ICU · Neurocritical care / monitoring

ICP Monitoring & Waveforms

Also known as Intracranial pressure monitoring · ICP monitoring · ICP waveforms · Lundberg waves · Plateau waves · A-waves · P1 P2 P3 · External ventricular drain · EVD · Intraparenchymal pressure monitor · Codman · Cerebral perfusion pressure · CPP

Intracranial pressure (ICP) monitoring measures the pressure within the skull, guiding the management of raised ICP (target under 22 mmHg in TBI). The cerebral perfusion pressure (CPP = MAP minus ICP) is the key derived variable, with a target of 60-70 mmHg. The intraventricular catheter (external ventricular drain) is the gold standard (it measures, drains, and samples the CSF); the intraparenchymal microsensor (Codman) is accurate but cannot drain. The normal ICP waveform has three peaks: P1 (the arterial percussion), P2 (the tidal wave reflecting compliance — a P2 rising above P1 indicates a loss of compliance), and P3 (the venous dicrotic). The Lundberg A-wave (the plateau wave — a sudden sustained plateau rise from a vasodilatory cascade) indicates a critical loss of the intracranial compliance and requires an urgent treatment.