1、An ED Approach to Blunt Aortic Injury and Myocardial ConfusionSteven Issley, MD, CCFPEmergency MedicineMcGill UniversitySeptember 12, 2001OverviewBlunt aortic injury (BAI)Myocardial contusionFocus:which investigationswhen should these investigations be donehow sensitive are these investigationsCase

2、OneSunday, 1600h. Case OneSunday, 1600h. On the way home from an afternoon of bongos in the park.20 yo healthy, but not-so-smart maleTrying to beat the light 80 km/h.Case OneSunday, 1600h. On the way home from an afternoon of bongos in the park.20 yo healthy, but not-so-smart maleTrying to beat the

3、light 80 km/h.T-boned to passengers sideAs usual, being drunk, he walks out of his car without a scratch. (.except for scratching his head in disbelief!)Case OneSunday, 1600h. On the way home from an afternoon of bongos in the park.20 yo healthy, but not-so-smart maleTrying to beat the light 80 km/h

4、.T-boned to passengers sideAs usual, being drunk, he walks out of his car without a scratch. (.except for scratching his head in disbelief!)Hes all yours!BAI: statsAorta & great vessel injury 1-4% of blunt chest traumas20% incidence when BAI suspected (mechanism or wide mediastinum)75-90% ruprured t

5、horacic aorta - immediate deathIf untreated:30% die within 1 day60% die within 1 week90% die within 1 month71-84% survive with prompt interventionBAI: pathophysiologyDeceleration:vertical (30 ft / 10 m)horizontal (30 mph / 50 km/h) Mediastinum and diaphragm compression TractionDissection, thrombosis

6、, pseudoaneurism, hemorrhageBAI: associated risksHigh speed head on or T-bone (30 mph / 50 km/h)EjectionOther passengers dead Steering wheel deformity Fall from height (30 ft / 10 m)NB: seat belt does not affect incidenceBAI: associated injuriesClosed head injury (39%)Other significant chest patholo

7、gy (67%)pelvic # (33%)Femur, tibia # (51%)T1-8 # liver & spleen injury 1st & 2nd rib #Sternum #BAI: associated injuries30-50% have no associated external injury!BAI: investigations - CXRWide mediastinum MS ration 0.25-0.4Blurred aortic knob Pleural effusion Apical Capping NG deviation 1st or 2nd rib

8、 #Depressed left mainstem bronchusBlunted AP window HTX, PTXEnlargement of the paratracheal stripeWhy do we screen with CXR?CheapReadily availableCan be done in the trauma baynon-invasiveBAI: investigations - CXRSensitivity: 75-90% (Pretre95, Fabian 98, Scaletta00) CXR completely normal up to 25% pt

9、s w/ aortic injury!Specificity: 5-10%PPV: 10-20% (low prevalence)BAI: investigations - CXRWide mediastinum (67-85%)MS ration 0.25-0.38Blurred aortic knob (24%) Pleural effusion (7-19%)Apical Capping (4-19%)NG deviation (3-11%)Depressed left mainstem bronchus (5%) Blunted AP window HTX, PTXEnlargemen

10、t of the paratracheal stripeBAI: investigations - CXRMW dependent on pt position and depth of inspirationErect PA view better than supine APSchwab, 89BAI: investigations - angioGold standard73-100% sensitive1% false positiveSpecificity 99%contrasttime consuminginvasivedone in non-critical care envir

11、onmentBAI: investigations - hCTRelatively widely availablenon-invasivefastalternate diagnosesRequires dyecostlyhCT - Fabian 98BAI: hCT - recommendationshCT has very high sensitivity, and can be used to exclude aortic injury if low clinical probability Specificity only moderateAortography, still the

12、gold standarddefine non-specific CT abnormalitiesnegative CT scan but high clinical probability As technology improves hCT may become the diagnostic modalities of choice Greenberg 99BAI: investigations - TEELess time consuming than angiono contrastbedsideserial examsother info about heart Invasivema

