Resusc Plus. 2025 Oct 22;26:101136. doi: 10.1016/j.resplu.2025.101136. eCollection 2025 Nov.

BACKGROUND: The difference between the jugular bulb venous and arterial carbon dioxide (CO₂) tension, the cerebral pCO₂ gap, is a marker of global tissue perfusion and can be affected by various mechanisms that underlie hypoxic-ischemic brain injury (HIBI). We hypothesized the CO₂ gap and SjvO₂ together could identify treatment responsive pathophysiology among those with abnormally elevated SjvO₂.

METHODS: In this retrospective study including post-arrest patients, we quantified the relationship between pCO₂ gap and SjvO₂ using hierarchical regression. Among patients with elevated SjvO₂, we assessed whether pCO₂ gap predicted response to treatment with hyperosmolar therapy using an interaction between time, treatment, and pCO₂ gap. We assessed the association between pCO₂ gap and indicators of HIBI using mixed regression models.

RESULTS: Among the 109 patients included, pCO₂ gap was lower among patients with normal (β = -4.3; 95 % CI, -5.6 to -3.1) or high SjvO₂ (β = -7.8; 95 % CI, -9.1 to -6.6) compared to low SjvO₂. In our interaction model, treatment with hyperosmolar therapy was associated with a 14.4 mmHg decrease in SjvO₂ (95 % CI, -18.4 to -10.3) among those with a high pCO₂ gap, but not those with normal pCO₂ gap. pCO₂ gap was significantly lower among patients with burst-suppression with identical bursts compared to those without (β = -1.8; 95 % CI, -2.8 to -0.9).

CONCLUSION: When interpreted with SjvO₂, the cerebral pCO₂ gap may uncover covert cerebral dysfunction, and can identify treatment-responsive causes of elevated SjvO₂. Thus, the pCO₂ gap may be a useful adjunct for phenotyping HIBI.

PubMed:41334152 | PMC:PMC12666575 | DOI:10.1016/j.resplu.2025.101136