Trauma Sistem Saraf Pusat

Dr Khairul Ihsan Nasution SpBS

ObjectivesStatisticsAnatomyMechanismsAssessmentICP PathologyICP ManagementICP Precautions

Head InjuryNumber One Killer in Trauma 25% of all trauma deaths50% of all deaths from MVC200,000 people in the US live with the disability caused by these injuries

Introduction ...150.000 trauma deaths per year in the US50% due to fatal head injuries200,000 people in the US live with the disability caused by these injuries

Basic AnatomyScalpSkullMeningesDura MaterArachnoidPia MaterBrain TissueCSF and Blood

Basic Anatomy - ScalpVery VascularBleeds FreelyVessels suspended in inelastic tissueAs a result, vasospasms are limited

Basic Anatomy - SkullLike a closed boxOnly opening is the foramen magnumRigid structure protects and contributes to several injury mechanisms

Basic Anatomy - MeningesPADIA MATER SOFT MOTHERRACHNOID MEMBRANEURA MATER TOUGH MOTHER

Intracranial Volume80% Brain Matter10% Blood10% CSF

Intracranial VolumeVolume is Fixed at 100%If more of one thing is added, then something else must go.This is called autoregulation Monroe-Kellie Doctrine

Mechanisms of InjuryMost brain injuries are not from direct injury to brain tissueMost occur as a result of external forces against outside of skullMovement of the brain inside of the skull causes damage to brain tissue or blood vessels

Mechanisms of Injury3 CollisionsCar hits objectHead hits windshieldBrain hits inside of skull

Mechanisms of Injury

Mechanisms of InjuryBrain movement inside the skullBase of skull is very roughMost brain movement is at the topBrain suspended by vessels and brain tissue that can be torn by movement, especially at the base

Mechanism of Injuries, cont.Rotational injuries injury occurs acceleration-deceleration of the brain does not follow straight linear path.Brain twists and moves at angles causing stretching and shearing of brain tissue and potential vascular injury.Penetrating include missile injuries, GSW or impalement.

Response to InjuryDue to increased blood volume (not edema)Natural response to injury anywhere on your bodyBody rushes nutrients to heal injured area

SWELLING

Penetrating Mechanism

Increase in blood volume exerts pressure on the brain tissueThis eventually decreases blood flow to the uninjured part of the brain

SWELLINGBRAIN TISSUE

Response to InjuryIncrease in cerebral edema (water) develops after 24-48 hours and peaks in 3-5 daysNot an acute concern, per say

Response to InjuryCO2 levels in the blood have a critical effect on cerebral blood vesselsCO2 is produced by hypoxic cellsCO2 is a very potent vasodilatorWhat would happen if CO2 levels were increased? Decreased?

CO2 LevelsNormal CO2 is in the range of 35-45 mm/hg (torr)Mean CO2 level is 40 torr.

How would you get rid of CO2? What would happen if you got rid of too much?

ReviewTwo main factors that increase intracranial volume are:

Vasodilation (immediately)Cerebral edema (24-48 hrs)

Other FactorsHydrocephalic patients have increased volume or reduced absorption of CSFBrain tumors and foreign bodies inside the cranium also increase the volumeBUT THE VOLUME IS FIXED!!!!

AutoregulationThe brain had the ability to control its environmentAs long as there is adequate perfusion

Intracranial VolumeVolume is Fixed at 100%If more of one thing is added, then something else must go.This is called autoregulation

AutoregulationBlood VolumeCSFBrain Matter

AutoregulationVasodilation cause increased intracranial volumeTo compensate, the brain releases CSF into the spinal column to make room for the increase in blood volumeHow much of the volume does CSF account for?