13、y reqire intubationneed specific expertisecontraindicated if esophageal, c-spine or maxillo-facial injuryBAI: investigations - TEEaccurate for isthmus, but misses arch and arch plications:respiratory distresshypotensioncardiac dysrhythmiasBAI: TEE vs. angioSmith, NEJM 95TEE: sens 100%, spec 98%Kearn

14、ey, J Trauma 93TEE: sens 100%, spec 100%aortography: sens 63%, spec 98%Buckmaster J Trauma 94TEE: sens 100%, spec 100%aortography: sens 73%, spec 99%BAI: TEE vs. angio (contd)Chirillo, Heart 96sens 93%, spec 98%suggested a positive test could be used to take patients directly to OR, significantly de

15、creasing time to definitive therapy.Goarin, J Trauma 00angio less sens than TEE, because did not Dx minor injuries (eg: intramural hematoma, limited intimal flap)However, these did not require surgeryFor clinically significant injuries, both angio and TEE had sens 97% and spec 100%BAI: TEE vs. angio

16、 (contd)Ahrar 97:1% injury to proximal ascending aorta9% injury to arch branches (14/17 intact aorta)missed if TEE aloneretrospectiveonly 20 casesBAI: algorithm(Greenberg 99)BAI: beta blockadeShort acting BB (eg Esmolol, labetalol)decrease wall stress with upstroketitrate to sys BP 100 mmHg and HR 6

17、0high speed decelerationsunrestrainedsteering column damage73% MC assocd with signs of external chest trauma: multiple rib fractures / flail chestpulmonary contusionmajor vascular injuryMC: complications3% develop comps requiring treatmentdysrhythmias acount for 77% of compspump failureMIvalve, card

18、iac rupture (rare)tamponade, ventricular aneurismMC: diagnosisNo gold standard short of autopsyscreening test:clinical symptoms and signsECGcardiac enzymesradionucleotide scansechoMC: clinical presentationNon-specific and inconsistent.Cannot be relied upon to make Dx.Findings:chest wall tenderness,

19、ecchymosis dysrhythmiaschest pain (sharp or angina-like)cardiac dysfunction similar to MIsternal # NOT predictiveMC: ECGBest screening test available in the EDSens 54%sinus tachy is most sensitivenon-spec ST depression and T changes most specificdysrhythmias, condction delay, axis deviationPrimary r

20、esearch inconsistent, small number of casesMost agree that asymptomatic, stable patients with normal ECG can be safely discharged from EDMC: ECG - Meta-analysis: Maenza, Am J Emerg Med 96All English retrospective, prospective and reviews from 1967-1993N= almost 5000 patientsECG abnormalities correla

21、ted with complicationsprospective: OR 9.18 (4.31-19.57)retrospective: OR 26 (18.5-36.5)combined: OR 19.9 (1.92-25.77)MC: cardiac enzymesMain problem: no gold standard to define MC.CK-MBNumerous prospective trials poor correlation 40-50% sensitiveTroponinfew, very small studiessens variable (30%-100%

22、)seems more specific than CK-MBdoes not change management: patients with documented elevation in Trops all had ECG abnormailitiesMC: echodoes not correlate with ECG or enzymesdoes not predict complicationsnot useful as screening tool in hemodynamically stable patientsshould be used to answer specifi

23、c clinical questions, when patients have the following:unexplained hemodynamic instability / pump failureabnormal ECGMC: radionucleotide scansNot useful at predicting complicationsNo better than echo and ECGMC: recommendationsEastern Assoc for the Surgery of Trauma 98:No test is consistently reliabl

24、e at Dx MCThose with abnormal ECG should be admitted for cardiac monitoring for 24-48 hours, although no reported life-threatening dysrhythmia 12hIf normal ECG, can D/C home, as risk of complication that requires treatment is insignificant.Hemodynamically unstable: echo Radionucleotide scans and enz

25、ymes are not usefulReferencesAhrar 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

26、 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 ch

27、est 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 transesophag

28、eal 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 injurie

29、s 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.ReferencesKram 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 excludin