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An ED Approach to Blunt Aortic Injury and Myocardial Confusion Steven Issley, MD, CCFP Emergency Medicine McGill University September 12, 2001.

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Presentation on theme: "An ED Approach to Blunt Aortic Injury and Myocardial Confusion Steven Issley, MD, CCFP Emergency Medicine McGill University September 12, 2001."— Presentation transcript:

1 An ED Approach to Blunt Aortic Injury and Myocardial Confusion Steven Issley, MD, CCFP Emergency Medicine McGill University September 12, 2001

2 Overview n Blunt aortic injury (BAI) n Myocardial contusion n Focus: –which investigations –when should these investigations be done –how sensitive are these investigations

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4 Case One n Sunday, 1600h.

5 Case One n Sunday, 1600h. n On the way home from an afternoon of bongos in the park. n 20 yo healthy, but not-so-smart male n Trying to beat the light @ 80 km/h...

6 Case One n Sunday, 1600h. n On the way home from an afternoon of bongos in the park. n 20 yo healthy, but not-so-smart male n Trying to beat the light @ 80 km/h... n T-boned to passenger’s side…

7 Case One n Sunday, 1600h. n On the way home from an afternoon of bongos in the park. n 20 yo healthy, but not-so-smart male n Trying to beat the light @ 80 km/h... n T-boned to passenger’s side… n As usual, being drunk, he walks out of his car without a scratch. (...except for scratching his head in disbelief!)

8 Case One n Sunday, 1600h. n On the way home from an afternoon of bongos in the park. n 20 yo healthy, but not-so-smart male n Trying to beat the light @ 80 km/h... n T-boned to passenger’s side… n As usual, being drunk, he walks out of his car without a scratch. (...except for scratching his head in disbelief!) n He’s all yours!

9 Case One n Normal CXR n Is this patient at risk for aortic dissection? n What Next? –A) discharge: no injuries and CXR is reassuring –B) hCT chest; if normal discharge. –C) angio, as high risk, despite negative studies

10 BAI: stats n Aorta & great vessel injury 1-4% of blunt chest traumas n 20% incidence when BAI suspected (mechanism or wide mediastinum) n 75-90% ruprured thoracic aorta --> immediate death n If untreated: –30% die within 1 day –60% die within 1 week –90% die within 1 month n 71-84% survive with prompt intervention

11 BAI: pathophysiology n Deceleration: –vertical (>30 ft / 10 m) –horizontal (>30 mph / 50 km/h) n Mediastinum and diaphragm compression n Traction n Dissection, thrombosis, pseudoaneurism, hemorrhage

12 BAI: associated risks n High speed head on or T-bone (>30 mph / 50 km/h) n Ejection n Other passengers dead n Steering wheel deformity n Fall from height (>30 ft / 10 m) n NB: seat belt does not affect incidence

13 BAI: clinical findings n Physical exam not sens or spec n 50% hypotension n pseudocoarctation syndrome n 30% harsh systolic murmur

14 BAI: associated injuries n Closed head injury (39%) n Other significant chest pathology (67%) n pelvic # (33%) n Femur, tibia # (51%) n T 1-8 # n liver & spleen injury n 1st & 2nd rib # n Sternum #

15 BAI: associated injuries n 30-50% have no associated external injury!

16 BAI: clinical prediction rule Blackmore, et al. Am J Rad 2000 n 7 clinical predictors: –age > 50: OR 12.1 (1.8-84) –unrestrained: OR 5.9 (1.1-31) –hypotension (sys<90): OR 9.9 (1.8-54) –head injury: OR 4.9 (1.2-20) –thoracic injury: OR 12.1 (2.7-54) –abdomino-pelvic injury: OR 4.5 (1.1-19) –extremity fracture: OR 8.4 (1.3-55) n composite predictor: –0  0% –1  0.2% –2  0.5% –3  4.5 % –4 to 7  30%

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18 BAI: investigations - CXR n Wide mediastinum MS ration >0.25-0.4 n Blurred aortic knob n Pleural effusion n Apical Capping n NG deviation n 1 st or 2 nd rib # n Depressed left mainstem bronchus n Blunted AP window n HTX, PTX n Enlargement of the paratracheal stripe

19 Why do we screen with CXR? n Cheap n Readily available n Can be done in the trauma bay n non-invasive

20 BAI: investigations - CXR n Sensitivity: 75-90% (Pretre’95, Fabian ‘98, Scaletta’00) n CXR completely normal up to 25% pt’s w/ aortic injury! n Specificity: 5-10% n PPV: 10-20% (low prevalence)

21 BAI: investigations - CXR n Wide mediastinum (67-85%) n MS ration >0.25-0.38 n Blurred aortic knob (24%) n Pleural effusion (7-19%) n Apical Capping (4-19%) n NG deviation (3-11%) n Depressed left mainstem bronchus (5%) n Blunted AP window n HTX, PTX n Enlargement of the paratracheal stripe

