Last updated: December 26, 2020
The medical procedure in which a tube is placed into the trachea (windpipe) through the nose or mouth is referred to as endotracheal intubation. Most of the time it is placed through the mouth. Endotracheal intubation is performed to keep the airway of the patient open in order to provide medicine, oxygen, or anesthesia and to prevent suffocation. It also helps to support breathing and to clear the airway (remove blockages). Endotracheal intubation enables medical professionals to get a better view of the upper airway. It is performed on people who cannot breathe on their own or are unconscious1.
Endotracheal intubation causes considerable discomfort for the patient as it is an invasive medical procedure. However, the patient is given muscle relaxant or general anesthesia to avoid the feeling of discomfort and pain.
The esophageal Detector Device (EDD) is a diagnostic tool used for the confirmation of endotracheal intubation. An EDD indicates the correct endotracheal tube position even in situations where the end-tidal carbon dioxide concentration fails, such as severe bronchospasm or CPR. However, EDD may not detect esophageal positioning of an ETT when negligently, gastric inflation occurs. In the emergency patient population, the EDD accurately confirms tracheal intubation. The EDD is more precise in its results than ETCO2 monitoring results in the overall emergency patient population because of its greater precision in cardiac arrest patients.4
In all EMS provider levels, waveform capnography is used to better check patients in cardiac arrest, respiratory distress, and shock. Capnography trustworthy feedback about how severe the patient's condition is and how they would respond to the treatment. Capnography provides the most reliable evidence of the placement of the endotracheal tube. It is essential to confirm the correct placement of the endotracheal tube (ETT) promptly after intubation. Waveform capnography provides 100% sensitive and specific results about the verification of the correct endotracheal tube location. This is why waveform capnography is considered as a standard method for the primary verification of the ETT placement3. The use of waveform capnography is favored during CPR because it includes reliable proof of correct placement of ETT and possible prediction of patient survival having a cardiac arrest2. The guidelines from the European Resuscitation Council (ERC) and American Heart Association state that continuous waveform capnography is recommended in addition to clinical assessment as it is the most reliable method of verifying and monitoring the correct placement of an ETT.
Upper airway ultrasonography is a simple, non-invasive, valuable, and portable point of care ultrasound for interpretation of airway management. In low pulmonary flow conditions like severe shock or cardiac arrest, the accuracy of quantitative capnography is a suspect. In such conditions, upper airway USG images are not disturbed by low pulmonary flow. Therefore, in order to confirm the endotracheal tube placement in such conditions, upper airway USG may be used. There are two types of verifications of the endotracheal tube (i.e., primary and secondary). Primary verifications refer to the procedures that are performed before securing the endotracheal tube. Studies show that the direct method to visualize the upper airway structures in real-time to identify ETT location is upper airway ultrasound. It also helps in determining whether the tube is in the esophagus or in the trachea after intubation3.
Self-inflating esophageal detectors, colorimetric end-tidal CO2 detectors, non-waveform end-tidal capnometers, and other such devices do not match up the efficiency of the waveform capnography. The absence of CO2 tracings during cardiopulmonary resuscitation signals the physician to reexamine the location of the endotracheal tube. Airway ultrasonography to detect placement of the endotracheal tube rapidly. It confirms the ETT placement with 100% specificity and 96% sensitivity. For prompt and real-time confirmation of endotracheal tube placement, airway ultrasonography can be used as an adjunct to waveform capnography. In airway USG, a saline-filled EET cuff can promptly and efficiently confirm the suitable depth of ETT placement in the trachea, avoiding the need for chest X-ray for tube confirmation2.
The Associations of Anaesthetists of Ireland and Great Britain and AHA have legitimately recommended the use of waveform capnography during CPR. Capnography is a great, direct method that detects the amount of CO2 in exhaled air. The continuous blunt waveforms reinforce the placement of the endotracheal tube on the trachea. The use of waveform capnography has increased in the last 3 decades which has helped medical professionals to understand its use in CPR more effectively. Also, in an emergency patient population, EDD decisively confirms tracheal intubation. It is more effective than ETCO2 monitoring due to its greater efficiency in cardiac arrest patients. However, upper airway ultrasonography is as efficient as capnography in diagnosing esophageal intubation. Both capnography and upper air ultrasonography (USG) have a great agreement, a great correlation, a great accuracy, and a quick confirmation time.