An ED Approach to Blunt An ED Approach to Blunt Aortic Injury and Aortic Injury and

Myocardial ConfusionMyocardial Confusion

Steven Issley, MD, CCFP

Emergency Medicine

McGill UniversitySeptember 12, 2001

OverviewOverview

Blunt aortic injury (BAI) Myocardial contusion

Focus:– which investigations– when should these investigations be done– how sensitive are these investigations

Case OneCase One

Sunday, 1600h.

Case OneCase One

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

Case OneCase One

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

Case OneCase One

Sunday, 1600h. On the way home from an afternoon of bongos in the park. 20 yo healthy, but not-so-smart male Trying to beat the light @ 80 km/h... T-boned to passenger’s side… As usual, being drunk, he walks out of his car without a

scratch. (...except for scratching his head in disbelief!)

Case OneCase One

Sunday, 1600h. On the way home from an afternoon of bongos in the park. 20 yo healthy, but not-so-smart male Trying to beat the light @ 80 km/h... T-boned to passenger’s side… As usual, being drunk, he walks out of his car without a

scratch. (...except for scratching his head in disbelief!)

He’s all yours!

Case OneCase One

Normal CXR Is this patient at risk for aortic dissection?

What Next?– A) discharge: no injuries and CXR is reassuring

– B) hCT chest; if normal discharge.

– C) angio, as high risk, despite negative studies

BAI: statsBAI: stats Aorta & great vessel injury 1-4% of blunt chest

traumas 20% incidence when BAI suspected (mechanism or

wide mediastinum) 75-90% ruprured thoracic aorta --> immediate death If untreated:

– 30% die within 1 day– 60% die within 1 week– 90% die within 1 month

71-84% survive with prompt intervention

BAI: pathophysiologyBAI: pathophysiology

Deceleration:– vertical (>30 ft / 10 m)

– horizontal (>30 mph / 50 km/h)

Mediastinum and diaphragm compression

Traction Dissection, thrombosis,

pseudoaneurism, hemorrhage

BAI: associated risksBAI: associated risks

High speed head on or T-bone (>30 mph / 50 km/h)

Ejection Other passengers dead Steering wheel deformity Fall from height (>30 ft / 10 m) NB: seat belt does not affect incidence

BAI: clinical findingsBAI: clinical findings

Physical exam not sens or spec 50% hypotension pseudocoarctation syndrome 30% harsh systolic murmur

BAI: associated injuriesBAI: associated injuries

Closed head injury (39%) Other significant chest pathology (67%) pelvic # (33%) Femur, tibia # (51%) T1-8 # liver & spleen injury 1st & 2nd rib # Sternum #

BAI: associated injuriesBAI: associated injuries

30-50% have no associated external injury!

BAI: clinical prediction ruleBAI: clinical prediction ruleBlackmore, et al. Blackmore, et al. Am J Rad 2000Am J Rad 2000 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)

composite predictor:– 0 0%

– 1 0.2%

– 2 0.5%

– 3 4.5 %

– 4 to 7 30%

BAI: investigations - CXRBAI: investigations - CXR

Wide mediastinum MS ration >0.25-0.4

Blurred aortic knob Pleural effusion Apical Capping NG deviation

1st or 2nd rib # Depressed left

mainstem bronchus Blunted AP window HTX, PTX Enlargement of the

paratracheal stripe

Why do we screen with CXR?Why do we screen with CXR?

Cheap Readily available Can be done in the trauma bay non-invasive

BAI: investigations - CXRBAI: investigations - CXR

Sensitivity: 75-90% (Pretre’95, Fabian ‘98, Scaletta’00)

CXR completely normal up to 25% pt’s w/ aortic injury!

