handouts.fall trauma conference ohsu 10.25.14 … reaction correlates with brainstem oxygenation and...
TRANSCRIPT
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Going Beyond the Gold Standard: Integrating new neuromonitoring technologies
to improve patient care
Diane Bräxmeyer Downey, RN BSN CNRN
Legacy Emanuel Medical Center Portland, OR
Disclosure
• No financial relationships to disclose
• This session provides a broad overview of available technology
• Any reference to a specific brand or product is not intended as an endorsement, but rather a reflection of the device or product in which we are familiar.
Objectives
• Identify limitations of traditional neuromonitoring devices
• Describe emerging neuromonitoring technologies
• Discuss the integration of traditional and newer neuromonitoring data on patient outcomes.
Historical Trepanning; from Greek trupanon, ‘borer’ • Oldest surgical
procedure • Transcultural • Transcontinental • Evidence of
survivability, multiple procedures on single human
Primary Injury
• Damage that is complete at time of impact
Secondary Injury
• Damage that continues to evolve after initial insult
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Secondary Injury
INFLAMMATION *éICP
* Edema
ISCHEMIA * Hypotension
* êHCT
HYPOXIA
INFECTION
METABOLIC *Hypercapnia *Acidosis *Release of
Neurotransmitters
Penumbra
Area of Infarct
Area of injured/at risk
tissue
Computed Tomography First ‘look’ • Midline shift • Mass or lesion
• Infarct (time limiting) • Hemorrhage
• Ventricle size • Grey/white
differentiation ONLY a SNAPSHOT! ***normal CT scan cannot exclude the presence of an elevated ICP as there is a high probability of false –negative results
Magnetic Resonance Imaging Uses magnetic fields and radio waves • More soft tissue
detail • Contrast less
nephrotoxic • Incompatibility
issues
Monroe Kellie Doctrine
For any increase in volume in one compartment of the cranial contents, there must be a compensation in
another
Intraventricular ICP monitoring
Developed by Dr. Lundberg 1960’s
Advantages • CSF drainage • Waveform analysis • Can re-zero • Place @ bedside or OR • Inexpensive Disadvantages • Global pressure • Accessing ventricle • Clotting
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Intraparanchymal ICP monitoring Pressure is transduced through or fiberoptic fibers or microchip
Advantages • Useful when ventricle
not accessible Disadvantages • Cannot drain CSF • Measures localized
pressure • Drift; Cannot be
recalibrated inVivo
MAP • 70 – 110 mmHg
ICP • 5 – 15 mmHg
CPP • 60- 90 mmHg
Normal Values
ICP and CPP Limitations
Global vs localized ICP Optimal CPP • Intact autoregulation • Injured brain
Loss of the “Box”
ICP/CPP • reference • specificity
Pupilometry Cranial Nerve III
Pupil reaction
correlates with brainstem
oxygenation and perfusion
Parasympathetic
*constriction
Sympathetic *dilatation
Pupilometer
Digital Video of pupil response to light • 30 pictures per
second • Multiple
measurements
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Pupilometer
Measures • Baseline size (max) • Constriction size(min) • Percent change of
pupil size • Latency • Constriction velocity • Dilatation velocity
Pupilometer
� NPiTM • Scale 0-5 • Score <3 indicates sluggish pupil and
abnormal pupillary response
NPiTM
Sluggish Normal Brisk
0 5 3 4 1 2
NR
NPi™ and ICP NPiTM and ICP
Pupil Size vs. Function Pupilometer Advantages
• Noninvasive, portable • QUANTITATIVE • Good on dark irises,
pinpoint pupils • Most ICU meds do not
affect light reactivity* • RN performs
Disadvantages • Cost of device • Maintaining headsets • Hand enter to EMR
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Variable Reported by
Pupilometer
Unit of Measure Definition/Calculation
Pupil Max/Min Size mm Minimum pupil size is the pupil size at the peak of the constriction. Maximum pupil size is the initial
resting pupil size and is defined by the mean pupil size during the latent period.
