Management Of High I C P And Traumatic Brain Injury

Management of Traumatic Head Injury
Dalhousie Critical Care Teaching Rounds

Objectives
Know how to calculate CPP and the normal CPP range.
Discuss the management principles for raised ICP.
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.
Know how to work up and treat different Na disorders including SIADH, cerebral salt wasting and DI

Neurophysiology
CPP = MAP – CIP
N= 50-70
Trauma
Increase volume of intracranial components
Loss of autoregulation
Increased CSF production
Hypercapnia and hypoxic insults

Management of Head Injury Emergency Diagnostic or Therapeutic Procedures Tracheal Intubation Fluid Resuscitation Ventilation/Oxygenation Sedation Severe Head Injury GCS≤8 ATLS Trauma Evaluation Deterioration Herniation CT Scan ICU ± Hyperventilate ± Mannitol Surgical Drainage

Management of Raised ICP
First Line Rx
Raised ICP>25mm Hg Measure ICP Maintain CPP>70 mm Hg Ventricular Drain Elevate HOB Normal Vent/Oxygenation Mannitol Sedation Raised ICP>25mm Hg CT

Management of Raised ICP
Second Line Rx
Raised ICP>25mm Hg Maintain CPP>70 mm Hg Furosemide Chemical Paralysis CSF Removal Vasopressor Barbiturates Hyperventilation Monitor S j O 2 Raised ICP>25mm Hg

Head Injury
Primary Head Injury
Result of energy absorption
Difficult to prevent
Results from
neuronal or axonal disruption
shear
laceration
vascular disruption
Secondary Head Injury
Result of insults that occur after primary injury
Easier to prevent
Causes
ischemia
hypoxia
cerebral edema
intracranial hypertension
abnormalities of cerebral blood flow
metabolic derangements

Role of ICP Monitoring
May help in earlier detection of intracranial mass lesions
Rationalizes therapy (ICP vs CPP)
CSF drainage
Helps in determining prognosis
May or may not improve outcome
CPP=MAP-ICP

ICP Monitors
Intraventricular Catheter
“ Gold standard”
Pros : Allows drainage of CSF (to dec ICP), allows “re-zeroing”
Cons : Invasive, difficult to insert, infection risk
Interparenchymal Probe
Pros : Low infection rate
Cons : Local pressure, “drift of zero”

ICP Monitors
Subarachnoid Probe
Pros: Low infection rate, no brain penetration
Cons: Limited accuracy, high failure, requires flushing
Epidural Probe
Pros: Easy to insert, extra cranial
Cons: Limited accuracy, relatively delicate
Others:
Transcranial doppler
Tympanic membrane displacement
Lumbar CSF pressure

Management of Traumatic Brain Injury Hypothermia Hypertonic Saline Neuro-protection Other Issues BP and Oxygen Indications for ICP CPP Mannitol Barbiturates Hyperventilation Glucocorticoids Guidelines Standards BTF and AANS Guidelines Process

AANS & BTF Head Injury Guidelines (2000)
Past
Reliance on expert opinion
Documented variability of practice
Rely on scientific evidence and not expert opinion
Task force of experts with each Expert assigned a topic
Medline search
Review and grading of papers on topic
Multiple iterations
Involvement of national and international organizations

Hyperventilation
CBF is the lowest in the first 24 hrs after injury
Hyperventilation decreases CBF (3%/torr)
Hypervent to a PCO2 26  CBF by 31% and CBV by 7%
Can  CBF and  A-VdO 2 to ischemic levels
Effect of hyperventilation transient (4 hours)
CBF 90% of control at 4 hours of hyperventilation

Hyperventilation
Muizelaar et al 1991 RCT
Obrist et al 1984 Cohort study
Hyperventilation had a greater effect on CBF than ICP
Schnieder et al 1995 Cohort study
Hyperventilation second leading cause of jugular desaturation
Sioutos et al 1995 Cohort study
1/3 of patients had CBF < 18 ml/100g/min
Hypervent decreased CBF further
N= 77

Xenon Perfusion CBF PCO 2 = 45 torr ICP = 44 mmHg CBF = 59 mL/min/100 gm PCO 2 = 30 torr ICP = 15 mmHg CBF = 14 mL/min/100 gm Skippen P et al: Crit Care Med 1997; 25:1402-1409

