ICU

Management of Traumatic Head Injury

Dalhousie Critical Care Teaching Rounds

ICUObjectives

n Know how to calculate CPP and the normal CPP range.

n Discuss the management principles for raised ICP.n Discuss the issues for prevention of secondary injury in

SAH including control of temperature, glucose control, prevention and treatment of vasospasm with nimodipine and HHH therapy.

n Know how to work up and treat different Na disorders including SIADH, cerebral salt wasting and DI

ICUNeurophysiology

n CPP = MAP – CIPn N= 50-70n Trauma

n Increase volume of intracranial components

n Loss of autoregulationn Increased CSF

productionn Hypercapnia and hypoxic

insults

ICU

ICU

Emergency Diagnosticor Therapeutic Procedures

Tracheal IntubationFluid ResuscitationVentilation/OxygenationSedation

Management Management of Head Injuryof Head Injury

Severe Head InjuryGCS≤8

ATLS TraumaEvaluation

Deterioration Herniation

CT Scan

ICU

± Hyperventilate± Mannitol

Surgical Drainage

ICU

Raised ICP>25mm HgRaised ICP>25mm Hg

Management of Management of Raised ICPRaised ICP

n First Line RxFirst Line Rx

Measure ICPMeasure ICP

Maintain CPP>70 mm HgMaintain CPP>70 mm Hg

Ventricular DrainVentricular Drain

Elevate HOBElevate HOBNormal Vent/OxygenationNormal Vent/OxygenationMannitolMannitolSedationSedation

Raised ICP>25mm HgRaised ICP>25mm Hg CTCT

ICU

Raised ICP>25mm HgManagement of Management of Raised ICPRaised ICP

n Second Line RxSecond Line Rx

Maintain CPP>70 mm Hg

FurosemideChemical ParalysisCSF RemovalVasopressor

BarbituratesHyperventilationMonitor SjO2

Raised ICP>25mm Hg

ICUHead Injury

n Primary Head Injuryn Result of energy

absorptionn Difficult to preventn Results from

n neuronal or axonal disruption

n shearn lacerationn vascular disruption

n Secondary Head Injuryn Result of insults that occur after

primary injuryn Easier to preventn Causes

n ischemian hypoxian cerebral edeman intracranial hypertensionn abnormalities of cerebral blood

flown metabolic derangements

ICURole of ICP Monitoring

n May help in earlier detection of intracranial mass lesions

n Rationalizes therapy (ICP vs CPP)n CSF drainagen Helps in determining prognosisn May or may not improve outcome

CPP=MAP-ICP

ICUICP Monitors

n Intraventricular Cathetern “Gold standard”n Pros: Allows drainage of CSF (to dec

ICP), allows “re-zeroing”n Cons: Invasive, difficult to insert, infection

riskn Interparenchymal Probe

n Pros: Low infection raten Cons: Local pressure, “drift of zero”

ICUICP Monitors

n Subarachnoid Proben Pros: Low infection rate, no brain penetrationn Cons: Limited accuracy, high failure, requires

flushingn Epidural Probe

n Pros: Easy to insert, extra cranialn Cons: Limited accuracy, relatively delicate

n Others:n Transcranial dopplern Tympanic membrane displacementn Lumbar CSF pressure

ICUManagement of Traumatic Brain Injury

BTF and AANS Guidelines Process

Standards Guidelines Other Issues

Hyperventilation

Glucocorticoids

BP and Oxygen

Indications for ICP

CPP

Mannitol

Barbiturates

Hypothermia

Hypertonic Saline

Neuro-protection

ICU

AANS & BTFHead Injury Guidelines (2000)

n Pastn Reliance on expert opinionn Documented variability of practice

n Rely on scientific evidence and not expert opinionn Task force of experts with each Expert assigned a topic

n Medline searchn Review and grading of papers on topic

n Multiple iterationsn Involvement of national and international organizations

ICUHyperventilation

n CBF is the lowest in the first 24 hrs after injuryn Hyperventilation decreases CBF (3%/torr)

n Hypervent to a PCO2 26 CBF by 31% and CBV by 7%

n Can CBF and A-VdO2 to ischemic levels

n Effect of hyperventilation transient (4 hours)n CBF 90% of control at 4 hours of hyperventilation

