Emergency physician use of end-tidal oxygen monitoring for rapidsequence intubation

End-tidal oxygen (ETO₂) monitoring is used by anesthesiologists to quantify the efficacy of preoxygenation before intubation but is generally not used in emergency departments (EDs). We have previously published our findings describing preoxygenation practices in the ED during blinded use of ETO₂. The purpose of this investigation is to determine whether the unblinded use of ETO₂ monitoring led to improvements in preoxygenation during rapid sequence intubation in the ED and also the oxygen device or technique changes that were used to achieve higher ETO₂ levels.

We conducted an interventional study at 2 academic EDs in Sydney, Australia and New York City, New York using ETO₂ monitoring to investigate the preoxygenation process and effectiveness. We used data collected during a previous descriptive study for the control group, in which care teams in the same 2 EDs were blinded to the ETO₂ value. In the study group, clinicians could utilize ETO₂ to improve preoxygenation. Following an education process, clinicians were able to choose the method of preoxygenation and the techniques required to attempt to achieve an ETO₂ level >85%. The primary outcome was the difference in ETO₂ levels at the time of induction between the control and study group and the secondary outcome included the methods that were attempted to improve preoxygenation.

A convenience sample of 100 patients was enrolled in each group. The median ETO₂ level achieved at the time of induction was 80% (interquartile range 61 to 86, overall range 73) in the control group and 90% in the study group (interquartile range 83 to 92, overall range 41); the median difference was 12 (95% confidence interval: 8, 16, P = < 0.001). The majority of oxygen device changes were from non-rebreather mask to bag-valve-mask (BVM) (15%, n = 15) and changes in technique from improvements in mask seal (54%, n = 34). The final device used in the study group was BVM in 87% of cases.

In 2 clinical studies of ETO₂ in academic EDs, we have demonstrated that the use of ETO₂ is feasible and associated with specific and potentially improved approaches to preoxygenation. A clinical trial is needed to further study the impact of ETO₂ on the preoxygenation process and the rate of hypoxemia.