The Science Behind Trauma Care

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The Science Behind Trauma Care

  1. 1. The Science Behind Trauma Care Dr. Bryan E. Bledsoe Professor, Emergency Medicine The George Washington University Medical Center
  2. 5. Audience Interaction <ul><li>Which of the following actresses is my favorite? </li></ul><ul><ul><li>A. Sandra Bullock </li></ul></ul><ul><ul><li>B. Angelina Jolie </li></ul></ul><ul><ul><li>C. Salma Hayek </li></ul></ul><ul><ul><li>D. Nicole Kidman </li></ul></ul><ul><ul><li>E. George Michael </li></ul></ul>
  3. 7. Science in Trauma Care Negative Evidence No Evidence Or Equivocal Evidence Positive Evidence
  4. 8. Levels of Evidence <ul><li>Not all scientific evidence is the same. </li></ul>
  5. 9. Audience Interaction <ul><li>My ambulance service practices evidence-based prehospital care? </li></ul><ul><ul><li>A. Strongly agree </li></ul></ul><ul><ul><li>B. Agree </li></ul></ul><ul><ul><li>C. Neither agree nor disagree </li></ul></ul><ul><ul><li>D. Disagree </li></ul></ul><ul><ul><li>E. Strongly disagree. </li></ul></ul>
  6. 10. Levels of Evidence <ul><li>Center for Evidence-Based Medicine (Oxford) </li></ul><ul><ul><li>Ia. Meta-analysis of RCTs </li></ul></ul><ul><ul><li>Ib. One RCT. </li></ul></ul><ul><ul><li>IIa. Controlled trial without randomisation. </li></ul></ul><ul><ul><li>IIb. One other type of quasi-experimental study. </li></ul></ul><ul><ul><li>III. Descriptive studies, such as comparative studies, correlation studies, and case-control studies. </li></ul></ul><ul><ul><li>IV. Expert committee reports or opinions, or clinical experience of respected authorities or both. </li></ul></ul>
  7. 11. Levels of Evidence <ul><li>American Heart Association </li></ul><ul><ul><li>1. Positive randomized controlled trials. </li></ul></ul><ul><ul><li>2. Neutral randomized controlled trials. </li></ul></ul><ul><ul><li>3. Prospective, non-randomized controlled trials. </li></ul></ul><ul><ul><li>4. Retrospective, non-randomized controlled trials </li></ul></ul><ul><ul><li>5. Case series (no control group) </li></ul></ul><ul><ul><li>6. Animal studies </li></ul></ul><ul><ul><li>7. Extrapolations </li></ul></ul><ul><ul><li>8. Rational conjecture (common sense) </li></ul></ul>
  8. 12. Levels of Evidence
  9. 13. Levels of Evidence <ul><li>The closer a study adheres to the scientific method, the more valid the study. </li></ul><ul><li>The more valid the study, the closer it is to the truth. </li></ul>
  10. 14. Ranking the Evidence <ul><li>Class I: </li></ul><ul><ul><li>Derived from the strongest studies of therapeutic interventions (RCTs) in humans. </li></ul></ul><ul><ul><li>Used to support treatment recommendations of the highest order called practice standards . </li></ul></ul>
  11. 15. Ranking the Evidence <ul><li>Class II: </li></ul><ul><ul><li>Derived from the comparative studies with less strength (nonrandomized cohort studies, RCTs with significant design flaws, and case-control studies). </li></ul></ul><ul><ul><li>Used to support recommendations called guidelines . </li></ul></ul>
  12. 16. Ranking the Evidence <ul><li>Class III: </li></ul><ul><ul><li>Derived from the other sources of information, including case series and expert opinion. </li></ul></ul><ul><ul><li>Used to support practice options . </li></ul></ul>
  13. 17. Ranking the Evidence <ul><li>Overall term for all of the recommendations is practice parameters. </li></ul>
  14. 18. EMS Practice Changes <ul><li>EMS Practices refuted by empiric evidence: </li></ul><ul><ul><li>Critical Incident Stress Management (CISM) </li></ul></ul><ul><ul><li>MAST/PASG </li></ul></ul><ul><ul><li>Trendelenburg Position </li></ul></ul><ul><ul><li>High-Volume Fluid Resuscitation </li></ul></ul>
  15. 19. EMS Practice Changes <ul><li>EMS Practices unsupported by empiric evidence: </li></ul><ul><ul><li>Medical Priority Dispatch </li></ul></ul><ul><ul><li>System Status Management </li></ul></ul><ul><ul><li>High-Dose Epinephrine </li></ul></ul><ul><ul><li>High-Dose Steroids for Acute Spinal Cord Injury </li></ul></ul><ul><ul><li>Intraosseous Needles </li></ul></ul><ul><ul><li>CPR Compression Vest </li></ul></ul>
  16. 20. EMS Practice Changes <ul><li>EMS Practice changes based upon empiric evidence: </li></ul><ul><ul><li>AED usage (first 6-8 minutes) </li></ul></ul><ul><ul><li>CPR </li></ul></ul><ul><ul><li>Field death pronouncement in blunt traumatic cardiac arrest. </li></ul></ul>
  17. 21. EMS Practice Changes <ul><li>EMS Practices at risk for change because of empiric evidence: </li></ul><ul><ul><li>Pediatric Endotracheal Intubation </li></ul></ul><ul><ul><li>Rapid Sequence Intubation (RSI) in Traumatic Brain Injury (TBI) </li></ul></ul><ul><ul><li>Endotracheal Intubation in TBI </li></ul></ul>
  18. 22. Guiding Prehospital Care <ul><li>There should be a link between the available evidence and treatment recommendations. </li></ul><ul><li>Empirical evidence should take precedence over expert judgement in the development of guidelines. </li></ul>
  19. 23. Guiding Prehospital Care <ul><li>“ In science, there are no authorities.” </li></ul><ul><li>Carl Sagan, PhD </li></ul><ul><li> 1934-1996 </li></ul>
