Prehospital determination of tracheal tube placement in severe head injury

Objectives: The aim of this prospective study in the prehospital setting was to compare three different methods for immediate confirmation of tube placement into the trachea in patients with severe head injury: auscultation, capnometry, and capnography. Methods: All adult patients (>18 years) with severe head injury, maxillofacial injury with need of protection of airway, or polytrauma were intubated by an emergency physician in the field. Tube position was initially evaluated by auscultation. Then, capnometry and capnography was performed (infrared method). Emergency physicians evaluated capnogram and partial pressure of end tidal carbon dioxide (EtCO2) in millimetres of mercury. Determination of final tube placement was performed by a second direct visualisation with laryngoscope. Data are mean (SD) and percentages. Results: There were 81 patients enrolled in this study (58 with severe head injury, 6 with maxillofacial trauma, and 17 politraumatised patients). At the first attempt eight patients were intubated into the oesophagus. Afterwards endotracheal intubation was undertaken in all without complications. The initial capnometry (sensitivity 100%, specificity 100%), capnometry after sixth breath (sensitivity 100%, specificity 100%), and capnography after sixth breath (sensitivity 100%, specificity 100%) were significantly better indicators for tracheal tube placement than auscultation (sensitivity 94%, specificity 66%, p < 0.01). Conclusion: Auscultation alone is not a reliable method to confirm endotracheal tube placement in severely traumatised patients in the prehospital setting. It is necessary to combine auscultation with other methods like capnometry or capnography.