Rapid identification of esophageal intubations is critical to avoid patient morbidity and mortality. Continuous waveform capnography remains the gold standard for endotracheal tube (ETT) confirmation, but it has limitations. Point-of-care ultrasound (POCUS) may be a useful alternative for confirming ETT placement. The objective of this study was to determine the accuracy of paramedic-performed POCUS identification of esophageal intubations with and without ETT manipulation.

A prospective, observational study using a cadaver model was conducted. Local paramedics were recruited as subjects and each completed a survey of their demographics, employment history, intubation experience, and prior POCUS training. Subjects participated in a didactic session in which they learned POCUS identification of ETT location. During each study session, investigators randomly placed an ETT in either the trachea or esophagus of four cadavers, confirmed with direct laryngoscopy. Subjects then attempted to determine position using POCUS both without and with manipulation of the ETT. Manipulation of the tube was performed by twisting the tube. Descriptive statistics and logistic regression were used to assess the results and the effects of previous paramedic experience.

During 12 study sessions, from March 2014 through December 2015, 57 subjects participated, evaluating a total of 228 intubations: 113 tracheal and 115 esophageal. Subjects were 84.0% male, mean age of 39 years (range: 22 - 62 years), with median experience of seven years (range: 0.6 - 39 years). Paramedics correctly identified ETT location in 158 (69.3%) cases without and 194 (85.1%) with ETT manipulation. The sensitivity and specificity of identifying esophageal location without ETT manipulation increased from 52.2% (95% confidence interval [CI], 43.0-61.0) and 86.7% (95% CI, 81.0-93.0) to 87.0% (95% CI, 81.0-93.0) and 83.2% (95% CI, 0.76-0.90) after manipulation (P<.0001), without affecting specificity (P=.45). Subjects correctly identified 41 previously incorrectly identified esophageal intubations. Paramedic experience, previous intubations, and POCUS experience did not correlate with ability to identify tube location.

Paramedics can accurately identify esophageal intubations with POCUS, and manipulation improves identification. Further studies of paramedic use of dynamic POCUS to identify inadvertent esophageal intubations are needed.

LemaPC, O’BrienM, WilsonJ, St. JamesE, LindstromH, DeAngelisJ, CaldwellJ, MayP, ClemencyB.Avoid the Goose! Paramedic Identification of Esophageal Intubation by Ultrasound. Prehosp Disaster Med.2018;33(4):406–410

Hand held, colorimetric, end-tidal CO2 detector devices are being used to verify correct endotracheal tube (ETT) placement. The accuracy of these devices has been questioned in situations of cardiac arrest. The use of the esophageal detector device (EDD) is an easy alternative for detection of ETT placement, and may be more accurate in situations of cardiac arrest.

The use of the esophageal aspiration device in comparison with a colorimetric end-tidal CO2 detector is more accurate in detecting proper ETT placement and easier to use in the prehospital setting than is the colorimetric end-tidal CO2 detection device.

This was a prospective alternating weeks, 6-month study in a prehospital setting. Participants included all patients older than 18 years who were intubated by the Portsmouth, Virginia Emergency Medical Services (EMS) personnel from 01 July 1993 through 31 December 1993. The aspiration device used, also known as an esophageal detector device (EDD), was a 60 ml, luer-lock syringe attached to a 15 mm ETT adapter. Its efficacy was compared with an already accepted method of ETT position detection, the colorimetric endtidal CO2 detector. Each device was used on alternating weeks, and correct ETT placement was determined by the receiving emergency department physician using standard techniques. Chi-square analysis and Fisher's Exact test were used to compare parameters, time of device use, and ease of use. Sensitivity and specificity were calculated, and provider preference was assessed using a survey instrument administered following completion of the study.

There were 49 patients who met the inclusion criteria, but six were excluded because of situational circumstances rendering use of the device a possible compromise of patient care. Twenty-five patients were in the EDD group, and 18 were in the endtidal CO2 detector group. There was no statistically significant difference detected between groups for the gender ratio, underlying condition, CPR in progress, perceived difficulty of intubation, or percentage of nasotracheal intubation. The EDD was significantly easier to use (p<0.005). There was no statistically significant difference in time required for use of end-tidal CO2 detector device versus the EDD. The sensitivity and specificity for correct tracheal placement using the EDD was 100%, and the sensitivity for correct tracheal placement using the end-tidal CO2 detector device was 78%. Use of the EDD was preferred over use of the end-tidal CO2 detector device by 75% of participating EMS providers. One case of nasotracheal intubation with an ETT placement above the cords raised the question of accuracy of this device in situations where direct visualization is not utilized.

The EDD was accurate in all cases of orotracheal intubation, and was easier to use than was end-tidal CO2 detector device. It was preferred by 75% of participating EMS providers. In cases in which the ETT may be above the vocal cords, caution must be used with interpreting the results obtained by use of the EDD.

The esophageal detector device (EDD) recently has been found to assess endotracheal (ET) tube placement accurately. This study describes the reliability of the EDD in determining the position of the ET tube in clinical airway situations that are difficult.

This was a prospective, randomized, single-blinded, controlled laboratory investigation. Two airway managers (an emergency-medicine attending physician and a resident) determined ET-tube placement using the EDD in five swine in respiratory arrest. The ET tube was placed in the following clinical airway situations: 1) esophagus; 2) esophagus with 1 liter of air instilled; 3) trachea; 4) trachea with 5 ml/kg water instilled; and 5) right mainstem bronchus. Anatomic location of the tube was verified by thoracotomy of the left side of the chest.

There was 100% correlation between the resident and attending physician's use of the EDD. The EDD was 100% accurate in determining tube placement in the esophagus, in the esophagus with 1 liter of air instilled, in the trachea, and in the right mainstem bronchus. The airway managers were only 80% accurate in detecting tracheal intubations when fluid was present.

The EDD is an accurate and reliable device for detecting ET-tube placement in most clinical situations. Tube placement in fluid-filled trachea, lungs, or both, which occurs in pulmonary edema and drowning, may not be detected using this device.