  20. 24. Guiding Prehospital Care <ul><li>3. The available research should be searched using appropriate and comprehensive search terminology. </li></ul><ul><li>4. A thorough review of the scientific literature should precede guideline development. </li></ul>
  21. 25. Guiding Prehospital Care <ul><li>5. The evidence should be evaluated and weighted, depending upon the scientific validity of the method used to generate the evidence. </li></ul><ul><li>6. The strength of the evidence should be reflected in the strength of the recommendations reflecting scientific certainty (or the lack thereof). </li></ul>
  22. 26. Guiding Prehospital Care <ul><li>7. Expert judgement should be used to evaluate the quality of the literature and to formulate guidelines when the evidence is weak or nonexistent. </li></ul><ul><li>8. Guideline development should be a multidisciplinary process, involving key groups affected by the recommendations. </li></ul>
  23. 27. Audience Interaction <ul><li>In regard to the OPALS study: </li></ul><ul><ul><li>A. I follow the OPALS study regularly. </li></ul></ul><ul><ul><li>B. I have read some of the OPALS study papers. </li></ul></ul><ul><ul><li>C. I have heard of the OPALS study but not seen any results. </li></ul></ul><ul><ul><li>D. What is the OPALS study? </li></ul></ul><ul><ul><li>E. None of the above applies. </li></ul></ul>
  24. 28. Empiric Research in EMS Phase I: Determined baseline survival rate for each study community (36 months) prior to Phase II. Phase II: Assessed the survival for 12 months after the introduction of rapid defibrillation and demonstrated that relatively inexpensive community rapid defibrillation programs increase survival for cardiac arrest patients (n=5,000+ patients). Phase III: Assessed survival outcomes months after the introduction of full ALS programs for 36 months for cardiac arrest patients and major trauma patients, and for 6 months for respiratory distress patients.
  25. 29. Empiric Research in EMS <ul><li>Phase I: Survival improved with: </li></ul><ul><li>Decreasing EMS response intervals </li></ul><ul><li>Bystander-CPR </li></ul><ul><li>First responder CPR by fire or police </li></ul><ul><li>Phase II: Survival improved with: </li></ul><ul><li>Rapid defibrillation (survival increased from 3.9% to 5.2%) resulted in 33% improvement in survival </li></ul><ul><li>An additional 21 lives saved each year </li></ul><ul><li>Increased survival was also associated with bystander and first responder CPR. </li></ul>
  26. 30. Empiric Research in EMS <ul><li>Phase III: </li></ul><ul><li>Cardiac Arrest: </li></ul><ul><ul><li>The addition of advanced-life-support interventions did not improve the rate of survival after out-of-hospital cardiac arrest in a previously optimized emergency-medical-services system of rapid defibrillation. </li></ul></ul><ul><ul><li>8-minute response time too long. </li></ul></ul>
  27. 31. Empiric Research in EMS <ul><li>Phase III: </li></ul><ul><li>Cardiac Arrest: </li></ul><ul><ul><li>Most cardiac arrests occur in private locations (84.7%) compared to public places (15.3%). Communities should review locations of their cardiac arrests when designing CPR training and public access defibrillation programs. </li></ul></ul>
  28. 32. Empiric Research in EMS <ul><li>Phase III: </li></ul><ul><li>Cardiac Arrest: </li></ul><ul><li>Among ALS interventions, intubation, atropine and epinephrine had a negative association and only lidocaine had a positive association with survival. </li></ul><ul><li>Pediatric cardiac arrests are most often due to respiratory arrests or trauma, SIDS, trauma and drowning. </li></ul><ul><li>Citizen-initiated CPR is strongly and independently associated with better quality of life. </li></ul>
  29. 33. Empiric Research in EMS <ul><li>Phase III: </li></ul><ul><li>Chest Pain: </li></ul><ul><li>Clearly showed important benefit from ALS programs for mortality and other outcomes. </li></ul>
  30. 34. Empiric Research in EMS <ul><li>Phase III: </li></ul><ul><li>Respiratory Distress: </li></ul><ul><li>After adjustment for demographic, clinical, and EMS factors, the only interventions associated with better survival were salbutamol and NTG. </li></ul><ul><li>Most children are not severely ill, most do not receive ALS interventions, there is a high rate of non-transport, and the vast majority are discharged home from the ED. </li></ul>
  31. 35. Empiric Research in EMS <ul><li>Phase III: </li></ul><ul><li>Pediatric Care: </li></ul><ul><li>The majority of patients did not require immediate or urgent medical care and had good short-term outcomes. </li></ul>
  32. 36. Science in Trauma Care <ul><li>Practices with strong positive evidence: </li></ul><ul><ul><li>Access to trauma centers </li></ul></ul><ul><ul><li>Specialized care (pediatrics, burns, spinal cord injury) </li></ul></ul>
  33. 37. Science in Trauma Care <ul><li>Practices with positive evidence: </li></ul><ul><ul><li>Permissive hypotension </li></ul></ul><ul><ul><li>Splinting </li></ul></ul><ul><ul><li>Pain management </li></ul></ul><ul><ul><li>Head injury management </li></ul></ul><ul><ul><li>Hemoglobin-Based Oxygen Carrying Solutions (HBOCs) </li></ul></ul>
