Traumatic Brain Injury andEvidence Based Medicine

TBI - What are the problems?TBI management strategiesTBI treatment in AustriaIntroduction into EBMHow to use EBM for continuous

quality improvement in the care of TBI patients

TBI: Treatment Goals

TO KEEP THE PERMANENT NEURO DEFICIT AT THE LEVEL DEFINED BY THE PRIMARY INJURY

TO AVOIDTO RECOGNIZE

IMMEDIATELYTO TREAT WITHOUT DELAY SECONDARY BRAIN

INSULTS

Secondary Brain Insults

HYPOTENSION (SAP < 90)HYPOXIA (paO2 < 60, SaO2 < 92)GLOBAL ISCHEMIA (CI < 2, CPP < 50)REGIONAL ISCHEMIA (vasospasm)ANEMIA (Hct < 30, Hb < 10)HYPERCARBIA (pCO2 > 40)HYPERTHERMIA (BT > 37.5)

Chesnut RM, New Horizons 1995; 3:366-375

Treatment in Anytown / USAICP monitoring in 50% of centersICP monitoring in 25% of casesOsmodiuretics in 83% of the centersHV to 25 mmHg in 54% of the centersHV < 25 mmHg in 29% of the centersSteroides in 64% of casesBarbiturate in 33% of the centersDehydration in > 90% of cases

Ghajar J, et al, Crit Care Med 1995; 23:560-567

Marshall LF, Bowers SA; Clin Neurosurg 1982; 29:312-315

„Classical“ Treatment

Analgesia, sedation, anesthesia, relaxationIntubation, hyperventilationHead elevation 30°Normovolemia, normotensionOsmotherapy accoring to monitored ICP

valuesMain goal: „normal“ intracranial pressure

Treatment in Birmingham, Ala.Anesthesia, sedation, relaxationNormoventilationSupine position, no head elevationHypervolemia, vasopressors, inotropes to

achieve and maintain CPP > 70 (more often > 90) mmHg

Treatment of raised ICP with osmodiuretics only, all other options are forbidden because of the risk of hypotension

Main goal: normal cerebral perfusion pressure

Rosner MJ, et al, J Neurosurg 1995; 83:949-954

Treatment in Philadelphia, Pa.Sedation, analgesia, no relaxantsIntubation, hyperventilationNormovolemia, normotensionHead elevation 30°Jugular bulb catheter to monitor cerebral

oxygen extractionHyperventilation to achieve / maintain

"normal" oxygen extraction ratio (pCO2 < 20 mmHg!)

Main goal: normal cerebral O2ER

Cruz J, et al, Crit Care Med 1993; 21:1242-1246

Treatment in Lund, SwedenBarbiturate anesthesia, analgesiaIntubation, normoventilation"relative" hypotension, hypovolemiaControl of MAP with clonidine and ß-blockers;

CPP maintained at 50 mmHgHyperosmolarity (Na = 150 mmol/l)Steroids, paracetamol, cooling to 35 °CDHE to achieve vasoconstrictionMain goal: minimal hydrostatic brain edema

Asgeirsson B, et al; Intensive Care Med 1994; 20:260-267

All centers have documented that their treatment strategy is superior

to published resultsfrom other centers / groups

Optimal Treatment ?

„Optimal ICP“ ?„Optimal CPP“ ?“Optimal O2ER“ ?

„Edema prevention“ ?

Treatment of severe traumatic brain injury in Austria (1998)

H. Drobetz, B. Freudenschuß,

E. Kutscha-Lissberg, W. Buchinger,

W. Mauritz

Austrian ICUs surveyed (n = 60)

Mostly run by anesthesiologists, all contacted by phone (for treatment data)

Phone calls (for patient statistics) to all Departments ofTrauma SurgeryNeurosurgerySurgery

15151212

2020

5454

19191616

991313

4141

13131717

1212

27273131

0%0%

10%10%

20%20%

30%30%

40%40%

50%50%

60%60%

0 - 100 - 10 11 - 2011 - 20 21 - 3021 - 30 31 - 5031 - 50 > 50> 50

Operative (n = 41/60)Operative (n = 41/60)

Conservative (n = 32/60)Conservative (n = 32/60)

GCS < 8 (n = 52/60)GCS < 8 (n = 52/60)

Patient numbers/ICU/1997

Surgical Treatment

82%82%

29%29%

4%4%Trauma surg.Trauma surg.

Neurosurg.Neurosurg.

