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A number of procedures are used to gain vascular access.

Peripheral Vein Catheterization

Most patients' needs for IV fluid and drugs can be met with a percutaneous peripheral venous catheter. Venous cutdown can be used when percutaneous catheter insertion is not feasible. Typical cutdown sites are the cephalic vein in the arm and the saphenous vein at the ankle.

Common complications (eg, local infection, venous thrombosis, thrombophlebitis, interstitial fluid extravasation) can be reduced by meticulous sterile technique during insertion and by replacing or removing the catheters within 72 h.

Central Venous Catheterization

Patients needing secure or long-term vascular access (eg, for administration of antibiotics, chemotherapy, or TPN) are best treated with a central venous catheter (CVC). CVCs allow infusion of solutions that are too concentrated or irritating for peripheral veins and also allow monitoring of central venous pressure (CVP—see Shock and Fluid Resuscitation: End point and Monitoring).

Procedure: CVCs are inserted using sterile technique and local anesthesia (eg, 1% lidocaine Some Trade Names
XYLOCAINE
Click for Drug Monograph
). The superior vena cava is entered via percutaneous puncture of the subclavian or the internal or external jugular vein or by venous cutdown on the basilic vein. The inferior vena cava may be entered through the common femoral vein percutaneously or by cutdown on the saphenous vein. The choice of site depends on operator preference and patient habitus and ambulatory status. However, femoral venous catheters have a slightly higher rate of complications than those above the waist. Also, during cardiac arrest, fluid and drugs administered through a femoral or saphenous vein CVC often fail to circulate above the diaphragm because of the increased intrathoracic pressure generated by CPR. In this case, a subclavian or internal jugular approach may be preferred.

Intraosseous (IO) Needle Insertion. The physician's fingers and thumb are wrapped around the proximal tibia to stabilize it; the hand should not be placed directly behind the insertion site (to avoid self-puncture). Instead, a towel may be placed behind the knee to support it. The physician holds the needle firmly in the palm of the other hand, directing the point slightly away from the joint space and growth plate. The needle is inserted with moderate pressure and a rotary motion, stopped as soon as a pop indicates penetration of the cortex. Some needles have a plastic sleeve, which can be adjusted to prevent them from being pushed too deeply into or through the bone.

If possible, the patient's coagulation status and platelet count should be normalized before CVC insertion. Percutaneous femoral lines must be inserted below the inguinal ligament. Otherwise, laceration of the external iliac vein or artery above the inguinal ligament may result in retroperitoneal hemorrhage; external compression of these vessels is nearly impossible. The subclavian vein also is not compressible with external pressure, and thus hemorrhage can be serious. A cutdown decreases the risk of bleeding-associated complications, particularly if coagulopathy is present.

After a subclavian or internal jugular catheter is inserted, a chest x-ray is taken to locate the catheter tip and to exclude a pneumothorax. To prevent cardiac arrhythmias, catheters in the right atrium or ventricle should be withdrawn until the tip is within the superior vena cava.

To reduce the risk of venous thrombosis and catheter sepsis, CVCs should be removed as soon as possible. The skin entry site must be cleansed and inspected daily for local infection; the catheter must be replaced if local or systemic infection occurs. Some clinicians feel it is beneficial to change CVC catheters at regular intervals (eg, q 5 to 7 days) in patients with sepsis who remain febrile; this may reduce the risk of bacterial colonization of the catheter. (See also Guidelines for Prevention of Intravascular Catheter-Related Infections at the CDC website.)

Complications: CVCs can cause many complications (see Table 5: Approach to the Critically Ill Patient: Complications Associated With Central Venous Lines). Pneumothorax occurs in 1% of patients after CVC insertion. Atrial or ventricular arrhythmias frequently occur during catheter insertion but are generally self-limited and subside when the guide wire or catheter is withdrawn from within the heart. The incidence of catheter bacterial colonization without systemic infection may be as high as 35%, whereas that of true sepsis is 2 to 8%. (See also the Infectious Diseases Society of America's Guidelines for the Management of Catheter-Related Infections.) Accidental arterial catheterization may rarely require surgical repair of the artery. Hydrothorax and hydromediastinum may occur when catheters are positioned extravascularly. Catheter damage to the tricuspid valve, bacterial endocarditis, and air and catheter embolism occur rarely.

