The ABCs of Statistics Anatomy TBI Classification of TBI Rachel - - PDF document

3/10/2012 1

The ABCs of TBI

Rachel Garvin, MD Assistant Professor, Emergency Medicine Fellow, Neurocritical Care University of Cincinnati

6th Annual Northern Kentucky TBI Conference March 23, 2012 www.bridgesnky.org

Outline

 Statistics  Anatomy  Classification of TBI  Pathophysiology behind increased ICP  PBtO2  Management Strategies  Mild TBI

TBI stats

 2 million TBI’s treated each year in US, one every 15

seconds

 Leading cause of M&M in young adults  Single severe TBI victim can generate 4 million dollars

in lifetime costs

 Falls are leading cause of TBI in adults >65  Adults ages >75 have highest rates of TBI related

hospitalization and death

 70-90% of TBI worldwide are considered “mild,” 1% of

those require a surgical intervention

Classification of TBI

Pathoanatomic Physical Mechanism Pathophysiologic Injury Severity

Pathoanatomic

Epidural Subdural Subarachnoid Contusion Axonal injury

Pathophysiologic

Primary Injury

 Immediate damage done

Secondary Injury

 Potentially avoidable factors  Hypoxia, hypotension, hypercarbia,

hyponatremia, seizures

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Injury Severity

GCS 13-15  Mild TBI 9-12  Moderate TBI <8  Severe TBI

Predicting Outcomes

 Study using data from CRASH trial looked

at predicting outcomes (death at 14 days and death/disability at 6 months)

 Best predictors: age (>40), low GCS,

• bliteration of basal cisterns/third ventricle,

pupillary response, other extracranial injuries

Rotterdam CT scoring

 Basal Cisterns: open, compressed, absent  Midline Shift: < or > 5mm  Epidural Mass Lesion  IVH or Traumatic SAH

Imaging

Noncon Head CT MRI CTA Other trauma imaging

ICP

 Monroe-Kellie Hypothesis: Blood, brain,

CSF

 Normal ICP  5-15mmHg (3-7mmHg young

children)

 In TBI, the balance gets disrupted

Cerebral Perfusion Pressure (CPP)

 CPP = MAP-ICP  Normal CPP >50mmHg  CBF:  Directly proportional to CPP and vessel

radius

 Inversely proportional to blood viscosity

and vessel length

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Causes of Increased ICP

 Intracranial

 Hematomas/Contusio

ns

 Ischemia  Hydrocephalus  Increased CBF

 Extracranial

 Hypoxia  Hypercarbia  Hyper/Hypotension  Head rotation  Fever  Seizure  Increased

intraabdominal pressure

Monitoring in TBI

 ICP  Brain tissue oxygen  Microdialysis  Jugular venous saturation  Cerebral blood flow

What about brain tissue oxygen?

 Secondary brain injury not always associated with

increased ICP

 Study by Spiotta et al looked at conventional ICP/CPP

management vs PbtO2-based therapy

 70 pts with severe TBI managed with Licox to keep PbtO2

> 20mmHg as well as ICP/CPP

 Compared with 53 historical controls with goal of ICP <20

and CPP >60

 Lower mortality and more favorable short term outcomes

How do we treat low PBtO2?

Increase oxygenation Increase MAP Change PCO2

Early Management of TBI

ABC’s Imaging Emergent treatment

ABC’s

 Airway

 Avoiding hypoxia  RSI  Post-intubation sedation

 Breathing

 Normocarbia

 Circulation

 Avoiding hypotension

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Treating ICP

Keeping things “normal” Sedation Positioning Mannitol/Hypertonic saline

Mannitol vs Hypertonic Saline

Mannitol

 Rheologic effects  Osmotic effects  Crosses BBB  Contraindicated in

hypovolemic pts HTS

 Osmotic effect  Can be used in

hypovolemic pts

 Can cause

hyperchloremic acidosis, decreased platelet aggregation

Emergent Treatment

Hyperventilation Decompressive

Hemicraniectomy

Hyperventilation

 Decreased PaCO2 alkalinizing CSF 

cerebral vasoconstriction

 Decreased CBV  decreased ICP, BUT………  Effects last around 6 hours until CSF pH

equilibrates

 Then there is re-dilation of cerebral arteries 

rebound ICP

Decompressive Hemicraniectomy

Most often a rescue procedure Data equivocal on whether

• utcomes improved

Outcomes

 Difficult to make early predictions on outcome  Initial GCS  Pupils/Motor Score  Other injuries  MR spectroscopy  Specialty care in neuro-ICU’s improve

• utcomes

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Mild TBI

Study by Bazarian et al looked at mild TBI in the ED

 Used the NHAMCS for isolated mild TBI  Less than ½ of patients were asked about pain  Only half of those were treated  Only 34% of those discharged from level I trauma

centers were referred for further follow-up

Mild TBI

 Study by Sterr et al looked at long term effects of

MTBI

 29% of MTBI patients had symptoms of PCS at

least 12 months post injury (as compared with matched controls)

 Problems mostly stemmed from issues in

cognitive function

 Loss of consciousness at time of injury was not

predictive of PCS

Help for Mild TBI

Educate patients on the possible

symptoms from mild TBI

Ensure follow-up

Summary

TBI is a serious healthcare issue,

especially in the elderly

There are many different ways to

classify TBI

Prevention of secondary injury is key Educate patients with mild TBI

References

 Bazarian JJ, McClung J, Cheng YT, Flesher W, Schneider SM. Emergency department management of mild traumatic brain injury in the USA. Emerg Med J 2005; 22:473-477  Marguiles S, Hicks R. Combination therapies for traumatic brain injury: Prospective considerations. Journal of Neurotrauma 2009; 26:925-939  Meixensberger J, Jaeger M, Vath A, Dings J, Kunze E, Roosen K. Brain tissue oxygen guided treatment supplementing ICP/CPP therapy after traumatic brain injury. J Neurol Neuroaurg Psychiatry 2003; 74:760-764.  Rangel-Castillo L, Gopinath S, Robertson C. Management of intracranial hypertension. Neurol Clin 2008 May; 26(2): 521-541  Saatman KE, Duhaime AC, Bullock R, Maas A, Valadka A, Manley GT. Classification of traumatic brain injury for targeted therapies. Journal of Neurotrauma 2008; 25: 719-738.  Sterr A, Herron K, Hayward C, Montaldi D. Are mild head injuries as mild as we think? Neurobehavioral concomittants of chronic post-concussion syndrome. BMC Neurology 2006: 1471-2377  Spiotta AM, Stiefel MF, Gracias VH, Garuffe AM, Kofke WA, Maloney-Wilensky E, Troxel AB, Levine JM, Le Roux PD. Brain tissue oxygen-directed management and outcome in patients with severe traumatic brain injury. J Neurosurg 2010: 113: 571-580  Thompson HJ, McCormick WC, Kagan SH. Traumatic brain injury in older adults: Epidemiology, outcomes, and future implications.