Obtaining vascular access is a critical first step in resuscitation and initiating treatment to patients presenting to the Emergency Department (ED). Patients may have characteristics that impede intravenous (IV) access such as hypotension, dialysis dependence, morbid obesity, histories of diabetes, sickle cell disease, or IV drug use. One prospective observational study identified nearly one in every 9 to 10 adults presenting to an urban ED had difficult venous access requiring 3 or more IV attempts.[1] If peripheral IVs are not established, patients may need a central venous catheter placed for life saving medications administered. In addition to requiring physician skill, central venous catheter insertion carries a risk of complications including infection, arterial puncture or aneurysm, and pneumothorax. Ultrasound-guidance for peripheral IV placement (UGPIV) has prevented the need for central venous catheter placement in 85% of patients with difficult IV access.[2] UGPIV has been performed by Emergency Medical Technicians (EMTs) in pre-hospital settings, as well as nurses and physicians. Patients who have been identified as having difficult access, have higher patient satisfaction scores when ultrasound is used in peripheral IV access attempts.[3]
Frequently, the large veins of the antecubital fossa are sufficient to place large bore peripheral IVs needed for resuscitation. The brachial and basilic veins are easy to locate. The basilic vein is located medial to the brachial vessels. Generally, the basilic vein is more superficial, larger, and does not have an accompanying artery or nerve at the level of the antecubital fossa. As you move proximally up the arm (towards the head) the basilic vein dives deeper toward the humerus, and longer angiocatheters may be required for cannulation.
Identify the Vein: Remember the C’s
The two C’s to remember for vein confirmation in UGPIV access or for central venous cannulation are Compression and Color (or Power) Doppler. Veins are thinner-walled and more easily compressed than arteries. Color or Power Doppler may be utilized to determine if pulsatile flow is consistent with an artery or vein. Color should not be relied on alone to determine arterial or venous flow due to the color scale setting can be flipped or reversed, or aliasing can occur. With Doppler, arterial flow is more pulsatile than venous. Venous flow may require distal augmentation (by squeezing the forearm distal to the probe) to appreciate the blush of color.
Once the target vein is identified, the depth from the skin surface should be noted. A common mistake is to use an angiocatheter that is too long or too short. A general rule of thumb is to use a catheter length that is more than twice the depth of the vessel to ensure at least half the catheter lies within the vein. To prevent the risk of multiple punctures, this author advocates for first bouncing the needle on the skin over the point of entry. The tissue should deform at the top of the screen, and confirm the needle is over the target vessel. One the skin is punctured, the needle tip is kept in view by angling the ultrasound probe until the target vessel is punctured.
To confirm placement, either a “bubble study” with agitated saline may be performed or Color (or Power) Doppler utilized to visualize saline flow through the cannulated vessel. A vessel that is not properly cannulated will demonstrate extravasation of saline around the vessel into the tissue before the tissue swells to a degree which is palpable on the surface of the skin.
For further information about UGPIV placement, visit: http://rmgultrasound.com/piv-access
References:
1) Fields, J.M., Piela, N.E., Au, A.K., Ku, B.S., Risk factors associated with difficult venous access in adult ED patients. Am J Emerg Med. 2014 Oct; 32(10):1179-82.
2) Au, A.K., Rotte, M.J., Grzybowski, R.J., Ku, B.S., Fields, J.M., Decrease in central venous catheter placement due to use of ultrasound guidance for peripheral intravenous catheters. Am J Emerg Med. 2012 Nov;30(9):1950-4.
3) Schoenfield, E., Shokoohi, H., Boniface, K. Ultrasound-guided peripheral intravenous access in the emergency department: patient-centered survey. West J Emerg Med. 2011 Nov;12(4):475-7.
Virginia Stewart
Director of Emergency Ultrasound
Director of Ultrasound Fellowship
Department of Emergency Medicine
Riverside Medical Group
Newport News, VA
001 757 510 8197
