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Table 3 Components of brain multimodality monitoring for poor grade SAH

From: Management of delayed cerebral ischemia after subarachnoid hemorrhage

Device

Physiological parameter measured

Normal range

Pathological condition

Continuous electroencephalography

Brain activity

Epileptiform discharges

• Alpha/delta ratio > 50 %

• No epileptiform discharges

• Reactivity to stimuli

• Alpha/delta ratio < 50 %

• Epileptiform discharges

• No reactivity

Transcranial Doppler ultrasound

Mean blood flow velocity (FVm)

• FVm MCA: 30–75 cm/s

• MCA FVm 120–180 cm/s: intermediate probability of vasospasm

• MCA FVm >180 cm/s: high probability of vasospasm

Cerebral blood flow monitor (Hemedex)

Cerebral blood flow (CBF)

• >40 ml/100 g/min

• <20 ml/100 g/min: indicative of ischemia assuming preserved metabolic demand

Jugular venous oximetry

Balance between oxygen delivery and consumption (SjO2)

• 50–75 %

• <50 %; increased oxygen extraction fraction, indicative of ischemia

Brain tissue oxygen tension (Licox)

Regional parenchymal brain tissue oxygen tension (PbtO2)

• 25–35 mmHg in white subcortical matter

• <20 mmHg: indicative of cerebral hypoxia

Cerebral microdialysis

• Glucose

• Lactate

• Pyruvate

• Lactate/pyruvate ratio

• Glutamate

• Glycerol

• 0.8–4.0 μmol/L

• 0.7–3.0 μmol/L

• Unknown

• < 25

• 2–10 μmol/L

• 10–90 μmol/L

• <0.2 μmol/L

• ≥4.0 μmol/L

• Unknown

• >40 indicative of anaerobic metabolism

• >10 μmol/L

• >90 μmol/L

  1. SAH subarachnoid hemorrhage