Table 5
Complications Associated With Central Venous Lines Complication Possible Sequelae Common   Carotid injury Bleeding, respiratory compromise, a neurologic event Puncture of pleura or lung Pneumothorax Puncture of vein Bleeding, extravasation of fluid, hemodynamic compromise Subclavian artery injury Bleeding, vascular compromise of the extremity, hemothorax, hemodynamic compromise Less common   Air embolism Cardiac arrest Arrhythmias Cardiac arrest Brachial plexus injury Compromise of an extremity Erosion of catheter Bleeding, extravasation of fluid, hemodynamic compromise Infection Sepsis Injury to clavicle, rib, or vertebra Osteomyelitis Lymphatic injury Chylothorax Valvular injury Endocarditis

Arterial Catheterization

The use of automated noninvasive BP devices has diminished the use of arterial lines simply for pressure monitoring. However, they are beneficial in unstable patients who require minute-to-minute pressure measurement and in those requiring frequent ABG sampling. Indications include refractory shock and respiratory failure. The BP is frequently somewhat higher when measured by an arterial catheter than by sphygmomanometry. Initial upstroke, maximum systolic pressure, and pulse pressure increase the more distal the point of measurement, while the diastolic and mean arterial pressures decline. Vessel calcification, atherosclerosis, proximal occlusion, and extremity position can all affect the value of arterial catheter measurements.

Procedure: Arterial catheters are inserted using sterile technique and local anesthesia (eg, 1% lidocaine Some Trade Names
XYLOCAINE
Click for Drug Monograph
). They are typically inserted percutaneously into the radial, femoral, axillary, brachial, dorsalis pedis, and (in children) temporal arteries. The radial artery is most frequently used; insertion into the femoral artery has fewer complications but should be avoided after vascular bypass surgery (due to potential injury to the bypass graft) or if distal vascular insufficiency is present (to avoid precipitating ischemia). When percutaneous insertion is unsuccessful, a cutdown may be performed.

Before radial artery catheterization, Allen's test (digital compression of both ulnar and radial arteries causes palmar blanching followed by hyperemia when either artery is released) can determine if there is sufficient ulnar collateral flow to perfuse the hand in the event of radial artery occlusion. If reperfusion does not occur within 8 sec of releasing the compressed ulnar artery, arterial catheterization should not be performed.

Complications: At all sites, bleeding, infection, thrombosis, and distal embolism may occur. Catheters should be removed if signs of local or systemic infection are present.

Radial arterial complications include ischemia of the hand and forearm due to thrombosis or embolism, intimal dissection, or spasm at the site of catheterization. The risk of arterial thrombosis is higher in small arteries (explaining the greater incidence in women) and with increased duration of catheterization. Occluded arteries nearly always recanalize after catheter removal.

Femoral arterial complications include atheroembolism during guide wire insertion. The incidence of thrombosis and distal ischemia is much lower than for radial arterial catheterization.

Axillary arterial complications include hematomas, which are infrequent but may require urgent care because brachial plexus compression can result in permanent peripheral neuropathy. Flushing the axillary arterial catheter may introduce air or a clot. To avoid neurologic sequelae of these emboli, the left axillary artery should be selected for catheterization (the left axillary artery branches further distal to the carotid vessels than does the right).

Intraosseous Infusion

Any fluid or substance routinely administered IV (including blood products) may be given via a sturdy needle inserted in the medullary cavity of select long bones. Fluids reach the central circulation as quickly as with venous infusion. This technique is used almost exclusively in infants and young children, whose bony cortices are thin and easily penetrated and in whom peripheral and central venous access can be quite difficult, particularly in shock or cardiac arrest, but it can be used in older patients.

Subclavian Venipuncture. Hand position during subclavian venipuncture (infraclavicular approach).

Procedure: A special-purpose intraosseous needle with stylet is used. The preferred insertion sites in children are the proximal tibia and distal femur; both areas are given a sterile preparation and included in the operative field. For tibial insertion, the needle is placed on the broad, flat anteromedial surface 1 to 2 cm distal to the tibial tubercle. For the femur, the site is 3 cm above the lateral condyle in the midline. For older children, the medial surface of the distal tibia 2 cm above the medial malleolus may be easier.

For all sites, the needle is inserted with a rotary, coring motion. Stabilizing the needle shaft at the skin surface with a gloved fingertip aids control, allowing advancement to be stopped once the cortex is penetrated. On entering the medullary cavity, the stylet is removed and infusion begun.

Complications: Poor control during insertion may result in the needle exiting the opposite cortex; subsequent infusion will largely enter the soft tissues, so a site on another bone should be tried. Osteomyelitis may occur, but is uncommon (eg, < 2 to 3%). Growth plate damage has not been reported. Other complications include bleeding and compartment syndrome.

Last full review/revision November 2005

Content last modified November 2005