22 BAI: investigations - CXR n MW dependent on pt position and depth of inspiration n Erect PA view better than supine AP n Schwab, ‘89

23 BAI: recommendation n CXR is good screening tool, but variably sensitive n Require further investigation: –WM or other cxr abnormality (not skeletal) OR –clinical suspicion OR –high risk mechanism

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25 BAI: investigations - angio n Gold standard n 73-100% sensitive n 1% false positive n Specificity 99% n contrast n time consuming n invasive n done in non-critical care environment

26 BAI: angio - recommendations n Even though CT and TEE can often obviate need for this invasive test n Still gold standard n Still needed to delineate injury n Still best at picking up proximal arch and arch branches

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28 BAI: investigations - hCT n Relatively widely available n non-invasive n fast n alternate diagnoses n Requires dye n costly

29 hCT - Fabian ‘98

30 BAI: hCT - recommendations n hCT has very high sensitivity, and can be used to exclude aortic injury if low clinical probability n Specificity only moderate n Aortography, still the gold standard –define non-specific CT abnormalities –negative CT scan but high clinical probability n As technology improves hCT may become the diagnostic modalities of choice [Greenberg ‘99]

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32 BAI: investigations - TEE n Less time consuming than angio n no contrast n bedside n serial exams n other info about heart n Invasive n may reqire intubation n need specific expertise n contraindicated if esophageal, c-spine or maxillo-facial injury

33 BAI: investigations - TEE n accurate for isthmus, but misses arch and arch branches. n complications: –respiratory distress –hypotension –cardiac dysrhythmias

34 BAI: TEE vs. angio n Smith, NEJM ‘95 –TEE: sens 100%, spec 98% n Kearney, J Trauma ‘93 –TEE: sens 100%, spec 100% –aortography: sens 63%, spec 98% n Buckmaster J Trauma ‘94 –TEE: sens 100%, spec 100% –aortography: sens 73%, spec 99%

35 BAI: TEE vs. angio (cont’d) n Chirillo, Heart ‘96 –sens 93%, spec 98% –suggested a positive test could be used to take patients directly to OR, significantly decreasing time to definitive therapy. n Goarin, J Trauma ‘00 –angio less sens than TEE, because did not Dx minor injuries (eg: intramural hematoma, limited intimal flap) –However, these did not require surgery –For clinically significant injuries, both angio and TEE had sens 97% and spec 100%

36 BAI: TEE vs. angio (cont’d) n Ahrar ‘97: –1% injury to proximal ascending aorta –9% injury to arch branches (14/17 intact aorta) –missed if TEE alone –retrospective –only 20 cases

37 BAI: algorithm ( Greenberg ‘99)

38 BAI: beta blockade n Short acting BB ( eg Esmolol, labetalol) n decrease wall stress with upstroke n titrate to sys BP < 100 mmHg and HR < 100 bpm n Systolic 110-120 mmHg tolerable if necessary, particularly in the elderly

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40 Case Two n 2nd passenger in the car n Our patient’s 70 year-old grandfather, who decided to join his grandson at the Tam Tam’s for the Sunday afternoon festivities. n Like his grandson, Gramps also seems well: –normal CXR –No chest pain –Mild sternal tenderness

41 Case Two n You consider the Dx of myocardial contusion. What next? –Discharge home –ECG: treatment plan based on results –ECG and enzymes –ECG and echo

42 MC: stats n Incidence: 3-75% n Depends on definition n On autopsy: well demarcated hemorrhagic area of anterior wall of right ventricle n lack of clinical gold standard makes it difficult to consistently define and difficult to interpret literature

43 MC: pathophysiology n Anterior force causing chest compression n sudden decel: heart moves freely and hits sternum n traction or torsion n fractured sternum

44 MC: associated risks n Age > 60 n high speed decelerations n unrestrained n steering column damage n 73% MC assoc’d with signs of external chest trauma: –multiple rib fractures / flail chest –pulmonary contusion –major vascular injury

45 MC: complications n 3% develop comp’s requiring treatment n dysrhythmias acount for 77% of comp’s n pump failure n MI n valve, cardiac rupture (rare) n tamponade, ventricular aneurism

46 MC: diagnosis n No gold standard short of autopsy n screening test: –clinical symptoms and signs –ECG –cardiac enzymes –radionucleotide scans –echo

47 MC: clinical presentation n Non-specific and inconsistent. n Cannot be relied upon to make Dx. n Findings: –chest wall tenderness, ecchymosis –dysrhythmias –chest pain (sharp or angina-like) –cardiac dysfunction similar to MI –sternal # NOT predictive

48 MC: ECG n Best screening test available in the ED n Sens 54% –sinus tachy is most sensitive –non-spec ST depression and T changes most specific –dysrhythmias, condction delay, axis deviation n Primary research inconsistent, small number of cases n Most agree that asymptomatic, stable patients with normal ECG can be safely discharged from ED

