Slow-wave ICP variations derived from continuous invasive monitoring.
Wave Pattern Scan
Analyze slow-wave ICP fluctuations to distinguish between physiological pulses and dangerous plateau waves indicating compliance exhaustion.
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Advanced neurocritical care telemetry (continuous monitoring).
Distinguishing physiological oscillations from pathological crises.
Pre-emptive detection of exhaustion of intracranial compliance.
Interpreting ICP "plateau" events.
Section 2
Formula & Logic
Wave Classification
Wave Type
Amplitude
Duration
Clinical Significance
A-Waves (Plateau)
50 – 100 mmHg
5 – 20 mins
Pathological; heralds herniation.
B-Waves
20 – 30 mmHg
30s – 2 mins
Suggests decreasing compliance.
C-Waves
< 20 mmHg
4 – 8 per min
Physiological (Blood Pressure).
The Vasodilatory Cascade
A-waves signify intact but struggling autoregulation. A slight drop in pressure triggers vasodilation to maintain flow; in a non-compliant brain, this extra blood volume spikes ICP, starting a vicious cycle (Rosner’s cascade) that peaks in a plateau wave.
Section 3
Pearls/Pitfalls
Plateau Warning
The appearance of A-waves is a neurosurgical emergency. It signifies that the intracranial space has zero remaining buffer. Small increases in volume (oedema, hypercapnia, or slight MAP drops) will now cause catastrophic, sustained spikes in ICP that may lead to permanent brainstem damage.
Section 4
Evidence Appraisal
Primary Reference
Continuous recording and control of ventricular fluid pressure in neurosurgical practice
Lundberg N. • Acta Psychiatr Neurol Scand Suppl. 1960;36(149):1-193
