The Science Beyond Trauma Care

8/10/2019 The Science Beyond Trauma Care

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The Science Behind

Trauma CareDr. Bryan E. Bledsoe

Professor, Emergency Medicine

The George Washington University MedicalCenter


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Audience Interaction

Which of the following actresses is myfavorite?

A. Sandra Bullock

B. Angelina Jolie

C. Salma Hayek

D. Nicole KidmanE. George Michael


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Science in Trauma Care

Negative

Evidence

No Evidence

Or

Equivocal Evidence

Positive

Evidence


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Levels of Evidence

Not all scientificevidence is the same.


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Audience Interaction

My ambulance service practicesevidence-based prehospital care?

A. Strongly agree

B. Agree

C. Neither agree nor disagree

D. DisagreeE. Strongly disagree.


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Levels of Evidence

Center for Evidence-Based Medicine(Oxford)

Ia. Meta-analysis of RCTsIb. One RCT.

IIa. Controlled trial without randomisation.

IIb. One other type of quasi-experimental study.

III. Descriptive studies, such as comparative studies,correlation studies, and case-control studies.

IV. Expert committee reports or opinions, or clinicalexperience of respected authorities or both.


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Levels of Evidence

American Heart Association

1. Positive randomized controlled trials.

2. Neutral randomized controlled trials.3. Prospective, non-randomized controlled trials.

4. Retrospective, non-randomized controlled trials

5. Case series (no control group)

6. Animal studies

7. Extrapolations

8. Rational conjecture (common sense)


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Levels of Evidence


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Levels of Evidence

The closer a study adheres to thescientific method, the more valid the

study.The more valid the study, the closer it isto the truth.


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Ranking the Evidence

Class I:

Derived from the strongest studies of

therapeutic interventions (RCTs) in humans.Used to support treatmentrecommendations of the highest order called

practice standards.


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Class II:

Derived from the comparative studies with

less strength (nonrandomized cohortstudies, RCTs with significant design flaws,and case-control studies).

Used to support recommendations calledguidelines.


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Class III:

Derived from the other sources of

information, including case series and expertopinion.

Used to support practice options.


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Overall term for all ofthe recommendations

is practice parameters.


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EMS Practice Changes

EMS Practices refuted by empiricevidence:

Critical Incident Stress Management (CISM)

MAST/PASG

Trendelenburg Position

High-Volume Fluid Resuscitation


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EMS Practices unsupported by empiricevidence:

Medical Priority DispatchSystem Status Management

High-Dose Epinephrine

High-Dose Steroids for Acute Spinal CordInjury

Intraosseous Needles

CPR Compression Vest


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EMS Practice changes based uponempiric evidence:

AED usage (first 6-8 minutes)

CPR

Field death pronouncement in blunt

traumatic cardiac arrest.


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Guiding Prehospital Care

1. There should be a link between theavailable evidence and treatment

recommendations.2. Empirical evidence should take

precedence over expert judgement in

the development of guidelines.


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In science, there are

no authorities.

Carl Sagan, PhD1934-1996


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3. The available research should besearched using appropriate and

comprehensive search terminology.4. A thorough review of the scientific

literature should precede guideline

development.


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5. The evidence should be evaluated andweighted, depending upon the scientific

validity of the method used to generatethe evidence.

6. The strength of the evidence should be

reflected in the strength of therecommendations reflecting scientificcertainty (or the lack thereof).


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7. Expert judgement should be used toevaluate the quality of the literature and

to formulate guidelines when theevidence is weak or nonexistent.

8. Guideline development should be a

multidisciplinary process, involving keygroups affected by the recommendations.


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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 arrestpatients(n=5,000+ patients).

Phase III:Assessed survival outcomes months after the

introduction of full ALS programs for 36 months for cardiacarrestpatients and major traumapatients, and for 6

months for respiratory distresspatients.


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Phase I:Survival improved with:

Decreasing EMS response intervals

Bystander-CPR

First responder CPR by fire or policePhase II:Survival improved with:

Rapid defibrillation (survival increased from 3.9% to5.2%) resulted in 33% improvement in survival

An additional 21 lives saved each year

Increased survival was also associated with bystander

and first responder CPR.


