Indications and Contraindications

Capillary blood sampling is frequently used to obtain blood samples from young infants. In infants, the heel is the most common location for capillary blood sampling, whereas in older children and adults, blood samples are more commonly obtained from the finger, toe, or earlobe. This technique is useful when repeated measurements such as blood glucose or serial hemoglobin are needed. It is also an option for obtaining “arterialized” blood for blood gas analysis when arterial access is unavailable, such as in chronically ill neonates and young infants or when the clinician is not comfortable obtaining a percutaneous arterial blood sample. If a sufficient volume is obtained, blood from a capillary sample can also be sent for other routine laboratory studies. Do not send this type of specimen for blood culture because of the risk for contamination. Heel sticks are more painful than venipuncture but are useful in the event of difficult access or when arterialized samples are needed.⁴

Avoid sampling from an area of local inflammation or hematoma. Avoid repetitive sampling from the same site because it may induce inflammation and subsequent scarring. In general, heel stick sampling is not ideal for blood gas analysis when the infant is hypotensive, the heel is markedly bruised, or there is evidence of peripheral vasoconstriction.

Equipment and Setup (Box 19-1)

Use a 3-mm lancet (Becton-Dickinson, Rutherford, NJ) or an automated disposable incision device (e.g., Tenderfoot, Surgicutt) to perform this procedure. Perform blood collection with either heparinized capillary tubes or 1-mL Microtainer tubes with a collector attachment (Becton-Dickinson, Rutherford, NJ).

Technique

The heel stick method of capillary blood sampling will be described, but capillary blood samples can also be obtained from a finger, toe, or earlobe (Fig. 19-1). To avoid penetration of the calcaneus and the risk for osteochondritis, puncture only the most medial and lateral portions of the plantar surface of the heel.⁵ Some research suggests that when using automated lancets, any site on the heel can be safely punctured in a term neonate.⁶ Prewarm the foot for 5 minutes to produce hyperemia and enhance blood flow. Immobilize the foot in a dependent position with one hand. First cleanse the heel with antiseptic solution and allow it to dry. Next, puncture the skin with the lancet. Allow the alcohol to dry to avoid false elevations in the glucose level. Avoid squeezing the foot because it may inhibit capillary filling and actually decrease the flow of blood. Furthermore, squeezing may lead to hemolysis and make analysis less accurate. If blood does not flow freely, another puncture may be required.

Wipe away the first small drop of blood with gauze and allow a second drop to form. Place a heparinized capillary tube in the drop of blood and invert the proximal end of the tube to allow it to fill by capillary action. Fill the capillary tube until blood reaches the demarcation line on the tube. Overfilling or underfilling may result in clotting or erroneous test results. If 1-mL Microtainer tubes are used, hold the tube at an angle of 30 to 45 degrees from the surface of the puncture site. Touch the collector end of the tube to the drop of blood and allow the blood to drain into the tube. Gently tap the tube to facilitate flow to the bottom. Once filled, seal the tube with the accompanying cap. After an adequate specimen is obtained, apply a dry dressing to the puncture site.

When a heel stick is performed for an arterialized blood sample, use a technique that is similar to that discussed previously for routine blood sampling, with the following differences. Wrap the infant’s foot in a warm towel for a few minutes and discard the first drop of blood while allowing the remaining blood to flow freely into a heparinized capillary tube. Place the tip of the tube as near the puncture site as possible to minimize exposure of the blood to environmental oxygen. Fill the tube as completely as possible. Avoid collecting air in the tube and excessive squeezing of the foot because this may artificially lower Po₂. When the tube is full, occlude the free end with the gloved finger to prevent the entry of air, and cap both ends.

Complications

When performed properly, heel sticks are associated with a low incidence of complications. Use a proper incision device to prevent lacerations. Rare complications include infection, scarring, and calcified nodules.⁷

Interpretation

Multiple studies have demonstrated a good correlation between arterial and capillary specimens for determining pH and Pco₂ in hemodynamically stable patients.8,9 However, determination of Po₂ is not reliable when performed on blood obtained by capillary sampling.

Indications and Contraindications

Although many laboratory tests for small infants may be performed on blood obtained by heel stick, larger volumes of blood may be required, which makes heel sticks impractical. Use venipuncture to obtain larger quantities of blood from infants and children and to obtain blood for culture. When collecting blood for culture, prepare the area of venipuncture with an appropriate antiseptic solution and allow the skin to dry. The blood culture collection bottle will probably indicate a desired volume of sample for optimal results, but 1 mL of blood is generally acceptable for a small infant. Wash off the cleanser promptly after blood has been collected because iodine solutions and other detergents can irritate infant skin.

Equipment and Setup (Box 19-2)

A small-gauge butterfly needle and syringe are usually preferred over a needle and syringe for obtaining blood from infants and young children. It is easier to control the position and to suction with a butterfly needle and syringe. If other access is not available, the butterfly needle may also serve as an infusion line after an adequate amount of blood is obtained. A 23-gauge butterfly needle will generally suffice for venipuncture, regardless of the age group. In older children and adolescents, a straight needle and syringe or the Vacutainer system (Becton-Dickinson, Rutherford, NJ) can be used more easily than in infants. However, the negative pressure within the evacuated blood tube may be sufficient to collapse the punctured vein. Use a 3- or 5-mL syringe because it is less likely than a 10-mL syringe to cause vein collapse in small children.

Technique

As in adults, the usual site for venipuncture in infants and children is the antecubital fossa. However, any reasonably accessible or easily visible peripheral vein may be used, such as those on the hands, feet, or scalp for very small infants (Fig. 19-2). Veins on the dorsum of the hand can be used, provided that they will not be needed for IV cannulation. The external jugular and femoral veins or arterial sites are rarely needed for routine samples in a stable patient. Imaging devices (e.g., ultrasound, transillumination, or infrared devices) may also be used to locate and identify veins for IV catheter placement. These devices are discussed later in this chapter (see “Vascular Line Placement: Venous and Arterial”).

Assemble all necessary equipment and make sure that everything is ready for immediate use. Ask an assistant to help immobilize the patient when drawing blood from infants and small children. Assemble the equipment, especially needles, out of sight of the child. If an extremity vein is to be used, apply a tourniquet proximal to the selected vein. In small infants, a rubber band can be used as a tourniquet. Be sure that the tourniquet is not so tight that it impedes arterial filling. It is absolutely essential that the tourniquet be removed after the procedure.