  34. 38. Science in Trauma Care <ul><li>Practices with no evidence or equivocal evidence: </li></ul><ul><ul><li>The “Golden Hour” </li></ul></ul><ul><ul><li>Medical helicopters </li></ul></ul><ul><ul><li>Trendelenburg position </li></ul></ul><ul><ul><li>Traction splints </li></ul></ul><ul><ul><li>Rapid sequence intubation (RSI) in traumatic brain injury (TBI) </li></ul></ul>
  35. 39. Science in Trauma Care <ul><li>Practices with negative evidence: </li></ul><ul><ul><li>MAST/PASG </li></ul></ul><ul><ul><li>Steroids for acute SCI </li></ul></ul><ul><ul><li>High-volume fluid therapy </li></ul></ul><ul><ul><li>Prehospital intubation in traumatic brain injury </li></ul></ul><ul><ul><li>Pediatric endotracheal intubation </li></ul></ul>
  36. 40. Audience Participation <ul><li>In regard to current prehospital practice in my system, which of the following best describes trauma care? </li></ul><ul><ul><li>A. We still used MAST/PASG and administer large volumes of fluid to restore normal BP. </li></ul></ul><ul><ul><li>B. We do not use the MAST/PASG but administer large volumes of fluid to restore BP. </li></ul></ul><ul><ul><li>C. We administer enough fluid to maintain a blood pressure >100 mm Hg. </li></ul></ul><ul><ul><li>D. We administer enough fluid to maintain a blood pressure > 90 mm Hg. </li></ul></ul><ul><ul><li>E. We administer enough fluid to maintain a blood pressure > 80 mm Hg. </li></ul></ul>
  37. 41. Science in Trauma Care <ul><li>Practices with strong negative evidence: </li></ul><ul><ul><li>Scene stabilization </li></ul></ul>
  38. 42. Changes in US Trauma Practice <ul><li>IV Fluid Restriction </li></ul><ul><li>Permissive Hypotension </li></ul><ul><li>Hemoglobin-Based Oxygen Carrying Solutions (HBOCs) </li></ul><ul><li>Less Aggressive Airway Management </li></ul><ul><li>Helicopter Overutilization </li></ul>
  39. 43. IV Fluid Restriction <ul><li>Should prehospital personnel administer large volumes of IV fluids rapidly to trauma victims or delay fluid resuscitation until hospital arrival? </li></ul>
  40. 44. IV Fluid Restriction <ul><li>Traditional approach to trauma patient with hypotension was 2 large bore IVs and wide open crystalloid administration. </li></ul>
  41. 45. IV Fluid Restriction <ul><li>Recommendation has been to replace lost blood with isotonic crystalloids at a 3:1 ratio (IVF:blood loss) </li></ul>
  42. 46. IV Fluid Restriction <ul><li>High volume IV fluid administration was based on several animal studies from the 1950s and 1960s. </li></ul>
  43. 47. IV Fluid Restriction <ul><li>High volume IV fluid treatment was used in Viet Nam and transferred to US and western civilian prehospital care practices. </li></ul>
  44. 48. IV Fluid Restriction <ul><li>Several animal studies in the 1980s and 1990s found that treatment with IV fluids before hemorrhage was controlled increased the mortality rate, especially if the BP was elevated. </li></ul>
  45. 49. IV Fluid Restriction <ul><li>Raising the BP and restoring perfusion to vital organs are clearly believed to be beneficial after hemorrhage is controlled. </li></ul><ul><li>Growing evidence indicates that raising it before achieving adequate hemostasis may be detrimental. </li></ul>
  46. 50. IV Fluid Restriction <ul><li>Administering large quantities of IV fluids without controlling the hemorrhage results in: </li></ul><ul><ul><li>hemodilution with decreased hematocrit </li></ul></ul><ul><ul><li>decreased available hemoglobin (and oxygen- carrying capacity) </li></ul></ul><ul><ul><li>decreased clotting factors. </li></ul></ul><ul><li>This effect is found regardless of the fluid used (blood, LR, NS, hypertonic saline). </li></ul>
  47. 51. IV Fluid Restriction <ul><li>Bickell WH, Wall MJ Jr, Pepe PE, et al. Immediate versus delayed fluid resuscitation for hypotensive patients with penetrating torso injuries. N Eng J Med . 1994;331:1105-9 </li></ul><ul><li>598 patients with penetrating torso injury and systolic BP ≤ 90 mmHg in prehospital setting. </li></ul><ul><li>Randomized to receive standard high-volume fluids or fluids delayed until patient in OR. </li></ul>
  48. 52. IV Fluid Restriction <ul><li>Results: </li></ul><ul><ul><li>Group Divisions </li></ul></ul><ul><ul><ul><li>Delayed: n=289 </li></ul></ul></ul><ul><ul><ul><li>Standard fluids: n=309 </li></ul></ul></ul><ul><ul><li>Survival: </li></ul></ul><ul><ul><ul><li>Delayed: 70% </li></ul></ul></ul><ul><ul><ul><li>Standard fluids: 62% </li></ul></ul></ul><ul><ul><li>Complications: </li></ul></ul><ul><ul><ul><li>Delayed: 23% </li></ul></ul></ul><ul><ul><ul><li>Standard fluids: 30% </li></ul></ul></ul>
  49. 53. IV Fluid Restriction <ul><li>CONCLUSIONS: For hypotensive patients with penetrating torso injuries, delay of aggressive fluid resuscitation until operative intervention improves the outcome. </li></ul>
  50. 54. IV Fluid Restriction <ul><li>Tentative Hypothesis: </li></ul><ul><li>At this time, intravenous fluid resuscitation should probably be delayed until hemostasis is obtained. </li></ul>
