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Blunt Chest Trauma: Some Newer Concepts

Blunt Chest Trauma: Some Newer Concepts. Joe Lex, MD, FACEP, MAAEM Temple University School of Medicine Philadelphia, PA – USA Joe@JoeLex.net @JoeLex5. Objectives. Discuss commotio cordis Describe current concepts in treating flail chest Discuss concept and treatment of traumatic asphyxia.

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Blunt Chest Trauma: Some Newer Concepts

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  1. Blunt Chest Trauma:Some Newer Concepts Joe Lex, MD, FACEP, MAAEM Temple University School of Medicine Philadelphia, PA – USA Joe@JoeLex.net @JoeLex5

  2. Objectives • Discuss commotio cordis • Describe current concepts in treating flail chest • Discuss concept and treatment of traumatic asphyxia

  3. Commotio Cordis Low Impact Trauma: Commotio Cordis / Blunt Cardiac Injury

  4. Commotio Cordis • From Latin: agitation of the heart • Most common cause of death in youths playing baseball • Also reported during hockey, softball, lacrosse, karate, others • Rarely discussed, but in textbooks since 1857 Link MS. Prog Biophys Mol Biol. 2003 May-Jul;82(1-3):175-86.

  5. What causes it? • Ventricular fibrillation triggered by chest wall impact over center of left ventricle • Timing dependent: immediate ventricular fibrillation if in 15-millisecond window occurring 15-30 milliseconds before T-wave peak Link MS, et al. J Am Coll Cardiol 2000; 37(2): 649-54

  6. What causes it? • At 60 beats / minute: total cardiac cycle ~1000 milliseconds • Probability of mechanical trauma in window of vulnerability: 1 to 3% • Faster heart rate during athletics  increases probability Link MS, et al. J Am Coll Cardiol 2000; 37(2): 649-54

  7. What causes it? • 120 beats / minute: cardiac cycle shortens to 500 ms without altering vulnerability window • Exercise hypoxia, heart conduction acceleration make it more susceptible to stretch-induced ventricular fibrillation Link MS, et al. J Am Coll Cardiol 2000; 37(2): 649-54

  8. What causes it? • Swine model with baseballs • Ventricular fibrillation caused by strikes of 20 kph • Perfectly timed strike with standard baseball caused ventricular fibrillation in 35% Link MS, et al. N Engl J Med 1998; 338(25): 1805-11

  9. What causes it? • Impact energies of 50 joules required to cause cardiac arrest • May be lower in ischemic states • 130 joules: measured with hockey pucks, lacrosse balls • 450 joules: karate punches Link MS, et al. N Engl J Med 1998; 338(25): 1805-11

  10. What causes it? Link MS, et al. N Engl J Med 1998; 338(25): 1805-11

  11. What causes it?

  12. What’s the pathophysiology? • In vivo studies suggest ventricular fibrillation caused by selective potassium-channel activation induced by impact Link MS, et al. Circulation 1999; 100(4): 413-8

  13. How often does it occur? • 1996-2007: 188 cases in National Commotio Cordis Registry (USA) • ~50% during organized sports • 96% of victims were male • Mean age of victim: 14.7 years • Survival: <20%

  14. History: what happens? • Sudden death following inconsequential chest blow • Eyewitnesses universally believe chest trauma minor • 50% collapse immediately • 50% brief purposeful behavior (pick up, throw ball) before final collapse

  15. History: what happens? • CPR delayed: observers underestimate severity • Survival better if… …CPR started in 1-3 minutes …chest thump …defibrillation • CPR delayed > 3 minutes: poor Link MS, et al. Cardiol Rev. 1999 Sep-Oct;7:265-9.

  16. Physical Findings • Unresponsive, apneic, pulseless, no audible heartbeat • Cyanosis common • Seizures in some • Chest wall bruising in one third • No damage to ribs or sternum

  17. Work-up of Survivors • Lab studies: invariably normal • Cardiac biomarkers: normal • Echocardiography: anatomically and functionally normal heart • Angiography: normal cardiac and coronary artery anatomy

  18. Most common initial ECG findings in both survivors and nonsurvivors: ventricular fibrillation and asystole Work-up of Survivors

  19. Sometimes have impressive V1-V3 ST elevation Significance unclear: ischemia not shown to result from commotio Work-up of Survivors

  20. Work-up of Survivors • Other findings in survivors: 3o heart block, left bundle branch block, idioventricular escape • Usually lasts only 2-3 days • Similar to swine model when chest wall impact timed to occur outside period of greatest vulnerability Link MS, et al. Chest. 1998 Jul;114(1):326-8.

  21. Treatment of Commotio • Early defibrillation • Within 1 minute of ventricular fibrillation: ~100% survival • Within 2 minutes: 80% survival • More than 4 minutes • 0% survival without CPR • 65% survival with CPR

  22. Precordial Thump • Class IIb (acceptable, possibly helpful) in adult CPR during witnessed arrest with no pulse • Not in pediatric CPR or PALS • Thump can convert ventricular fibrillation to sinus rhythm… • …but can also cause deterioration to ventricular fibrillation, PEA, asystole

  23. AEDs • July 2003: PALS Task Force of ILCOR said Automated External Defibrillators (AEDs) may be used in children aged 1 – 8 years with no signs of circulation • Ideally: pediatric pads and cable • AED algorithms highly specific, reasonably sensitive in children Link MS, et al. J Cardiovasc Electrophys. 2003;14:83-7.

