Accuracy of real time transtracheal ultrasonography and waveform capnography to detect endotracheal intubation – A prospective observational study.

Endotracheal intubation and securing airway is a crucial step in patient resuscitation whether in an emergency setting, intensive care unit (ICU) or operation theatre (OT). Endotracheal intubation can be difficult even for a skilled and experienced individual in certain cases. Any delay in confirmation of endotracheal tube placement can lead to life threatening complications like aspiration, cardiopulmonary arrest, hypoxemia and hypoxic brain injury ultimately leading to death, increasing both mortality and morbidity. Various techniques like visualization of vocal cords during laryngoscopy, fogging or misting of endotracheal tube, chest wall expansion following ventilation, visualization of tracheal rings and carina by bronchoscopy, chest auscultation to check for bilateral equal air entry, watching for abdominal distension, epigastric auscultation, oesophageal detector device, chest X-ray, capnometry or capnography and real time ultrasonography are available for confirmation of endotracheal tube placement. Capnography which is used for confirmation of correct placement of endotracheal tube can yield false positive results in cases of oesophageal intubation and also its dependency on pulmonary blood flow makes its accuracy questionable in pulmonary embolism, low cardiac output states and cases of cardiac arrest where the initiation of cardiopulmonary resuscitation (CPR) was delayed. It is also not readily available in settings like emergency room and intensive care unit (ICU) which imposes a major limitation. Portable ultrasonography machine (USG) is now widely available in all settings and can be made use for correct identification of endotracheal tube placement. Real time transtracheal ultrasonography is considered to be one of the newest and reliable modality. It is considered to be faster compared to capnography which is the gold standard method for endotracheal tube placement (ACLS 2015). Ultrasonography has various advantages such as non-invasiveness, cost effective, safety record, reproducibility of images and also the learning curve of ultrasonography has been found to be not so difficult. Hence, ultrasonography (USG) can be used as a potential alternative to capnography.