Constriction % or Percentage Change
% Constriction percentage is defined as maximum size minus minimum size divided by the maximum size.
Latency seconds Time difference between the initiation of retinal light stimulation and the onset of pupillary constriction.
Constriction Velocity mm/sec Amount of the constriction divided by the duration of the constriction; this results in a average velocity
Maximum Constriction
Velocity mm/sec Peak value of the velocity during constriction; this is
larger than the previous average velocity. Dilation Velocity mm/sec Amount of pupil size recovery (after the constriction)
divided by the duration of the recovery NPi
(Neurological Pupil index) Scalar
value Algorithm that takes all variables above as inputs and
compares to normative model to give a composite score of pupillary response
Optic Nerve Anatomy
• Potential space • Size increases
with edema
Optic Nerve Ultrasound
� Measures Optic nerve sheath (ONS) diameter
� ONS diameter > 0.5cm correlates to an ICP>20
� 95% specificity
(Rajajee, Neurocrit Care 2011)
Optic Nerve Ultrasound Advantages
• Noninvasive • Existing
equipment • Low operator
variability
Disadvantages • No optic nerve
injury • Cannot predict
specific ICP value above 20
Near Infrared Spectroscopy (NIRS)
Uses near infrared light technology
Reflects the balance of oxygen delivery to oxygen consumption in a regional capillary tissue bed
Regional Saturation of Oxygen (rSO2) Capillary tissue bed
• Arterial (75%) • Venous (25%)
Intervention Trigger
<50 or >20% from baseline
Critical Threshold <45 or >25% from baseline
Normal: rSO2 60-80
Increases with a rise in delivery or a fall in demand
Decreases with a fall in delivery or an uncompensated rise in demand
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Supply and Demand Balance
Pain Fever
Shivering Seizure
Environmental Stimulus
Cardiac Output CPP FiO2 HCT
R/O mechanical obstruction
NIRS Advantages • Noninvasive • Continuous reading • Requires caregiver
interpretation Disadvantages • Site specific • Limited depth • Chromophore
influenced • Requires caregiver
interpretation
Transcranial Doppler Measures velocity of flow in cerebral vasculature
Increased velocity =
vasospasm
Transcranial Doppler Advantages
• Noninvasive • Detection of
vasospasm • Detection of
microemboli
Disadvantages • Snapshot only • Inaccuracy due to
loss/poor windows • Special training
Continuous EEG Measures voltage fluctuations resulting from ionic
current flows within the neurons of the brain • Detect subclinical seizures • Can precede ICP increases
• Identification of further deterioration
Continuous EEG Advantages • Realtime continuous
read • Non invasive • Treatment of
subclinical pathology
• Indications in post cardiac arrest
Disadvantages • RN training • CT/MRI
compatibility • Cost
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Physical Exam What it tells you about the “black box”
Advantages • Free • Performed
anywhere • Validator for
monitoring data
Disadvantages • Operator
experience • Consistency
Cerebral Oxygen Must be a constant supply
Delivery O2 Content Affinity
Venous Jugular Bulb
Fiber-optic catheter, placed retrograde in one of the internal jugular (IJ) veins Reflection of global cerebral oxygen Rarely used anymore
Intraparanchymal Cerebral Oxygen Monitor
Intraparanchymal catheter measures interstitial brain tissue oxygenation
Licox • Measures
partial pressure
• Assumes PbtO2 is a marker for adequate CBF
• Individualize CPP goal
Licox Values
PbtO2 Value Indication
25-50 mmHg Adequate oxygenation
< 20 mmHg Cerebral hypoxia
<10 mmHg Severe cerebral ischemia
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PbtO2 < 20
• Reduce ICP • Increase CPP • Check Airway • Increase FiO2
• Optimize CO • Check Airway • Adjust ventilator
• éventilation • éoxygenation
• Euvolemia • Consider transfusion
ICP > 20 mmHg ICP < 20 mmHg
PbtO2 Demand
ü Normothermia ü Sedation/Analgesia ü êEnvironmental Stimulus ü Shivering? ü Seizure?