Cleanse the area surrounding the chosen site of skin penetration with antiseptic solution and allow it to dry. Apply slight distal traction to the skin to immobilize the vein. Insert the needle quickly through the skin and advance it slowly into the vein at an angle of approximately 30 degrees with the bevel facing up (Fig. 19-3, step 1). Successful vessel penetration is heralded by a flashback, or flow, of blood into the butterfly tubing. Apply gentle suction by slowly withdrawing the plunger of the syringe. If the required amount of blood is greater than the capacity of the attached syringe, pinch off the tubing, remove the filled syringe, attach a new syringe, and apply gentle suction again after releasing the pinched tubing. After the required amount of blood is withdrawn, remove the needle and apply a sterile dressing and direct pressure to the puncture site.

Apply suction with a Vacutainer system in which the needle punctures the sealed end of the butterfly device (see Fig. 19-3, step 2). There are also butterfly systems available with a second needle that is occluded by a rubber shield located at the opposite end of the butterfly tubing. Once the vein has been entered, the needle at the opposite end of the butterfly tubing is pushed through the top of the vacuum-sealed tube. In either case, if the suction is excessive, the vein will collapse and blood flow will stop.

Although peripheral sites for venous blood sampling are preferable in infants, the external jugular and femoral veins may also be used for venipuncture during resuscitation or when peripheral sites are inadequate. The external jugular vein lies in a line from the angle of the jaw to the middle of the clavicle and is usually visible on the surface of the skin (Fig. 19-4). When the infant is crying, this vein is more prominent. Ask an assistant to restrain the infant in a supine position with the head and neck extended over the edge of the bed. Alternatively, place a towel roll or pillow under the child’s shoulders. Turn the head approximately 40 to 70 degrees from the midline. Cleanse the skin surrounding the area to be punctured with alcohol or another antiseptic solution. Apply finger pressure just above the clavicle to help distend the jugular vein. Use a 21- to 25-gauge straight needle or a 21- to 25-gauge butterfly needle attached to a syringe. Puncture the skin and then advance the needle slowly until the jugular vein is entered and a flashback of blood is observed. Keep the syringe connected to the needle at all times to maintain constant negative pressure and avoid air embolism. After the appropriate amount of blood is obtained, withdraw the needle and apply slight pressure to the vessel. Place the infant in an upright position after the needle is removed, and hold pressure over the puncture site for 3 to 5 minutes. Observe the puncture site closely afterward to identify persistent bleeding.

In most patients, the femoral vein lies medial to the femoral artery and inferior to the inguinal ligament (Fig. 19-5A). Ask an assistant to position the patient’s hips in mild abduction and extension while you palpate the artery. Identify its location by placing a mark on the skin just superior to the femoral triangle. If available, use ultrasound to assess the position of the femoral vessels. Prepare the femoral triangle with alcohol or another antiseptic agent. Use a povidone-iodine or chlorhexidine scrub when obtaining blood for culture. Use a technique of needle insertion that is similar to that for external jugular venipuncture (see Fig. 19-4). Puncture the skin and then direct the needle or catheter toward the umbilicus at a 30- to 45-degree angle to the skin and just medial to the pulsation of the femoral artery (see Fig. 19-5B). Apply slight negative pressure constantly throughout insertion. After the needle enters the femoral vein, withdraw the desired blood samples. Afterward, remove the needle or catheter unless an IV catheter for venous access is desired in this location. Apply pressure over the puncture site in the femoral triangle for a minimum of 5 minutes. Observe closely for recurrent bleeding.

Scalp veins can be very useful for venous sampling in small infants when other options are not possible or readily available.¹⁰ The anatomic considerations and technique are discussed later (see “Peripheral Venous Catheterization: Percutaneous” and “Peripheral Venous Catheterization: Venous Cutdown”).

Complications

Complications of venipuncture include hematoma formation, local infection, injury to adjacent structures (e.g., vessels), and phlebitis. These complications are all uncommon. Use special care when attempting to puncture the external jugular or femoral vein. Inadvertent deep puncture in the neck can injure the carotid artery, the vagus nerve, the phrenic nerve, or the apex of the lung. The femoral artery or nerve can be injured during puncture of the area around the femoral triangle. Fortunately, these injuries are unlikely when proper technique is used.

Indications and Contraindications

Arterial blood gas analysis provides useful and important information for evaluating the respiratory status and acid-base equilibrium in infants or children with respiratory distress or metabolic derangements. Use arterial blood for routine laboratory analysis or blood culture if venous blood is difficult to obtain. Potential sites for arterial blood sampling include the radial, brachial, dorsalis pedis, posterior tibial, and, in newborn infants, the umbilical arteries.

The radial artery has several advantages that make it the most commonly used artery for blood sampling. First, its location makes it easy to palpate and puncture (Fig. 19-6A). The ulnar artery is more difficult to locate. Second, no vein or nerve is immediately adjacent to the radial artery, which minimizes the risk of obtaining venous blood or damaging a nerve. Another advantage of the radial artery is the presence of good collateral circulation from the ulnar artery. The brachial artery has little collateral circulation and should be avoided unless no other options are available.¹¹ Limit use of the ulnar artery to preserve collateral circulation to the hand. As a general rule, do not use the femoral artery for obtaining routine blood samples.

Avoid puncture of an artery if the overlying skin is infected, burned, or otherwise damaged. Also, consider the presence of adequate collateral circulation and any potential coagulation disorders.

Equipment and Setup (Box 19-3)

For arterial puncture in infants and children, a small-gauge butterfly needle is preferable to a needle and syringe. As for venipuncture, a 23-gauge butterfly needle is used most often, although a 25-gauge butterfly needle may be better in newborns. Some clinicians prefer to use a 25-gauge needle connected to a syringe, but a butterfly allows better control of the needle while an assistant aspirates the syringe. This technique may also permit a larger volume of blood to be withdrawn.

Technique

The radial artery is the one most frequently used vessels to obtain intermittent arterial samples, so the technique for arterial puncture at this site will be described. (See also Chapter 20 for a discussion of the Allen test and the effect of heparin on arterial blood sampling.)

