Pediatric Arterial Puncture and Venous Minicutdown

CHAPTER 182 Pediatric Arterial Puncture and Venous Minicutdown



John J. Andazola, Karyn B. Kolman



Arterial Puncture


Arterial blood may be needed for blood gas analysis or for routine laboratory analysis. In the infant or child, the radial artery is the most appropriate and most commonly selected site for arterial puncture. The posterior tibial and dorsalis pedis arteries are optional sites, but each has its own risk of complications. Because of the risk of thrombosis, use of the femoral artery for arterial puncture in the infant or child should be reserved for emergencies. Likewise, because of the risk of median nerve damage and the fact that the brachial artery has minimal collateral circulation, the brachial artery should be reserved as a last resort in emergencies. The temporal artery should probably not be used because of the high risk of neurologic complications.


The radial artery is located just medial to the styloid process of the radius. It is palpable between the radius and the tendon of the flexor carpi radialis (see Chapter 208, Arterial Puncture and Percutaneous Arterial Line Placement).



Indications



• To obtain arterial blood from the pediatric patient in respiratory distress or for other studies that require arterial blood

• To guide the management of the pediatric patient receiving ventilatory support or undergoing intensive respiratory therapy (e.g., to confirm hypoxia or hypercapnia when pulse oxymetry [SaO2] or end-tidal CO2 [ETCO2] monitoring, respectively, indicates it)

• To obtain blood for routine laboratory analysis when venous blood cannot be obtained

NOTE: The last indication is controversial. The benefit must outweigh the higher risk of obtaining an arterial sample.



Contraindications


Infection, burns, local skin damage, trauma, or severely disturbed anatomy at the site of the intended puncture are all contraindications. They are considered relative contraindications in a life-threatening situation.



Equipment and Supplies



• Commercially available heparinized arterial blood gas (ABG) syringe or 1-mL (tuberculin syringe) to 3-mL syringe (to be flushed with heparin)

• Rubber stopper or syringe plug to seal blood sample

• 23- to 27-gauge butterfly scalp vein needle or standard 23- to 27-gauge needle (the smaller the needle, the lower the risk of complications)

• Antiseptic skin preparation, such as povidone–iodine or chlorhexidine, and 70% isopropyl alcohol

• Container of crushed ice for sample transport

• Sterile 4 × 4 gauze pads

• Sterile gloves

• Goggles or eye protection

• Bright light source (e.g., bright penlight, otoscope) for transillumination (optional)

• 1 or 2 mL heparin, 1000 U/mL (optional, for use in nonheparinized syringe)

• In the alert patient (optional), 1% or 2% lidocaine without epinephrine and a 1- or 3-mL syringe with 25- or 27-gauge, image-inch (1.6-cm) needle

• Arm or leg board (optional)


Precautions


The modified Allen test is performed to ensure patency of the ulnar artery before an arterial puncture or the placement of an indwelling arterial catheter. Verifying adequate collateral circulation may reduce the risk of ischemic complications if thrombosis of the radial artery occurs. (See Chapter 208, Arterial Puncture and Percutaneous Arterial Line Placement, for a description of the modified Allen test as well as other techniques available to test for collateral circulation.)



Technique



1 Always perform a modified Allen test (or equivalent) to confirm adequate collateral circulation.

2 Attach a butterfly needle (preferred for infants and neonates) or a standard 23- to 27-gauge needle to a heparinized ABG syringe. Alternatively, draw a small amount of heparin into the syringe and eject the heparin. The heparin remaining in the syringe will prevent the sample from clotting as well as decrease the dead space in the syringe. Heparin has a very low pH, so avoid using excessive heparin, which could result in falsely abnormal ABG results. If the sample will be used for another laboratory test, do not use heparin.

3 Immobilize the upper extremity by taping it to an arm board or by having an assistant manually stabilize it.

4 Grasp the wrist with the nondominant hand and identify the radial artery by dorsiflexing and slightly externally rotating the wrist and palpating over the distal volar (palmar) radius. Using a bright light source for transillumination may help locate the artery, especially in newborns. Cleanse the site of intended puncture with an antiseptic solution, which can be wiped off with alcohol swab. If the patient is alert, the area can also be infiltrated with 1% to 2% lidocaine without epinephrine.

5 Universal blood and body fluid precautions should be followed. Insert the needle with the bevel up, at the point of maximum pulsation, at a 30- to 45-degree angle (Fig. 182-1) to the distal skin. Usually little aspiration is needed to fill the syringe when the artery is pierced. If the syringe does not flash blood immediately, continuous gentle suction can be applied with the plunger of the syringe as the needle is removed or on the next attempt. Be aware that arterial blood may not flash into the syringe as vigorously in a child as in the adult patient. If using the butterfly needle, have an assistant maintain gentle suction while the needle is advanced.

6 If resistance is encountered, most likely the needle has made contact with underlying bone (radius). At this point, withdraw the needle very slowly while maintaining gentle suction on the plunger until there is blood return. If there is no blood return and the tip of the needle has been withdrawn to a point just beneath the skin, readvance the needle toward the point of maximal pulsation before withdrawing it from the skin. Although the risk of complications increases with the number of attempts, several attempts can be made in this manner causing minimal trauma to the infant before choosing another site.

7 When arterial blood is encountered, withdraw 0.3 to 0.5 mL into the syringe before removing the needle. Leave the butterfly needle in place (with its extension tubing) if more blood is needed for other analyses. This will facilitate changing the syringe. For blood gas analysis, remove any bubbles from the syringe and then seal it. Place it on ice and immediately transport to the laboratory.
image

Figure 182-1 Pediatric arterial puncture. A, Anatomic location of the radial artery with immobilization of the wrist in hyperextension. B, The artery is entered with the bevel up and the needle at 30 to 45 degrees from horizontal.


NOTE: The total blood volume in a neonate is usually about 80 mL/kg, and the volume of blood withdrawn should not exceed 3% to 5% of this total blood volume. As an example, 8 mL is 5% of the total blood volume in a 2-kg infant.


8 After removing the needle, always maintain manual compression at the arterial puncture site for a minimum of 5 minutes to prevent the formation of a hematoma. Apply firm, but not occlusive pressure.

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May 14, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Pediatric Arterial Puncture and Venous Minicutdown

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