Blunt and Penetrating Chest Trauma Adam Oster R4 Arun Abbi, MD FRCP Core Rounds September 9, 2004. Topics Blunt Aortic Injuries Myocardial Contusion Occult Pneumothorax ED Thoracotomy Hemothorax Pulmonary Contusion Penetrating Pneumothorax Tamponade Case 1 23M unrestrained driver struck a light pole at highway speeds. Ejected. Found 20meters from his car. GCS 9 Hemodynamics normal Facial trauma Case 1 Blunt Aortic Injury MC mechanism is Rapid deceleration Why? Aortic arch is mobile and descending arch is immobile d/t ligamentum arteriosum Rapid deceleration places aortic isthmus under tension shearing stress can result in tearing opposite to fixation site. 90% die on scene Remaining 50% within 24hrs without prompt definitive treatment Blunt Aortic Injury Clinical presentation Sensitivity of screening DI (CXR) Imaging controversies; CXR vs CT CT vs angiography CT vs TEE Blunt Aortic Injury Sensitivity of the CXR What are the high risk findings? Mediastinal widening (>8cms?? 1970s Marsh and Sturm) Apical cap Loss of AP window Loss of aortic knob Rightward deviation of NG (of the T3/4 SP) Rightward deviation of the trachea Downward displacement of lt mainstem Thickening of right paratracheal stripe (>5mm) NB isolated # 1 st /2 nd ribs are not predictive of injury Blunt Aortic Injury: Sensitivity of the CXR Sensitivity of CXR approx 90% Loss of aortic knob (sens= %, spec 21-55%) Mediastinal widening (sens= , spec %) Defn of widening is ambiguous in the literature >8cm at origin lt subclavian or Ratio of mediastinal width to width of thorax at aortic knob Sensitivity of the CXR Approx 90-98% NPV of a normal CXR is 96% CXR can be normal in up to 5% with TAI Cannot completely r/o the injury Take into account pre-test probability PPV low 5-20% Blunt Aortic Injury and the CXR Radiology vol. 163 (abstract only) N=205 retrospective review with BCT 41 with angiographically-proven BAI Analyzed 16 distinct CXR features most discriminating signs were loss of the AP window, abnormality of the aortic arch rightward tracheal shift widening of the left paraspinal line No single or combination of radiographic signs demonstrated sufficient sensitivity to indicate all cases of traumatic aortic rupture on plain chest radiographs The bedside anteroposterior upright view of the chest proved far more valuable than the supine view in detecting true-negative studies. significant reader variability Blunt Aortic Injury Journal of Trauma. July, 2004 Mediastinal width (MW), left mediastinal width (LMW) and the ratio (MWR) measured on resusc CXR GS = either surgery or angio 51 had CT, 45 had aortogrpahy, 6 thoracotomy after CT Results 21/51 TAI Surgically-proved in 20 Successful repair in 18 19/20 pathology at isthmus Results Best combination predictor is LMW >6.0 and MWR >0.60 LR = 3.0 Blunt Aortic Injury Journal of Trauma. December, Prospective, n=93 MVC >10MPH (76%) Fall >5ft (24%) Excluded hemodynamically unstable and severe HI All had CXR and CT Sensitivity 82% Specificity 57% CXR missed 2/3 BAI Sensitivity of CXR for Chest Injuries Blunt Aortic Injury 7.3% with confirmed TAI had normal mediastinum on CXR. Blunt Aortic Injury: The CXR Retrospective review of white peoples CT chest to determine normal AP width Excluded abnormal mediastinums Mean width 6.1cms on CT Modern trauma rooms cms Historic upper limit of normal does not apply FFD and OFD The CXR in BAI Emergency Medicine Clinics of North America. February, Meta-analysis. Most specific findings Lt tracheal deviation (80-95%) NG deviation (90-94%) Depressed lt mainstem bronchus (80-100%) No association with sternal # or thorasic rib# Blunt Aortic Injury: Identification by Mechanism Journal Of Trauma. June 1, 2001. Blunt Aortic Injury: Identification by Mechanism Retrospective review of crash site data GS was radiographic or autopsy N=34 (12%) Head-on crash = 5% Side impact = 59% (20/34) 74% in compact cars 65% vehicle-vehicle 35% vehicle- pole/wall ##Presence of delta V>20mph or near-side impact was present in All TAI. Either had NPV =100% Mechanics Blunt Aortic Injury: Identification by Mechanism Journal of Trauma. April, Cohort design. NASS database. Independent positive predictors for BAI Age > 60 Front-seated Frontal and near- side impacts Delta V>40mph Crush >40cms Intrusion >15cms Negative predictors Seat-belt use Occupant of large vehicle Blunt Aortic Injury: Identification by Mechanism Journal of Trauma. Jan, Retrospective autopsy review of all BAI. N=242 (12% all trauma deaths) MC mechanism Head-on>side-impact CXR Abnormal How to diagnose BAI CT Angio TTE TEE OR CT vs Angiography Parallel CT and angiography for n=142 with suspected BAI All had unclearable CXR Blinded Radiologists CT vs Angio CT neg = 121 (kappa 0.7) CT pos = 7 (kappa 0.9!) Sens = 100% NPV = 100% Spec = 87% $500 cost savings/pt CT vs Angiography Journal of Trauma. Feb, 2004. CT vs Angiography Retrospective registry data All pts had aortography Most had CT Findings confirmed surgically NB CXR normal in 7% Non-specifically abnormal in 53% (BAI not suspected) CT vs Angiography CT performance 1 miss 5 FP Agreed in 93 cases Sens = 87% Spec = 98% Chest, Prospective review of TAI patients (n=28) confirmed by angio/surgery/MRI All had TEE Control group of 30 with chest trauma and wide mediastinum but no TAI Describe the echo findings associated with TAI MC findings Thick stripe Intimal lesions False aneurysms Aortic wall hematoma TEE for Detection of Mediastinal Lesions Journal of Trauma, Prospective, n=70. All intubated TEE within 48hrs TEE for Detection of Mediastinal Lesions. Journal of Trauma, But Only 1 lesion Unclear GS ?blinded to other investigations TEE Smith et al. NEJM, Prospective, n=93 TEE followed by angio GS = angio/surgery/autopsy Mean time to TEE 29mins Sens = 100% Spec 98% TEE Chrillo et al., Heart Prospective, consecutive, n=134. Clinical evidence chest trauma or mechanism Sens = 93% Spec = 98% Time to surgery shorter (30 vs 71mins) Blunt Aortic Injury Journal of Trauma. Jan, Retrospective registry data Early repair = 2hrs Ongoing transfusion requirements?? Case The Physical Exam: Sensitivity for Hemothorax and Pneumothorax Journal of Trauma. December, Prospective, non-consecutive, n=676 (523 blunt) Blunt and penetrating chest trauma Signs and symptoms of hemothorax and pneumothorax defined apriori Accuracy of the physical exam dissimilar for penetrating and blunt trauma Eg sens/NPV for auscultation 100% for blunt but 50% for penetrating ??specificity of auscultation is 100% for disease in penetrating But, non-blinded to CXR Disease spectrum? Did not demonstrate altered management Resuscitation Retrospective review of patients with pulmonary contusion and with high FiO2 requirements (FiO2/PaO2