Hold the infant’s wrist and hand in your nondominant hand (see Fig. 19-6B). Hold the hand fully supinated with the wrist slightly extended (i.e., dorsiflexed). Palpate the arterial pulsation just proximal to the transverse wrist creases. Do not overextend the wrist because this can cause loss of the arterial pulse during palpation. Make a small indentation in the skin with a fingernail to mark the insertion site. Cleanse the area with antiseptic and allow the skin to dry. The topical anesthetic options discussed previously may be used if the clinical situation permits. Penetrate the skin at a 30- to 45-degree angle. While the plunger of the syringe is gently withdrawn by an assistant, advance the needle slowly until the radial artery is punctured or resistance (bone) is met (Fig. 19-7). In contrast to performing the procedure in adults, provide continuous, but gentle suction with the plunger of the syringe in infants. Pulsating or rapidly flowing blood that appears in the hub of the needle is a good indication that the radial artery has been punctured. Some clinicians prefer to attach the syringe to the butterfly needle only after blood return is noted. Suction can be applied afterward.

If resistance is met while pushing the needle deeper, withdraw the needle slowly since both walls of the artery may have been punctured but the tip may reenter the lumen on withdrawal. If no blood returns, withdraw the needle slowly to the point at which only the distal tip of the needle remains beneath the skin. Repeat the procedure after checking the location of the pulse. Reorient the needle slightly more laterally or medially if necessary. After the desired amount of blood is obtained, remove the needle and apply pressure for 5 minutes or longer to control the bleeding.

Complications

Complications of radial artery puncture include infection, hematoma formation, arterial spasm, tendon injury, and nerve damage.12,13 With proper technique, however, the complication rate is extremely low. If the infant starts to cry before blood is obtained, the Po₂ and Pco₂ values may not reflect the infant’s true steady state.

Indications and Contraindications

In general, peripheral IV lines are indicated when the patient is unable to attain medical and nutritional goals with enteral therapy. These lines provide fluids for resuscitation and maintenance and access for the administration of medications.

Equipment and Setup (Box 19-4)

Over-the-needle catheters such as the Angiocath, Medicut, or Quikcath are the mainstay of peripheral venous catheterization. These thin-walled, flexible catheters range in size from 14 to 24 gauge. Select the appropriate gauge and length of the catheter based on the size of the child and the clinical situation. Larger-diameter catheters allow more rapid administration of fluids in emergency situations, but large catheters may decrease the success of cannulation in young children with small veins. In general, use the smallest-gauge catheter that is appropriate for the clinical situation. For infants, a 22- to 24-gauge catheter is generally appropriate.

Use a T-connector extension tubing connected to the catheter after insertion to facilitate withdrawal of blood for specimen collection. This device makes flushing the catheter and maintaining patency easier (especially while taping and securing the IV line). It also allows dressing changes without disturbing the IV insertion site. In recent years, traditional catheters have been replaced with similar over-the-needle catheters that have a protective cap into which the needle is retracted after cannulation to reduce needlestick injuries.

Use either a homemade or commercially available device to protect the IV site from a child’s attempts to remove the line. An arm or leg board appropriate for the size of the child should be handy to provide stabilization of the extremity after insertion. In newborns or small infants, fashion an arm board from two tongue depressors taped together and covered with a 4- × 4-inch piece of gauze to provide the length needed. Keep an IV fluid chamber with microdrip tubing and a continuous infusion pump nearby, primed, and ready to use. Monitor fluid administration in an infant very carefully. Do not use macrodrip tubing or liter bags because they can result in the inadvertent infusion of large amounts of fluid in an infant. An infusion pump is an ideal way of limiting fluid infusion while keeping the vein open.

Vein Imaging Devices

A variety of imaging modalities, including ultrasound, transillumination, and infrared technologies, have been used to help locate peripheral veins for cannulation. In adults there are data supporting the use of ultrasound to facilitate peripheral vein cannulation in those with difficult access.14,15 However, the use of ultrasound to aid in the placement of peripheral IV lines in pediatric patients is not common practice. One recently published study demonstrated that ultrasound could be used to detect peripheral veins in young children that were not “clinically apparent” (nonvisible and nonpalpable).¹⁶ The study also found that lack of ultrasound visualization increased the chance of unsuccessful placement.¹⁶ Other small studies have shown mixed results, and further research is needed.^17–19

Some emergency departments (EDs) use transillumination devices commonly found in neonatal intensive care units to assist in finding veins in infants.20,21 The Venoscope II (Venoscope LLC, Lafayatte, LA) and the Neonatal Transilluminator (Graykon Scientific, Victoria, Australia) are two such devices that work by projecting a high-intensity light into the patient’s subcutaneous tissue. The light causes the veins to contrast with the surrounding tissue, which makes them easier to locate.²²

A newer vein imaging technology, VeinViewer (Luminetx Corp., Memphis, TN) uses near-infrared technology to project an enhanced image of the subcutaneous veins onto the patient’s skin. Theoretically, knowledge of the location of the venous valves and the course of the vessel can assist the clinician in selecting the best area to be cannulated.²³ Early small studies have not demonstrated improved overall success rates in obtaining IV access, but the technology may be useful in patients with difficult IV access.^24–26

Technique

A number of IV sites are available for placement of a peripheral IV line in an infant (see Fig. 19-2). The most common sites chosen for IV insertion in infants and children are the superficial veins of the dorsum of the hand, the antecubital fossa, the dorsum of the foot, and the scalp (in newborns and small infants). The veins of the dorsum of the hand are the vessels most frequently used. Because these veins are relatively straight and lie flat on the metacarpals, they are easily stabilized. If the hand is chosen, take the child’s age and hand preference into consideration. Avoid placing an IV line in a hand used for thumb sucking whenever possible. Veins in the antecubital fossa (cephalic and basilic veins) are easily accessible; however, the angulation across the fossa makes advancement of the catheter difficult. These veins may not be easily visible and yet may be palpable. Select the most distal vein that is large enough to accommodate the catheter and leave the larger, more proximal veins in case the initial attempts are unsuccessful or if prolonged IV therapy is needed and percutaneous central venous catheter placement (e.g., a peripherally inserted central catheter line) is being contemplated. Tributaries of the dorsal venous arch on the dorsum of the foot, like those on the dorsum of the hand, are relatively straight, and the extremity is easily immobilized after insertion. Because indwelling catheters in this location prevent mobility, consider using this site only in preambulatory patients or after attempts at other sites have been unsuccessful. The scalp veins are easy to cannulate, but their use is primarily limited to very small infants. If a peripheral vein on the hands, feet, or antecubital fossa is being used, immobilize the extremity first by taping it to an arm board, a padded splint, or a commercially available immobilization device. The particular site is a matter of preference, so choose the vein that appears to be the easiest to cannulate.