ICUHyperventilation

n Muizelaar et al 1991Muizelaar et al 1991 RCT RCT

n Obrist et al 1984Obrist et al 1984 Cohort studyCohort studyn Hyperventilation had a greater effect on CBF than ICPHyperventilation had a greater effect on CBF than ICP

n Schnieder et al 1995Schnieder et al 1995 Cohort studyCohort studyn Hyperventilation second leading cause of jugular desaturationHyperventilation second leading cause of jugular desaturation

n Sioutos et al 1995Sioutos et al 1995 Cohort studyCohort studyn 1/3 of patients had CBF < 18 ml/100g/min1/3 of patients had CBF < 18 ml/100g/minn Hypervent decreased CBF furtherHypervent decreased CBF further

0

20

40

60

80

G/MD SD/V Dead

Control

Hypervent

N= 77N= 77

ICU Xenon Perfusion CBFXenon Perfusion CBF

PCOPCO22 = 45 torr = 45 torr

ICP = 44 mmHgICP = 44 mmHgCBF = 59 mL/min/100 gmCBF = 59 mL/min/100 gm

PCOPCO22 = 30 torr = 30 torr

ICP = 15 mmHgICP = 15 mmHgCBF = 14 mL/min/100 gmCBF = 14 mL/min/100 gm

Skippen P et al: Crit Care Med 1997; 25:1402-1409

ICUUse of Hyperventilation

n Standardsn In absence of increased ICP chronic hyperventilation

should be avoided (PCO2 < 25)n Guidelines

n Use of prophylactic hyperventilation (PaCO2 < 35) should be avoided during the first 24 hrs after head injury because it may compromise CBF

n Optionsn Hyperventilation may be necessary for brief periods

when there is neurologic deterioration or for raised ICP refractory to standard therapy

ICU

ICUGlucocorticoids

n Useful in patients with brain tumorn Experimental evidence

n Restoration of altered permeability in the labn Reduced CSF productionn Attenuation of free radical production

n Meta analysis has showed no benefitn Alderson et al 1997

n No benefit in clinical trial ofn Tirilazad 17 amino steroid

n N=1170 North American N=1128 Europe

ICUCRASH Study

n Head injury with GCS ≤ 14n Primary outcome

n Death at 2 weeksn Disability at 6 months (not yet reported)

n 10,008 subjectsn Multicentre RCT Randomization groups

n Placebon Methylprednisolone

n Load 2 gmsn Maintenance 0.4 gm/hr for 47 hours

n Mortality n Placebo 18%n Steroids 21%

Lancet 2004; 364: 1321-38

ICU Glucocorticoids in Severe Head InjuryGlucocorticoids in Severe Head Injury

n StandardsStandardsn Not recommended for reducing ICP or Not recommended for reducing ICP or

improving outcomeimproving outcome

ICUBlood Pressure and OxygenationBlood Pressure and Oxygenation

n TCDB studyTCDB studyn Large prospectively collected data Large prospectively collected data

setsetn N=717N=717

n Anesthesia StudyAnesthesia Studyn Observational study of patients Observational study of patients

with severe head injury requiring with severe head injury requiring surgery with in 72 hours of surgery with in 72 hours of admissionadmission

n N=53N=53

0

10

20

30

40

50

60

70

80

Vegitative or Dead

None

Early

Late

Both

DeathDeath

Chesnut et al 1997Chesnut et al 1997

0

10

20

30

40

50

60

70

80

90

G/M Sev/Veg Dead

IntraopHypotension

IntraopNormotension

Pietropaoli et al 1992Pietropaoli et al 1992

OutcomeOutcome

%%

ICUBlood Pressure and Oxygenation

No class I evidenceRandomization probably not ethicaln Standards

n niln Guidelines

n Hypotension (SBP<90) and hypoxia (PO2<60)must be avoided and if present corrected immediately

n Optionsn Mean arterial pressure > 90n CPP >70

ICURational for ICP Monitoring

n Correlation between high ICP and poor outcome

n Intracranial hypertension more likely in those with CT abnormalities or adverse features