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Phase III:

Cardiac Arrest:

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 rapiddefibrillation.

8-minute response time too long.


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Phase III:

Cardiac Arrest:

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 andpublic access defibrillation programs.


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Phase III:

Chest Pain:

Clearly showed important benefit from ALS programs

for mortality and other outcomes.


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Phase III:

Respiratory Distress:

After adjustment for demographic, clinical, and EMS

factors, the only interventions associated with better

survival were salbutamol and NTG.

Most children are not severely ill, most do not receiveALS interventions, there is a high rate of non-transport,

and the vast majority are discharged home from the

ED.


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Phase III:

Pediatric Care:

The majority of patients did not require immediate or

urgent medical care and had good short-term

outcomes.


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Practices with positive evidence:

Permissive hypotension

Splinting

Pain management

Head injury management

Hemoglobin-Based Oxygen CarryingSolutions (HBOCs)


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Practices with no evidence or equivocalevidence:

The Golden HourMedical helicopters

Trendelenburg position

Traction splintsRapid sequence intubation (RSI) in traumaticbrain injury (TBI)


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Practices with negative evidence:

MAST/PASG

Steroids for acute SCI

High-volume fluid therapy

Prehospital intubation in traumatic brain

injuryPediatric endotracheal intubation


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Audience Participation

In regard to current prehospital practice in mysystem, which of the following best describestrauma care?

A. We still used MAST/PASG and administer largevolumes of fluid to restore normal BP.B. We do not use the MAST/PASG but administerlarge volumes of fluid to restore BP.C. We administer enough fluid to maintain a blood

pressure >100 mm Hg.D. We administer enough fluid to maintain a bloodpressure > 90 mm Hg.E. We administer enough fluid to maintain a bloodpressure > 80 mm Hg.


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Practices with strong negative evidence:

Scene stabilization


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IV Fluid Restriction

Should p rehospi tal

personnel adm inis ter

large volumes of IV fluid s

rapidly to trauma vict ims

or delay f lu id

resusci tat ion unt i l

hosp ital arr ival?


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Traditional approachto trauma patient

with hypotensionwas 2 large bore IVsand wide opencrystalloid

administration.


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High volume IV fluidadministration was

based on severalanimal studies fromthe 1950s and 1960s.


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High volume IV fluidtreatment was usedin Viet Nam andtransferred to US andwestern civilianprehospital carepractices.


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Several animal studies inthe 1980s and 1990sfound that treatment with

IV fluids beforehemorrhage wascontrolled increased themortality rate, especiallyif the BP was elevated.


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Raising the BP and restoring perfusion tovital organs are clearly believed to be

beneficial afterhemorrhage is controlled.Growing evidence indicates that raising itbeforeachieving adequate hemostasis

may be detrimental.


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Administering large quantities of IV fluidswithout controlling the hemorrhage results in:

hemodilution with decreased hematocrit

decreased available hemoglobin (and oxygen- carrying capacity)decreased clotting factors.

This effect is found regardless of the fluid used(blood, LR, NS, hypertonic saline).


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Bickell WH, Wall MJ Jr, Pepe PE, et al. Immediateversus delayed fluid resuscitation for hypotensivepatients with penetrating torso injuries. N Eng J Med.

1994;331:1105-9598 patients with penetrating torso injury and systolicBP 90 mmHg in prehospital setting.

Randomized to receive standard high-volume fluids or

fluids delayed until patient in OR.


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Results:Group Divisions

Delayed: n=289

Standard fluids: n=309Survival:

Delayed: 70%Standard fluids: 62%

Complications:Delayed: 23%Standard fluids: 30%


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CONCLUSIONS:For hypotensive patientswith penetrating torso injuries, delay of

aggressive fluid resuscitation untiloperative intervention improves theoutcome.