With few exceptions, the same techniques used for IV insertion in adults may be used in infants and children, especially in the veins of the distal ends of the extremities. If the peripheral end of an extremity is used, place a tourniquet proximal to the planned site of entry. Warm the extremity to induce vasodilation in the surface veins, which makes them easier to cannulate. Flush the tubing of the T-extension set before venipuncture with a sterile IV solution, such as normal saline (NS), to prevent air embolism. Direct the IV catheter through the skin at a 10- to 20-degree angle and slowly advance it until blood return is noted (Fig. 19-8, step 1). Next, advance the catheter over the needle and into the vein. Retract the needle and connect the IV line to the hub of the catheter by means of a T-extension set (see Fig. 19-8, step 2). After 1 mL of saline has been flushed through the line, inspect the site for signs of infiltration, such as hematoma or local swelling.

Fix the catheter to the skin with a 0.5-inch piece of tape passed over the catheter hub and skin. Place a second piece of tape adhesive side up and slip it under the catheter hub. Cross it over the catheter hub in a V shape (Fig. 19-8, step 2). After securing the catheter with tape, cover the entire area with a transparent sterile dressing such as Tegaderm (3M, St. Paul, MN) or OP Site (Smith and Nephew Medical, Massillon, OH). Loop back the tubing of the T-extension set, place a piece of tape midway over the tubing, and secure it to the skin. This ensures that the IV tubing will not be accidentally dislodged if is suddenly pulled. Securely tape the hand and forearm to an arm board for immobilization (see Fig. 19-8, step 3). Occasionally, the flow rate of the infusion may depend on the position of the catheter, especially if the catheter spans a joint or the tip abuts a venous valve. Adjust the hand position or catheter with strategically placed sterile gauze or withdraw the catheter slightly to remedy the problem.

Obtain blood specimens just after IV insertion. If the IV line has been flushed, the initial blood draw will be diluted. To prevent dilution, withdraw 5 mL of blood from the catheter before collecting the samples. This 5 mL of “waste” can be either discarded or reinstilled into the patient. Next, remove the syringe. Connect the T-extension tubing to the IV infusion tubing, and set the infusion pump at the desired rate. Send blood for culture only if the skin was cleaned with an appropriate antiseptic before insertion of the IV catheter.

If the scalp veins are used, trim the hair in the surrounding area to expose the vessels. To differentiate between arteries and veins on the scalp, arteries are usually more tortuous than veins.¹⁰ If an artery is entered during placement of the needle and fluid is infused, blanching will occur in the area. If this happens, remove the IV catheter, maintain slight pressure for 5 minutes, and repeat the procedure at another site. A rubber band may be used as a tourniquet around the scalp to produce venous dilation, but it is rarely required. Place a piece of tape on the rubber band before placement on the scalp to facilitate lifting the rubber band away from the scalp.

If a scalp vein butterfly infusion set is used, grasp the wings of the butterfly between the thumb and forefinger and introduce the needle beneath the skin approximately 0.5 cm distal to the anticipated site of vein entrance (Fig. 19-9, step 1). Advance the needle slowly toward the vessel until blood appears in the tubing, which indicates that the vessel has been entered. Next, remove the tourniquet. Flush the needle with 0.5 to 2 mL of IV fluid, such as NS, to ensure that the needle is properly in place within the vein. If infiltration occurs, as noted by a subcutaneous bump, remove the IV line and repeat the process at another site.

After the wings are secured, tape the tubing of the butterfly set in a loop on the scalp so that it is not pulled inadvertently. Place a wisp of cotton under the wings of the butterfly if the flow rate of the infusion is affected by the position of the catheter. Tape a small medication cup over the wings and the needle to protect the IV line (see Fig. 19-9, step 2). Connect the tubing of the butterfly set to the tubing from the IV system. It is generally preferable to use standard over-the-needle IV catheters whenever possible, whether for extremity or scalp IV lines, because they are less likely to infiltrate and will last longer. However, a small butterfly needle that can be inserted temporarily until additional access is possible is sometimes the only option short of IO access.

Complications

Complications of peripheral IV lines and IV fluid therapy include infection, phlebitis, inadvertent arterial puncture, injection of sclerosing agents into the subcutaneous space with resultant necrosis and sloughing of the skin (especially in small infants), air embolism, and administration of inappropriate volumes of fluid. Because the life span of an IV needle or catheter is usually fairly short (<72 hours) in a small infant, the decision concerning elective removal and replacement of the IV system is not usually a problem. Of course, it is important to pay meticulous attention to antiseptic procedures during insertion and maintenance of the IV system to decrease the risk for infection.

Indications and Contraindications

With the development of small IV catheters and the rapidity and safety of IO needle placement for emergency access (Chapter 25), peripheral venous cutdown is rarely performed in the ED. Even in experienced hands a saphenous vein cutdown may take more than 10 minutes and is associated with a higher rate of infection than other routes of vascular access are.²⁸ Nevertheless, if peripheral venous, central venous, or IO access cannot be obtained, venous cutdown may provide an alternative means of emergency venous access. For the purpose of illustration, exposure and cannulation of the saphenous vein will be discussed (Fig. 19-10). The same principles apply when cutdown is performed on most peripheral veins.

Equipment and Setup (Box 19-5)

Successful venous catheterization via cutdown in infants and small children requires sterile instruments, an assistant, good lighting, and a selection of catheters. Silastic catheters, which can be obtained in 2-, 3-, and 4-Fr sizes (Dow Chemical Company, Midland, MI), seem to remain patent longer and can be sterilized with the instruments to make a “cutdown tray.” Standard 18- to 22-gauge IV catheters are also useful.

Technique

Begin with complete immobilization of the thigh, leg, ankle, and foot by taping them to a padded leg board. Attach this board in turn to the table or bed where the procedure is being performed (Fig. 19-10, step 1). Prepare the area around the medial malleolus with antiseptic solution and drape it with sterile towels. Perform local anesthesia (intradermal 1% lidocaine) in an area about 1 cm proximal and 1 cm anterior to the medial malleolus. No major nerves or tendons accompany the vein in this location.

