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Traumatic Brain Injury : Review, Update, and Controversies

Shirley I. Stiver MD, PhD

Case 1

32 year old male

• s/p high speed MVA • Difficult extrication • Intubated at scene

Case

• BP 75 systolic / palp

• GCS 3 (2T)

• Pupils 4 mm bilateral, reactive

• Motor – nil

• Open femur fracture

First Management Steps ?

A) Give Mannitol 0.5 g/kg iv bolus

B) GCS 3 - donor ?

C) Get stat CT scan

D) Elevate sys BP > 90 mmHg

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Intracranial Pressure (ICP)

ICP = Brain + CSF + Blood vascular volume + Mass Lesion

Pressure Volume Curve

Compliance ∆V/∆P

• Small increase in the intracranial volume

• significantly increase the ICP and ppt herniation

Low

High

Raised Intracranial Pressure

Cerebral Herniation

Indications for Mannitol

• Signs of impending cerebral herniation

(Level III)

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Motor

Motor Score

1 Nil

2 Decerebrate posturing

3 Decorticate posturing

4 Withdrawal

5 Localizes

6 Obeys commands

Treatment Raised ICP

Mannitol

• Osmotic diuresis

• Reduces blood viscosity

1-1.4gm/kg, bolus

Watch for hypotension

Glasgow Coma Scale

Motor component of the GCS is most predictive of outcome

GCS

Eyes 4

Verbal 5

Motor 6

Perform after resuscitation & before sedation or paralytics

Poor GCS check Brainstem reflexes

Importance of testing

• Pupils

• Corneals,

• Cough and gag

Before Paralytics

• Often determines whether to take patient to OR

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Differentiating primary versus secondary injury

• Early GCS in the field – gives you the closest assessment of the severity of the primary impact – Resuscitated evaluation ; …

hypoxia / hypotension – false positive

– No drugs / alcohol on board

• Importance of the reports from the emergency response team

• Importance of serial GCS & neurological testing

Guidelines Blood Pressure – Level II

Hypotension strong predictor of outcome

• Single episode sys BP<90 doubles mortality

• Avoid hypotension sys BP < 90 mmHg

• Isotonic saline

• Fluid resuscitation a balance:

Maintain cerebral perfusion ↔ avoid fluid overload, osmotic shifts, brain edema

Case Non –Contrast CT scan Next ?

A) OR for decompressive craniectomy

B) ICU observation

C) ICU and ICP monitoring

D) Ortho to OR femur repair

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Guideline for ICP Monitoring

GCS < 8

With Abnormal CT scan Unresponsive with

absence of a neurological exam that

can be followed

Normal CT scan with -age > 40 -unilateral or bilateral posturing -systolic pressure < 90 mmHg -ethanol intoxication

Guideline

ICP Treat for threshold > 20mmHg

ICP Monitoring

Tiers of Therapy

Tier 1 • EVD drainage ; Sedation (Mannitol x 1)

Tier 2 • Osmotic therapy; Mannitol or Hypertonic N/S ;

pCO2 30-35 mmHg; paralysis

Tier 3 • Decompressive craniectomy ;

• Induced Barbiturate or propofol coma

Cerebral Perfusion Management

CPP = Mean arterial blood pressure – ICP

CPP goal > 60 mmHg Lund Therapy

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Advanced Monitoring ?

• What advanced monitoring might best help you manage this patient ?

A) Cerebral blood flow probe

B) Brain tissue oxygen monitor

C) SjVO2 –jugular venous saturation

Brain Tissue Oxygen

• Brain O2 probes placed in white matter

• Normal values for white matter 20-30mmHg

Brain Tissue Oxygenation

• Cerebral blood flow •

• O2 content of blood • Dissociation

& Diffusion of O2

BBB

Normal values

(white matter)

20-30

mmHg

Critical values < 15

Jugular Venous Saturation

Global measure of cerebral metabolism:

Measures total venous brain tissue oxygen in jugular bulb

Oxygen extraction by the brain

SjvO2 Normal values 50-75%

Critical values < 50

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Case ICP 18

MAP 86

FiO2 50%

7.4/35/141

PBrO2 18

SjVO2 90

UpDATES

1. “A Trial of Intracranial-Pressure Monitoring in TBI” R. Chesnut et al. NEJM 367: 2471-81 (2012).