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Tentative Hypothesis:

At this t ime, intravenous f lu id

resusci tat ion shou ld p robably be delayed

un t i l hemostasis is ob tained.


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Literature has primarilylooked at penetratingtrauma.

The role of fluidresuscitation in patientswith blunt trauma is lessclear.

Further studies areneeded.


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Current recommendationfor blunt trauma is toadminister just enough

fluid to maintainperfusion.

Rapid, high-volume fluidadministration is

discouraged.


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Fluid resuscitationmay be of value in

patients who aremoribund withsystolic pressures


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Patients withhypotension due tosevere hemorrhage from

isolated extremityinjuries may do betterwith aggressiveprehospital IV fluidresuscitation after

hemostasis.


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Complications of preoperative fluidresuscitation:

Secondary bleeding or acceleration of ongoing

hemorrhageAdult respiratory distress syndrome (Danang Lung)

Sepsis

Coagulopathies

Renal failure


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Conclusions:More research is needed.

Data on penetrating trauma is compelling.

Fluid resuscitation probably indicated for moribundpatients.

Best management strategies for blunt trauma and headinjuries is to administer just enough fluid to maintainperfusion.

Rapid transport probably remains the best treatment formost trauma cases.


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Limitations:

Most studies on urban trauma patients with

short transport times.Findings may not be applicable to ruraltrauma patients.


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Permissive Hypotension

Should prehospital

personnel attempt to

restore blood pressure in

trauma patients to pre-trauma levels or practice

permissive hypotension?


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Human researchseems to support

this premise.Primarily the Bickell,Wall, Pepe, et al.study previously

detailed.


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Elevation of BP to pre-injury levels,without hemostasis, has been associated

with:Progressive and repeated re-bleedingDecrease in platelets and clotting factors.

Dislodgement of a clot at the site of injury.


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Interestingly, thestandard treatment forruptured AAAs has beento keep patients

hypotensive untilproximal control of theaorta (above the leakage)is attained.This preserves

intravascular bloodvolume and preventsnew additional bloodloss from the rupture.


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Large animal studiesof uncontrolledhemorrhage indicate

that the clot ispopped at about 80mmHg systolicpressure.This level has beenreproducible inhuman subjects.


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Dutton RP, MacKenzie CF, Scalea TM, et al. Hypotensiveresuscitation during active hemorrhage: Impact on in-hospitalmortality. J Trauma.2003;52(6):1141-1146

110 patients with hemorrhagic shock were randomized

into two groups: BP maintenance > 100 (n=55) or BPmaintenance of 70 (n=55).Conclusion:Titration of initial fluid therapy to a lowerthan normal SBP during active hemorrhage did notaffect mortality in this study. Reasons for the

decreased overall mortality and the lack ofdifferentiation between groups likely includeimprovements in diagnostic and therapeutictechnology, the heterogeneous nature of humantraumatic injuries, and the imprecision of SBP as amarker for tissue oxygen delivery.


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Holmes JF, Sakles JC, Lewis G, Wisner DH. Effects of delaying fluidresuscitation on an injury to the systemic arterial vasculature.Acad Emerg Med.2002;9(4):267-274

21 sheep underwent thoracotomy and transection ofthe left internal mammary artery.

Group 1: No fluid resuscitationGroup 2: Resuscitation 15 minutes after injuryGroup 3: Resuscitation 30 minutes after injury

CONCLUSIONS:Rates of hemorrhage from an arterialinjury are related to changes in mean arterial pressure.

In this animal model, early aggressive fluidresuscitation in penetrating thoracic traumaexacerbates total hemorrhage volume. Despiteresumption of hemorrhage from the site of injury,delaying fluid resuscitation results in the besthemodynamic parameters.


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This paradigm shifthas significantimplications onemergency care:

Trendelenburgposition

Use of rapid infusersIntraosseousinfusions


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Fluid restriction andpermissivehypotension go

hand-in-hand.Fluid resuscitationshould beadministered in smallboluses to maintainperipheral pulse(systolic BP +/- 80mmHg)


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During prolonged transportthe prehospital care providermust attempt to maintainperfusion to the vital organs.