Cerebral Perfusion
Different for intact vs. nonintact autoregulation
Each person’s ‘sweet spot’ is different
Make assumptions that 60 is a magic #
Cerebral Blood Flow Monitor Measures actual cerebral blood flow (CBF) in ml/100 g/min
Uses thermal conductivity Diminished Flow Vasospasm Tissue water content
Cerebral Vascular Resistance (CVR)
CBF = CPP/CVR
Cerebral Vascular Resistance
n 10
mmHg/ml/100gm/min
Probe
Three phases of Measurement
• Temperature Stabilization • Calibration • Perfusion Measurement Takes approx. 7 minutes Cool down is flow dependent
Long cool down = Low Flow
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Hemedex Measurements
CBF = 20-35 ml/100g/min
K = 4.8 - 5.9 ΔT = 2.5 - 3.5 PPA = < 4.9
Cerebral Blood Flow Monitoring Advantages • Realtime, continuous
monitoring • Placed @ bedside • Brain temp • Early detection/
interventions Disadvantages • Location specific • Sensitive to nearby
chatter • Unable to use when
brain temp>39.5 • Not MRI compatible
Driving Practice
CBF = 20-35 ml/100g/min
K = 4.8 - 5.9 ΔT = 2.5 - 3.5 PPA = < 4.9
Driving Practice
Day 3
CBF = 20-35 ml/100g/min
K = 4.8 - 5.9 ΔT = 2.5 - 3.5 PPA = < 4.9
Cerebral Microdialysis
Measures local tissue chemistry of brain
FDA approved for bedside use in 2005 Indicates impact of tissue injury
Glucose
Pyruvate Lactate
NAD +
NADH NAD +
Citric Acid Cycle
Ischemia
ATP ATP ATP
ADP
ATP
Anaerobic Metabolism
Glucose
L/P ratio
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Lactate # Pyruvate $ Glucose $ Glutamate # Glycerol #
Cerebral Microdialysis
Mic
rodi
alys
is C
athe
ter
Cap
illar
y
Glycerol Reflects cell injury/lysis
Normal: 20-50 uM
êEdema
• 3% • Fever control • Stimulation • Head position Glutamate
Reflects cell membrane breakdown
Normal: 10 uM
Glucose
Reflects available energy
Approx. 2/3
systemic glucose
Normal:
1.7 ± 0.9 mM
é Systemic Glucose
• Early enteral feeds • Widen insulin gtt
parameters
Lactate
Reflects Cell Metabolism
Normal:
2.9 ± 0.9 mM
L/P Ratio
Reflects anaerobic
metabolism
Normal: 23 ± 4
é Available energy
• Glucose • CBF • O2
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Driving Practice
Changes in LP ratio following depressive craniectomy
Driving Practice
Changes in LP ratio during vasospasm
Driving Practice
LP ratio changes in both ‘good’ and bad brain
Driving Practice
Changes in LP ratio in tight vs. loose glycemic control
Cerebral Microdialysis Advantages • Early warning • Evaluate
interventions • Trigger for further
intervention • Performed at
bedside Disadvantages • Location sensitive • POC Regulations • No continuous read • RN training
Current Controversies in Neuromonitoring
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BEST TRIP Trial
ü No statistical difference between survival or functional outcome
ü Shorter ICU stay, less interventions in ICP group
“Although it questions how we currently interpret the ICP values, it does not question their importance. For all centers, it solidly supports
that sTBI patients require aggressive treatment of intracranial pressure by whatever means is available”.- Dr. Randy Chestnut
• Multi-center study • 324 pts; age 13 and older • Treatment based on ICP
monitoring vs. Exam/Imaging
Benchmark Evidence from South American Trials: Treatment of Intracranial Pressure
TRACK- TBI Study
• Multi center study @ 3 Level 1 facilities
• 135 pts. w/mild TBI • CT scan on admission • MRI about 1 week later
ü 99 had no detectable signs of injury on a CT scan ü More than a quarter (27) who had a “normal” CT
scans had focal lesions on MRI
Transforming Research and Clinical Knowledge in Traumatic Brain Injury
CT Radiation
ü 33% of patients underwent five or more lifetime CT examinations
ü 5% of patients had received estimated cumulative radiation doses that were higher than the radiation exposure from 1,000 chest X-rays.