  24. AEDs

  25. Deterrence and Prevention • Special athletic gear to protect precordial area • Specially designed softer-than-normal safety baseballs in recreational baseball • Prompt recognition, early CPR, and readily available AEDs Link MS, et al. Pediatrics. 2002 May;109(5):873-7.

  26. Chest Protectors

  27. Chest Protectors • Seven deaths reported in baseball players who wore chest protectors Weinstock J, Maron BJ, Song C, Mane PP, Estes NA 3rd, Link MS. Failure of commercially available chest wall protectors to prevent sudden cardiac death induced by chest wall blows in an experimental model of commotio cordis. Pediatrics. 2006 Apr;117(4):e656. Doerer JJ, Haas TS, Estes NA 3rd, Link MS, Maron BJ. Evaluation of chest barriers for protection against sudden death due to commotio cordis. Am J Cardiol. 2007 Mar 15;99(6):857-9.

  28. Manslaughter and Murder Washington, DC, 1998: 18 years in prison for involuntary manslaughter after the sudden death of 11-year-old boy immediately following two seemingly innocuous, but punitive, chest blows by his father http://www.mnmed.org/publications/MnMed2000/June/Emerson.cfm

  29. Manslaughter and Murder Cook County (Chicago) Medical Examiner: brothers aged 3 years and 14 month died after they were deliberately struck with closed fist. Medics found both in ventricular fibrillation, could not resuscitate. Denton JS. Forensic Science, 2000: 45(3), 734-735

  30. Blunt Cardiac Injury Level 1 recommendation • Perform admission electrocardio-gram on patients with suspected blunt cardiac injury Clancy K, et al. J Trauma Acute Care Surg 2012:73;S301-S306

  31. Blunt Cardiac Injury Level 2 recommendation • If admission EKG shows a new abnormality (arrhythmia, ST changes, heart block, unexpected ST changes) admit for continuous EKG monitoring Clancy K, et al. J Trauma Acute Care Surg 2012:73;S301-S306

  32. Blunt Cardiac Injury Level 2 recommendation • Normal EKG and troponin I  blunt cardiac injury is ruled out • Optimal timing not yet determined • Normal EKG but elevated troponin  admit to monitored setting Clancy K, et al. J Trauma Acute Care Surg 2012:73;S301-S306

  33. Blunt Cardiac Injury Level 2 recommendation • Hemodynamically unstable or persistent new arrhythmia  perform echocardiogram (transthoracic or transesophageal) Clancy K, et al. J Trauma Acute Care Surg 2012:73;S301-S306

  34. Blunt Cardiac Injury Level 2 recommendation • Sternal fracture alone does not predict blunt cardiac injury • Routine monitoring not recommended in absence of EKG or troponin changes Clancy K, et al. J Trauma Acute Care Surg 2012:73;S301-S306

  35. Blunt Cardiac Injury Level 2 recommendation • Creatinine phosphokinase with isoenzymes NOT recommended • Not useful in determining complications Clancy K, et al. J Trauma Acute Care Surg 2012:73;S301-S306

  36. Blunt Cardiac Injury Level 2 recommendation Nuclear medicine studies NOT recommended Add nothing useful to echocardiogram Clancy K, et al. J Trauma Acute Care Surg 2012:73;S301-S306

  37. Blunt Cardiac Injury Level 3 recommendation • Routinely measure troponin I in patients with suspected blunt cardiac injury • If elevated, admit to monitor setting and follow serial troponin • Optimal timing: unknown Clancy K, et al. J Trauma Acute Care Surg 2012:73;S301-S306

  38. Flail Chest High Impact Trauma: Flail Chest

  39. Historical Note • NATO Handbook for Emergency War Surgery (1958): treatment is "firm strapping" of affected area to prevent flail-like motion • Old surgery texts: towel clips around ribs / K-wire through chest / weights from pulleys Maloney JV Jr, et al. J Thorac Cardiovasc Surg. 1961 Mar;41:291-8.

  40. Historical Note

  41. Historical Note

  42. Pathophysiology • Multiple anterior and posterior rib fractures  unstable chest wall • Profound ventilation / perfusion mismatch: lung contusion, pain of rib fractures • Paradoxical or reverse motion of chest wall segment with spontaneous breathing

  43. Pathophysiology • Flail movement limited by surrounding structures • Limitation affects size of changes in thoracic volume and patient-generated tidal volume • Underlying pulmonary or cardiac disease determines physiologic perturbations to respiration

  44. Pathophysiology • More important: injury to underlying structures • Respiratory insufficiency due to underlying severity of pulmonary contusion and ventilation perfusion mismatch, NOT mechanical flail • ARDS rate increases 20 – 30% Richardson JD. Ann Surg 1982 Oct;196(4): 481-7

  45. Frequency • No registry: unknown with certainty • American College of Surgeons: Level 1 or Level 2 trauma center sees 1–2 cases / month • Incidence at nontrauma centers: unknown Champion HR. J Trauma 1990 Nov;30 (11):1356-65

  46. Imaging Studies • Flail segment: clinical diagnosis • Chest x-ray: easiest to perform, delineates number of fractured ribs • Three-dimensional reconstruction of thoracic helical CT scan… …identifies rib fractures …identifies underlying lung and mediastinal trauma

  47. Radiograph

  48. Radiograph

  49. Medical Therapy • Internal pneumatic stabilization unnecessary in most patients • Pain control + pulmonary toilet better than mechanical ventilation • Current standard: patient-controlled analgesia, oral pain medicine, epidural catheters Trinkle JK. Ann Thorac Surg 1975;19(4): 355-63

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