49 MC: ECG - Meta-analysis: Maenza, Am J Emerg Med ‘96 n All English retrospective, prospective and reviews from 1967-1993 n N= almost 5000 patients n ECG abnormalities correlated with complications –prospective: OR 9.18 (4.31-19.57) –retrospective: OR 26 (18.5-36.5) –combined: OR 19.9 (1.92-25.77)

50 MC: cardiac enzymes n Main problem: no gold standard to define MC. n CK-MB –Numerous prospective trials poor correlation –40-50% sensitive n Troponin –few, very small studies –sens variable (30%-100%) –seems more specific than CK-MB –does not change management: patients with documented elevation in Trops all had ECG abnormailities

51 MC: echo n does not correlate with ECG or enzymes n does not predict complications n not useful as screening tool in hemodynamically stable patients n should be used to answer specific clinical questions, when patients have the following: –unexplained hemodynamic instability / pump failure –abnormal ECG

52 MC: radionucleotide scans n Not useful at predicting complications n No better than echo and ECG

53 MC: recommendations n Eastern Assoc for the Surgery of Trauma ‘98: –No test is consistently reliable at Dx MC –Those with abnormal ECG should be admitted for cardiac monitoring for 24-48 hours, although no reported life-threatening dysrhythmia >12h –If normal ECG, can D/C home, as risk of complication that requires treatment is insignificant. –Hemodynamically unstable: echo –Radionucleotide scans and enzymes are not useful

54 References n Ahrar K, et al. Angiography in blunt thoracic aortic injury. J Trauma Apr 1997; 42(4):665-9. n Blackmore CC, et al. Determining risk of traumatic aortic injury: how to optimize image strategy. Am J Rad Feb 2000; 174: 343-7. n Fabian TC, et al. Prospective study of blunt aortic injury: multicenter trial of the American Association for the Surgey of Trauma. J Trauma Mar 1997; 42(3):374-80. n Fabian TC, et al. Prospective study of blunt aortic injury: helical CT […] reduces rupture. Ann Surg May 1998; 227(5):666-77. n Fisher RG, et al. Diagnosis of injuries of the aorta […] caused by chest trauma. Am J Roentgenol 1994; 162: 1047. n Gavant MI, et al. Blunt traumatic aorta rupture […] CT of the chest. Radiology 1995; 197:125. n Gendreau MA, et al. Complications of transesophageal echocardiography in the ED. Am J of Emerg Med May 1999; 17(3): 248-51. n Goarin JP, et al. Evaluation of transesophageal echocardiography for diagnosis of traumatic aortic injury. Anaesthesiology December 2000; 93(6). n Greenberg MD, Rosen CL. Evaluation of the patient with blunt chest trauma: an evidence based approach. Emer Med Clin North Am Feb 1999; 17(1): 41-62. n Hills, et al. Sternal fractures: associated injuries and management. J Trauma July 1993; 35(1):55-60. n Kearney PA, et al. Use of transesophageal echocardiography in the evaluation of traumatic aortic injury. J Trauma May 1993; 34(5):696-701.

55 References n Kram HB, et al. Diagnosis of traumatic thoracic aortic rupture: a ten year retrospective analysis. Ann Thorac Surg Feb 1989; 47(2): 282-6. n Maenza RL, et al. A meta-analysis of blunt cardiac trauma: ending myocardial confusion. Am J Emerg Med May 1996; 14(3):237-41. n Mirvis SE, et al. Value of chest radiography in excluding traumatic aortic rupture. Radiology May1987; 163(2): 487-93. n Morgan PB, Buechter KJ. Blunt thoracic aorta injuries: initial evaluation and management. Southern Medical Journal. Feb 2000; 93(2): 173-5. n Nagy K, et al. Diagnosis and management of blunt aortic injury[…]. J Trauma June 2000; 48(6): 1128-43. n Pasquale MD, et al. EAST practice management guidelines for screening of blunt cardiac injury. http://www.east.org/tpg.html n Pretre R, Chilcott M. Blunt trauma to the heart and great vessels. NEJM Feb 1997; 336(9): 626-632. n Rosen P, Barkin R. Emergency Medicine: Concepts and Clinical Practice, 4ed St Louis: Mosby, 1998. n Scaletta TA, Schaider JJ. Emergency Management of Trauma, 2nd Ed. New York: McGraw Hill, 2001. n Schwab CW, et al. Aortic injury: comparison of supine and upright portable chest films to evaluate the widened mediastinum. Ann Emerg Med Oct 1984; 13(10): 896-9. n Smith MD, et al. Transesophageal echocardiograpphy in the diagnosis of traumatic rupture of the aorta. NEJM Feb 1995; 332(6):356-62.


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