BIS monitoring may help detect delayed cerebral ischemia after aneurysmal SAH.

A BIS value lesser than 85 in the right and/or left side was the best predictor.

BIS might be more accurate in the detection of clinical DCI than TCD.

Asymmetry index failed to detect delayed cerebral ischemia.

Evaluate the bispectral index (BIS) monitoring to detect delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH).

A single-center prospective study in patients with aSAH. BIS monitoring was recorded during 25–120 min in two periods, within the initial 72 h (BIS1) and between days 4 and 6 (BIS2) from admission. The median for each exported BIS parameter was analyzed. Transcranial Doppler (TCD) sonography was simultaneously performed with BIS1 (TCD1) and BIS2 (TCD2) monitoring. A multivariate logistic regression model was built to identify the variables associated with DCI.

Sixty-four patients were included and 16 (25%) developed DCI. During BIS2 monitoring, significant differences were found in BIS value (left, p = 0.01; right, p = 0.009), 95% spectral edge frequency (left and right, p = 0.04), and total power (left and right, p = 0.04). In multivariable analysis, vasospasm on TCD2 (OR 42.8 [95% CI 3.1–573]; p = 0.005), a median BIS2 value <85 in one or both sides (OR 6.2 [95% CI 1.28–30]; p = 0.023), and age (OR 1.08 [95% CI 1.00–1.17]; p = 0.04) were associated with the development of DCI.

BIS value is the most useful BIS parameter for detecting DCI after aSAH. Pending further validation, BIS monitoring might be even more accurate than TCD.

Subarachnoid hemorrhage

Intracranial aneurysm

Consciousness monitors

Bispectral index

Vasospasm

Delayed cerebral ischemia

aneurysmal subarachnoid hemorrhage

bispectral index value

continuous electroencephalography

delayed cerebral ischemia

electromyography activity

neurological intensive care unit

quantitative electroencephalography

subarachnoid hemorrhage

95% spectral edge frequency

signal quality indicator

World Federation of Neurological Surgeons score

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