Classically, brain monitoring after SAH can be divided into the time spent on the ICU, with the patient supported by ventilation, and afterwards. Brain monitoring in the ICU does not differ generally from monitoring after TBI. After the ICU period, monitoring is mainly focused on the detection of vasospasm and autoregulation of blood flow, mainly using transcranial Doppler ultrason0graphy (TCD) or near-infrared spectroscopy (NIRS).
ICM+ monitoring in poor grade SAH resembles general multimodal brain monitoring following TBI:
ICP, CPP, PbtO2, and cerebral microdialysis probes are used. ICM+ is used to integrate separate monitors and to calculate secondary indices.
From non-invasive modalities, TCD and NIRS are often used both inside and outside of the NCCU, where daily assessments of autoregulation and spasm are necessary.
Autoregulation can be assessed intermittently using TCD with the transient hyperaemic response test (THRT, left). NIRS is helpful for continuous monitoring of Cox or TOx indices. It is unclear if it can be used for assessment with the THRT.