Atlas of Procedures in Neonatology, 4th Edition

Blood Sampling


Arterial Puncture

Dawn M. Walton

Billie Lou Short

  1. Indications (1, 2)
  2. Sampling for arterial blood gas determination
  3. Sampling for routine laboratory test when venous and capillary sampling not suitable or unobtainable
  4. Contraindications
  5. Coagulation defects, thrombocytopenia
  6. Circulatory compromise in the extremity
  7. Inappropriate artery
  8. Femoral artery
  9. Use of radial artery if inadequate collaterals (see Allen's test below)
  10. Infection in sampling area
  11. When cannulation of that vessel is anticipated
  12. Use of peripheral arteries on the ipsilateral arm in an infant with congenital heart disease requiring a shunt via the subclavian artery
  13. Precautions
  14. Perform arterial sampling only when venous or capillary sampling is inappropriate.
  15. Arterial blood gas analyses prior to placement of indwelling access.
  16. Ammonia levels
  17. Large quantities of blood to be obtained
  18. Very low-birthweight infants with poor venous access
  19. Use smallest possible needle to minimize trauma to vessel (23 to 27 gauge).
  20. Avoid laceration of the artery caused by puncturing both sides of arterial wall in exactly opposite locations.
  21. Guarantee hemostasis at end of procedure.
  22. Check distal circulation after puncture.
  23. Arterial pulse
  24. Capillary refill time
  25. Color, temperature
  26. Take action to reverse arteriospasm, if necessary (see Chapter 33).
  27. Selection of Arterial Site
  28. Peripheral site preferred
  29. Radial artery preferred if ulnar collateral intact
  30. Dorsalis pedis, posterior tibial arteries satisfactory
  31. Brachial artery onlyif urgent indication and no more peripheral arterial or umbilical artery access is available(3)
  32. Temporal artery should be avoided because of risk of neurologic damage (4, 5).
  33. Equipment
  34. Gloves
  35. Needle
  36. A 23- to 25-gauge venipuncture needle
  37. Safety-engineered needle should be used
  38. Appropriate syringes
  39. Materials for minor skin preparation; povidone–iodine solution preparation preferred for blood culture
  40. Gauze pads
  41. Sterile glove to cover transilluminator
  42. High-intensity fiber-optic light for transillumination (see Chapter 12)
  43. Oral sucrose solution (24% to 25%) for pain control, if indicated (6, 7)
  44. Technique

General Principles (12)

  1. Transillumination may assist location of vessel (Fig. 12.1) (8).
  2. Position needle for arterial puncture against direction of blood flow.
  3. Keep angle of entry shallow for superficial vessels.
  4. 15 to 25 degrees for superficial artery, bevel down
  5. 5 degrees for deep artery, bevel up
  6. Penetrate skin first, and then puncture artery to minimize trauma to vessel.


  1. Use fresh needle and repeat skin preparation if withdrawal from skin is necessary.
  2. Apply firm, local pressure for 5 minutes to achieve complete hemostasis.

FIG. 14.1. Position of wrist for puncture of radial artery. (1) distal wrist crease; (2) proximal wrist crease.

Radial Artery Puncture (2)

  1. Extend wrist, supine, not hyperextended (Fig. 14.1), which may occlude vessel.
  2. Locate radial and ulnar arteries at proximal wrist crease (Fig. 14.2).
  3. Radial artery is lateral to flexor carpi radialis tendon.
  4. Ulnar artery is medial to flexor carpi ulnarius tendon.
  5. Transillumination may be helpful.
  6. Perform modified Allen's test for collateral supply (9).
  7. Elevate infant's hand.
  8. Occlude both radial and ulnar arteries at wrist.
  9. Massage palm toward wrist.
  10. Release occlusion of ulnar artery only.
  11. Look for color to return to hand in less than 10 seconds, indicating adequate collateral supply.
  12. Do not puncture radial artery if color return takes more than 15 seconds.

FIG. 14.2. Anatomy of the major arteries of the wrist and hand.

  1. P.91

FIG. 14.3. A: Penetration of artery at angle of 15 to 25 degrees with bevel down. Preferred method for small premature infants. B:Penetration of artery at angle of 45 degrees with bevel up.

