Ultrasonography for proper endotracheal tube placement confirmation in out-of-hospital cardiac arrest patients: two-center experience

Background A secure airway and effective ventilation are key components of advanced life support [1]. Unrecognized misplacement of endotracheal tube can lead to morbidity and mortality, with a reported incidence of approximately 2.9–16.7% in previous cardiac arrest studies [2–4]. Many traditional methods, including direct visualization of the vocal cords, observation of chest expansion, and chest auscultation can be employed to confirm endotracheal tube position, but each of these methods has limitations and may interrupt chest compressions during cardiopulmonary resuscitation (CPR)[5,6]. Quantitative waveform capnography is recommended as the gold standard for confirming correct endotracheal tube placement in the 2010 American Heart Association (AHA) Guidelines for CPR and Emergency Cardiovascular Care (ECC) [1]. However, it has well-known limitations in cardiac arrest patients, and can be affected by low cardiac output, low pulmonary flow, airway obstruction, or epinephrine use [6,7]. Ultrasonography is a non-invasive, real-time diagnostic tool commonly used during resuscitation. Realtime airway sonographic approaches could enhance physician confidence and decision-making in relation to tracheal tube placement, and may have a role in combination with continuous capnography in emergency patients [8-10].