Scalp Vein Catheterization 

Vascular access is an important, sometimes critical, step in the care of sick infants and children. Peripheral vascular catheterization provides a direct route for administration of fluids and medications. Many anatomical sites are available for intravenous catheterization, with peripheral sites being the most common and most readily available. For more information, see eMedicine article Catheterization, Axillary Vein.

Placing an intravenous line into a peripheral vein in a small child or infant can be a difficult task for many reasons. Small children and infants have smaller peripheral veins, they may have more subcutaneous fat, they are prone to vasoconstriction, and they are much less likely to remain motionless and cooperative during a painful procedure than adults. The scalp veins provide a secondary option for peripheral intravascular access in small children and infants because of minimal subcutaneous fat and less movement and the lack of a flexible joint; this reduces the likelihood of dislodging the catheter, which is common with intravenous catheters placed in the arms or legs.

• Scalp vein catheterization is indicated in any patient who requires intravascular access for the administration of fluids or medications.
• The decision to attempt access via one of the scalp veins should be based on inspection/palpation of various sites. Although the scalp veins provide certain advantages, the best site at which to attempt access is whichever vein the clinician feels offers the greatest chance for successful catheterization based on his or her ability to visualize or palpate the vessel. Using scalp veins can also help preserve the vessels of the arms and legs for peripherally inserted central catheters.^[1]
• Scalp vein catheterization is often considered only after attempts to insert a catheter at other peripheral sites have failed.

• Attempting intravenous access near sites of superficial skin injury or infection should be avoided.^[2]

• Use of anesthesia is generally not indicated.
• Topical anesthesia may be considered with the use of a lidocaine cream or patch, but these require at least 20-30 minutes to be effective. For more information, see Anesthesia, Topical.

• Having the appropriate equipment is of utmost importance for successful scalp vein catheterization. Minimum equipment required includes the following:

  • Elastic band tourniquet
  • Adequate lighting
  • Antiseptic wipes
  • Syringes, filled with 0.9% saline, for flush
  • Tape for securing the intravenous catheter and tubing
  • Appropriately sized intravenous over-the-needle catheter: 22- to 24-gauge catheters are frequently selected for use in small children and infants and are usually an appropriate choice for the scalp veins.

• The patient should be lying in a supine position with his or her head turned so that the desired scalp vein is visible and readily accessible.
• The clinician should be located at the head of the bed with the patient’s feet extending away from the clinician.
• A slight head down position may facilitate catheterization by distending the veins of the head and neck.
• Ensure that the patient is appropriately restrained to minimize the risk of injury to the patient and clinician.

• Locate the frontal, superficial temporal, or posterior auricular vein in the scalp, as shown in the image below.Common sites of insertion for peripheral scalp vein catheterization include the frontal, posterior auricular, and superficial temporal veins.

  • Select a site that is behind the hairline to minimize the risk of leaving a visible scar.
  • Shaving the site may be necessary to allow proper visualization and to properly secure the catheter once it has been inserted.
• Place an elastic band around the patient’s head just above the eyes and ears, from forehead to occiput, or occlude the vein proximally with the index finger of the nondominant hand, as shown below. An elastic band is used as a tourniquet to distend the scalp veins. A small piece of tape attached to the elastic facilitates removal.
• Clean the site of insertion thoroughly with antiseptic wipes.
• Use the thumb of the nondominant hand to secure the vein distally to the insertion site to prevent movement of the vessel.
• Hold the intravenous needle and catheter in the dominant hand, parallel to the vessel, pointing in the direction of blood flow.
• Insert the needle into the vein, angled 20-30 degrees off the skin surface, as depicted in the image below. When the needle enters the vessel lumen, a flash of blood should be seen in the hub of the catheter. The catheter-over-needle device is inserted at a 30-degree angle to the skin surface, with the needle pointing in the direction of blood flow and a flash of blood in the hub as the needle enters the lumen of the vein.
• Carefully lower the needle and catheter until they are just off the skin surface and advance slightly further into the vein so that the needle and the catheter tip are in the vessel lumen, as shown below. Once the needle has entered the vein, the catheter-over-needle device is lowered (1) so that it is just off the skin surface. The device is then advanced slightly further (2) to ensure that both the needle tip and the catheter tip are in the vessel lumen.
• Slide the catheter forward off of the needle using the nondominant hand while the dominant hand continues to hold the needle in place, as shown below. When both the needle tip and the catheter tip are inside the vessel lumen, the catheter is advanced forward (1) off of the needle and further into the vein.
• Once the catheter has been advanced completely into the vein, secure the catheter with the index finger of the dominant hand by compressing the skin overlying the vein where the tip of the catheter lies. Use the middle finger of the same hand to compress the vein immediately proximal to the catheter tip to prevent bleeding from the intravenous line while the needle is removed.
• Attach extension tubing preflushed with saline and a saline-filled syringe, as depicted below. Gently inject saline solution into the catheter and observe for any infiltration into surrounding tissues. Intravenous extension tubing (preflushed with normal saline) is attached to the catheter after removal of the needle. A saline-filled syringe is used to gently flush the catheter while observing for signs of infiltration.
• If no infiltration is seen, secure the catheter in place with a clear, sterile adhesive dressing, as shown below. This prevents manipulation and contamination of the entry site and allows visualization for frequent assessment. Place rolled 2 X 2 cm gauze under the catheter hub to prevent pressure on the underlying skin. The catheter is secured using clear plastic dressing. A piece of folded 2 X 2 cm gauze is used to protect the skin from the hard plastic of the catheter hub and extension tubing connector.
• Secure the extension tubing onto the skin with tape, as shown in the image below.The extension tubing is secured with tape to prevent inadvertent removal of the catheter.

• Shaving the site prior to catheterization makes taping the catheter in place easier and more secure.
• Carefully warming the site prior to attempting catheterization can improve vasodilatation and make catheterization easier. Caution is necessary to prevent burns.
• Attaching a piece of tape to the elastic band tourniquet, as shown below, facilitates removal while decreasing the chances of inadvertent disruption of the vein or the catheter. An elastic band is used as a tourniquet to distend the scalp veins. A small piece of tape attached to the elastic facilitates removal.
• Keep in mind that tourniquets are more likely to disrupt the scalp veins than vessels at other peripheral sites.
• Attempting to advance the catheter over the needle before the catheter tip is in the vessel lumen can push the vein off of the needle and prevent successful catheterization.

• Hematoma is reported as the most common complication from peripheral intravenous catheterization; fortunately, it is often not significant.^{[2, 3]}
• Vasospasm is also a common complication and usually only significant in that it makes successful catheterization difficult.^[2]
• Less common but more significant complications include the following:

  • Phlebitis^{[2, 4]}
  • Infection^{[2, 4]}
  • Embolization of air or clots (possibly to cerebral veins)^[5]
  • Injury of adjacent structures (artery or nerve)
  • Infiltration of subcutaneous tissues with intravenous medication or fluids, which may result in superficial blistering, deep tissue necrosis, or tissue calcification if calcium-containing fluids are used^{[2, 4]}