Anesth Analg 2008; 106:1015-1016
© 2008 International Anesthesia Research Society
doi: 10.1213/ane.0b013e318161528a
ANALGESIA
A Novel Approach for Assessing Catheter Position After Ultrasound-Guided Placement of Continuous Interscalene Block
Jeffrey D. Swenson, MD,
Jennifer J. Davis, MD, and
Jennifer A. DeCou, MD
From the Department of Anesthesiology, University of Utah Health Science Center and University of Utah Orthopaedic Center, Salt Lake City, Utah.
Address Correspondence to Jeffrey D. Swenson, MD, Department of Anesthesiology, University of Utah, Health Sciences Center, Salt Lake City, UT 84132. Address e-mail to jeff.swenson{at}hsc.utah.edu.
Abstract
The increasing use of ultrasound has allowed anesthesiologists to perform nerve blocks with a high success rate and without nerve stimulation or eliciting a paresthesia. The ability to visualize peripheral nerve catheters using ultrasound is limited. We present a novel method to confirm the position of an interscalene catheter tip using injection of agitated contrast. The described technique is simple and allows timely assessment of catheter tip position.
Ultrasound has allowed more anesthesiologists to perform nerve blocks with a high success rate in the absence of nerve stimulation or paresthesia.1–3 High resolution ultrasound allows direct visualization of nerves and surrounding structures and can demonstrate spread of local anesthetic in the appropriate tissue planes. Verification of catheter position for a continuous infusion is challenging, because the catheter itself cannot be reliably visualized with ultrasound.4 This is one reason that the use of ultrasound as a "stand alone" technique for the placement of a catheter has been criticized.4,5 We present a novel method to accurately confirm the effective position of an interscalene catheter using ultrasound in conjunction with agitated contrast injection.
CASE REPORT
A 25-yr-old, 93 kg, 180 cm, healthy male patient (ASA I) was scheduled for arthroscopic Bankart repair of his right shoulder. After informed consent, a continuous interscalene catheter was placed for postoperative pain management.
With standard monitors in place, the patient was premedicated with 1 mg of midazolam and 50 mcg of fentanyl. The brachial plexus was then identified by placing a variable frequency ultrasound probe (GE Medical, Milwaukee, WI) immediately superior and parallel to the mid-clavicle. The subclavian artery was identified on short axis and the brachial plexus was seen superficial and posterior to the artery. While maintaining the brachial plexus in the center of the image, the probe was moved in a cephalad direction until the brachial plexus could be identified between the anterior and middle scalene muscles. At this point, a chlorhexadene skin preparation was used and a sterile fenestrated drape was placed with an adhesive border separating the needle insertion point from the ultrasound transducer. An 18-gauge, 2.5-in. needle was inserted into the middle scalene muscle immediately superior to and out of plane with the transducer. At the middle portion of the scalene muscle, the needle was redirected anteriorly and advanced toward the interscalene space. Local anesthetic (1–2 mL) was injected in increments at the anterior border of the middle scalene muscle to expand the fascial plane between the brachial plexus and the middle scalene muscle. While intermittently aspirating, and under direct ultrasound visualization, 20 mL of 0.125% bupivacaine with epinephrine (5 mcg/mL) was injected into the interscalene space. The catheter was then inserted through the thin-walled needle to a depth of 10 cm at the skin.
Before placement of a clear adhesive dressing, it was noted that the catheter had been accidentally pulled back to a depth of 7 cm. It was unclear if the tip remained within the interscalene space. To locate the catheter position, 5 mL of agitated 0.125% bupivacaine was injected while imaging the interscalene space. The ultrasound image clearly demonstrated echogenic contrast entering and spreading within the interscalene space, confirming appropriate position of the catheter (Figs. 1A and B). Further evidence of adequate block was provided by appropriate motor and sensory changes in the upper extremity. The patient underwent general anesthesia for his surgery and had excellent postoperative pain relief for 2 days, after which the catheter was removed uneventfully at home.
View larger version (44K):
[in this window]
[in a new window]
|
Figure 1. A: An ultrasound image of the interscalene region before the injection of 5 mL of agitated contrast. The anterior scalene muscle (AS), sternocleidomastoid muscle (SCM), brachial plexus (BP), and the interscalene space (ISS) are displayed. The interscalene space has been expanded with 20 mL of local anesthetic. B: The same view with an arrow indicating the echogenic injectate within the interscalene space.
|
|
DISCUSSION
The use of ultrasound guidance for placement of peripheral nerve blocks continues to grow and offers several advantages over other methods.6,7 One criticism of ultrasound-only techniques is the inability to reliably visualize the catheter after it has been placed. Contrast agents containing microbubbles have been effectively used for years to better visualize the anatomy of the heart.8 It reasonably follows that the same approach of using an echogenic contrast may also aid in the placement of peripheral nerve block catheters. Other techniques, such as the injection of local anesthetic through the catheter to observe local anesthetic distribution around neural structures and the use of color flow Doppler, have been described anecdotally.
In the case presented, there was concern that the catheter had been accidentally dislodged after placement. Although the catheter depth was still adequate at the skin (7 cm), we wanted to confirm that the catheter tip was still within the interscalene space. A malpositioned catheter would likely result in a failed block that would not be detected until after the effects of the initial bolus resolved. To verify proper catheter position, we injected an agitated solution of dilute local anesthetic through the catheter. The ultrasound image of agitated contrast verified that the injectate was within the interscalene space. This technique is simple; it provides timely assessment of catheter position, and may allow the patient to avoid an unnecessary repeat procedure.
The benefits of ultrasound are increasingly evident as we refine techniques for both the placement and assessment of peripheral nerve catheters. This case is an example of one more method that may be used to facilitate catheter placement.
Footnotes
Accepted for publication October 31, 2007.
Reprints will not be available from the author.
REFERENCES
- Swenson JD, Bay N, Loose E, Bankhead B, Davis J, Beals TC, Bryan NA, Burks RT, Greis PE. Outpatient management of continuous peripheral nerve catheters placed using ultrasound guidance: an experience in 620 patients. Anesth Analg 2006; 103:1436–43[Abstract/Free Full Text]
- Marhofer P, Greher M, Kapral S. Ultrasound guidance in regional anesthesia. Br J Anaesth 2005;94:7–17[Abstract/Free Full Text]
- Sandhu NS, Capan LM. Ultrasound-guided infraclavicular brachial plexus block. Br J Anaesth 2002;89:254–9[Abstract/Free Full Text]
- Chan VWS. The use of ultrasound for peripheral nerve blocks. In: Boezaart AP, ed. Anesthesia and orthopaedic surgery. New York: McGraw-Hill, 2006:284–90
- Boezaart AP. Author reply to letter to the editor. Anesthesiology 2007;106:191–2[Web of Science][Medline]
- Marhofer P, Schrögendorfer K, Koinig H, Kapral S, Weinstabl C, Mayer N. Ultrasonographic guidance improves sensory block and onset time of three-in-one blocks. Anesth Analg 1997;85: 854–7[Abstract]
- Marhofer P, Schrögendorfer K, Wallner T, Koinig H, Mayer N, Kapral S. Ultrasonographic guidance reduces the amount of local anesthetic for 3-in-1 blocks. Reg Anesth Pain Med 1998;23:584–8[Web of Science][Medline]
- Gramiak R, Shah PM, Kramer DH. Ultrasound cardiography: contrast studies in anatomy and function. Radiology 1969; 92:939–48[Web of Science][Medline]
|