Place a tourniquet proximally on the leg and make a transverse skin incision (usually about 2 cm in length) in the anesthetized area. Insert a small mosquito hemostat into the wound with the concavity of the clamp upward. Advance the tip of the hemostat to the bone in one corner of the wound, and “scoop up” all tissue lying against the bone and in the subcutaneous region with the hemostat (see Fig. 19-10, step 2). This will invariably lift the vein out of the wound along with the surrounding tissue. Use fine forceps or a mosquito hemostat to separate and remove all nonvenous structures so that only the saphenous vein is left tented over the hemostat (see Fig. 19-10, step 3). To avoid injury to the vein during dissection, spread the ends of the hemostat parallel to the direction of the vein, never transversely.

Pass two 4-0 silk sutures under the vein. Pull one distally to stabilize the vein, and pull the other proximal to the site of venipuncture. The distal suture may be tied, but if left untied it can still be used for stabilization of the vein and to occlude blood flow by applying gentle traction. Removing the untied distal suture after cannulation of the vein may allow subsequent recannulation after eventual catheter removal. Use fine scissors or a scalpel blade to make an oblique or V-shaped incision (venotomy) in the anterior wall of the vein between the sutures (see Fig. 19-10, step 4).

Grasp the Silastic catheter (prefilled with saline solution) with forceps and advance it into the vein for a distance of 2 to 3 cm (see Fig. 19-10, steps 5 and 6). This is usually the most difficult and time-consuming portion of the procedure. Use a vein dilator, L-shaped lifter, or forceps to hold the venotomy incision open (see Fig. 19-10, steps 7 and 8). Pull downward on the distal tie to provide countertraction and stabilize the vein during advancement of the catheter. Remove the tourniquet and tie the proximal suture around the vein with the catheter inside while taking care to not occlude the catheter by tying the suture too tightly. If the distal suture was tied, the free ends of the suture can be tied around the catheter to provide additional stability. If the distal suture was not tied, remove it at this point. Tie the proximal suture to secure the catheter, but leave the ends long enough so that the suture can be removed to allow recannulation once the infusion is removed.

Continued infusion of saline through the catheter from an attached syringe will ensure patency. Orient the catheter into either corner of the incision and close the incision with interrupted 4-0 nylon suture. Wrap the skin suture nearest the catheter around it and tie it to hold the catheter in place. Control bleeding with direct pressure. Place antibiotic ointment over the wound, and apply a sterile occlusive dressing. Connect the IV tubing and tape it securely to the foot board to prevent inadvertent removal of the catheter (see Fig. 19-10, step 9).

Change the dressing carefully every day with sterile technique and reapply antibiotic ointment. When cared for properly, catheters can remain in place for as long as 7 to 10 days. Generally, though, it is best to replace the catheter and insert it into another site after 3 to 4 days. At the first sign of infiltration or infection, remove the catheter. Unfortunately, once the vein has been used for cutdown, it is usually rendered useless for future venous cannulation.

Mini-Cutdown

Cannulation of a small vein with a catheter or tube may be difficult and very time-consuming if one is not experienced in the technique. As an alternative, use the mini-cutdown procedure. For this technique, once the vein is exposed through a skin incision and subcutaneous dissection, cannulate it directly with a standard IV catheter (e.g., Medicut, Angiocath, Quikcath) rather than nicking it with a scalpel (Fig. 19-11). Place a silk suture or hemostat under the vein to immobilize it during the puncture, but do not tie off the vein after cannulation. Although the catheter will not be as secure with this modification, the technique is useful when time is critical. Moreover, the vein is not destroyed by this technique. In essence, a mini-cutdown uses the percutaneous technique of cannulation, except that venipuncture is performed through a skin incision under direct visualization (see Chapter 23).

Complications

In addition to the problems with percutaneous catheter placement that were discussed previously, venous cutdown can result in wound infection and phlebitis. Adjacent structures may be injured during the incision and subsequent blunt dissection. When using the mini-cutdown technique without ligatures, extravasation of infusate may result. Light pressure on the closed wound will generally prevent continued extravasation.

Indications and Contraindications

Central venous cannulation is indicated in the ED when peripheral venous access is limited or impossible and when precise hemodynamic monitoring is needed in a critically ill or injured child. Contraindications to percutaneous placement of central venous catheters include an uncorrected coagulopathy; local infection or burns at the insertion site; malformations or deformations that may distort the vascular anatomy; vascular insufficiency of an extremity; or obstruction or compression of the access veins by tumor, abnormal vessels, hematoma, thrombus, abscess, or malformation. Peripheral venous or IO access is preferred over central access during cardiac arrest to minimize complications and interruptions in cardiopulmonary resuscitation (CPR), but if a central line is in place, medications should be given centrally rather than peripherally.²⁹

Equipment and Setup (Box 19-6)

Percutaneous central venous catheterization in infants and children can be performed with any number of sterile over-the-needle catheters ranging in size from 22 to 16 gauge (the choice depends on the age of the patient) and equipment similar to that used for percutaneous peripheral venous catheterization. If insertion of a larger indwelling catheter is desired, commercially available kits are convenient because they contain most of the items needed for the procedure (Gesco International, Inc., San Antonio, TX; Arrow International, Inc., Reading, PA; Cook, Inc., Bloomington, IN). The catheters in these kits are typically made of a silicone elastomer, polyvinyl chloride, or polyethylene; some are available with an antimicrobial coating, which may reduce infection rates. Catheter length is variable, and one- to three-lumen catheters are available. Rapid volume replacement, as in the case of severe dehydration or acute blood loss from trauma, is best achieved by inserting a short, large-bore catheter for the initial resuscitation and stabilization.

Other equipment necessary includes antiseptic solution, gauze pads, sterile drapes, gowns, sterile gloves, caps, masks, syringes (3, 5, and 10 mL), sterile transparent skin coverings (e.g., Tegaderm, 3M Company, St. Paul, MN; OP Site, Smith and Nephew Medical, Massillon, OH), Luer-Lok three-way stopcocks, 0.25% to 1.0% lidocaine, flush solution (1 to 2 U heparin/mL NS), and IV tubing with a T-connector extension. Depending on the vein to be accessed, restraint of the extremity, pelvis, or head may require a padded support, an assistant, or both.