Maintaining the systolic bloodpressure in the range of 80-90 mm Hg or the MAP in therange of 60-65 mm Hg, canusually accomplish this with

less risk of renewing internalhemorrhage.


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Gain IV access en route butgive only enough Ringerslactate solution or normalsaline solution to maintain a

blood pressure high enoughfor adequate peripheralperfusion. Maintainingperipheral perfusion may bedefined as producing a

peripheral pulse, maintaininglevel of consciousness, ormaintaining blood pressure(90-100 mm Hg systolic).


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What about patientswith TBI?


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Traumatic Brain Injury

Oxygenation and Blood Pressure

Hypoxemia (


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Why does TBI require a higher systolic BP thanrequired for permissive hypotension?

CPP = MAP- ICPMAP = [DBP+1/3 (SBP-DBP)]


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Slightly highersystolic pressure

may be required tomaintain CPP inTBI.


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Oxygen-Carrying IV Fluids

Do oxygen-

carry ing IV f lu ids

have a futu re rolein prehospi ta l

care?


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HBOCs

Each molecule ofhemoglobin cancarry 4 molecules ofoxygen.


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HBOCs

The amount ofoxygen on thehemoglobin (oxygen

saturation) isdependent upon thepartial pressure ofoxygen.


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HBOCs

The amount ofoxygen that can betransported is also

dependent upon theamount of circulatingred blood cells andthe hemoglobin

contained within.


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HBOCs

Blood loss andcrystalloid fluidtherapy decreasesthe percentage ofcirculating red bloodcells and

hemoglobin.


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Oxygen-Carrying IV Fluids

Perflurocarbon emulsions

Hemoglobin-based oxygen carrying

solutions (HBOCs):PolyHeme

Hemopure


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HBOCs


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HBOCs


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HBOCs

PolyHeme

Solution of chemically-modified hemoglobin

derived from discarded donated humanblood.

Hemoglobin extracted and filtered to removeimpurities.


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HBOCs

PolyHeme

Chemically-modified to create a polymerized form ofhemoglobin designed to avoid problems previouslyexperienced with hemoglobin-based blood

substitutes:VasoconstrictionRenal dysfunctionLiver dysfunctionGI distress

Polymerized hemoglobin incorporated into asolution that contains 50 grams of hemoglobin perunit (the same as transfused blood).


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HBOCs


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HBOCs

CaliforniaUCSD (San DiegoScripps Mercy (San Diego)

ColoradoDenver H&H (Denver)

DelawareChristiana (Newark)

IllinoisLoyola (Chicago)

IndianaWishard (Indianapolis)Methodist Hospital (Indianapolis)

KentuckyU of K (Lexington)

MinnesotaMayo (Rochester)

OhioMetro Health (Cleveland)

PennsylvaniaLehigh Valley (Allentown)

TennesseeUT (Memphis)

TexasMemorial-Hermann (Houston)UTHSCSA (San Antonio)

VirginiaSentara (Norfolk)VCU (Richmond)


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HBOCs

Artificial polymerized hemoglobin cantransport oxygen within the plasma.


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HBOCs

Gould SA, Moore EE, Hoyt DB, et al. The first randomizedtrial of human polymerized hemoglobin as a bloodsubstitute in acute trauma and emergency surgery. J AmColl Surg. 1998;187(2):113-20

44 trauma patients (33 male, 11 female) wererandomized to receive red cells or PolyHeme as theirinitial fluid replacement after trauma.There were no serious or unexpected outcomes relatedto PolyHeme.

CONCLUSIONS:PolyHeme is safe in acute blood loss,maintains total [Hb] in lieu of red cells despite a markedfall in RBC [Hb], and reduces the use of allogenicblood. PolyHeme appears to be a clinically-useful bloodsubstitute.


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HBOCs

Gannon CJ, Napolitano LM. Severe anemia after

gastrointestinal hemorrhage in a Jehovahs Witness: new

treatment strategies. Critical Care Medicine. 2002;30:1930-1931

50year-old Jehovahs Witness had massive UGI bleedfrom pre-pyloric ulcer (Hb=3.5 grams). Hemorrhage controlwith injection of epinephrine.