n Age >40n Motor posturingn SBP<90

0

10

20

30

40

50

60

Inci

denc

e IC

H

Abn CT N CT N CT withAdverseFeatures

Narayan et al 1982Narayan et al 1982

ICU

Intracranial Pressure Monitoring

n Standardsn nil

n Guidelinesn Indicated for severe head injury with abnormal

CTn Indicated for severe head injury with normal

CT with 2 or more ofn age greater than 40n motor posturingn Systolic BP less than 90 mm Hg

n Not indicated for mild or moderate head injury

ICU

Does ICP Monitoring Improve Outcome

n No randomized controlled trialn Improved outcome with ICP monitoring over historical

datan Saul and Ducker 1982 (Class II)

n Rx ICP 20-25 mortality 46%n Rx ICP >15 mortality 28%

n Eisenberg et al 1988 (Class I)n Better outcome if ICP responded to Pentobarb

n Colohan et al 1989 (Class II)n 2 centers with lower mortality in center with ICP monitoring

Groups managed at different time periods

Other confounding factors

ICU

Does ICP Monitoring Improve Outcome

n No randomized controlled trialn Ghajar et al 1995 (Class III)

n Meta analysis demonstrating decreased mortality with CSF drainagen Lane et al 2000 (Class II)

n Retrospective study of trauma databasen 5507 head injured patientsn Used AIS scores to define injuryn Results

n multivariate analyses controlling for AIS head, ISS and injury mechanism indicated that ICP monitoring was associated with significantly improved survival (p < 0.015)

ICUCerebral Perfusion Pressure

n CBF low following head injuryn Compression of cerebral vesselsn Reduced cerebral metabolismn Vasospasm

n CBF lowest first 24 hrs after injuryn Ischemia common at autopsyn Correlation with CBF, GCS and outcomen Failure to maintain adequate CPP may lead to

increased ICP and poor outcome

ICU Physiology

n ICP, CPP, CBF and CMRO2ICP, CPP, CBF and CMRO2n CPP = MAP – ICP (or CVP)CPP = MAP – ICP (or CVP)n Monroe-Kellie DoctrineMonroe-Kellie Doctrine

ICU

Cerebral Perfusion PressureCerebral Perfusion Pressure

n Fortune et al 1994 (Class II) N=14n CPP maintained above 70 mm Hgn Mortality 14%

n Rosner et al 1990 (Class II) N= 34n CPP kept above 70 mm Hgn Mortality 21%, good outcome 68%

n Bruce et al 1973 (Class II) N=14n Study of the effect of increasing the blood pressure on ICPn When BP increased by 30 mm Hg, ICP increased by 5 mm Hg

n Robertson et al 1999 (Class I) N=189n Comparison of ICP vs CPP targeted therapyn Fewer SVO2 episodes in CPP targeted groupn No difference in GOS, ICP, Higher ARDS in CPP targeted

group

ICU

Guidelines for Cerebral Perfusion Pressure

n Standardsn nil

n Guidelinesn CPP maintained at a

minimum of 60 mm Hg

ICUMannitol

n No controlled trials with placebon Mechanism of action (Early vs Late)

n Plasma volume expansionn reduces blood viscosityn increases CBFn increases cerebral oxygen delivery

n Osmotic gradientn Circulating mannitol may cross BBB

n avoid continuous administrationn contraindicated in renal failure

ICUMannitol

n Schwartz et al 1984 (Class I)N=59n Mannitol group had lower outcome mortality in DAI

n 41% vs 77%

n Better CPP in mannitol group

n Fortune et al 1995 (Class II) N=22n Studied effect of mannitol and hyperventilation on

SJVO2

n 196 interventions on 22 patientsn SJVO2 increased with mannitol and decreased with

hyperventilation

ICU

Mannitol Use in Severe Head Injury

n Standardsn nil

n Guidelinesn Mannitol effective for control of ICP after severe head injuryn 20 percent solutionn 0.25 to 1 g/kg IV bolusn Repeat doses can be administered every six to eight hours

n Optionsn indications transtentorial herniation and neurologic deterioration not

attributable to systemic pathologyn Serum osmolarity kept < 320n Maintain euvolemian Intermittent boluses may be more effective than continuous infusion

