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