Patient became hemodynamically unstable.

Received 7 units of bovine HBOC and human

erythropoietin.Within 24 hours patient stable and Hb 7.2 grams.

Conclusions:Survival without allogenic blood attained.


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HBOCs

HBOCs look quitepromising for prehospitaland battlefield

emergency care.Furtherrecommendations awaitresult of first prehospital

study.


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Audience Participation

In my ambulance service, we use medicalhelicopters for scene responses:

A. Very FrequentlyB. Often

C. Occasionally

D. RarelyE. Never


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Helicopters

Are EMS

hel icopters

effect ive indecreasing

mortal ity and

enhanc ing trauma

care?


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Helicopters

Initial studies in the 1980s showed that traumapatients have better outcomes whentransported by helicopter.

Today, other than speed, helicopters offer littleadditional care than provided by groundambulances.


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Helicopters

The number ofmedical helicoptersin the United Stateshas increased from400 to >700 in the last4 years.


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Helicopters

Considerations:

Severe injury:ISS > 15

TS < 12RTS 11Weighted RTS 4Triss Ps< 0.90

Non-life-threatening injuries:Patients not in above criteriaPatients who refuse ED treatmentPatients discharged from EDPatients not admitted to ICU


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Helicopters

Shatney CH, Homan SJ, Sherek JP, et al. The utility ofhelicopter transport of trauma patients from the injury scenein an urban trauma system. J Trauma. 2002;53(5):817-22

10-year retrospective review of 947 consecutivetrauma patients transported to the Santa ClaraValley trauma center.

Blunt trauma: 911

Penetrating trauma: 36


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Helicopters

Mean ISS = 8.9

Deaths in ED = 15

Discharged from ED = 312 (33.5%)Hospitalized = 620

ISS 9 = 339 (54.7%)

ISS 16 = 148 (23.9%)Emergency surgery = 84 (8.9%)


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Helicopters

Only 17 patients (1.8%) underwent surgery forimmediately life-threatening injuries.Helicopter arrival faster = 54.7%Helicopter arrival slower = 45.3%Only 22.4% of the study population were poss ib lyhelped by helicopter transport.CONCLUSION:The helicopter is used excessively forscene transport of trauma victims in our metropolitantrauma system. New criteria should be developed forhelicopter deployment in the urban traumaenvironment.


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Helicopters

Eckstein M, Jantos T, Kelly N, et al. Helicopter transport ofpediatric trauma patients in an urban emergency medicalservices system: a critical analysis. J Trauma, 2002;53:340-344.

Retrospective review of 189 pediatric trauma patients( 7 = 82%ISS < 15 = 83%Admitted to ICU = 18%Discharged from ED = 33%


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Helicopters

CONCLUSION:The majority of pediatrictrauma patients transported by helicopterin our study sustained minor injuries. Arevised policy to better identify pediatricpatients who might benefit fromhelicopter transport appears to be

warranted.


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Helicopters

Braithwaite CE, Roski M, McDowell R, et al. Acritical analysis of on-scene helicopter transport onsurvival in a statewide trauma system. J Trauma.1998;45(1):140-4

Data for 162,730 Pennsylvania trauma patientsobtained from state trauma registry.

Patients treated at 28 accredited trauma centers15,938 patients were transported from the scene by

helicopters.6,273 patients were transported by ALS groundambulance.


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Helicopters

Patients transported by helicopter:Significantly youngerMalesMore seriously injured

Had lower blood pressureHelicopter patients:

ISS


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Helicopters

Cocanour CS, Fischer RP, Ursie CM. Are scene flights forpenetrating trauma justified? J Trauma. 1997;43(1):83-86

122 consecutive victims of non-cranial penetratingtrauma transported by helicopter from the scene.