ü 7% of the patients had enough recurrent CT imaging to raise their estimated cancer risk
• Brigham and Women’s Hospital
• 31, 462 pts • Retrospective 22 yr CT
exposure history BOOST 2 Trial
• Phase 2 randomized clinical trial • Median time when PbtO2<20mmHg
• 0.44 in the ICP group
• 0.14 in the ICP+PbtO2 group (p<0.00001)
NCS/SCCM Consensus Statement
• Use of ICP and CPP protocol
• Monitoring brain temp
• Monitoring brain oxygen for all pts at risk for cerebral ischemia
• Use of TCD to detect vasospasm in SAH
• Use of EEG • Altered LOC
• Induced hypothermia
• Use of cerebral microdialysis
Putting Neuromonitoring Devices into Practice
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Jimmy 14 year old wearing helmet
Unwitnessed bicycle crash on dirt trail
GCS on scene 6; intubated in field
Airlift to hospital
** Report of Concussion 6 Weeks PTA**
Initial Scan and Physical Assessment
• CT scan: Large left basal ganglia hemorrhage
• Small Right frontal contusion
• Small SAH • Nondisplaced left
mandibular fracture
Physical Exam
• Sedated • Fixed Dilated
Right pupil • Moves hand
slightly to noxious stimuli
• Temp 39.1, BP 126/61, HR 76
Initial Interventions
• Foley placed
• A line placed
• Versed and Fentanyl Gtt
• Right Frontal Camino
• Opening ICP 19
TBI Goals 2007 Brain Trauma Foundation
• CPP >50 mmHg • Titrate MAP for CPP goal • ICP <20 mmHg • Normothermic* • PaO2 >75 • Euvolemic • Na+ 140-150 mmEq/L
Hospital Day 3
• Increasing ICP 24-28 mmHg
• Left Temporal Craniectomy; flap out
• Placement of Neuromonitoring devices: • Microdialysis x 2; left parietal, left frontal • Hemedex • Licox • Ventriculostomy
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Day 4: 0800-1100
BP 118-122/48-52 mmHg
MAP 64-70 mmHg
ICP 9-10 mmHg
CPP 54-61mmHg
CBF 21-26 ml/min
PbtO2 8.5-9.8 mmHg*
L/P ratio 26-28
Cerebral CBG 0.9-1 mmol/L
Midazolam gtt
Fentanyl gtt
Phenylephrine gtt
Day 4 @ 1140
Fentanyl Bolus IV given for anticipated
placement of weighted feeding tube
Day 4 @ 1200
• BP 95-98/35-40
• MAP 55-60
• ICP 7-9
• CPP 49-53
Hemedex • 9-10 ml/min
Licox • 8mmHg
L/P • 32
No alarms are generated; Is there a problem?
Day 4 @ 1400
• BP 118-122/50-53 mmHg
• MAP 65-72 mmHg
• ICP 8-10 mmHg
• CPP 55-65 mmHg
• CBF 21 ml/min
• PbtO2 10 mmHg
• L/P ratio 36
The Bottom Line
• No one monitor tells the whole story
• Location
• Context
• Validation
• Triggers additional assessment
• ‘Sweet Spot’ targeted care
1. Amini A, Kariman H, Arhami Dolatabadi A, Hatamabadi HR, Derakhshanfar H, Mansouri B, Safari S, Eqtesadi R: Use
of the sonographic diameter of optic nerve sheath to estimate intracranial pressure. Am J Emerg Med 2013, 31(1):236-239.
2. Bader MK: Gizmos and gadgets for the neuroscience intensive care unit. The Journal of neuroscience nursing : journal of the American Association of Neuroscience Nurses 2006, 38(4):248-260.
3. Bader MK, Littlejohns LR, March K: Brain tissue oxygen monitoring in severe brain injury, II. Implications for critical care teams and case study. Critical care nurse 2003, 23(4):29-38, 40-22, 44.