  51. 55. IV Fluid Restriction <ul><li>Literature has primarily looked at penetrating trauma. </li></ul><ul><li>The role of fluid resuscitation in patients with blunt trauma is less clear. </li></ul><ul><li>Further studies are needed. </li></ul>
  52. 56. IV Fluid Restriction <ul><li>Current recommendation for blunt trauma is to administer just enough fluid to maintain perfusion. </li></ul><ul><li>Rapid, high-volume fluid administration is discouraged. </li></ul>
  53. 57. IV Fluid Restriction <ul><li>Fluid resuscitation may be of value in patients who are moribund with systolic pressures <40 mmHg. </li></ul>
  54. 58. IV Fluid Restriction <ul><li>Patients with hypotension due to severe hemorrhage from isolated extremity injuries may do better with aggressive prehospital IV fluid resuscitation after hemostasis. </li></ul>
  55. 59. IV Fluid Restriction <ul><li>Complications of preoperative fluid resuscitation: </li></ul><ul><ul><li>Secondary bleeding or acceleration of ongoing hemorrhage </li></ul></ul><ul><ul><li>Adult respiratory distress syndrome (Danang Lung) </li></ul></ul><ul><ul><li>Sepsis </li></ul></ul><ul><ul><li>Coagulopathies </li></ul></ul><ul><ul><li>Renal failure </li></ul></ul>
  56. 60. IV Fluid Restriction <ul><li>Conclusions : </li></ul><ul><ul><li>More research is needed. </li></ul></ul><ul><ul><li>Data on penetrating trauma is compelling. </li></ul></ul><ul><ul><li>Fluid resuscitation probably indicated for moribund patients. </li></ul></ul><ul><ul><li>Best management strategies for blunt trauma and head injuries is to administer just enough fluid to maintain perfusion. </li></ul></ul><ul><ul><li>Rapid transport probably remains the best treatment for most trauma cases. </li></ul></ul>
  57. 61. IV Fluid Restriction <ul><li>Limitations : </li></ul><ul><ul><li>Most studies on urban trauma patients with short transport times. </li></ul></ul><ul><ul><li>Findings may not be applicable to rural trauma patients. </li></ul></ul>
  58. 62. Permissive Hypotension <ul><li>Should prehospital personnel attempt to restore blood pressure in trauma patients to pre-trauma levels or practice permissive hypotension? </li></ul>
  59. 63. Permissive Hypotension <ul><li>Animal studies in the 1980s and 1990s indicated that treatment with IV fluids before hemorrhage was controlled increased the mortality rate, especially if the blood pressure is elevated. </li></ul>
  60. 64. Permissive Hypotension <ul><li>Human research seems to support this premise. </li></ul><ul><li>Primarily the Bickell, Wall, Pepe, et al. study previously detailed. </li></ul>
  61. 65. Permissive Hypotension <ul><li>There is a natural physiologic compensation when blood pressure is maintained between 70-85 mmHg. </li></ul><ul><li>Urine output and cerebral perfusion usually maintained when the BP is within this range. </li></ul>
  62. 66. Permissive Hypotension <ul><li>Elevation of BP to pre-injury levels, without hemostasis, has been associated with: </li></ul><ul><ul><li>Progressive and repeated re-bleeding </li></ul></ul><ul><ul><li>Decrease in platelets and clotting factors. </li></ul></ul><ul><ul><li>Dislodgement of a clot at the site of injury. </li></ul></ul>
  63. 67. Permissive Hypotension <ul><li>Interestingly, the standard treatment for ruptured AAAs has been to keep patients hypotensive until proximal control of the aorta (above the leakage) is attained. </li></ul><ul><li>This preserves intravascular blood volume and prevents new additional blood loss from the rupture. </li></ul>
  64. 68. Permissive Hypotension <ul><li>Large animal studies of uncontrolled hemorrhage indicate that the clot is “popped” at about 80 mmHg systolic pressure. </li></ul><ul><li>This level has been reproducible in human subjects. </li></ul>
  65. 69. Permissive Hypotension <ul><li>Many hypothesize that one should not raise blood pressure to more than ¾ of pre-injury levels (~80 mmHg). </li></ul>
  66. 70. Permissive Hypotension <ul><li>Dutton RP, MacKenzie CF, Scalea TM, et al. Hypotensive resuscitation during active hemorrhage: Impact on in-hospital mortality. J Trauma. 2003;52(6):1141-1146 </li></ul><ul><li>110 patients with hemorrhagic shock were randomized into two groups: BP maintenance > 100 (n=55) or BP maintenance of 70 (n=55). </li></ul><ul><li>Conclusion: Titration of initial fluid therapy to a lower than normal SBP during active hemorrhage did not affect mortality in this study. Reasons for the decreased overall mortality and the lack of differentiation between groups likely include improvements in diagnostic and therapeutic technology, the heterogeneous nature of human traumatic injuries, and the imprecision of SBP as a marker for tissue oxygen delivery. </li></ul>
