Validation of the esophageal detector device (EDD) in elective and emergency intubation in a medical ICU

Objective

(i) To confirm the validity of the esophageal detector device (EDD) as an indicator of correct positioning of endotracheal tubes (ETTs) in patients intubated under elective and emergency conditions in a medical ICU. (ii) To establish the positive and negative predictive values sensitivity and specificity of the EDD for correct positioning of ETTs.

Patients and methods

All patients that underwent elective or emergency intubation in a medical ICU during a 4 month period (from August until November 1996) were included in the study. ETT positioning was initially evaluated by auscultation of lung fields and epigastrium during 1 to 2 Ambu-bag ventilations, followed by EDD monitoring. If EDD monitoring was consistent with esophageal ETT placement, the ETT was removed and a new attempt was made by the same or another physician. The technique and the comparison of the EDD with end-tidal carbon dioxide measurements (ETCO₂) have been described previously (Ann Emerg Med 1996, 27:595–599) and will not be discussed in this study.

Results

Of 117 intubations in 71 patients EDD monitoring correctly indicated tracheal placement in 94 and falsely indicated esophageal placement in three (sensitivity = 97%). EDD correctly indicated esophageal placement in 20 (specificity = 100%). The positive predictive value (PPV) was 100% and the negative predictive value (NPV) was 87%. All three patients in which the EDD falsely indicated esophageal placement were severely bronchospastic with copious tracheal secretions, possibly creating a vacuum effect. After suctioning of secretions and a further 3 to 4 Ambu-bag ventilations the EDD confirmed correct tracheal intubation in these three patients. No adverse effects or reactions were noted with the use of the EDD.

Conclusion

This study supports the validity of the EDD for confirmation of correct tracheal intubation in the setting of elective and emergency intubation of medical ICU patients. In patients with extreme bronchospasm, excessive copious secretions or lung edema suctioning of secretions and an extra 3 to 4 Ambu-bag ventilations should be done before EDD testing to prevent false negative results. The EDD has excellent specificity, sensitivity, PPV and NPV. In addition and in comparison to ETCO₂ monitoring it is cheap and easy to use.