Fig. 3
From: Hydrocephalus and the neuro-intensivist: CSF hydrodynamics at the bedside
Example of a constant rate infusion test in a post-SAH patient with HCP. HCP with normal baseline ICP. The dark red area depicts infusion period. Although baseline ICP was normal (4.75 mmHg), it rises until 36.5 mmHg until the end of the infusion study (plateau pressure), whereas the R to CSF outflow (Rcsf) is increased (18.59 mmHg × ml−1 × min−1). There are also a lot of spikes in both ICP and AMP (amplitude) tracings reflecting strong vasogenic B waves. Changes in AMP are well correlated with changes in ICP. The RAP index that is the correlation coefficient between the pulse amplitude AMP and the mean value of ICP is close to + 1, signifying poor compensatory reserve. This is a case of post-SAH communicating HCP