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 (SjvO 2 ), higher brain tissue oxygen tension (PbtO 2 ), normal jugular bulb venous-to-arterial carbon dioxide gradient (PbCO 2 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 SjvO 2 or PbtO 2 monitoring. We categorized EEG patterns as BSIB, malignant without BSIB, and non-malignant. Using mixed effects linear regression, we examined associations between EEG and SjvO 2 , PbCO 2 gap, PbtO 2 , and ICP. Results The SjvO 2 and PbtO 2 cohorts included 109 and 33 patients, respectively. SjvO 2 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 PbCO 2 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. PbtO 2 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.