  67. 71. Permissive Hypotension <ul><li>Holmes JF, Sakles JC, Lewis G, Wisner DH. Effects of delaying fluid resuscitation on an injury to the systemic arterial vasculature. Acad Emerg Med. 2002;9(4):267-274 </li></ul><ul><li>21 sheep underwent thoracotomy and transection of the left internal mammary artery. </li></ul><ul><ul><li>Group 1: No fluid resuscitation </li></ul></ul><ul><ul><li>Group 2: Resuscitation 15 minutes after injury </li></ul></ul><ul><ul><li>Group 3: Resuscitation 30 minutes after injury </li></ul></ul><ul><li>CONCLUSIONS: Rates of hemorrhage from an arterial injury are related to changes in mean arterial pressure. In this animal model, early aggressive fluid resuscitation in penetrating thoracic trauma exacerbates total hemorrhage volume. Despite resumption of hemorrhage from the site of injury, delaying fluid resuscitation results in the best hemodynamic parameters. </li></ul>
  68. 72. Permissive Hypotension <ul><li>This paradigm shift has significant implications on emergency care: </li></ul><ul><ul><li>Trendelenburg position </li></ul></ul><ul><ul><li>Use of rapid infusers </li></ul></ul><ul><ul><li>Intraosseous infusions </li></ul></ul>
  69. 73. Permissive Hypotension <ul><li>Fluid restriction and permissive hypotension go hand-in-hand. </li></ul><ul><li>Fluid resuscitation should be administered in small boluses to maintain peripheral pulse (systolic BP +/- 80 mmHg) </li></ul>
  70. 74. Permissive Hypotension <ul><li>“ During prolonged transport the prehospital care provider must attempt to maintain perfusion to the vital organs. Maintaining the systolic blood pressure in the range of 80-90 mm Hg or the MAP in the range of 60-65 mm Hg, can usually accomplish this with less risk of renewing internal hemorrhage.” </li></ul>
  71. 75. Permissive Hypotension <ul><li>“ Gain IV access en route but give only enough Ringer’s lactate solution or normal saline solution to maintain a blood pressure high enough for adequate peripheral perfusion. Maintaining peripheral perfusion may be defined as producing a peripheral pulse, maintaining level of consciousness, or maintaining blood pressure (90-100 mm Hg systolic).” </li></ul>
  72. 76. Permissive Hypotension <ul><li>What about patients with TBI? </li></ul>
  73. 77. Traumatic Brain Injury <ul><li>Oxygenation and Blood Pressure </li></ul><ul><ul><li>Hypoxemia (<90% SpO 2 ) and/or hypotension (<90 mm Hg systolic) are associated with poor outcomes. </li></ul></ul><ul><ul><li>Pulse oximetry and blood pressure must be monitored. </li></ul></ul><ul><ul><li>Continuous waveform capnography beneficial. </li></ul></ul>
  74. 78. Traumatic Brain Injury <ul><li>Oxygenation and Blood Pressure </li></ul><ul><ul><li>In children, hypotension is: </li></ul></ul><ul><ul><ul><li>0-1 year: Systolic <65 mm Hg </li></ul></ul></ul><ul><ul><ul><li>2-5 years: Systolic < 75 mm Hg </li></ul></ul></ul><ul><ul><ul><li>6-12 years: Systolic < 80 mm Hg </li></ul></ul></ul><ul><ul><ul><li>13-16 years: Systolic < 90 mm Hg </li></ul></ul></ul>
  75. 79. Traumatic Brain Injury <ul><li>Why does TBI require a higher systolic BP than required for permissive hypotension? </li></ul><ul><li> CPP = MAP- ICP </li></ul><ul><li>MAP = [DBP+1/3 (SBP-DBP)] </li></ul>
  76. 80. Traumatic Brain Injury <ul><li>Slightly higher systolic pressure may be required to maintain CPP in TBI. </li></ul>
  77. 81. Audience Participation <ul><li>In regard to hemoglobin-based oxygen carrying solutions: </li></ul><ul><ul><li>A. I have administered them in the prehospital setting. </li></ul></ul><ul><ul><li>B. I have seen them administered in the prehospital setting. </li></ul></ul><ul><ul><li>C. I have read about them but never seen them. </li></ul></ul><ul><ul><li>D. I have never heard of them. </li></ul></ul><ul><ul><li>E. None of the above. </li></ul></ul>
  78. 82. Oxygen-Carrying IV Fluids <ul><li>Do oxygen-carrying IV fluids have a future role in prehospital care? </li></ul>
  79. 83. Oxygen-Carrying IV Fluids <ul><li>Crystalloid solutions have been the primary IV fluid used in prehospital trauma care in the United States. </li></ul>
  80. 84. Oxygen-Carrying IV Fluids <ul><li>In most Commonwealth and in many Latin American countries colloids [polygeline (Haemaccel)] is used. </li></ul>
  81. 85. HBOCs <ul><li>Each molecule of hemoglobin can carry 4 molecules of oxygen. </li></ul>
  82. 86. HBOCs <ul><li>The amount of oxygen on the hemoglobin (oxygen saturation) is dependent upon the partial pressure of oxygen. </li></ul>
  83. 87. HBOCs <ul><li>The amount of oxygen that can be transported is also dependent upon the amount of circulating red blood cells and the hemoglobin contained within. </li></ul>
  84. 88. HBOCs <ul><li>Blood loss and crystalloid fluid therapy decreases the percentage of circulating red blood cells and hemoglobin. </li></ul>
  85. 89. Oxygen-Carrying IV Fluids <ul><li>Perflurocarbon emulsions </li></ul><ul><li>Hemoglobin-based oxygen carrying solutions (HBOCs): </li></ul><ul><ul><li>PolyHeme ® </li></ul></ul><ul><ul><li>Hemopure ® </li></ul></ul>
  86. 90. HBOCs <ul><li>Hemopure ® </li></ul><ul><ul><li>Derived from bovine blood </li></ul></ul><ul><ul><li>Approved for use in South Africa </li></ul></ul><ul><ul><li>Intensive study underway in the US. </li></ul></ul>
  87. 91. HBOCs
  88. 92. HBOCs <ul><li>Hemopure ® </li></ul><ul><ul><li>Jul 2002: FDA application filed. </li></ul></ul><ul><ul><li>Sep 2002: US Army provides $908,900.00 grant to conduct single-center trial in trauma patients. </li></ul></ul><ul><ul><li>Nov 2002: Trial expanded to include both in- hospital and prehospital patients. </li></ul></ul><ul><ul><li>Feb 2003: Congress awards $4 million to fund clinical trials. First trials in Dallas with DFR and Parkland. </li></ul></ul>
