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A study on invasively ventilated adults in the emergency department found that an elevated arterial to end-tidal carbon dioxide gap was common post-intubation but did not significantly correlate with clinical outcomes, including in-hospital mortality.

The following is a summary of “Arterial to end-tidal carbon dioxide gap and its characterization in mechanically ventilated adults in the emergency department,” published in the November 2023 issue of Emergency Medicine by Upchurch, et al.

For a study, researchers sought to assess the early measurement of the arterial to end-tidal carbon dioxide (PaCO₂-PetCO₂) gap, acting as a surrogate for physiologic dead space, and its correlation with clinical outcomes in intubated adults within the emergency department (ED).

The observational cohort study focused on invasively mechanically ventilated adults in an academic medical center from 2009 to 2016. The association of the PaCO₂-PetCO₂ gap with clinical outcomes was examined, with in-hospital mortality as the primary outcome.

A total of 519 patients were included, and 325 (63%) had an elevated PaCO₂-PetCO₂ gap (>5 mmHg). Those with an elevated gap were notably older, had higher APACHE II scores, a higher prevalence of chronic obstructive pulmonary disease (COPD), lower arterial oxygen to fraction of inspired oxygen (P:F) ratios, and were more likely to be intubated for COPD exacerbation or sepsis. However, there was no significant difference in mortality for patients with an elevated PaCO₂-PetCO₂ gap (25% vs. 26%) in both unadjusted (P = 0.829) and adjusted analysis (aOR = 0.81 [95% CI: 0.53–1.26]), compared to those with a non-elevated gap.

While an elevated PaCO₂-PetCO₂ gap was commonly observed in the post-intubation period in the ED, it did not show a significant association with clinical outcomes.

Source: sciencedirect.com/science/article/abs/pii/S0735675723004618