Association between burst-suppression with identical bursts and multimodal measures of cerebral oxygenation after cardiac arrest.

OBJECTIVE

Burst-suppression with identical bursts (BSIB) is an electroencephalographic (EEG) pattern associated with severe post-cardiac arrest brain injury (PCABI). Whether modifiable mechanisms of brain injury underlie BSIB is unknown. We hypothesized BSIB is associated with impaired cerebral oxygen metabolism, reflected as pathologically elevated jugular bulb venous oxygen saturation (SjvO2), higher brain tissue oxygen tension (PbtO2), normal jugular bulb venous-to-arterial carbon dioxide gradient (PbCO2 gap, and lower intracranial pressure (ICP) compared to other EEG patterns.

METHODS

This single-center retrospective study included patients resuscitated from cardiac arrest who underwent EEG and SjvO2 or PbtO2 monitoring. We categorized EEG patterns as BSIB, malignant without BSIB, and non-malignant. Using mixed effects linear regression, we examined associations between EEG and SjvO2, PbCO2 gap, PbtO2, and ICP.

RESULTS

The SjvO2 and PbtO2 cohorts included 109 and 33 patients, respectively. SjvO2 did not differ between BSIB and malignant EEGs (β=3; 95% CI, -0.6 to 7.0), butwas higher with BSIB compared to non-malignant patterns (β=12; 95% CI, 7.0 to 16.0). BSIB was associated with lower PbCO2 gap compared to malignant (β=-1.4; 95% CI, -2.6 to -0.3) and non-malignant (β=-2.6; 95% CI, -4.1 to -1.0) patterns. PbtO2 was highest with BSIB, but not significantly higher compared to malignant patterns in our adjusted model (β=4.0; 95% CI, -4.7 to 13.0). ICP was lower in those with BSIB compared to malignant patterns (β=-19.0; 95% CI, -32.5 to -5.6). Interpretation BSIB may represent a distinct subtype of PCABI characterized by impaired oxygen metabolism with preserved oxygen delivery and diffusion.