SurgeonSurgeon

Prehospital Treatment

GCS 90% (n = 51/60)

MAP, HR, SaO2 100% (n = 44/60)

Intubation 74% (n = 47/60)

Prehospital „small volume resuscitation“ and steroids (n = 50/60)

1212%%

50%50%

32%32%

6%6%

70%70%

12%12%6%6% 10%10%

nevernever rarelyrarely frequentlyfrequently usuallyusually

SVRSVRSteroidsSteroids

ICP Monitoring in Austria

1

10 - 100%

77,21%77,21%

40,21%40,21%

Neurosurgeons (13-100%)Neurosurgeons (13-100%)n = 7n = 7

Trauma Surgeons (15-100%)Trauma Surgeons (15-100%)n = 31n = 31

ICP Monitoring

(n = 46/60)91%91%

41%41%

24%24%15%15% 11%11%

EpiduralEpidural VentricleVentricle differentdifferent ParenchymParenchym SubduralSubdural

ICP Monitoring Devices

uninjured59%

both7%

injured34%

ICP Monitoring - Side

(n = 52/60)

19%19% 15%15%

44%44%

21%21%

79%79%

13%13%8%8%

94%94%

4%4% 2%2%

nevernever rarelyrarely frequentlyfrequently usuallyusually

Hyperventilation to 30 mm Hg COHyperventilation to 30 mm Hg CO22

Hyperventilation 25 - 30 mm Hg COHyperventilation 25 - 30 mm Hg CO22

Hyperventilation < 25 mm Hg COHyperventilation < 25 mm Hg CO22

Hyperventilation

(n = 52/60)65%65%

19%19%

6%6% 10%10%

nevernever rarelyrarely frequentlyfrequently usuallyusually

Steroids at the ICU

8%8%

27%27%

50%50%

15%15%

nevernever rarelyrarely frequentlyfrequently usuallyusually

Osmotherapy (n = 52/60)

(n = 52/60)

12%12%

31%31%

46%46%

12%12%

nevernever rarelyrarely frequentlyfrequently usuallyusually

Barbiturate Treatment

So what?Every center has its own standardsMost centers see only few patientsComparison of results between centers

are rare

Approach:Creation of an (inter)national database to

collect patient data from different centersData can be used for quality assurance

programsIntroduction of guidelines and clinical

pathways

Available Guidelines“Guidelines for the Management of Severe

Head Injury” (1995), published in major journals, revised in 1997

Formulated by the “Joint Section on Neurotrauma and Critical Care” of the AANS and CNS

Reviewed & discussed in:New Horizons Vol. 3, #3, August 1995

J Trauma, Vol. 42, #5, Supplement May 1997

Other Guidelines

European Brain Injury Consortium (EBIC)Scandinavian GuidelinesOther national guidelines

Most guidelines were created using the same process (EBM)and the same published evidence, and therefore came to similar conclusions

Evidence Based Medicine

Basis for decisions in medicine„clinical experience“, EBM criteria

What is EBM?Principle, methods, problems

Why use EBM?Safety (?), quality, standardisation (?)

How to use EBM?Individual Search StrategiesStandards & Guidelines, Clinical Pathways

Clinical Experience (1)

Is the (partially sub-cortically) available summary of

Knowledge of pathophysiology (basic knowledge)

Medical tradition (e.g. Dopamin) TrainingAnalogies (treatment results in similar

cases)

which forms the basis for daily decisions.

Clinical Experience (2)

Advantages:Increases with ageAvailable immediately and everywhereUsually sufficient„flexible“ compared to EBM

Disadvantages:Huge individual differencesErrors may have a long tradition, tooAcceptance of new findings may be slowEffectivity of treatment overestimated

Evidence Based Medicine

Developed by Clinical Epidemiologists from McMaster Medical School, Canada, since 1985

Positioned as alternative to traditional „opinion-based“ medicine

„best available evidence“ should be the basis for treatment decisions: multi-center PRCT, meta-analysis, guidelines, clinical pathways

What is „evidence“? (1) Clinical experience („non-experimental"

evidence) overestimates effectivity: Treatment successes are remembered

more frequently than treatment failures Patient compliance improves outcome,

even with placebo Many diseases, symptoms or conditions

improve anyway Treatment is never „blind“, and the

placebo effect may suggest effectivity

What is „evidence“? (2)

EBM criteria: Only "experimental“ evidence (i.e. results from clinical trials) should be used as basis of treatment decisions.