Average RTS = 10.6Dead patients = 15.6%

Helicopter did not hasten arrival in for any of the 122patients.Only 4.9% of patients required patient care

interventions beyond those of ground ALS units.CONCLUSION:Scene flights in this metropolitan areafor patients who suffered noncranial penetratinginjuries demonstrated that these flights were notmedically efficacious.


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Helicopters

Cunningham P, Rutledge R, Baker CC, Clancy TV. A comparison of theassociation of helicopter and ground ambulance transport with theoutcome of injury in trauma patients transported from the scene. JTrauma 1997;43(6):940-946

Data obtained from NC trauma registry from 1987-1993on trauma patients and compared:

1,346 transported by air17,144 transported by ground

CONCLUSION:The large majority of trauma patientstransported by both helicopter and ground ambulance

have low severity measures. Outcomes were notuniformly better among patients transported byhelicopter. Only a very small subset of patientstransported by helicopter appear to have any chance orimproved survival.


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Helicopters

Moront ML, Gotschall CS, Eichelberger MR. Helicopter transport ofinjured children: system effectiveness and triage criteria. J Pediatr Surg.1996;31(8):1183-6

3,861 children transported by local EMS1,460 arrived by helicopter

2,896 arrived by ground

Helicopter transported patients:ISS


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Helicopters

Wills VL, Eno L, Walker C, et al. Use of an ambulance-based helicopterretrieval service.Aust N Z J Surg.2000;70(7):506-510

179 trauma patients arrived by helicopter during study year.122 male57 female

Severity of injuries:ISS < 9 = 67.6%ISS 16 = 17.9%12 (6.7%) discharged from the ED46 (25.7%) discharged within 48 hours.

Results:17.3% of patients were felt to have benefited from helicopter transport81.0% of patients were felt to have no benefit from helicopter transport1.7% of patients were felt to have been harmed from helicoptertransport

H li


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Helicopters

Bledsoe BE, Wesley AK, Eckstein M, Dunn TM, OKeefeMF. Helicopter Transport of Trauma Patients: A Meta-

Analysis J Trauma (In Press).

Meta-Analysis of 22 papers with a cohort of 37,350

patients.ISS 15 (minor injuries): 60% (99% CI: 54.5-64.8)TS 13 (minor injuries): 61.4% (99% CI: 60.8-62.0)TRISS Ps >0.90 (minor injuries): 69.3% (99% CI: 58.5-80.2)Discharged < 24 hours: 24.1% (99% CI: -0.90-52.6)

H li t


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Helicopters

54

5658

60

62

64

66

68

70

ISS TS TRISS

Percentagewith minorinjuries

H li t (US A id t )


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Helicopters (US Accidents)

0

5

10

15

20

25

2004 2002 2000 1998 1996 1994

Accidents

Deaths

Injuries

H li t


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Helicopters

5

26 27

74

0

10

20

30

40

5060

70

80

All

Workers

Farming Mining Air

Medical

Crew

Occupational Deaths per 100,000/year (U.S. 1995-2001)

Source: Johns Hopkins University School of Public Health

H li t


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Helicopters

An EMS helicopter (HEMS) pilot orcrew member flying 20 hours/week for20 years would have a 40% chance ofa fatal crash.Since 2002, more people have beenkilled in air ambulance crashes than

aboard U.S. commercial airlines,though the helicopters travel just afraction of the distance.

C l i


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Conclusions

Helicopter transport of trauma patients isover utilized.

Utilization criteria must be studied andrevised.

Few trauma patients benefit from

helicopter transport.

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Conclusions

Data show that helicopters are over utilizedfor trauma scene responses.

Over triage of trauma patients primary factor

Costs and risks may not justify benefit forthe vast majority of trauma patients.

Triage criteria should be based on

physiological parameters and notmechanism of injury.

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Conclusions

More research isneeded.

Proliferation ofhelicopter operationsreflects economicfactors more thanpatient outcomefactors.

Data may not beapplicable to ruralareas.


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Ai M t


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Airway Management

And then, there isairway management.Do you have the rest

of the afternoon?


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The Science Beyond Trauma Care

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