Use of Hyperventilation
Standards
In absence of increased ICP chronic hyperventilation should be avoided (PCO2 < 25)
Guidelines
Use of prophylactic hyperventilation (PaCO2 < 35) should be avoided during the first 24 hrs after head injury because it may compromise CBF
Options
Hyperventilation may be necessary for brief periods when there is neurologic deterioration or for raised ICP refractory to standard therapy

Glucocorticoids
Useful in patients with brain tumor
Experimental evidence
Restoration of altered permeability in the lab
Reduced CSF production
Attenuation of free radical production
Meta analysis has showed no benefit
Alderson et al 1997
No benefit in clinical trial of
Tirilazad 17 amino steroid
N=1170 North America
N=1128 Europe

CRASH Study
Head injury with GCS ≤ 14
Primary outcome
Death at 2 weeks
Disability at 6 months (not yet reported)
10,008 subjects
Multicentre RCT Randomization groups
Placebo
Methylprednisolone
Load 2 gms
Maintenance 0.4 gm/hr for 47 hours
Mortality
Placebo 18%
Steroids 21%
Lancet 2004; 364: 1321-38

Glucocorticoids in Severe Head Injury
Standards
Not recommended for reducing ICP or improving outcome

Blood Pressure and Oxygenation
TCDB study
Large prospectively collected data set
N=717
Anesthesia Study
Observational study of patients with severe head injury requiring surgery with in 72 hours of admission
N=53
Death Chesnut et al 1997 Pietropaoli et al 1992 Outcome %

Blood Pressure and Oxygenation
No class I evidence
Randomization probably not ethical
Standards
nil
Guidelines
Hypotension (SBP<90) and hypoxia (PO2<60)must be avoided and if present corrected immediately
Options
Mean arterial pressure > 90
CPP >70

Rational for ICP Monitoring
Correlation between high ICP and poor outcome
Intracranial hypertension more likely in those with CT abnormalities or adverse features
Age >40
Motor posturing
SBP<90
Narayan et al 1982

Intracranial Pressure Monitoring
Standards
nil
Guidelines
Indicated for severe head injury with abnormal CT
Indicated for severe head injury with normal CT with 2 or more of
age greater than 40
motor posturing
Systolic BP less than 90 mm Hg
Not indicated for mild or moderate head injury

Does ICP Monitoring Improve Outcome
No randomized controlled trial
Improved outcome with ICP monitoring over historical data
Saul and Ducker 1982 (Class II)
Rx ICP 20-25  mortality 46%
Rx ICP >15  mortality 28%
Eisenberg et al 1988 (Class I)
Better outcome if ICP responded to Pentobarb
Colohan et al 1989 (Class II)
2 centers with lower mortality in center with ICP monitoring
Groups managed at different time periods Other confounding factors

Does ICP Monitoring Improve Outcome
No randomized controlled trial
Ghajar et al 1995 (Class III)
Meta analysis demonstrating decreased mortality with CSF drainage
Lane et al 2000 (Class II)
Retrospective study of trauma database
5507 head injured patients
Used AIS scores to define injury
Results
multivariate analyses controlling for AIS head, ISS and injury mechanism indicated that ICP monitoring was associated with significantly improved survival (p < 0.015)

Cerebral Perfusion Pressure
CBF low following head injury
Compression of cerebral vessels
Reduced cerebral metabolism
Vasospasm
CBF lowest first 24 hrs after injury
Ischemia common at autopsy
Correlation with CBF, GCS and outcome
Failure to maintain adequate CPP may lead to increased ICP and poor outcome

Physiology
ICP, CPP, CBF and CMRO2
CPP = MAP – ICP (or CVP) ‏
Monroe-Kellie Doctrine

Cerebral Perfusion Pressure
Fortune et al 1994 (Class II) N=14
CPP maintained above 70 mm Hg
Mortality 14%
Rosner et al 1990 (Class II) N= 34
CPP kept above 70 mm Hg
Mortality 21%, good outcome 68%
Bruce et al 1973 (Class II) N=14
Study of the effect of increasing the blood pressure on ICP
When BP increased by 30 mm Hg, ICP increased by 5 mm Hg
Robertson et al 1999 (Class I) N=189
Comparison of ICP vs CPP targeted therapy
Fewer SVO 2 episodes in CPP targeted group
No difference in GOS, ICP, Higher ARDS in CPP targeted group

Guidelines for Cerebral Perfusion Pressure
Standards
nil
Guidelines
CPP maintained at a minimum of 60 mm Hg

Mannitol
No controlled trials with placebo
Mechanism of action (Early vs Late)
Plasma volume expansion
reduces blood viscosity
increases CBF
increases cerebral oxygen delivery
Osmotic gradient
Circulating mannitol may cross BBB
avoid continuous administration
contraindicated in renal failure