Specificity: 5-10% PPV: 10-20% (low prevalence)

BAI: investigations - CXRBAI: investigations - CXR

Wide mediastinum (67-85%)

MS ration >0.25-0.38 Blurred aortic knob

(24%) Pleural effusion

(7-19%) Apical Capping

(4-19%)

NG deviation (3-11%) Depressed left

mainstem bronchus (5%)

Blunted AP window HTX, PTX Enlargement of the

paratracheal stripe

BAI: investigations - CXRBAI: investigations - CXR

MW dependent on pt position and depth of inspiration

Erect PA view better than supine AP Schwab, ‘89

BAI: recommendationBAI: recommendation

CXR is good screening tool, but variably sensitive

Require further investigation:– WM or other cxr abnormality (not skeletal)

OR– clinical suspicion

OR– high risk mechanism

BAI: investigations - angioBAI: investigations - angio

Gold standard 73-100% sensitive 1% false positive Specificity 99%

contrast time consuming invasive done in non-critical

care environment

BAI: angio - recommendationsBAI: angio - recommendations

Even though CT and TEE can often obviate need for this invasive test

Still gold standard Still needed to delineate injury Still best at picking up proximal arch and

arch branches

BAI: investigations - hCTBAI: investigations - hCT

Relatively widely available

non-invasive fast alternate diagnoses

Requires dye costly

hCT - Fabian ‘98hCT - Fabian ‘98

hCT Angio

Sensitivity 100% 92%

Specificity 83% 99%

PPV 50% 100%

NPV 100% 97%

BAI: hCT - recommendationsBAI: hCT - recommendations

hCT has very high sensitivity, and can be used to exclude aortic injury if low clinical probability

Specificity only moderate Aortography, still the gold standard

– define non-specific CT abnormalities

– negative CT scan but high clinical probability As technology improves hCT may become the

diagnostic modalities of choice [Greenberg ‘99]

BAI: investigations - TEEBAI: investigations - TEE

Less time consuming than angio

no contrast bedside serial exams other info about heart

Invasive may reqire intubation need specific expertise contraindicated if

esophageal, c-spine or maxillo-facial injury

BAI: investigations - TEEBAI: investigations - TEE

accurate for isthmus, but misses arch and arch branches.

complications:– respiratory distress– hypotension– cardiac dysrhythmias

BAI: TEE vs. angioBAI: TEE vs. angio

Smith, NEJM ‘95– TEE: sens 100%, spec 98%

Kearney, J Trauma ‘93– TEE: sens 100%, spec 100%

– aortography: sens 63%, spec 98% Buckmaster J Trauma ‘94

– TEE: sens 100%, spec 100%

– aortography: sens 73%, spec 99%

BAI: TEE vs. angio (cont’d)BAI: TEE vs. angio (cont’d)

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.

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%

BAI: TEE vs. angio (cont’d)BAI: TEE vs. angio (cont’d)

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

BAI: algorithmBAI: algorithm

(Greenberg ‘99)

BAI: beta blockadeBAI: beta blockade

Short acting BB (eg Esmolol, labetalol) decrease wall stress with upstroke titrate to sys BP < 100 mmHg

and HR < 100 bpm Systolic 110-120 mmHg tolerable if

necessary, particularly in the elderly

Case TwoCase Two

2nd passenger in the car Our patient’s 70 year-old grandfather, who decided to join

his grandson at the Tam Tam’s for the Sunday afternoon festivities.

Like his grandson, Gramps also seems well:– normal CXR

– No chest pain

– Mild sternal tenderness

Case TwoCase Two

You consider the Dx of myocardial contusion. What next?

– Discharge home

– ECG: treatment plan based on results

– ECG and enzymes

– ECG and echo

MC: statsMC: stats

Incidence: 3-75% Depends on definition On autopsy: well demarcated hemorrhagic

area of anterior wall of right ventricle lack of clinical gold standard makes it

difficult to consistently define and difficult to interpret literature

MC: pathophysiologyMC: pathophysiology

Anterior force causing chest compression sudden decel: heart moves freely and hits

sternum traction or torsion fractured sternum

MC: associated risksMC: associated risks

Age > 60 high speed decelerations unrestrained steering column damage 73% MC assoc’d with signs of external chest

trauma: – multiple rib fractures / flail chest

– pulmonary contusion

– major vascular injury

MC: complicationsMC: complications

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

MC: diagnosisMC: diagnosis

No gold standard short of autopsy screening test:

– clinical symptoms and signs– ECG– cardiac enzymes– radionucleotide scans– echo

MC: clinical presentationMC: clinical presentation

Non-specific and inconsistent. Cannot be relied upon to make Dx. Findings:

– chest wall tenderness, ecchymosis – dysrhythmias– chest pain (sharp or angina-like)– cardiac dysfunction similar to MI– sternal # NOT predictive

MC: ECGMC: ECG

Best screening test available in the ED Sens 54%

– sinus tachy is most sensitive

– non-spec ST depression and T changes most specific

– dysrhythmias, condction delay, axis deviation Primary research inconsistent, small number of

cases Most agree that asymptomatic, stable patients with

normal ECG can be safely discharged from ED

MC: ECG - MC: ECG - Meta-analysis:Meta-analysis: Maenza, Am J Emerg Med ‘96Maenza, Am J Emerg Med ‘96

All English retrospective, prospective and reviews from 1967-1993

N= almost 5000 patients 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)

MC: cardiac enzymesMC: cardiac enzymes

Main problem: no gold standard to define MC. CK-MB

– Numerous prospective trials poor correlation – 40-50% sensitive

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

MC: echoMC: echo

does not correlate with ECG or enzymes does not predict complications not useful as screening tool in hemodynamically

stable patients should be used to answer specific clinical

questions, when patients have the following:– unexplained hemodynamic instability / pump failure

– abnormal ECG

MC: radionucleotide scansMC: radionucleotide scans

Not useful at predicting complications

No better than echo and ECG

MC: recommendationsMC: recommendations

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

ReferencesReferences Ahrar K, et al. Angiography in blunt thoracic aortic injury. J Trauma Apr 1997; 42(4):665-9. Blackmore CC, et al. Determining risk of traumatic aortic injury: how to optimize image strategy. Am J Rad Feb

2000; 174: 343-7. 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. Fabian TC, et al. Prospective study of blunt aortic injury: helical CT […] reduces rupture. Ann Surg May 1998;

227(5):666-77. Fisher RG, et al. Diagnosis of injuries of the aorta […] caused by chest trauma. Am J Roentgenol 1994; 162: 1047. Gavant MI, et al. Blunt traumatic aorta rupture […] CT of the chest. Radiology 1995; 197:125. Gendreau MA, et al. Complications of transesophageal echocardiography in the ED. Am J of Emerg Med May 1999;

17(3): 248-51. Goarin JP, et al. Evaluation of transesophageal echocardiography for diagnosis of traumatic aortic injury.

Anaesthesiology December 2000; 93(6). 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. Hills, et al. Sternal fractures: associated injuries and management. J Trauma July 1993; 35(1):55-60. Kearney PA, et al. Use of transesophageal echocardiography in the evaluation of traumatic aortic injury. J Trauma

May 1993; 34(5):696-701.

ReferencesReferences Kram HB, et al. Diagnosis of traumatic thoracic aortic rupture: a ten year retrospective analysis. Ann Thorac Surg

Feb 1989; 47(2): 282-6. Maenza RL, et al. A meta-analysis of blunt cardiac trauma: ending myocardial confusion. Am J Emerg Med May

1996; 14(3):237-41. Mirvis SE, et al. Value of chest radiography in excluding traumatic aortic rupture. Radiology May1987; 163(2):

487-93. Morgan PB, Buechter KJ. Blunt thoracic aorta injuries: initial evaluation and management. Southern Medical

Journal. Feb 2000; 93(2): 173-5. Nagy K, et al. Diagnosis and management of blunt aortic injury[…]. J Trauma June 2000; 48(6): 1128-43. Pasquale MD, et al. EAST practice management guidelines for screening of blunt cardiac injury.

http://www.east.org/tpg.html Pretre R, Chilcott M. Blunt trauma to the heart and great vessels. NEJM Feb 1997; 336(9): 626-632. Rosen P, Barkin R. Emergency Medicine: Concepts and Clinical Practice, 4ed St Louis: Mosby, 1998. Scaletta TA, Schaider JJ. Emergency Management of Trauma, 2nd Ed. New York: McGraw Hill, 2001. 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. Smith MD, et al. Transesophageal echocardiograpphy in the diagnosis of traumatic rupture of the aorta. NEJM Feb

1995; 332(6):356-62.