  1. Locate artery by palpation and/or transillumination.
  2. Prepare area with antiseptic, as for minor procedure.
  3. Check function of syringe.
  4. Puncture skin and penetrate artery at 45 degrees with bevel up. For very small infants, use angle of 15 to 25 degrees with bevel down (Fig. 14.3).
  5. While maintaining gentle suction, advance until there is blood return or resistance from bone.
  6. If no blood obtained prior to encountering resistance, withdraw needle cautiously until blood returns. Artery may spasm when needle is introduced. Be patient; change angle of needle as necessary.
  7. Collect sample and remove needle.
  8. Compress site for 5 minutes or until hemostasis is complete.
  9. Verify satisfactory peripheral blood flow (10, 11).

Dorsalis Pedis Puncture

  1. Locate artery by palpation and transillumination on dorsum of foot between extensor hallucis longus and extensor digitorum longus tendons (Fig. 14.4).
  2. Choose an angle of 15 to 25 degrees.
  3. See F, “General Principles.”

Posterior Tibial Puncture

  1. Locate artery by palpation and transillumination between Achilles tendon and medial malleolus (Fig. 14.5).
  2. Choose an angle of 45 degrees.
  3. See F, “General Principles.”

FIG. 14.4. Anatomic relations of the dorsalis pedis artery.


FIG. 14.5. Anatomic relations of the posterior tibial artery.



  1. Complications (10)

See Chapter 30 for complications of arterial cannulation.

  1. Distal ischemia from arteriospasm, hematoma, thrombosis, or embolism
  2. Infection
  3. Osteomyelitis (12)
  4. Infected hip joint after femoral puncture (12)
  5. Hemorrhage or hematoma
  6. Nerve damage (13)
  7. Median nerve (brachial artery puncture)
  8. Posterior tibial nerve
  9. Femoral nerve
  10. Extensor tendon sheath injury, resulting in “false cortical thumb” (14)
  11. Forearm compartment syndrome following brachial artery puncture (15)
  12. Inaccuracy of blood gas estimated (16, 17)
  13. Excessive heparinization of syringe (falsely low PCO2and pH)
  14. Hypothermic or hyperthermic infant
  15. Gas bubbles in syringe
  16. Spuriously high PO2
  17. Spuriously low PCO2
  18. Excessive delay in processing
  19. Clot in syringe


  1. Smith AD.Arterial blood sampling in neonates. Lancet. 1975;1:254.
  2. Shaw JC.Arterial sampling from the radial artery in premature and full-term infants. Lancet. 1968;2:389.
  3. Okeson GC, Wulbrecht PH.The safety of brachial artery puncture for arterial blood sampling. Chest. 1998;114:748.
  4. Bull MJ, Schreiner RL, Garg BP, et al. Neurologic complications following temporal artery catheterization. J Pediatr. 1980;96:1071.
  5. Simmons MA, Levine RL, Lubchenco LO, et al. Warning: serious sequelae of temporal artery catheterization. J Pediatr. 1978;92:284.
  6. Acharya AB, Annamali S, Taub NA, Field D.Oral sucrose analgesia for preterm infant venipuncture. Arch Dis Childhood Fetal Neonatal Ed. 2004;89:F17.
  7. Stevens B, Yamada J, Ohlsson A.Sucrose for analgesia in newborn infants undergoing painful procedures. Cochrane Database Syst Rev. 2004;(3):CD001069.
  8. Wall PM, Kuhns LR.Percutaneous arterial sampling using transillumination. Pediatrics. 1977;59:1032.
  9. Cable DG, Mullany CJ, Schaff HV.The Allen test. Ann Thorac Surg. 1999;67:876.
  10. Gillies ID, Morgan M, Sykes MK, et al. The nature and incidence of complications of peripheral artery puncture. Anaesthesia. 1979;34:506.
  11. Noreng MF.Blood flow in the radial artery before and after arterial puncture. Acta Anaesthesiol Scand. 1986;30:281.
  12. Nelson DL, Hable KA, Matsen JM.Proteus mirabilis osteomyelitis in two neonates following needle puncture. Successful treatment with ampicillin. Am J Dis Child. 1973;125:109.
  13. Pape KE, Armstrong DL, Fitzhardinge PM.Peripheral median nerve damage secondary to brachial arterial blood gas sampling. J Pediatr. 1978;93:852.
  14. Skogland RR, Giles EJ.The false cortical thumb. Am J Dis Child. 1986;140:375.
  15. Safran MR, Bernstein A, Lesavoy MA.Forearm compartment syndrome following brachial arterial puncture in uremia. Ann Plast Surg. 1994;32:535.
  16. Fan LL, Dellinger KT, Mills AL.Potential errors in neonatal blood gas measurements. J Pediatr. 1980;97:650.
  17. Goldsmith JP.Error in blood gas sampling results in spurious interpretation of compensated metabolic acidosis. J Perinatol. 1993;13:165.