Review Article

Brain Multimodality Monitoring: A New Tool in Neurocritical Care of Comatose Patients

Figure 1

Intracranial pressure (ICP) waveforms. Percussion wave (P1) represents arterial pulsation, tidal wave (P2) represents brain tissue compliance, and dicrotic wave (P3) is due to closure of aortic valve. Under normal conditions, P1 > P2, indicative of normal compliant brain. In ABI brain compliance starts decreasing resulting in reversal of P1 : P2 ratio (i.e., P2 > P1) which is a sensitive predictor of poor brain compliance.