  89. 93. HBOCs
  90. 94. HBOCs <ul><li>PolyHeme ® </li></ul><ul><ul><li>Solution of chemically-modified hemoglobin derived from discarded donated human blood. </li></ul></ul><ul><ul><li>Hemoglobin extracted and filtered to remove impurities. </li></ul></ul>
  91. 95. HBOCs <ul><li>PolyHeme ® </li></ul><ul><ul><li>Chemically-modified to create a polymerized form of hemoglobin designed to avoid problems previously experienced with hemoglobin-based blood substitutes: </li></ul></ul><ul><ul><ul><li>Vasoconstriction </li></ul></ul></ul><ul><ul><ul><li>Renal dysfunction </li></ul></ul></ul><ul><ul><ul><li>Liver dysfunction </li></ul></ul></ul><ul><ul><ul><li>GI distress </li></ul></ul></ul><ul><ul><li>Polymerized hemoglobin incorporated into a solution that contains 50 grams of hemoglobin per unit (the same as transfused blood). </li></ul></ul>
  92. 96. HBOCs
  93. 97. HBOCs <ul><li>PolyHeme ® </li></ul><ul><ul><li>Product must be refrigerated. </li></ul></ul><ul><ul><li>Shelf-life is 1 year. </li></ul></ul><ul><ul><li>Clinical prospective randomized controlled trial of prehospital usage started Sep 2003 in several US cities (1-year, 700-800 patients). </li></ul></ul><ul><ul><li>Paramedics cannot be blinded for study as PolyHeme looks like blood. </li></ul></ul><ul><ul><li>Patients who receive PolyHeme will receive up to 6 more units if needed during the first 12 hours. </li></ul></ul>
  94. 98. HBOCs <ul><li>California </li></ul><ul><ul><li>UCSD (San Diego </li></ul></ul><ul><ul><li>Scripps Mercy (San Diego) </li></ul></ul><ul><li>Colorado </li></ul><ul><ul><li>Denver H&H (Denver) </li></ul></ul><ul><li>Delaware </li></ul><ul><ul><li>Christiana (Newark) </li></ul></ul><ul><li>Illinois </li></ul><ul><ul><li>Loyola (Chicago) </li></ul></ul><ul><li>Indiana </li></ul><ul><ul><li>Wishard (Indianapolis) </li></ul></ul><ul><ul><li>Methodist Hospital (Indianapolis) </li></ul></ul><ul><li>Kentucky </li></ul><ul><ul><li>U of K (Lexington) </li></ul></ul><ul><li>Minnesota </li></ul><ul><ul><li>Mayo (Rochester) </li></ul></ul><ul><li>Ohio </li></ul><ul><ul><li>Metro Health (Cleveland) </li></ul></ul><ul><li>Pennsylvania </li></ul><ul><ul><li>Lehigh Valley (Allentown) </li></ul></ul><ul><li>Tennessee </li></ul><ul><ul><li>UT (Memphis) </li></ul></ul><ul><li>Texas </li></ul><ul><ul><li>Memorial-Hermann (Houston) </li></ul></ul><ul><ul><li>UTHSCSA (San Antonio) </li></ul></ul><ul><li>Virginia </li></ul><ul><ul><li>Sentara (Norfolk) </li></ul></ul><ul><ul><li>VCU (Richmond) </li></ul></ul>
  95. 99. HBOCs <ul><li>Artificial polymerized hemoglobin can transport oxygen within the plasma. </li></ul>
  96. 100. HBOCs <ul><li>Gould SA, Moore EE, Hoyt DB, et al. The first randomized trial of human polymerized hemoglobin as a blood substitute in acute trauma and emergency surgery. J Am Coll Surg . 1998;187(2):113-20 </li></ul><ul><li>44 trauma patients (33 male, 11 female) were randomized to receive red cells or PolyHeme as their initial fluid replacement after trauma. </li></ul><ul><li>There were no serious or unexpected outcomes related to PolyHeme. </li></ul><ul><li>CONCLUSIONS: PolyHeme is safe in acute blood loss, maintains total [Hb] in lieu of red cells despite a marked fall in RBC [Hb], and reduces the use of allogenic blood. PolyHeme appears to be a clinically-useful blood substitute. </li></ul>
  97. 101. HBOCs <ul><li>Gannon CJ, Napolitano LM. Severe anemia after gastrointestinal hemorrhage in a Jehovah’s Witness: new treatment strategies. Critical Care Medicine . 2002;30:1930-1931 </li></ul><ul><li>50–year-old Jehovah’s Witness had massive UGI bleed from pre-pyloric ulcer (Hb=3.5 grams). Hemorrhage control with injection of epinephrine. </li></ul><ul><li>Patient became hemodynamically unstable. </li></ul><ul><li>Received 7 units of bovine HBOC and human erythropoietin. </li></ul><ul><li>Within 24 hours patient stable and Hb 7.2 grams. </li></ul><ul><li>Conclusions: Survival without allogenic blood attained. </li></ul>
  98. 102. HBOCs <ul><li>HBOCs look quite promising for prehospital and battlefield emergency care. </li></ul><ul><li>Further recommendations await result of first prehospital study. </li></ul>
  99. 103. Audience Participation <ul><li>In my ambulance service, we use medical helicopters for scene responses: </li></ul><ul><ul><li>A. Very Frequently </li></ul></ul><ul><ul><li>B. Often </li></ul></ul><ul><ul><li>C. Occasionally </li></ul></ul><ul><ul><li>D. Rarely </li></ul></ul><ul><ul><li>E. Never </li></ul></ul>
  100. 104. Helicopters <ul><li>Are EMS helicopters effective in decreasing mortality and enhancing trauma care? </li></ul>
  101. 105. Helicopters <ul><li>Initial studies in the 1980s showed that trauma patients have better outcomes when transported by helicopter. </li></ul><ul><li>Today, other than speed, helicopters offer little additional care than provided by ground ambulances. </li></ul>