Techniques

Percutaneous placement of central venous catheters can be accomplished with either a guidewire (Seldinger) technique or an over-the-needle catheter. Details of the femoral, internal jugular, and subclavian approaches follow. In the last several years, experience in using real-time ultrasound to facilitate placement of central venous lines in adults has prompted a number of organizations to recommend it for widespread use.30,31 The use of ultrasound to guide placement of central venous catheters in children has been studied, but the body of literature remains small.³² Pediatric studies have focused primarily on localization of the internal jugular and have shown mixed results when comparing ultrasound-guided cannulation with a landmark-based technique. One study looked specifically at femoral vein catheterization and found no difference in success rates with the use of ultrasound but a significantly lower complication rate when ultrasound was used.³³

Complications

Infection and thrombosis are the major risks associated with central venous catheters.38,44 Subclavian and internal jugular catheters additionally carry serious risks for pneumothorax and hemothorax. Other complications include arterial puncture, accidental displacement, phlebitis, hemorrhage, hematoma, dysrhythmia, air embolism, vascular obstruction or perforation, right atrial perforation, and localized edema. Perform blood sampling from indwelling central venous lines with caution because the risk for contamination increases each time that the system is opened. Remove catheters as soon as they are no longer needed to minimize the risk for these complications.

Emergency Vascular Access

Vascular access is a key component of any resuscitation to allow the administration of fluid and medications and to obtain blood samples. However, achieving venous access during pediatric resuscitation can challenge even the most seasoned clinician.45,46 In a review of pediatric resuscitations by Rossetti and colleagues, IV access required 10 or more minutes in 24% of cases.⁴⁵ The average time required for a cutdown was 24 minutes. Children who were successfully resuscitated had vascular access achieved significantly sooner than did those who were not resuscitated. Emergency IV access was most prolonged in children younger than 2 years. This last finding is important because the majority of cardiopulmonary arrests in children occur in this younger age group.

For these reasons, clinicians should obtain IO access in critical patients if IV access is not established quickly rather than delay treatment with attempts to place peripheral or central venous catheters (see Chapter 25).²⁹ IO lines are underused in many EDs.⁴⁷ If no IV or IO line is available, give certain drugs via the endotracheal tube (see Chapter 26) while attempts at venous access are initiated. However, endotracheal drug administration has been shown to be less efficacious than IV administration in adults, and this route of administration should be used only when no alternatives are available.^48,49 Central venous access may be desirable in critical patients. In pediatric resuscitation, the femoral vein is generally chosen because its consistent anatomic location and large size make it the safest and easiest central vein to catheterize. The femoral vein can also be accessed with minimal interference with resuscitative efforts. However, central venous access in children takes significantly longer than IO line placement. Generally, placement of a central line in children should occur after initial stabilization through a peripheral IV or an IO line.

Indications and Contraindications

The major indication for umbilical vein catheterization is the need to access the vascular system for emergency resuscitation and stabilization of neonates. It may also be used for exchange transfusions and short-term central venous access in newborns. The umbilical vein may remain patent for up to 2 weeks after birth.⁵⁰ In neonates who require emergency access in the ED, a peripheral vein would be preferable, but attempting to cannulate one of the umbilical vessels could be lifesaving. Moreover, umbilical vein catheterization is technically easier than umbilical artery cannulation.

Equipment and Setup

See Box 19-7 for the supplies and equipment necessary for catheterization. Place the infant beneath a radiant warmer because keeping the infant warm during the procedure is critical. Restrain the extremities. Wear a mask, cap, gown, and sterile gloves. Assess the length of catheter needed before the procedure. Methods to estimate the best length for both umbilical vein and artery lines are discussed below.

Technique

Hold the umbilical stump upright and scrub the cord with a bactericidal solution. Avoid pooling of liquid at the infant’s side because this may be associated with blistering of the skin under a radiant warmer. Drape the umbilical area in sterile fashion with the infant’s head left exposed for observation.

Place a loop of umbilical tape or a purse-string suture at the junction of the skin and the cord to provide hemostasis and to anchor the line after placement (Fig. 19-14, step 1). Cut the cord with a scalpel about 1 cm from the skin (often less in infants who are not newly born), and identify the vessels. The vein is usually located at 12 o’clock and has a thin wall and large lumen. It may continue to bleed after cutting. The two arteries have thicker walls and smaller lumens. Constriction reduces bleeding after the vessels are cut. Occasionally, a persistent urachus may be mistaken for the umbilical vein, but the presence of urine in the urachus may help correctly identify that structure.

Flush the catheter (3.5 Fr [preterm infants] to 5.0 Fr [term infants]) with heparinized saline and attach it to a three-way stopcock. Place the catheter into the lumen of the umbilical vein and advance it gently (see Fig. 19-14, step 2). An umbilical vein line can be placed in a fashion that is intended either for emergency use or for more chronic use. In an emergency case, advance the catheter only 1 to 2 cm beyond the point at which good blood return is obtained. This is usually only 4 to 5 cm in a term-sized infant. If the catheter is pushed farther than this distance, it may enter the ductus venosus and then move into the inferior vena cava, or it may enter a branch of the portal vein within the liver (as evidenced by resistance at 5 to 10 cm). Infusion of medications into a catheter in this location can result in liver necrosis.

The inferior vena cava site may be a desirable location in some newborn infants in whom peripheral vascular access is limited and for whom longer-term central venous access is desired. It is also useful for monitoring central venous pressure or infusion of medications, high concentrations of glucose (>10%), IV fluids, and hyperalimentation solutions. The catheter must be inserted approximately 10 to 12 cm in a term-sized infant to reach the inferior vena cava. Radiographs are required in this case to identify and prevent accidental entry into the portal vein, thereby limiting utility in an emergency situation. Note that an umbilical venous catheter will proceed directly cephalad (without making a downward loop) until it passes through the ductus venosus (Fig. 19-15).