AutoregulationA rapid increase in intracranial volume cannot be compensated for by the small amount of area occupied by CSFThis condition could be rapidly catastrophic

Intracranial PressureThe pressure of the brain contents within the skull is intracranial pressure (ICP)The pressure of the blood flowing through the brain is referred to as the cerebral perfusion pressure (CPP)The pressure of the blood in the body is the mean arterial pressure (MAP)

Intracranial PressureMAP (Mean Arterial Pressure) can be determined by a simple formula:

MAP = systolic + 2x diastolic 3

Intracranial PressureExample of MAP

B/P is 120/80

MAP = 120 + 160 = 280 = 93 mm/hg 3 3

Intracranial PressureIntracranial pressure (ICP)is measured by a device that is implanted through the skull by a surgeon

The normal value for ICP is 0 - 10 mm/hg

Intracranial PressureCerebral Perfusion Pressure (CPP) can be determined by the following formula:CPP = MAP - ICP

Normal CPP range is 60 - 150 for autoregulation to work well!

Intracranial PressureExample of CPPBlood Pressure is 140/80ICP is 30CPP = 100 - 30 = 70 mm/hgIs this enough for autoregulation?What would happen if the ICP was 80?

Assessment FindingsIncreased ICP

Hypoxia is a common cause of increased ICP that can be overlookedO2

Assessment FindingsLOC ChangesConfusionLethargyDisorientationRestlessnessApathyAgitation /combativenessMotor response

Assessment FindingsPupillary ChangesIrregular shapedEquality?Constricted?Dilated? Vision Problems?

Assessment FindingsConstricted?narcotics?Sluggish/dilated?mid brain ICPUnilateral dilation?pressure on CNIIIFixed and Dilated?herniation

Assessment FindingsVision ChangesDiplopiaBlurred Vision

Abnormal reflexesDolls eyes

Assessment FindingsVital SignsVS do not change much until late in the ICP processVS changes indicate uncompensated compression to the brain stemRule out other factors that alter VSSHOCK!

Assessment FindingsCushings Triadhypertensionbradycardiaaltered respirationsLATE SIGN!

Why do we get into Cushings Triad?

Assessment FindingsHead injured patient is combative with a B/P of 110/70, P=90, RR=18What is the MAP?

Is it in the normal range?

Assessment FindingsAfter 10 minutes:B/P is 140/70Pulse is 90Pt is still combative.Now what is the MAP?Explain the change

Assessment FindingsAs ICP rises, autoregulation increases the MAP (by raising the BP) to maintain an adequate cerebral perfusion pressure ICP

Assessment FindingsUnderstanding what the brain is trying to do, consider the classic increased ICP vital signs:

Widening pulse pressure: 250/130Bradycardia: HR = 40Abnormal Respirs: Cheyne Stokes

Assessment FindingsBP of 250/130MAP would be 170!Why is the MAP so high?The ICP is 100!Is this a good thing?Should we lower the blood pressure?

Assessment FindingsCPP=MAP-ICP170 - 100 = 70

Lower B/P to 190/100

MAP would be 130New CPP is 30!Is this a good thing?

Assessment FindingsBradycardia is due to pressure on the 10th Cranial Nerve (CNX) Vagus nerve, causing a parasympathetic reaction (Bradycardia)Would you treat the heart rate?

Assessment FindingsAbnormal Breathing PatternsCheyne-Stokesgradual increase then decrease to apneaCentral Neurogenic Hyperventilationrapid, deep respirationsBiots RespirationsIrregular, agonal , gaspingKussmaul

Assessment FindingsBody temperature can be high or lowThe patient has herniated when the patient had elevated ICP (Cushings Triad) and then suddenly dropped ICP and Vital signs

This is NOT GOOD! Dont go there!

Assessment FindingsOther changes seen with ICP

HeadacheNauseaVomitingProjectile Vomiting!

A Slip of the PenPatient was alert and unresponsiveShe was numb from her toes downWhen she fainted, her eyes rolled around the roomExamination of genetalia reveals that he is circus-sized

More?Indwelling urinary catheter draining clear yellow rosesIndwelling catheter draining large amount of urine the color of American beerMD at bedside attempting to urinate. Unsuccessful. (physician was actually trying to intubate!)

