icp waveform analysis j ball 2004

8/16/2019 ICP Waveform Analysis J Ball 2004

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ICPICP

WaveformWaveform

Analysis Analysis

Joanne Ball RNJoanne Ball RN

Intensive Care UnitIntensive Care UnitWestmeadWestmead HospitalHospital


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Why look at ICP waveformWhy look at ICP waveform

analysis?analysis?

“…provides information about intracranial dynamics that can help

identify individuals

who have decreased adaptive capacity and are

at risk for increases in ICP

and decreases in CPP,

which may contribute to secondary brain injuryand have a negative impact on neurologic outcome.”

C.J Kirkness et. al, 2000, 32;5, 271.


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MonroMonro--Kellie doctrineKellie doctrine

increase in one component

(brain swelling)

or

addition of new component

(haematoma)

displaces another component

• skull – closed box, fixed volume

• contents

– blood, brain and CSF

– non-compressible fluids


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ATLS Course Manual, American College of Surgeons, 1997


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“compliance reflects theability of the intracranial

system to compensate for

increases in volumewithout subsequent

increases in ICP. When

compliance is decreased

even small increases in

intracranial volume

result in large increases

in ICP”

C.J Kirkness et. al, 2000, 32,5 271


7/16 ATLS Course Manual, American College of Surgeons, 1997


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Methods of Methods of

ICP measurementICP measurementTechnology

• external strain gauge

• catheter tip (internal)

strain gauge

• fibre-opticLocation

• Ventricular (EVD/IVC)

• Intraparenchymal• Subarachnoid

• Subdural/Extradural

• External Fontanelle


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Normal ICPNormal ICP

It is difficult to establish a universal“normal value” for ICP as it depends on

age, body posture and clinicalconditions.


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The ICP WaveformThe ICP Waveform• P1 (percussion wave)

– sharp peak and a fairly

constant amplitude.

• P2 (tidal wave)

– ends on the dicrotic

notch.

• P3 (dicrotic wave)

– follows the dicroticnotch.

– Influenced by

• 3 peaks

• relation to the arterial &

venous pulse waveforms.

North B, in ‘Head Injury’ Ed. Reilly & Bullock, 1997


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Increase waveform amplitude (P2)

(rounding of ICP waveform due to

increase in later waveform components)

↑ venous volume

Hypoventilation

Venous compression

Increase waveform amplitude (P1)↑ BP (hypertension)

Increase/ decrease waveform amplitude

Little change in waveform components

↑ CSF volume

Increase waveform amplitude (P2)↑ Mass lesion

Waveform changesCondition that

↑ ICP

adapted from C.J Kirkness et. al, 2000, 32;5, 273.


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Interpretation of ICPInterpretation of ICP

• Elevation of P2

• suggests poor compliance

• predictive of poor outcome C.J Kirkness et. al, 2000, 32;5, 273.


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The ICP WaveformThe ICP Waveform

• related to

– cardiac cycle : within individual waves

– respiratory cycle : between consecutive waves

North B, in ‘Head Injury’ Ed. Reilly & Bullock, 1997


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ICPICP wavetrendswavetrends :: ‘‘ A A’’ waveswaves• Waves that plateau as high as 30-70mmhg and remain elevated for

as long as 20 minutes indicate that CPP is being significantly

compromised.

Muller et al. Pan Arab Journal of Neurosurgery 2000 4;2.


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SummarySummary

• Visual assessment of the ICP waveform

can provide information about decreasedintracranial compliance and altered

intracranial dynamics :

• Increased amplitude

• Elevated P2 and• Rounding of the waveform

• ‘A’ or plateau waves


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ReferencesReferences• Kirkness CJ et al. (2000)

Intracranial Pressure Waveform Analysis: Clinical and ResearchImpications.

Journal of Neuroscience Nursing 32:5

• Czosnyka M & Pickard JD (2004)Monitoring and Interpretation of Intracranial Pressure.

Journal of Neurology Neurosurgery & Psychiatry 75:813-821

• North B (1997)Intracranial Pressure Monitoring

in Reilly & Bullock (eds) Head Injury, Chapman & Hall.

• Muller et al. (2000)Intracranial Pressure (ICP) and Cerebrospinal Fluid (CSF)

DynamicsPan Arab Journal of Neurosurgery 2000 4;2.

icp waveform analysis j ball 2004

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