The following is a summary of “End-tidal carbon dioxide after sodium bicarbonate infusion during mechanical ventilation or ongoing cardiopulmonary resuscitation,” published in the February 2024 issue of Emergency Medicine by Roh, et al.

For a study, researchers sought to investigate changes in end-tidal CO₂ following sodium bicarbonate administration, a common intervention during mechanical ventilation or cardiopulmonary resuscitation (CPR).

The single-center, prospective observational study enrolled adult patients who received sodium bicarbonate during mechanical ventilation or CPR. End-tidal CO₂ elevation was assessed as an increase of ≥20% from baseline. The lag time to initial increase (T_lag), time to peak (T_peak), and duration of end-tidal CO₂ rise (T_duration) were compared between patients with spontaneous circulation (SC group) and those undergoing CPR (CPR group).

The study included 33 patients (SC group: n = 25; CPR group: n = 8). Median peak end-tidal CO₂ post-sodium bicarbonate injection increased by 100% (from 21 to 41 mmHg) overall, 89.5% (from 21 to 39 mmHg) in the SC group, and 160.2% (from 15 to 41 mmHg) in the CPR group. Median T_lag was 17 s (IQR: 12–21), T_peak was 35 s (IQR: 27–52), and Tduration was 420 s (IQR: 90–639). There were no significant differences in T_lag , T_peak , or T_duration between groups. T_duration correlated with the amount of sodium bicarbonate in the SC group (correlation coefficient: 0.531, P = 0.006).

Sodium bicarbonate administration resulted in a substantial, prolonged increase in end-tidal CO₂ in patients with spontaneous circulation and those undergoing CPR. The utility of end-tidal CO₂ as a physiological indicator may be limited following intravenous sodium bicarbonate administration.

Reference: sciencedirect.com/science/article/abs/pii/S0735675723006393