ICUBarbiturates

n Lower ICPn Mechanisms

n alterations of vascular tonen suppression of metabolismn inhibition of free radical lipid peroxidationn coupling of CBF to metabolic demands

n Assumptionsn Can effect long term ICP control when other

treatments have failedn Absolute ICP control improve outcome

ICUBarbiturates

n 3 randomized control trialsn 2 prophylactic trials showed no benefitn 1 raised intracranial pressure therapeutic

trial showed improved survival if ICP responded to barbiturates

ICUSchwartz et al (1984)

n Barbiturates with mannitol for initial therapy for increased ICP

n Randomized when ICP>25 mm Hg for more than 15 minutes

0

50

100

SOL DI

Mannitol

Pentobarb

N=59

Mortality

ICUEisenberg et al (1988)Eisenberg et al (1988)

n Control of ICP primary Control of ICP primary outcomeoutcome

n Randomized to barbiturates Randomized to barbiturates or controlor control n=73n=73

n Treatment failure in control Treatment failure in control arm resulted in barbituratesarm resulted in barbiturates

n Survival 92% if ICP Survival 92% if ICP responded to barbiturates vs responded to barbiturates vs 17% if no ICP response17% if no ICP response

0

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30

40

ICP Control

Control Barbiturates

ICP Control %ICP Control %

ICU

Barbiturate Use in Severe Head Injury

n Standardsn nil

n Guidelinesn Barbiturates may be considered

n hemodynamically stablen salvageable head injuryn refractory intracranial hypertension

ICUHypothermia

n Use supported by;n Animal datan Single centre trialsn Success in related conditions global cerebral

hypoxia

n One Multi-centre RCT (NABISH)NEJM 2001; 344: 556-63

n N=368n Target temp 33n Hypothermia for 48 hours

ICU

Temperature Control and Induced Temperature Control and Induced HypothermiaHypothermia

n Most effective method for brain protection

n decreases both basal and electrical metabolic requirements

n CMR decreases by 6% to 7%/°C n metabolic requirements continue to

decrease even after electrical silence

ICU

NABISH Results NEJM 2001; 344: 556-63

n Hypothermian More hospital days with complicationsn Lower ICP

n Criticismsn Accepted MAP of 50n Slow coolingn Rapid and active rewarming

ICUBut Food for Thought…

n JAMA 2003 Jun 11;289(22):2992-9. n Prolonged therapeutic hypothermia after

traumatic brain injury in adults: a systematic review.

n Meta-analysis of 12 rctn Decreased risk of death RR0.81 and poor

neurologic outcome RR0.78n Prolonged duration of hypothermia seemed

better

ICUHypertonic Saline

n Potential advantagesn Quicker management of hypotensionn Osmotic dehydration lower ICPn WBC immunomodulationn May decrease glutamate

n Earlier studies suggested a mortality benefit and lower ICPn Meta-analysis demonstrated improved survival rates, especially in

head trauma (38% versus 27%)n Wade CE, Kramer GC, Grady JJ, et al. Efficacy of hypertonic 7.5% saline and6%dextran-70 in treating

trauma: a meta-analysis of controlled clinical studies. Surgery 1997;122:609–16.

n Cooper et al JAMA 2004n Prehospital admin of 250 ml 7.5% HS vs RLn RCT 229 subjectsn 6 mos GOS main outcomen No difference in GOS or survivaln Trend to lower ICP with HS

ICUSAFE trial

n Subgroup analysis of trauma patients with severe brain injury

n 460 patientsn Mortality higher in albumin group

33.2% vs. 20.4 saline groupn Saline or Albumin for Fluid Resuscitation in Patients with Traumatic Brain InjuryN Engl J Med

2007;357:874-84.

ICUOther stuff to consider

n Decompressive craniectomyn Antieplileptic therapyn Management of fevern Positionn Treatment of hypertension

n ICP >20 and CPP>160n Fluid/electrolyte

n Osmolarity should be 280-305n Avoid hyponatremian Hypertonic saline in mannitol resistant ICP

ICUSummary

n Avoid hypotension and hypoxian Maintain CPPn Hyperventilation should only be

undertaken with herniation or appropriate monitoring of CPP and cerebral oxygenation