Some practitioners use standardized graphs to estimate the length of insertion. Such graphs are based on the shoulder-to-umbilicus length (Fig. 19-16A) and are useful if stored in the drawers of the warming beds used to resuscitate newborns and small infants, along with the catheters and other equipment. Shoulder-to-umbilicus length is the perpendicular line measured from the tip of the shoulder to the horizontal level of the umbilicus. If the graph is not available, the shoulder-to-umbilicus length multiplied by 0.6 gives an approximate insertion length that will result in the tip of the catheter being above the diaphragm but below the right atrium in the inferior vena cava.⁵⁰ Formulas based on birth weight are also used to estimate catheter length.⁵¹

Air embolism may occur at the time of catheter removal if the infant generates sufficient negative intrathoracic pressure (as during crying) to cause air to be drawn into the patent umbilical vein. Therefore, caution must be used during removal of the catheter to ensure that the vein is promptly occluded (by tightening a purse-string suture or applying pressure on or just cephalad to the umbilicus).

Complications

Complications of umbilical venous catheters include hemorrhage, infection, injection of sclerosing substances into the liver (resulting in hepatic necrosis), air embolism, catheter tip embolism, and vessel perforation.52,53 Follow careful technique during insertion and maintenance of catheters to minimize such complications.

Indications and Contraindications

Umbilical artery catheterization is a useful procedure in the care of newborn infants who require frequent monitoring of arterial blood gases and arterial blood pressure, fluid and medication administration, and exchange transfusions.⁵³ Either one of the two umbilical arteries may be cannulated for resuscitation purposes, but an umbilical vein is generally technically easier to cannulate and may be preferred in an emergency. Complications are discussed later, but one should avoid cannulating the arteries if omphalitis, peritonitis, necrotizing enterocolitis, or intestinal hypoperfusion is present.

Equipment and Setup

The equipment required for umbilical artery catheterization is identical to that used for umbilical venous catheterization (see Box 19-7). Additional equipment needed for continuous arterial pressure monitoring and infusion should be readily available. Estimate the catheter length needed before starting the procedure. Do this by using a standard graph (see Fig. 19-16B) or a birth weight regression formula.

Technique

The technique of umbilical artery catheterization is similar to that described for umbilical vein catheterization in the preceding section. After the umbilical arteries have been located (Fig. 19-17, step 1), grasp the cord with a curved hemostat near the selected artery. Ask an assistant to use two hemostats to grasp each side of the cord and slightly evert the edges to aid in exposure of the arteries. Using curved iris forceps without teeth, gently dilate the artery (see Fig. 19-17, step 2). Sometimes, repeated passes of the forceps are required because the umbilical artery can spasm and make the procedure difficult. Attach a 3.5- to 5-Fr catheter to a three-way stopcock and flush it with a sterile heparinized solution. Introduce the catheter into the dilated artery (see Fig. 19-17, step 3). Use a 3.5- to 4-Fr catheter for infants weighing less than 2 kg and a 5-Fr catheter for those weighing 2 kg or more.

When the catheter is being inserted, place gentle tension on the cord in a cephalad direction, and advance the catheter with slow, constant pressure toward the feet. Resistance is occasionally felt at 1 to 2 cm. Overcome this with gentle, sustained pressure. On the other hand, if the catheter passes 4 to 5 cm and then meets resistance, this generally indicates that a “false passage” through the vessel wall has occurred. Occasionally, one may bypass the perforation by reattempting catheterization with a larger catheter.

Acceptable positions of umbilical arterial catheters are between T6 and T9 (“high line”) and between L3 and L5, just above the aortic bifurcation (“low line”). High lines are associated with a lower incidence of thrombotic complications.⁵⁴ Use graphs and formulas to estimate the proper catheter length for insertion at both the high and low positions (see Fig. 19-16B), but confirm placement with a radiograph. These formulas may not be as accurate in babies at the extremes of weight. Once sterile technique is broken, do not advance the line. It is therefore preferable to position the catheter too high and to withdraw it as necessary according to postinsertion radiographs. This will show the catheter proceeding from the umbilicus down toward the pelvis, making an acute turn into the internal iliac artery, continuing toward the head into the bifurcation of the aorta, and then moving up the aorta slightly to the left of the vertebral column (Fig. 19-18). After it has been properly positioned, tie the catheter with the previously placed suture and tape it to the abdominal wall (see Fig. 19-17, steps 4 and 5).

Most unsuccessful umbilical artery catheterization attempts fail because the catheter perforates the arterial wall approximately 1 cm below the umbilical stump, where the umbilical artery begins curving toward the feet. In this instance, the catheter is advanced in the extraluminal space, and resistance is encountered at 4 to 6 cm.

Complications

Complications of umbilical artery catheterization include hemorrhage, infection, thromboembolic phenomena (especially involving the kidneys, gastrointestinal tract, and lower extremities), aortic thrombosis, aortic aneurysm, vasospasm, air embolism, vessel perforation, peritoneal perforation, and hypertension.⁵³

If the catheter becomes plugged or fails to function properly or if there is blanching or discoloration of the buttocks, the heels, or the toes, remove the catheter at once. Umbilical arteries are most easily cannulated in the first few hours of life but may provide a viable vascular route as late as 5 to 7 days of age.

Indications and Contraindications

Despite the growing use of noninvasive devices for monitoring transcutaneous oxygen and carbon dioxide, percutaneous peripheral arterial catheterization is indicated when there is a need for frequent blood gas sampling, cotinuous monitoring of arterial blood pressure, or both. Arteries used for peripheral catheters in infants and children include the radial, ulnar,⁵⁵ femoral,⁵⁶ dorsalis pedis, and posterior tibial arteries. This procedure is rarely performed in the ED.

Percutaneous radial artery catheterization has become widely accepted and has been shown to be safe in infants and children. The catheter allows preductal blood gas determinations if placed in the right radial artery. Only the procedure for radial artery catheterization is described here, but catheterization of other vessels is similar.

Peripheral arterial catheterization is contraindicated when (1) adequate peripheral arterial samples can be obtained by percutaneous puncture, (2) the circulation of the extremity to be catheterized is compromised, (3) occlusion of the vessel to be catheterized compromises perfusion of the extremity, (4) there is an ongoing bleeding diathesis, (5) localized infection or inflammation overlies the artery to be cannulated, or (6) intensive monitoring of line function is not available.