"Therapeutic reports with controls tend to have no enthusiasm, and reports with enthusiasm tend to have no controls"

Sackett DL, CHEST 1989; 95:(Suppl.) 2S

Levels of evidence

Classification of scientific reports:

1. Prospective randomized controlled trial (PRCT), enough power to limit alpha (false pos) and beta (false neg) error (= large patient numbers, multi-centered)

2. PRCT with less power

3. Study with controls not randomized

4. Study with historic controls

5. Study without controls; "expert opinion"

Basis for Guidelines

Grade A, Class I evidence: Standards; supported by one or more level 1 studies

Grade B, Class II evidence: Guidelines; supported by one or more level 2 studies

Grade C, Class III evidence: Options; supported by studies classified as level 3, 4, or 5

Sackett DL, CHEST 1989; 95:(Suppl.)2S

EBM - Methods (1) For any questions regarding diagnosis,

prognosis or treatement:1. Formulate a clear question2. Search for relevant studies3. Evaluate retrieved studies for validity

and usefulness4. Use results in clinical practice Rosenberg W, Donald A: Evidence-based

medicine: an approach to clinical problem solving. Br Med J 1995; 310:1122-1226

EBM - Methods (2) Evaluation of retrieved studies:1. Are the results correct?

Patient sample large enough, representative? Study groups homogenous? Collection of patient, treatment and outcome

data complete? Valid criteria used for evaluation?

2. What are the results? Incidences of outcomes, complications? How good are estimates of likelihoods?

3. Are the results useful? Is the situation comparable to the study? Can the results be used in clinical practice?

EBM – Problems (1)Formulation of a clear question

Easy: scoring systems or grading scales available; high incidence of disease or problem

Difficult: low incidence of disease or problem, no scoring systems or grading scales available

Time factorMedline search, retrieval and evaluation of

studies take timeEquipment factor

Internet, database connections, computers, library services must be available

EBM – Problems (2)Evaluation of retrieved studies

Easy: guidelines, consensus conference results available

Difficult: individual evaluation; incorrect estimation of probability of outcomes

Not all that can be measured is usefulNot all that is useful can be measuredLack of evidence of efficiacy is not equal to

evidence of lack of efficiacyHow to deal with different level-1 studies

EBM - Problems (3)

Use of selected evidence: even use of „best available evidence“ may lead to errors in management due to

Ignorance of local situationApplication to patients or patient groups

who are different from the study groupOveruse of resources in settings where

resources are limited

GuidelinesAvailable for frequent problems Developed by Consensus Conferences,

Working Groups etcShould be peer/reviewedEffect of guideline compliance should be

evaluatedShould be updated regularelyNon-compliance may lead to litigation!

0

5

10

15

20

25

30

66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98

n

Published Guidelines for ICUs (n=167; medline 66-9/99)

Why use EBM?Validity

EBM-Review instead of tradition / opinionBUT: Application of „best available evidence“

to an individual situation is still a medical decision, and may be wrong

QualityCritical re-evaluation of clinical practiceScoring systems, grading scales required

StandardisationTreatment „state of the art“

How to use EBM?Clinical experience should be assisted,

not replaced by EBMUse of EBM requires time, patience, good

knowledge of English, computer skills, internet and database connections, and critical intellect

EBM-based solutions for critical situations are available ONLY if the hard work is done before

Individual search, use of guidelines and clinical pathways possible

Individual Search

If no guidelines are availableMedline: use different key words for search

runs, identify possibly relevant studiesLibrary: retrieve papersEvaluate, identify relevant papersCreate treatment algorithmImplement treatment algorithmCheck results of algorithm implementation

Guidelines

Available for frequent problemsMedline: identify relevant guidelinesLibrary: retrieve original publicationCreate treatment algorithm adapted to local

situation (= clinical pathway)Implement treatment algorithmCheck results of algorithm implementation

Medicl Decisions (1)

Starting point: Problem with diagnosis, prognosis, treatment

Can the problem be exactly defined?NO: decision according to „clinical

experience“YES:

Is the problem exactly defined?NO: try to define the problemYES:

Medical Decisions (2)Are guidelines available?

YES: Creation and implementation of algorithm

NO:

Is experimental evidence (PRCT, MA) available?YES: decision according EBM criteriaNO: decision according to „clinical

experience“ – possible approaches should be tested in clinical study

Ultimate Goal of our Project

To improve quality of care

for brain trauma patients

by using

evidence based medicine (EBM)

and

continuous quality management (CQM)

CQM

Analysis of ICU outcomes and treatment strategies for each ICU

Comparison to other ICUs (pooled data, or „best ICU“ data)

Development of strategies to improve performance (together with IGEH)

Implementation of improvement strategies

Re-evaluation.....................

Implementation

Guideline

Research

OutlookGuidelines define goals but (usually) DO

NOT explain how to reach these goalsOne of the most important steps in our

project will be to develop, implement and test „clinical pathways“

Clinical pathways should explain how to reach the goals defined by the guidelines

I LOOK FORWARD TO WORK WITH YOU ON THIS FASCINATING PROJECT

THANK YOU