and nerves that may be affected during intraosseous catheter placement include the brachiocephalic muscle/spinal accessory nerve to the proximal humerus, the gluteal muscles/cranial or caudal gluteal nerve to the transtrochanteric fossa of the femur, and the quadriceps nerve to the femur. proximal.⁵Bilateral radiographs can confirm proper placement (FIGURE 10).

As with all other catheters, placement of an intraosseous catheter must be sterile. For injured extremities, fractures must be ruled out before placing an intraosseous catheter, as any fluid or medication injected through the catheter could leak from the bone into the surrounding muscle and tissue.¹³Patients who are not ideal candidates for intraosseous catheters are those with diseases or conditions that make the bone prone to fracture (eg, in geriatric patients).^sixteen

Abstract

For veterinary nurses, preparing for the unexpected should be considered part of a normal day. When cephalic veins are not available for any reason, veterinarians should have a backup plan for alternative routes of venous access. Knowledge of the correct anatomical locations of individual blood vessels, including bony landmarks, as well as the underlying muscles and nerves, is critical to correct catheter placement and to reduce catheter-related trauma. Of the many options for obtaining intravenous access, the option chosen should be the one that best suits the patient's condition and needs.

Editor's note:An earlier version of this article incorrectly referred to the ilium as the ileum. Additionally, the legend to Figure 10 misidentified the proximal humerus. This has been fixed. I apologize for the mistake.

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