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American Journal of Emergency Medicine (2012) 30, 2099.e5–2099.e7

Case Report

Sonographic evaluation of a paralyzed hemidiaphragmfrom ultrasound-guided interscalene brachial plexusnerve block

Abstract

The ultrasound-guided interscalene brachial plexus isbecoming increasingly popular for anesthesia in themanagement of upper-extremity injuries by emergencyphysicians. Traditional high-volume injections of localanesthesia will also affect the phrenic nerve, leading totemporary paralysis of the ipsilateral hemidiaphragm. Withdirect ultrasound guidance, more precise needle placementallows for lower-volume injections that reduce inadvertentspread of local anesthetic to the phrenic nerve withoutdecreasing the efficacy of onset of time and quality of theblock. However, the risk of incidental paralysis of thehemidiaphragm is still not eliminated with low-volumeintraplexus injections. This case highlights this commoncomplication of interscalene brachial plexus nerve blocksand demonstrates how emergency physicians can easily useB-mode and M-mode ultrasound to evaluate the paralysis ofthe hemidiaphragm.

Ultrasound-guided nerve blocks are being increasinglyused by emergency physicians for upper-extremity pro-cedures instead of procedural sedation that is more time-consuming and theoretically carries more risk [1]. Theultrasound-guided interscalene brachial plexus block is usedto provide regional anesthesia to the upper extremityincluding the shoulder. However, tracking of injected localanesthetic over the anterior scalene muscle to the phrenicroutinely induces a paralyzed ipsilateral hemidiaphragm [2].This common adverse effect may only be clinically relevantin patients with underlying pulmonary dysfunction, andemergency physicians should be aware when selecting thebest option for the patient. This case highlights the risks ofthe interscalene block and demonstrates how to easilyconfirm this common complication with ultrasound.

A 61-year-old man presented to the emergency depart-ment complaining of left elbow pain and deformity after

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falling 15 ft from a ladder. No other gross injuries were notedother than a posterior elbow dislocation on plain radiographs.An ultrasound-guided interscalene brachial plexus nerveblock was chosen for elbow reduction due to lack of nursingavailability secondary to multiple concurrent traumas.

The patient was placed on continuous cardiac moni-toring and pulse oximetry. Using a linear high-frequencytransducer placed over the lateral border of the sterno-cleidomastoid at the level of the larynx, the hypoechoicC5 to C7 nerve roots of the brachial plexus wereidentified (Fig. 1). The area was prepped with chlorhex-idine, and a skin wheal of 1% lidocaine was injected.Using an in-plane approach under real-time ultrasoundguidance, a 22-g 3.5-in spinal needle was advanced to thelateral border of the brachial plexus. After aspiration toensure the lack of inadvertent puncture of the vessels andwith direct visualization of the needle tip, 20 mL of 1%lidocaine was injected around the target nerve roots. Localanesthetic was visualized, tracking around the brachialplexus sheath producing the classic “doughnut” sign.

After 10 minutes, the patient reported a moderate-to-complete reduction in pain in the elbow, with a dense motorand sensory deficit in the upper extremity. Vital signsremained stable, and the patient denied any shortness ofbreath. A low-frequency curvilinear probe was placed in thecontralateral anterior axillary line (sagittal plane with probemarker cephalad) to evaluate the unaffected hemidiaphragm.B-mode and M-mode were then used to confirm normalrespiratory movement of the hemidiaphragm. (Fig. 2). Theipsilateral (affected) hemidiaphragm was then interrogated ina similar fashion under B-mode and M-mode. Thehemidiaphragm lacked cephalad rise during the respiratorycycle in the same manner as the unaffected hemidiaphragm(Fig. 2). The patient's elbow dislocation was successfullyreduced, without any episodes of hypoxia or hypercarbiaduring the 1-hour period of cardiac monitoring. The affecteddiaphragm was reevaluated approximately 2 hours post-procedure, demonstrating normal respiratory excursion (ascompared with the unaffected side).

Ultrasound-guided nerve blocks for upper-extremity inju-ries are effective and safe and may be an ideal method in

Fig. 1 In-plane technique for ultrasound-guided interscalene block. SCM (sternocleidomastoid), IJV (Internal Jugular Vein). Note needle tipis just lateral to C5-7 plexus.

2099.e6 Case Report

patients in which procedural sedation may not be ideal. Also,ultrasound-guided nerve blocksmay have a lower incidence ofhypotension, respiratory depression respiratory depression andaspiration, and requires significantly shorter one-on-oneprovider time as compared with procedural sedation [1].Unfortunately, the ultrasound-guided interscalene brachialplexus nerve block carries a known risk of ipsilateralhemidiaphragmatic paralysis. Traditional high-volume in-jections of local anesthetic (N30 mL) will result in near-universal involvement of the phrenic nerve [2]. Although this

Fig. 2 M-Mode evaluation of each hemidiaphragm. The right hemidiapNote the lack of movement of the left hemidiaphragm 10 minutes after p

is almost always tolerated in healthy individuals, performingthe interscalene block under direct ultrasound guidance canallow formore precise needle placement, which permits lower-volume intraplexus injections (needle tip placed between thenerve roots) that has been shown to have the same efficacy ofonset time and quality of the block [3]. Lower-volumeinjections may reduce but not nullify the risk of diaphragmaticparalysis [4,5]. Emergency department physicians who plan toinclude ultrasound-guided interscalene brachial plexus nerveblocks in their armamentarium for pain reduction and as an

hragm demonstrates normal movement during the respiratory cycle.erforming the left interscalene nerve block.

2099.e7Cse Report

alternative to procedural sedation must recognize that this is acommon adverse effect. Patients with low pulmonary reservemay not be ideal candidates for this block. Also, use of a short-acting local anesthetics and keeping the patient on cardiacmonitoring until clear diaphragmatic excursion is noted maybe recommended. Evaluation of each hemidiaphragm with acurvilinear probe using both B-mode and M-mode can easilydetect this common complication and should be performed onall patients after receiving an interscalene brachial plexusnerve block.

Daniel Mantuani MD/MPHArun Nagdev MD

Department of Emergency MedicineACMC Highland, CA 94602, USA

E-mail address: dmantuani@yahoo.com

http://dx.doi.org/10.1016/j.ajem.2012.02.004

References

[1] Blaivas M, Adhikari S, Lander L. A prospective comparison ofprocedural sedation and ultrasound-guided interscalene nerve block forshoulder reduction in the emergency department. Acad Emerg Med2011;18(9):922-7.

[2] Urmey WF, Talts KH, Sharrock NE. One hundred percent incidence ofhemidiaphragmatic paresis associated with interscalene brachial plexusanesthesia as diagnosed by ultrasonography. Anesth Analg 1991;72(4):498-503.

[3] Liu SL, Zayas VM, Gordon MA, et al. A prospective, randomized,controlled trial comparing ultrasound versus nerve stimulator guidancefor interscalene block for ambulatory shoulder surgery for postoperativeneurological symptoms. Reg Anesth 2009;109(1):265-71.

[4] Al-Kaisy AA, Chan VWS, Perlas A. Respiratory effects of low-dose bupivacaine interscalene block. Br J Anaesth 1999;82(2):217-20.

[5] S. Riazi, N. Carmichael, C.J.L. McCartney, Effect of local anestheticvolume (20 vs 5 ml) on the efficacy and respiratory consequences ofultrasound-guided interscalene brachial plexus block. 2008;101(4):549-56.