Venous Cutdown

The basilic vein in the antecubital fossa and the saphenous vein in the leg are the most commonly utilized vessels for cutdowns. The basilic vein is located two fingerbreadths above and two fingerbreadths medial to the olecranon. The saphenous vein is just anterior to the malleolus at the ankle and is also accessible in the proximal thigh three fingerbreadths below the midpoint of the inguinal ligament ( Fig 17:8). Although experienced operators may be able to complete the procedure in less than a minute, for most operators 5 or 6 min will be required. In many situations, this implies that cutdown should be resorted to only when percutaneous access has failed or is deemed likely to be unsuccessful.

FIG. 17-8. Venous cutdown. A. A skin incision is made perpendicular to the course of the vein. B. Skin retracted and vein exposed. C. Proximal and distal ties are passed under the vein. If the vein is to be sacrificed, the distal suture is tied to prevent bleeding, and the ends are left long to help stabilize the vein during cannulation. The proximal tie is not tied at this point, but traction on it will control back bleeding. D. The vein is stretched flat and incised at a 45° angle. Approximately one-third of the lumen must be exposed. Traction on the proximal tie will control back bleeding. (From Roberts JR, Hedges JR: Clinical Procedures in Emergency Medicine, 2d ed. Philadelphia, Saunders, 1991, p 321. With permission. Parts B and C first appeared in Vander Salm TJ et al: Atlas of Bedside Procedures. Boston, Little, Brown, 1979.)

The operator begins by prepping and anesthetizing the skin. A transverse skin incision is made, and by blunt dissection the subcutaneous tissue is separated until the vein is exposed. Any accompanying artery is identified by slipping a forceps or hemostat under the vessels and applying pressure; pulsatile flow will be evident in the artery. (However, with patients who are in shock, this maneuver may be unsuccessful.) After freeing the vein from the surrounding tissues, two separate sutures are passed beneath the vein, one proximally and one distally. The proximal sutures are left untied, while the distal suture is tied to occlude the vein. The ends of the sutures are kept long so that they can be used for applying traction to the vein. A small incision is made in the vein between the proximal and the distal sutures. (It should not be cut through and through). While applying traction on the vein, the operator inserts the catheter into the vein. Some cutdown kits contain a vein "holder," which may help to prepare the vein to accept a catheter. The proximal suture is tied to secure the catheter in the vein and the skin is closed. Care must be exercised throughout the procedure, since poor technique can result in injury to a tendon or nerve or extensive hemorrhage from soft tissue.

An alternate method of cannulating the vessel is to perform a "mini-cutdown" (Fig 1..7.-9). In this technique, the vein is fully exposed and an over-the-needle catheter is inserted into the vein under direct visualization. Great care must be taken to avoid through-and-through puncture. The advantage of this technique is that it is easier to perform, especially in young children; and the vessel does not have to be sacrificed. Extensive tissue dissection and complete isolation of the vein are avoided, there is no need to place proximal and distal suture ties, and the catheter can be discontinued with simple pressure at the site.

FIG. 17-9. The vessel is elevated with a hemostat and occluded with gentle traction from a distal tie. The needle is inserted and the sheath is advanced into the vessel. The vessel should not be tied off with this techinque.

The potential complications of venous cutdown include infection, phlebitis, and laceration of a nerve or artery. INTRAOSSEOUS VASCULAR ACCESS

When vascular access cannot be obtained through other sites, intraosseous infusion may be life- or limb-saving. This method of vascular access, usually considered for children, may be used in adults as well. After 5 years of age, however, red marrow is steadily replaced by yellow marrow in the limbs, making infusion more difficult, and decreasing the infusion rate.

For pediatric patients up to 5 years of age, the tibia is the preferred site ( Fig 1.7-10). In adults, the most commonly used site is the medial malleolus. Although the sternum offers higher infusion rates for adults, this approach is attended by the potentially disastrous complication of puncture into the thoracic cavity. The tibia is technically more difficult in adults than in children because the adult bone is thicker and the needle tends to slip off the bone. Other potential insertion sites include the distal femur, clavicle, humerus, and ileum.

FIG. 17-10. The needle is inserted 2-cm distal to the tibial tuberosity on the medial aspect of the tibia. It is inserted in a caudal direction, away from the joint space.

A word about skeletal vascular anatomy is in order. Arterial supply to bones is by a nutrient artery that pierces the cortex and bifurcates into ascending and descending branches; these further divide into arterioles that pierce the endosteal surface to become capillaries. The capillaries drain into medullary venous sinusoids within the medullary space; these then drain into a central venous channel. Catheter placement in the sinusoids provides ready access to the venous circulation.

Technique

Either standard bone marrow aspiration needles or specialized intraosseous infusion needles must be used because standard intravenous stylets and spinal needles are likely to bend during the procedure. For the proximal tibia, the puncture site is 1 to 2 cm distal to the midpoint between the tibial tuberosity and the medial aspect of the tibia; for the distal tibia, it is the medial surface of the ankle just proximal to the medial malleolus; and for the distal femur, it is the dorsal surface at the point where the condyles join the shaft of the bone. After prepping and anesthetizing skin and periosteum, the operator inserts the needle with the point directed away from the joint space (distally if the site is the proximal tibia, proximally at the other two sites). The needle is grasped in the palm of the hand and directed into the bone using a twisting motion to break through the cortex. Once this has occurred, resistance decreases and crepitus is encountered as the needle enters the marrow cavity. The stylet is then removed and aspiration with a syringe is performed to obtain blood and marrow for confirmation of positioning. If shock is present, aspiration may be unsuccessful; if this is the case, cautious infusion of several milliliters of saline should be attempted with careful observation for extravasation. If there is none, then the needle may be assumed to be positioned in the marrow cavity. A postprocedure x-ray should be performed to rule out the complication of iatrogenic fracture.

Complications

The incidence of infection, including both cellulitis and osteomyelitis, is less than 1 percent, similar to that for other techniques. The potential for infection can be minimized by limiting the duration of intraosseous infusion and avoiding hypertonic solutions. Fractures of the tibia have been reported. Fat embolism is rare and has been reported only in adult patients. Injury to the growth plate has also been mentioned as a potential complication, but there are no reports of serious morbidity arising from an injury to developing bone.

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