PRO:

Central venous cannulation is commonly performed by anesthesiologists to monitor cardiac filling pressures, to facilitate rapid fluid infusion, to administer vasoactive drugs, and when peripheral intravenous access is tenuous. The right internal jugular vein (IJV) is the site most frequently chosen by anesthesiologists for percutaneous cannulation because it is easily accessible during most operations and is associated with fewer complications when compared to the subclavian approach. The most common complication of IJV cannulation is carotid artery puncture with an incidence ranging from 3-10% that is independent of the technique chosen or operator experience. Although carotid artery puncture is usually a benign event, it can be life-threatening when it results in inadvertent intraarterial cannulation, stroke, hemothorax, carotid artery-IJV fistula, or airway compromise due to a neck hematoma. In a recent analysis of central line complications from the ASA Closed Claims Project, 16/26 cases (61%), including 7 fatalities, resulted from vascular injury, often from accidental cannulation of the artery instead of the vein with an introducer sheath or large bore catheter.¹

Percutaneous cannulation of the IJV is routinely facilitated by the use of landmark methods that are performed in blind fashion that incorporates knowledge of the underlying anatomical relationship between the artery and the vein. However, increasing data support the routine application of Doppler and non-Doppler ultrasound during central venous cannulation. Benefits of ultrasound guided cannulation include determination of the vessel location and size; identification of aberrant anatomical relationships between the artery and vein; visualization of needle puncture of the vessel; and confirmation of guidewire and catheter placement within the vessel. In a recent meta-analysis and report from the Agency for Healthcare Research and Quality, surface ultrasound was associated with a reduced incidence of complications and number of venipuncture attempts, thereby improving the rate of successful catheter placement.^2,3

Real-time ultrasound successfully identifies underlying vessel relationships and is not dependent upon surface landmarks. This characteristic is particularly beneficial in patients with distorted external landmarks that include obesity, previous neck surgery or neck radiation; previous IJV cannulation with thrombosis of the vessel; and carotid artery stenosis. It is particularly useful in the presence of coagulopathy or planned anticoagulation (ie, cardiopulmonary bypass). Aberrant anatomic relationships between the IJV and carotid artery were observed in as many as 3% of adult patients studied by ultrasound when their heads are rotated 30^o from midline.⁴ In 2% the IJV was positioned medial to the carotid artery. The carotid artery coursed posteriorly to the IJV in 10% of pediatric cardiac patients who were studied by ultrasound, thereby predisposing them to accidental carotid artery puncture.⁵

Anatomical variation in the size of the left and right IJVs is well documented. The right IJV is slightly larger than the left IJV in most patients.⁶ In 34% of healthy adults, the left IJV is less than one-half the size of the right IJV, making cannulation more difficult. Additionally, the left IJV is less responsive to Valsalva and steep Trendelenburg maneuvers. Normal anatomical relationships between the carotid artery and IJV are lost when the head is rotated away from the midline, a technique commonly used to facilitate exposure of the IJV prior to cannulation. As the head is rotated greater than 40^o from midline, the percent overlap of the carotid artery and IJV increases significantly as does the risk of inadvertent puncture of the carotid artery.⁷ At a head rotation of 80° the left IJV has a greater overlap with the carotid artery than does the right IJV.

Real-time ultrasound determination of the anatomical relationship of the vessels reduces the risks of carotid artery puncture, neck hematoma and accidental cannulation. Cannulation of the carotid artery with an introducer sheath often requires surgical repair of the vessel and has been associated with stroke and death. In a meta-analysis of eight randomized trials, the use of ultrasound resulted in a 78% relative risk reduction for complications and a 68% relative risk reduction for catheter placement failures.^2,3 The reduction in complications is attributed to visual determination of vessel location, recognition of anatomic variants and identification of the guidewire within the vein prior to catheter insertion. The number of venipuncture attempts also is significantly decreased (relative risk reduction 40%), thus avoiding potential complications from repeated punctures.³ Ultrasound-guided placement does not completely eliminate the risk of complications, but lowers them significantly.

Routine use of real-time ultrasound for central venous cannulation has been criticized because of equipment costs, reduced clinical experience with placement by landmark methods (particularly by residents in training), and the need for operator expertise. In my view, however, ultrasound techniques are relatively simple to learn. The equipment is portable, and it generally requires minimal training to gain expertise in its use. Although equipment cost is a valid concern, the expense of a major adverse event associated with central venous cannulation is potentially much greater. In my view, ultrasonography for central venous cannulation will soon be a standard of practice.

References

1. Bowdle TA: Central line complications from the ASA Closed Claims Project: An Update. ASA Newsletter 2002: 66.
2. Randolph AG, Cook DJ, Gonzales CA, Pribble CG: Ultrasound guidance for placement of central venous catheters: A meta-analysis of the literature. Crit Care Med 1996; 24: 2053-2058.
3. Rothschild JM: Ultrasound guidance of central vein catheterization. Evidence Report/Technology Assessment, No. 43. Making Health Care Safer. A Critical Analysis of Patient Safety Practices. Agency for Healthcare Research and Quality Publication No. 01-E058. 2001; 245-253.
4. Denys BG, Uretsky BF: Anatomical variations of internal jugular vein location: impact on central venous access. Crit Care Med 1991; 19: 1516-1519.
5. Alderson PJ, Burrows FA, Stemp LI , Holtby HM: Use of ultrasound to evaluate internal jugular vein anatomy and to facilitate central venous cannulation in paediatric patients. Br J Anaesth 1993; 70: 145-148.
6. Lobato EB, Sulek CA, Moody RL, Morey TE: Cross-sectional area of the right and left internal jugular veins. J Cardiothorac Vasc Anesth 1999; 13: 136-138.
7. Sulek CA, Gravenstein N, Blackshear RH, Weiss L: Head rotation during internal jugular vein cannulation and the risk of carotid artery puncture. Anesth Analg 1996; 82: 125-128.

Cheri A. Sulek, MD