  102. 106. Helicopters <ul><li>The number of medical helicopters in the United States has increased from 400 to >700 in the last 4 years. </li></ul>
  103. 107. Helicopters <ul><li>Considerations: </li></ul><ul><ul><li>Severe injury: </li></ul></ul><ul><ul><ul><li>ISS > 15 </li></ul></ul></ul><ul><ul><ul><li>TS < 12 </li></ul></ul></ul><ul><ul><ul><li>RTS ≤ 11 </li></ul></ul></ul><ul><ul><ul><li>Weighted RTS ≥ 4 </li></ul></ul></ul><ul><ul><ul><li>Triss P s < 0.90 </li></ul></ul></ul><ul><ul><li>Non-life-threatening injuries: </li></ul></ul><ul><ul><ul><li>Patients not in above criteria </li></ul></ul></ul><ul><ul><ul><li>Patients who refuse ED treatment </li></ul></ul></ul><ul><ul><ul><li>Patients discharged from ED </li></ul></ul></ul><ul><ul><ul><li>Patients not admitted to ICU </li></ul></ul></ul>
  104. 108. Helicopters <ul><li>Shatney CH, Homan SJ, Sherek JP, et al. The utility of helicopter transport of trauma patients from the injury scene in an urban trauma system. J Trauma . 2002;53(5):817-22 </li></ul><ul><li>10-year retrospective review of 947 consecutive trauma patients transported to the Santa Clara Valley trauma center. </li></ul><ul><ul><li>Blunt trauma: 911 </li></ul></ul><ul><ul><li>Penetrating trauma: 36 </li></ul></ul>
  105. 109. Helicopters <ul><li>Mean ISS = 8.9 </li></ul><ul><li>Deaths in ED = 15 </li></ul><ul><li>Discharged from ED = 312 (33.5%) </li></ul><ul><li>Hospitalized = 620 </li></ul><ul><ul><li>ISS ≤ 9 = 339 (54.7%) </li></ul></ul><ul><ul><li>ISS ≥ 16 = 148 (23.9%) </li></ul></ul><ul><ul><li>Emergency surgery = 84 (8.9%) </li></ul></ul>
  106. 110. Helicopters <ul><li>Only 17 patients (1.8%) underwent surgery for immediately life-threatening injuries. </li></ul><ul><li>Helicopter arrival faster = 54.7% </li></ul><ul><li>Helicopter arrival slower = 45.3% </li></ul><ul><li>Only 22.4% of the study population were possibly helped by helicopter transport. </li></ul><ul><li>CONCLUSION: The helicopter is used excessively for scene transport of trauma victims in our metropolitan trauma system. New criteria should be developed for helicopter deployment in the urban trauma environment. </li></ul>
  107. 111. Helicopters <ul><li>Eckstein M, Jantos T, Kelly N, et al. Helicopter transport of pediatric trauma patients in an urban emergency medical services system: a critical analysis. J Trauma , 2002;53:340-344. </li></ul><ul><li>Retrospective review of 189 pediatric trauma patients (<15) transported by helicopter from the scene in LA. </li></ul><ul><li>Median age: 5 years </li></ul><ul><li>RTS > 7 = 82% </li></ul><ul><li>ISS < 15 = 83% </li></ul><ul><li>Admitted to ICU = 18% </li></ul><ul><li>Discharged from ED = 33% </li></ul>
  108. 112. Helicopters <ul><li>CONCLUSION: The majority of pediatric trauma patients transported by helicopter in our study sustained minor injuries. A revised policy to better identify pediatric patients who might benefit from helicopter transport appears to be warranted. </li></ul>
  109. 113. Helicopters <ul><li>Braithwaite CE, Roski M, McDowell R, et al. A critical analysis of on-scene helicopter transport on survival in a statewide trauma system. J Trauma . 1998;45(1):140-4 </li></ul><ul><li>Data for 162,730 Pennsylvania trauma patients obtained from state trauma registry. </li></ul><ul><ul><li>Patients treated at 28 accredited trauma centers </li></ul></ul><ul><ul><li>15,938 patients were transported from the scene by helicopters. </li></ul></ul><ul><ul><li>6,273 patients were transported by ALS ground ambulance. </li></ul></ul>
  110. 114. Helicopters <ul><li>Patients transported by helicopter: </li></ul><ul><ul><li>Significantly younger </li></ul></ul><ul><ul><li>Males </li></ul></ul><ul><ul><li>More seriously injured </li></ul></ul><ul><ul><li>Had lower blood pressure </li></ul></ul><ul><li>Helicopter patients: </li></ul><ul><ul><li>ISS <15 = 55% </li></ul></ul><ul><li>Logical regression analysis revealed that when adjusted for other risk factors, transportation by helicopter did not affect the estimated odds of survival. </li></ul><ul><li>CONCLUSION: A reappraisal of the cost-effectiveness of helicopter triage and transport criteria, when access to ground ALS squads is available, may be warranted. </li></ul>
  111. 115. Helicopters <ul><li>Cocanour CS, Fischer RP, Ursie CM. Are scene flights for penetrating trauma justified? J Trauma . 1997;43(1):83-86 </li></ul><ul><li>122 consecutive victims of non-cranial penetrating trauma transported by helicopter from the scene. </li></ul><ul><ul><li>Average RTS = 10.6 </li></ul></ul><ul><ul><li>Dead patients = 15.6% </li></ul></ul><ul><li>Helicopter did not hasten arrival in for any of the 122 patients. </li></ul><ul><li>Only 4.9% of patients required patient care interventions beyond those of ground ALS units. </li></ul><ul><li>CONCLUSION: Scene flights in this metropolitan area for patients who suffered noncranial penetrating injuries demonstrated that these flights were not medically efficacious. </li></ul>
