Comparison of three different methods to confirm tracheal tube placement in emergency intubation

OBJECTIVES: Verification of endotracheal tube placement is of vital importance, since unrecognized esophageal intubation can be rapidly fatal (death, brain damage).The aim of our study was to compare three different methods for immediate confirmation of tube placement: auscultation, capnometry and capnography in emergency conditions in the prehospital setting. DESIGN AND SETTING: Prospective study in the prehospital setting. PATIENTS AND INTERVENTIONS: All adult patients (>18 years) were intubated by an emergency physician in the field. Tube position was initially evaluated by auscultation. Then, capnometry was performed with infrared capnometry and capnography with infrared capnography. The examiners looked for the characteristic CO(2) waveform and value of end-tidal carbon dioxide (EtCO(2)) in millimeters of mercury. Determination of final tube placement was performed by a second direct visualization with laryngoscope. Data are mean +/- SD and percentages. MEASUREMENTS AND RESULTS: Over a 4year period, 345 patients requiring emergency intubation were included. Indications for intubation included cardiac arrest ( n=246; 71%) and non-arrest conditions ( n=99; 29%). In nine (2.7%) patients, esophageal tube placement occurred. The esophageal intubations were followed by successful endotracheal intubations without complications. The capnometry (sensitivity and specificity 100%) and capnography (sensitivity and specificity 100%) were better than auscultation (sensitivity 94% and specificity 83%) in confirming endotracheal tube placement in non-arrest patients ( p<0.05). Capnometry was highly specific (100%) but not sensitive (88%) for correct endotracheal intubation in patients with cardiopulmonary arrest (capnometry versus auscultation and capnometry versus capnography, p<0.05). CONCLUSION: Capnography is the most reliable method to confirm endotracheal tube placement in emergency conditions in the prehospital setting.