Emergency Department Diagnosis of Pneumothorax Using Goal-directed Ultrasound

A 23-year-old female with a history of fibromyalgia andrecurrent back and neck spasms presented to the emergencydepartment (ED) complaining of right-sided upper back andchest pain with associated dyspnea. She had just receivedtrigger point injections to her upper back and neck, performedby a pain management specialist. The symptoms developedimmediately following the procedure, as she was leaving thephysician’s office.

Medication history included Ortho Tri-Cyclen and as-neededDarvocet. Her initial vital signs in the ED were blood pressure99 ⁄ 69 mm Hg, pulse 97 beats ⁄ min, respirations 24 breaths ⁄min, temperature 98.9�F, and oxygen saturation of 93%. On

examination she appeared to be in obvious pain, with splintingnoted during respirations. She had clear speech, no jugularvenous distention was noted, and her trachea was midline withno neck or chest wall crepitus. She had no heart murmurs anda rapid but regular heart beat. On lung auscultation it was feltthat she might have decreased breath sounds on the right, butthe exam was limited by the patient’s refusal to take deepbreaths due to the pleuritic nature of her pain. The extremityexam revealed no dependant edema, no calf tenderness, nega-tive Homan’s sign, and normal distal pulses and capillary refillbilaterally.

An electrocardiogram revealed sinus tachycardia at a rate of105, with no evidence of right heart strain. Goal-directed bed-side sonography was performed by the emergency physician,who noted an absence of pleural sliding on the right with adefinitive lung point. The chest x-ray was completed while thephysician prepped for needle aspiration of the pneumothorax.

Figure 2. Seashore sign.

Figure 3. Stratosphere sign.

Figure 4. Power slide.

Figure 1. A-line and comet tail artifacts.

ª 2009 by the Society for Academic Emergency Medicine ISSN 1069-6563doi: 10.1111/j.1553-2712.2009.00542.x PII ISSN 1069-6563583 1379

DYNAMIC EMERGENCY MEDICINE

Needle aspiration was completed successfully without compli-cation and the patient was admitted to the cardiothoracicsurgery service for observation.

DISCUSSION

This patient presented with concern for possible pulmonaryembolism versus pneumothorax. Her diagnosis was quicklymade via focused bedside ultrasound. If no pneumothorax hadinitially been noted, the physician could have quickly movedon to a focused exam for deep vein thrombosis or evidence ofright heart strain. The use of ultrasound to diagnose pneumo-thorax was first described in Europe by intensivists. Using alinear or curvilinear array transducer in the sagittal position,beginning in the second to fourth midclavicular intercostalspaces in a supine patient, one looks for the absence of normalpleural sliding.1,2 From this starting point, the exam should becarried out as far laterally as the midaxillary line. Whereas thesupine chest x-ray has a sensitivity of 36% to 75% for detect-ing pneumothorax, the sensitivity of ultrasound in the detec-tion of anterior pneumothoraces has been found to be 92% to100% based on studies using computed tomography as the cri-terion standard.1,3,4 The finding of a lung point, which is thetransition point from the absence of normal pleural sliding toits presence as the pneumothorax ends, is 100% specific forpneumothorax2 (see Video Clip S1 available as supportinginformation in the online version of this paper).

Normal pleural sonographic artifacts that should be notedare comet tail artifacts (B-lines) originating along the pleuralinterface and the presence of A-lines (Figure 1). The comet tailis an important reverberation artifact that is absent in the pres-ence of a pneumothorax. These appear as hyperechoic laser-like reverberations that project down from the pleural inter-face through the depth of the image. Comet tails move alongthe pleura with respiration and vary in width and appearancein real time. These B-lines also will cover up the A-lines andare at times more prominent in certain patient populations,such as those presenting with congestive heart failure. The A-line is a horizontal reverberation artifact noted at twice the dis-tance from the skin to pleural interface. A-lines may be seen innormal lung or in the presence of a pneumothorax. Using M-mode (motion mode), the practitioner may see a seashore sign,which is an irregular tracing at the depth of the pleura due tonormal lung sliding (Figure 2). The abnormal stratosphere signis seen in M-mode as a smooth motionless baseline when apneumothorax is present and lung sliding is absent (Figure 3).An additional finding called the power slide can be seen whena power Doppler signal is noted at the site of normal pleuralsliding (Figure 4). In the presence of a pneumothorax, a powerDoppler signal would be absent.2,3

Although focused bedside sonography can be very usefulfor detecting pneumothoraces, the examination does have itslimitations, and in certain instances the diagnosis may bemissed. A small apical or perimediastinal pneumothorax canbe missed, and failure to perform the exam with the patient ina supine position can decrease its sensitivity, as free pleural airmight not collect in the anterior chest where it is likely to bedetected using ultrasound. It must be noted that a lung pointmay not be visualized in very large pneumothoraces, wherethere may be no lung contact with the chest wall, or if thesonographer fails to scan a significant area of the chest wall toidentify the borders of the pneumothorax. Any pathologyoutside the actual scanned region of the chest wall willobviously be missed by ultrasound. Finally, it is worthwhile tonote that conditions like pleural adhesions, blebs, a rightmainstem intubation, and others can result in the absence oflung sliding.

Alexis Johnson, MD, MPH

(lex201@mac.com)Department of Emergency Medicine

North Shore University HospitalManhasset, NY

References

1. Lichtenstein DA, Meziere G, Lascola N, et al. Ultra-sound diagnosis of occult pneumothorax. Crit CareMed. 2005; 33:1231–8.

2. Ma OJ, Mateer J, Blaivas M. Emergency Ultrasound,2nd ed. McGraw-Hill, 2008.

3. Blaivas M, Lyon M, Duggard S. A prospectivecomparison of supine chest radiography and bedsideultrasound for the diagnosis of traumatic pneumotho-rax. Acad Emerg Med. 2005; 12:844–9.

4. Soldati D, Testa A, Sher S, et al. Occult traumaticpneumothorax: diagnostic accuracy of lung ultraso-nography in the emergency department. Chest. 2008;133:204–11.

SUPPORTING INFORMATION

The following supporting information is available in the onlineversion of this paper:

Video Clip S1. Lung sliding and lung point.The video clip is in QuickTime.Please note: Wiley Periodicals Inc. is not responsible for

the content or functionality of any supporting informationsupplied by the authors. Any queries (other than missingmaterial) should be directed to the corresponding author forthe article.

1380 • DYNAMIC EMERGENCY MEDICINE