From the Guidelines
The most reliable indicator of successful endotracheal intubation is end-tidal CO2 (option b). When an endotracheal tube is correctly placed in the trachea, the detection of carbon dioxide in exhaled breath provides immediate confirmation that the tube is in the respiratory tract rather than the esophagus. End-tidal CO2 monitoring, through colorimetric devices or capnography, gives real-time feedback on tube placement and continues to provide information about ventilation adequacy. While cord visualization during laryngoscopy suggests proper positioning, it doesn't confirm final tube placement. Chest auscultation can be misleading as sounds may transmit even with esophageal intubation. Pulse oximetry detects hypoxemia too late after failed intubation, and chest x-ray, though definitive, has impractical time delays in emergency situations. End-tidal CO2 detection is therefore considered the gold standard for confirming correct endotracheal tube placement due to its immediacy, reliability, and continuous monitoring capability, as supported by the American Heart Association guidelines 1.
Some key points to consider when evaluating the options include:
- Cord visualization is important but does not confirm tube placement in the trachea 1
- Chest auscultation and pulse oximetry have limitations in confirming endotracheal tube placement 1
- Exhaled CO2 detection is effective for confirmation of endotracheal tube placement in various patient populations, including neonates and adults 1
- The use of end-tidal CO2 monitoring is recommended as the most reliable method for confirming and monitoring correct placement of an endotracheal tube 1
In clinical practice, end-tidal CO2 detection should be used as the primary method for confirming endotracheal tube placement, given its high sensitivity and specificity, as well as its ability to provide real-time feedback on ventilation adequacy 1.
From the Research
Reliable Indicators of Successful Endotracheal Intubation
- The most reliable indicator of successful endotracheal intubation is end-tidal CO2 monitoring, as it has been shown to be highly sensitive and specific in various studies 2, 3, 4, 5, 6.
- End-tidal CO2 monitoring can confirm tracheal intubation more rapidly than chest auscultation and capnography 3.
- Capnography is considered the gold standard for verification of proper endotracheal tube placement, with 100% sensitivity and specificity in a cadaveric experimental model 6.
- Ultrasound can also be used to confirm successful endotracheal intubation, and has been shown to be faster than end-tidal CO2 monitoring in some cases 2.
- Other methods, such as chest x-ray, cord visualization, and pulse oximetry, are not as reliable as end-tidal CO2 monitoring for confirming successful endotracheal intubation.
Comparison of Methods
- A study comparing three different methods for confirming tracheal tube placement found that capnometry and capnography were better than auscultation in confirming endotracheal tube placement in non-arrest patients 4.
- Another study found that colorimetric end-tidal CO2 monitoring was a safe, reliable, rapid, simple, and portable method for determining endotracheal tube position 3.
- End-tidal CO2 monitoring has been shown to be useful in verifying endotracheal tube position and during cardiopulmonary resuscitation in the field 5.