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E NEUROSURGERY
ESSENTIAL INFORMATION FOR THE BUDDING NEUROSURGEON
WAVE FORMS

ICP

ICP monitoring waveform has a flow of 3 upstrokes in one wave.

P1 = (Percussion wave) represents arterial pulsation
P2 = (Tidal wave) represents intracranial compliance
P3 = (Dicrotic wave) represents aortic valve closure

In normal ICP waveform P1 should have highest upstroke, P2 in between and P3 should show lowest upstroke.

On eyeballing the monitor, if P2 is higher than P1 - it indicates intracranial hypertension.
Lundberg A waves “or plateau waves” are steep increases in ICP lasting for 5 to 10 minutes. They are always pathological and represent reduced intracranial hypertension indicative of early brain herniation.

Lundberg B waves are oscillations of  ICP at a frequency of  0.5 to 2 waves/min and are associated with an unstable ICP. Lundberg B waves are possibly the result of cerebral vasospasm, because during the occurrence of these waves, increased velocity in the middle cerebral artery can be demonstrated on transcranial Doppler.

Lundberg C waves are oscillations with a frequency of 4-8 waves/min. They have been documented in healthy subjects and are probably caused by interaction between the cardiac and respiratory cycles.