  112. 116. Helicopters <ul><li>Cunningham P, Rutledge R, Baker CC, Clancy TV. A comparison of the association of helicopter and ground ambulance transport with the outcome of injury in trauma patients transported from the scene. J Trauma 1997 ;43(6):940-946 </li></ul><ul><li>Data obtained from NC trauma registry from 1987-1993 on trauma patients and compared: </li></ul><ul><ul><li>1,346 transported by air </li></ul></ul><ul><ul><li>17,144 transported by ground </li></ul></ul><ul><li>CONCLUSION: The large majority of trauma patients transported by both helicopter and ground ambulance have low severity measures. Outcomes were not uniformly better among patients transported by helicopter. Only a very small subset of patients transported by helicopter appear to have any chance or improved survival. </li></ul>
  113. 117. Helicopters <ul><li>Moront ML, Gotschall CS, Eichelberger MR. Helicopter transport of injured children: system effectiveness and triage criteria. J Pediatr Surg . 1996;31(8):1183-6 </li></ul><ul><li>3,861 children transported by local EMS </li></ul><ul><ul><li>1,460 arrived by helicopter </li></ul></ul><ul><ul><li>2,896 arrived by ground </li></ul></ul><ul><li>Helicopter transported patients: </li></ul><ul><ul><li>ISS <15 = 83% </li></ul></ul><ul><ul><li>But survival rates for children transported by air were better than those transported by ground. </li></ul></ul><ul><li>CONCLUSION: The authors conclude that (1) helicopter transport was associated with better survival rates among injured urban children; (2) pediatric helicopter triage criteria based on GSC and heart rate may improve helicopter utilization without compromising care; (3) current air triage practices result in overuse in approximately 85% of flights. </li></ul>
  114. 118. Helicopters <ul><li>Wills VL, Eno L, Walker C, et al. Use of an ambulance-based helicopter retrieval service. Aust N Z J Surg. 2000;70(7):506-510 </li></ul><ul><li>179 trauma patients arrived by helicopter during study year. </li></ul><ul><ul><li>122 male </li></ul></ul><ul><ul><li>57 female </li></ul></ul><ul><li>Severity of injuries: </li></ul><ul><ul><li>ISS < 9 = 67.6% </li></ul></ul><ul><ul><li>ISS ≥ 16 = 17.9% </li></ul></ul><ul><ul><li>12 (6.7%) discharged from the ED </li></ul></ul><ul><ul><li>46 (25.7%) discharged within 48 hours. </li></ul></ul><ul><li>Results: </li></ul><ul><ul><li>17.3% of patients were felt to have benefited from helicopter transport </li></ul></ul><ul><ul><li>81.0% of patients were felt to have no benefit from helicopter transport </li></ul></ul><ul><ul><li>1.7% of patients were felt to have been harmed from helicopter transport </li></ul></ul>
  115. 119. Helicopters <ul><li>Bledsoe BE, Wesley AK, Eckstein M, Dunn TM, O’Keefe MF. Helicopter Transport of Trauma Patients: A Meta-Analysis J Trauma (In Press). </li></ul><ul><li>Meta-Analysis of 22 papers with a cohort of 37,350 patients. </li></ul><ul><li>ISS ≤ 15 (minor injuries): 60% (99% CI: 54.5-64.8) </li></ul><ul><li>TS ≥ 13 (minor injuries): 61.4% (99% CI: 60.8-62.0) </li></ul><ul><li>TRISS P s > 0.90 (minor injuries): 69.3% (99% CI: 58.5-80.2) </li></ul><ul><li>Discharged < 24 hours: 24.1% (99% CI: -0.90-52.6) </li></ul>
  116. 120. Helicopters
  117. 121. Helicopters (US Accidents)
  118. 122. Helicopters Occupational Deaths per 100,000/year (U.S. 1995-2001) Source: Johns Hopkins University School of Public Health
  119. 123. Helicopters <ul><li>An EMS helicopter (HEMS) pilot or crew member flying 20 hours/week for 20 years would have a 40% chance of a fatal crash. </li></ul><ul><li>Since 2002, more people have been killed in air ambulance crashes than aboard U.S. commercial airlines, though the helicopters travel just a fraction of the distance. </li></ul>
  120. 124. Conclusions <ul><li>Helicopter transport of trauma patients is over utilized. </li></ul><ul><li>Utilization criteria must be studied and revised. </li></ul><ul><li>Few trauma patients benefit from helicopter transport. </li></ul>
  121. 125. Conclusions <ul><li>Data show that helicopters are over utilized for trauma scene responses. </li></ul><ul><li>Over triage of trauma patients primary factor </li></ul><ul><li>Costs and risks may not justify benefit for the vast majority of trauma patients. </li></ul><ul><li>Triage criteria should be based on physiological parameters and not mechanism of injury. </li></ul>
  122. 126. Conclusions <ul><li>More research is needed. </li></ul><ul><li>Proliferation of helicopter operations reflects economic factors more than patient outcome factors. </li></ul><ul><li>Data may not be applicable to rural areas. </li></ul>
  123. 128. Audience Participation <ul><li>In my opinion, which country has the best EMS system? </li></ul><ul><ul><li>A. United Kingdom </li></ul></ul><ul><ul><li>B. United States </li></ul></ul><ul><ul><li>C. Australia </li></ul></ul><ul><ul><li>D. South Africa </li></ul></ul><ul><ul><li>E. France </li></ul></ul>
  124. 129. Airway Management <ul><li>And then, there is airway management. Do you have the rest of the afternoon? </li></ul>
  125. 130. Audience Questions <ul><li>Questions? </li></ul><ul><li>For details on publications, presentations, or biography, see: </li></ul><ul><li>http://www.bryanbledsoe.com </li></ul>

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