– Treatment based on ICP monitor vs Clinical Exam

2. Protect Study – Methylprednisolone

3. Pharmacologic DVT Prophylaxis in TBI

ICP versus Clinical Exam

324 severe TBI patients

• Randomly assigned to

1. ICP monitor group

2. Clinical group

– Outcome measures : survival, functional and neuropsychological outcome at 6 months

No randomized trial to show that treatment based on monitored ICP improves outcome

R. Chesnut NEJM 367: 2471-81 (2012)

ICP versus Clinical Results

At 6mo ICP Clinical p value

1° Outcome score

56 53 0.5

Mortality 39% 44% 0.4

Favorable Outcome

44% 39%

Unfavorable Outcome

17% 17%

Conclusions Management guided by ICP Monitoring NOT > Clinical Exam

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DVT Prophylaxis after TBI

The controversy :

• TBI : enoxaparin has the potential to iatrogenically exacerbate intracranial hemorrhage

• View that hemorrhage stabilizes with time

• Is there an early prohibitive period, but once hemorrhage stabilizes, anticoagulation is safe -- Timing ?

Recent Studies Pharmacologic DVT Prophylaxis in TBI

Importance of hemorrhage stability before starting prophylaxis

Worsening of hemorrhage between 1st and 2nd CT scan followed by enox 13-fold increase in rate of continued hemorrhage

Stable scan – no hemorrhage expansion

A. Levy et al, J. Trauma 68: 886-94 (2010)

Recent Studies Pharmacologic DVT Prophylaxis in TBI

• Risk stratification by injury patterns -different lesions have different risks of hemorrhage progression different time frames for stabilization, and different times for starting prophylaxis

Low risk for enox at 24h :

SDH < 9mm EDH < 9mm Contusion < 2cm Single contusion per lobe

S. Norwood J Trauma 65: 1021-27 (2008)

Parkland Model

Risk Stratification for Starting Enoxaparin

Low Risk

Repeat CT at 24h

Stable ?

Start Enox at 24 h

Moderate Risk

Repeat CT at 72 h Stable ?

Start Enox at 72 h

High Risk

Consider IVC filter

H. Phelan, J Neurotrauma 29: 1821-28 (2012)

yes yes

no no

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Controversy

Does Decompressive Craniectomy Improve Outcome ?

DECRA Study

Decra: Study Methods

• Severe TBI (GCS 3-8) with Diffuse injury

• Tier 1 therapy: osmotics, sedation, paralytics, EVD drainage

• Refractory ICP defined as >20mmHg for > 15min

Bifrontal decompressive craniectomy

Continued ICU Care

Tier 2 & 3 therapy :

• mild hypothermia to 35’

• Barbiturate coma

DECRA Study Results : GOSE @6mo

DC

0

5

10

15

20

25

Die Veg LS US LM UM LG UG

DC

MC

• DC shifted survivors from favorable unfavorable outcome (dependent for ADLs)

Hemi- Craniectomy

RescueICP • www.rescueicp.com

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Conclusions

Basic Principles – Once ICP already used up compensatory

reserves

– Mannitol for impending herniation

– Poor GCS brainstem exam

– Distinguish primary v secondary injury

– Hypoxia / hypotension / drugs & ethanol may mask GCS

– ICP monitoring for unresponsive without neuro exam

DECRA: Study Design

• 155 adults, aged 15-59 yrs

• Severe TBI (GCS 3-8) with Diffuse injury

• Randomized Standard Care vs Bifrontal craniectomy for Refractory ICP

• Outcome : GOS-E @ 6mo ‡

Exclusions - Dilated, unreactive pupils - Mass lesions (unless small) - Cardiac arrest at scene

History Pharmacologic DVT Prophylaxis in TBI

History • No role for pharmacologic prophylaxis in TBI before

2000

• Gearhart 2000 – – DVT prophylaxis in 102 trauma patients

– 26 TBI with intracranial blood no instance of TBI worsening

• Kim 2002 - – 76 severe TBI, unfrac heparin; groups <72 h and > 72 h ;

– no increase in intracranial bleeding between groups

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Decra: Study Methods

• Severe TBI (GCS 3-8) with Diffuse injury

• Tier 1 therapy: osmotics, sedation, paralytics, EVD drainage

• Refractory ICP defined as >20mmHg for > 15min

Bifrontal decompressive craniectomy

Continued ICU Care

Tier 2 & 3 therapy :

• mild hypothermia to 35’

• Barbiturate coma

Life saving DC >72 h after admission

DECRA: Study Results

• Icp control