4. Brain Trauma F, American Association of Neurological S, Congress of Neurological S: Guidelines for the management of severe traumatic brain injury. J Neurotrauma 2007, 24 Suppl 1:S1-106.
5. Bullock R, Chesnut RM, Clifton G, Ghajar J, Marion DW, Narayan RK, Newell DW, Pitts LH, Rosner MJ, Wilberger JW: Guidelines for the management of severe head injury. Brain Trauma Foundation. European journal of emergency medicine : official journal of the European Society for Emergency Medicine 1996, 3(2):109-127.
6. Cecil S, Chen PM, Callaway SE, Rowland SM, Adler DE, Chen JW: Traumatic brain injury: advanced multimodal neuromonitoring from theory to clinical practice. Critical care nurse 2011, 31(2):25-36; quiz 37.
7. Chen JW, Gombart ZJ, Rogers S, Gardiner SK, Cecil S, Bullock RM: Pupillary reactivity as an early indicator of increased intracranial pressure: The introduction of the Neurological Pupil index. Surgical neurology international 2011, 2:82.
8. Chen JW, Rogers SL, Gombart ZJ, Adler DE, Cecil S: Implementation of cerebral microdialysis at a community-based hospital: A 5-year retrospective analysis. Surg Neurol Int 2012, 3(57).
9. Chesnut RM, Temkin N, Carney N, Dikmen S, Rondina C, Videtta W, Petroni G, Lujan S, Pridgeon J, Barber J et al: A trial of intracranial-pressure monitoring in traumatic brain injury. The New England journal of medicine 2012, 367(26):2471-2481.
10. Gerber LM, Chiu YL, Carney N, Hartl R, Ghajar J: Marked reduction in mortality in patients with severe traumatic brain injury. Journal of neurosurgery 2013, 119(6):1583-1590.
References:
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11. Kampfl A, Pfausler B, Denchev D, Jaring HP, Schmutzhard E: Near infrared spectroscopy (NIRS) in patients with severe brain injury and elevated intracranial pressure. A pilot study. Acta neurochirurgica Supplement 1997, 70:112-114.
12. Kristiansson H, Nissborg E, Bartek JJ, Andresen M, Reinstrup P, Romner B: Measuring elevated intracranial pressure through noninvasive methods: a review of the literature. J Neurosurg Anesthesiol 2013, 25(4).
13. Peberdy MA, Callaway CW, Neumar RW, Geocadin RG, Zimmerman JL, Donnino M, Gabrielli A, Silvers SM, Zaritsky AL, Merchant R et al: Part 9: post-cardiac arrest care: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010, 122(18 Suppl 3):S768-786.
14. Popovic D, Khoo M, Lee S: Noninvasive Monitoring of Intracranial Pressure. Recent Patents on Biomedical Engineeringe 2009, 2(3):165-179.
15. Rajajee V, Vanaman M, Fletcher JJ, Jacobs TL: Optic nerve ultrasound for the detection of raised intracranial pressure. Neurocritical care 2011, 15(3):506-515.
16. Rosenberg JB, Shiloh AL, Savel RH, Eisen LA: Non-invasive methods of estimating intracranial pressure. Neurocritical care 2011, 15(3):599-608.
17. Springborg JB, Frederiksen HJ, Eskesen V, Olsen NV: Trends in monitoring patients with aneurysmal subarachnoid haemorrhage. British journal of anaesthesia 2005, 94(3):259-270.
18. Taylor WR, Chen JW, Meltzer H, Gennarelli TA, Kelbch C, Knowlton S, Richardson J, Lutch MJ, Farin A, Hults KN et al: Quantitative pupillometry, a new technology: normative data and preliminary observations in patients with acute head injury. Technical note. Journal of neurosurgery 2003, 98(1):205-213.
19. Zauner A, Muizelaar JP: Head Injury. London: Chapman and Hall; 1997.
References Continued
Thank You!
Diane Bräxmeyer Downey 503.413.4921