Neuromonitoring

ICP, CPP, Autoregulatory indices

To allow CPP optimization through derivation of PRx and ORx

Relatively easy insertion
Low procedural complication rate
Low infection risk

In vivocalibration not possible
Measures localized pressure
Small zero-drift with time

As above

As above, plus: To allow therapeutic drainage of CSF

Measures global ICP
Therapeutic CSF drainage
In vivocalibration possible

More difficult insertion
Risk of procedure-related haemorrhage
Risk of catheter-related ventriculitis

Blood flow velocity, Pulsatility index, Autoregulatory indices

May detect cerebral hypoperfusion and facilitate early goal-directed therapy

Noninvasive
Can be used on an intermittent or continuous basis
Good temporal resolution

Measures relative (not absolute) CBF
Operator dependent
Failure rate in 5–10% of patients (absent acoustic window)
Little evidence base in TBI

Jugular venous oxygen saturation, Arterio-venous oxygen content difference

To evaluate the adequacy of cerebral perfusion and oxygen delivery
To supplement ICP/CPP-guided therapy
To assist titration of medical and surgical therapies to guide ICP/CPP therapy

Global assessment of balance between CBF and metabolism

Non-quantitative assessment of cerebral perfusion
Insensitive to regional ischemia
Risk of extracranial contamination of samples

Brain tissue oxygen partial pressure, Oxygen reactivity

As for jugular venous oximetry, plus:
To allow CPP optimization through derivation of ORx

Regional assessment of balance between CBF and metabolism
Continuous
Ischaemic ‘thresholds’ defined

Minimally invasive
Measures oxygenation within a small region of interest
One hour run-in period limits intraoperative applications

Regional cerebral oxygen saturation, Autoregulatory indices

As for jugular venous oximetry, plus:
Detection of intracranial haematoma

Noninvasive
Real time
Multisite measurement

rScO₂-derived ‘ischaemic’ threshold not defined
Readings affected by the presence of intracranial haematoma and ‘contamination’ of signals by extracranial tissue
Little evidence base in TBI

Glucose, Lactate, pyruvate, and LPR, Glycerol, Glutamate, Multiple biomarkers for research purposes

To detect cerebral ischaemia, hypoxia, cellular energy failure, and glucose deprivation
To predict the development of secondary injury before it is detectable clinically or by other monitoring modalities
To optimize CPP
To assist titration of medical therapies such as systemic glucose control

Assessment of cerebral glucose metabolism
Detection of hypoxia/ischemia
Assessment of non-ischemic causes of cellular bioenergetic dysfunction

Focal measure
Thresholds for abnormality unclear
Not continuous
Labour-intensive

Seizures, Diagnosis-specific EEG patterns, Some evidence that detection of SDs might be possible

To detect convulsive and non-convulsive seizures
To diagnose characteristic EEG patterns to facilitate prognostication

Noninvasive
Detection of non-convulsive seizures
Correlates with cerebral ischaemic and metabolic changes

Skilled interpretation required
Affected by anaesthetic and sedative agents

Cortical SDs

To detect spreading cortical depolarizations

Currently the only method to identify SDs accurately

Highly invasive
No evidence that treatment of SDs improves outcome
Little evidence base in TBI and currently remains a research tool