Mannitol
Schwartz et al 1984 (Class I) N=59
Mannitol group had lower outcome mortality in DAI
41% vs 77%
Better CPP in mannitol group
Fortune et al 1995 (Class II) N=22
Studied effect of mannitol and hyperventilation on S JV O 2
196 interventions on 22 patients
S JV O 2 increased with mannitol and decreased with hyperventilation

Mannitol Use in Severe Head Injury
Standards
nil
Guidelines
Mannitol effective for control of ICP after severe head injury
20 percent solution
0.25 to 1 g/kg IV bolus
Repeat doses can be administered every six to eight hours
Options
indications transtentorial herniation and neurologic deterioration not attributable to systemic pathology
Serum osmolarity kept < 320
Maintain euvolemia
Intermittent boluses may be more effective than continuous infusion

Barbiturates
Lower ICP
Mechanisms
alterations of vascular tone
suppression of metabolism
inhibition of free radical lipid peroxidation
coupling of CBF to metabolic demands
Assumptions
Can effect long term ICP control when other treatments have failed
Absolute ICP control improve outcome

Barbiturates
3 randomized control trials
2 prophylactic trials showed no benefit
1 raised intracranial pressure therapeutic trial showed improved survival if ICP responded to barbiturates

Schwartz et al (1984)
Barbiturates with mannitol for initial therapy for increased ICP
Randomized when ICP>25 mm Hg for more than 15 minutes
N=59 Mortality

Eisenberg et al (1988)
Control of ICP primary outcome
Randomized to barbiturates or control n=73
Treatment failure in control arm resulted in barbiturates
Survival 92% if ICP responded to barbiturates vs 17% if no ICP response
ICP Control %

Barbiturate Use in Severe Head Injury
Standards
nil
Guidelines
Barbiturates may be considered
hemodynamically stable
salvageable head injury
refractory intracranial hypertension

Hypothermia
Use supported by;
Animal data
Single centre trials
Success in related conditions global cerebral hypoxia
One Multi-centre RCT (NABISH)
NEJM 2001; 344: 556-63
N=368
Target temp 33
Hypothermia for 48 hours

Temperature Control and Induced Hypothermia
Most effective method for brain protection
decreases both basal and electrical metabolic requirements
CMR decreases by 6% to 7%/°C
metabolic requirements continue to decrease even after electrical silence

NABISH Results NEJM 2001; 344: 556-63
Hypothermia
More hospital days with complications
Lower ICP
Criticisms
Accepted MAP of 50
Slow cooling
Rapid and active rewarming

But Food for Thought…
JAMA 2003 Jun 11;289(22):2992-9.
Prolonged therapeutic hypothermia after traumatic brain injury in adults: a systematic review.
Meta-analysis of 12 rct
Decreased risk of death RR0.81 and poor neurologic outcome RR0.78
Prolonged duration of hypothermia seemed better

Hypertonic Saline
Potential advantages
Quicker management of hypotension
Osmotic dehydration lower ICP
WBC immunomodulation
May decrease glutamate
Earlier studies suggested a mortality benefit and lower ICP
Meta-analysis demonstrated improved survival rates, especially in head trauma (38% versus 27%)
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.
Cooper et al JAMA 2004
Prehospital admin of 250 ml 7.5% HS vs RL
RCT 229 subjects
6 mos GOS main outcome
No difference in GOS or survival
Trend to lower ICP with HS

SAFE trial
Subgroup analysis of trauma patients with severe brain injury
460 patients
Mortality higher in albumin group 33.2% vs. 20.4 saline group
Saline or Albumin for Fluid Resuscitation in Patients with Traumatic Brain InjuryN Engl J Med 2007;357:874-84.

Other stuff to consider
Decompressive craniectomy
Antieplileptic therapy
Management of fever
Position
Treatment of hypertension
ICP >20 and CPP>160
Fluid/electrolyte
Osmolarity should be 280-305
Avoid hyponatremia
Hypertonic saline in mannitol resistant ICP

Summary
Avoid hypotension and hypoxia
Maintain CPP
Hyperventilation should only be undertaken with herniation or appropriate monitoring of CPP and cerebral oxygenation

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Management Of High I C P And Traumatic Brain Injury

by Andrew Ferguson on Mar 04, 2008

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Management Of High I C P And Traumatic Brain Injury — Presentation Transcript