OK, This is it!The skin was moist and dryExamination of genitalia normal except for the right footShe stated she had been constipated for most of her life until 1989 when she got a divorce

Management of ICP The goal to the management of ICP is to optimize respiratory gas exchange to maintain normal or decrease ICP levels.One must also be aware of the things that cause increased ICP and take steps to avoid or limit them.

Management of ICP

Accomplished by maintaining PaO2, PaCO2, pH and specified levelsPaCO2PaO2pH

Management of ICPMaintain a good pulmonary toiletLimit suctioning to < 15 secondsHyperventilate before and after Limit to one or two passes

Management of ICPpH Changesas pH decreases (acidosis) ICP increasesas pH increases (alkalosis) seizure threshold is loweredseizures dramatically increase ICP!

Management of ICPBVM Ventilation100% OxygenCan correct acute increases in ICP in a little as 2-3 minutes

Management of ICPHyperoxygenationIf PaO2 drops below 50 it will cause an increase in cerebral blood flow - increasing ICPO2ICP

Management of ICPHyperventilation?Removes CO2CO2 Causes vasodilationVasodilation increase blood volume in brainThis increases ICP

Management of ICP

Hyperventilation?How much?How fast?Can we do too much?Can we do too little?

Management of ICPHyperventilationTo an ETCO2 (capnometry) reading of about 30 mm/hgThat would be about 12-15 B/M on an intubated patient30 mm/Hg

Management of ICPOver doing the hyperventilation can reduce the CO2 levels to where there is severely constricted vessels to the brain, causing ischemia and further edema.Capnography should be the standard to guide ventilation

This is the end of the hard stuff

Now for the surprising cool, unexpected and sometimes weird, controversial and yet respected, paramedic lookin, nurse laughing, stuff!

ICP PrecautionsPositional ChangesLaying flat increases ICPelevate backboard at head 15-30 degrees

ICP PrecautionsHip flexion decreases venous return and increases ICPCoughing and valsalva increase ICPBody temperatureToo high causes increases metabolism = ICPToo low causes shivering = ICP

ICP PrecautionsHead and neck in neutral position. Anything else will flatten jugular veins and inhibit venous return that leads to ICP

ICP PrecautionsProper sizing of the C-Collar helps maintain neutral positionPadding 2-4 cm behind the head on a LSB is needed on most adults to achieve neutral

ICP PrecautionsIntubation precautionsPre-medicate with Lidocaine, 1mg/kg IV 2 minutes prior to attemptLaryngoscopy produces an ICP Spike (CN IX)

ICP PrecautionsSpeaking of ET Tubes:Avoid using any circumferential device to secure tubeOccludes jugular veins - increases ICP

Never Stop LearningIntubation, and other skills in head injured persons are important.They are also dangerousPractice your sequences and procedures

ICP PrecautionsEnvironmentExternal stimuli can increase ICPIf possible, avoid loud sounds and bright lights

ICP PrecautionsBetter Living through ChemistrySedation - Neurologists hate it, but great for reducing ICPFentanyl is a good choice as is Versed

ICP PrecautionsParalytics (RSI)Decreases metabolic requirementsUse with sedation!Can mask seizures - unseen increased ICPDilantin, Valium, others

Initial Resuscitation RSIAlthough a neuromuscular blockade would make our job easier in the fieldpatients who receive these medications:longer ICU staysincreased risk of sepsishigher rate of pneumoniano improvement in outcome

ICP PrecautionsDiureticsDecrease ICP by removing fluidsMay decrease MAP and CPPMannitol osmosisIntermittent bolus, not continuous infusionLasix - loop

ICP PrecautionsFluid selectionIsotonic CrystalloidNormal Saline or LRAvoid sugar containing or hypotonic solutions like D5W Maintain normal MAP with bolus therapy

ICP PrecautionsSteroidsDecadron, SolumedrolNo proven benefit in traumatic head injurySome benefit in spinal trauma

Summary - ICP PrecautionsBLSNeutral PositionBVM with 100% O2Properly size C-collar / paddingProtect airwayElevate head of backboardALSSecure airwayPre-medicate with LidocaineSecure tube on one side onlyMaintain MAP/CPPConsider sedation