Equipment and Setup

The equipment needed for arterial catheterization is essentially the same as that required for percutaneous peripheral venous catheterization (see Box 19-4). Some centers use commercially available arterial line kits, which come with all the necessary supplies and equipment. Alternatively, standard 22- or 24-gauge over-the-needle IV catheters, a T-piece connector, and a three-way stopcock will work fine. Connect the T-piece and the stopcock and then fill them with NS solution. Prepare an infusion pump with heparinized saline.⁵⁷

Technique

Perform the procedure with good lighting and an adequate work area and monitor the infant’s heart rate and respiratory rate closely. Palpate the radial artery proximal to the transverse wrist crease on the palmar surface of the wrist, medial to the styloid process of the radius. Before the procedure, compress the artery and observe the hand and fingers for change in color. If blanching or cyanosis is noted (indicating poor collateral circulation), do not perform catheterization. If locating the artery by palpation is difficult, a transillumination device,⁵⁸ Doppler probe, or ultrasound may be helpful.^59–61

Secure the infant’s or child’s hand and lower part of the forearm to an arm board with the wrist dorsiflexed 45 to 60 degrees by placing a roll of gauze underneath it. Take care to leave the fingers exposed to allow assessment of the peripheral circulation. Palpate the radial artery at the point of maximal impulse and mark it by making a gentle indentation with a gloved fingernail. Prepare the area over the radial artery with povidone-iodine or another antiseptic solution and wash it with alcohol. Use a topical or local anesthetic (such as 1% lidocaine without epinephrine), or both, at the planned insertion site. Insert the catheter with the needle through the skin just proximal to the transverse wrist crease at a 10- to 20-degree angle (Fig. 19-19A). Advance the catheter with the needle slowly until blood appears in the catheter hub, which signifies puncture of the anterior arterial wall. Slowly advance the catheter until blood appears in the needle and then carefully lower the angle of the needle to approximately 10 degrees. Slowly advance the catheter over the needle and into the lumen of the artery. Remove the needle. Attach the stopcock and T-piece connector to the catheter hub. Open the stopcock to the syringe to confirm return of pulsatile blood. Flush it with 0.5 mL of heparinized solution very gently to clear the catheter while observing the fingers and the hand for evidence of blanching or cyanosis.

Fix the catheter to the skin with a thin piece of tape placed adhesive side up under the catheter hub and cross it over the catheter in a V shape. Pass a second piece of tape around and over the catheter hub to fix it to the wrist (Fig. 19-19B). Add a transparent sterile dressing such as Tegaderm (3M, St. Paul, MN) or OP Site (Smith and Nephew Medical, Massillon, OH) for an additional layer of security and protection. Use a small piece of tape to attach the T-piece connector to the wrist area or to the splint. Be sure that the fingers are easily visible.

Use only heparinized NS or half-normal saline for infusion. Do not infuse medications, blood, blood products, amino acid solutions, IV fat solutions, or hypertonic solutions through the catheter. Remove the catheter if there is evidence of blanching or cyanosis, if it is impossible to withdraw blood from the catheter, or if it becomes difficult to flush the catheter.

Complications

Complications, which have been reported with every type of arterial catheter, include hemorrhage, thrombosis, spasm, infection, scars, air embolism, retrograde blood flow, transient elevation in blood pressure with rapid (<1 second) infusion, and nerve damage. Thrombosis or spasm may result in blanching or cyanosis of the extremity or skin.⁵³ There is the potential for loss of digits, an entire extremity, or large areas of skin. However, complications from ED-placed arterial lines are uncommon and generally minor.¹²

Indications and Contraindications

Arterial catheterization by cutdown of the posterior tibial artery or radial artery may be indicated when frequent monitoring of arterial blood gases or blood pressure is needed and percutaneous access is not possible. Contraindications to arterial cutdown are similar to those cited for percutaneous arterial catheterization. Because of their experience with a wide variety of percutaneous vascular access techniques, emergency clinicians may find that percutaneous arterial catheterization is easier and likely to be more successful than performing an arterial cutdown.⁶²

Equipment and Setup (Box 19-8)

Successful arterial cutdown catheterization in a small infant requires sterile instruments, an assistant, good lighting, and a selection of catheters. The equipment required can be found on a cutdown tray, which is available in most EDs. Also needed are a 22- or 24-gauge over-the-needle catheter, T-extension connector tubing, a stopcock, a 5- or 10-mL syringe filled with flush solution (NS with 1 to 5 U heparin/mL), and silk suture ties. The operator prepares for the procedure by scrubbing and donning a mask, cap, gown, and sterile gloves.

Technique

The anatomy (Fig. 19-20) and technique for posterior tibial arterial cutdown are described in detail (Fig. 19-21). The same technique is applicable for the radial artery. Stabilize the foot in a neutral position by taping the externally rotated lower part of the leg to a splint. Localize the posterior tibial artery with Doppler ultrasound just posterior to the medial malleolus. Prepare the skin of the foot with a povidone-iodine or other antiseptic solution.

After subcutaneous injection of 1% lidocaine, make a 5- to 7-mm transverse incision in the skin over the artery posterior to and at the midlevel of the medial malleolus (see Fig. 19-21, step 1). Using blunt dissection in a vertical direction (parallel to the vessels), separate the tissue with a pair of small, curved forceps. Identify the artery, which courses with the vein just anterior and superficial to the nerve and is usually pulsatile. Isolate the artery by sliding small, curved forceps beneath it and gently elevating the vessel (see Fig. 19-21, step 2). Excessive manipulation of the artery can cause spasm; if this occurs, apply a few drops of 1% lidocaine locally to induce dilation. Place a silk tie (without a needle) beneath the artery to stabilize it during cannulation (see Fig. 19-21, step 3).

At a 10-degree angle, insert a 22- or 24-gauge over-the-needle catheter (bevel downward) into the artery over the surface of the forceps. When blood return is seen, advance the catheter over the stylet to its full length (see Fig. 19-21, steps 4 and 5). Remove the needle stylet and connect the catheter to the T-connector tubing and a three-way stopcock that has been prefilled with heparinized flush solution. Check for patency by observing blood return with pulsations. Flush the catheter slowly and gently. Remove the silk suture and secure the skin incision with sutures. Suture the catheter to the skin over the heel. Secure the catheter and connector to the heel with tape (see Fig. 19-21, step 6). Connect the stopcock to the infusion line.

Complications

The complications of arterial cutdown are similar to those with percutaneous arterial catheterization and include hemorrhage, thrombosis, or spasm resulting in loss of tissue; infections; permanent scars; and nerve damage. These complications have been reported with all types of arterial cutdowns.