ClinicalVerification of endotracheal tube placement: A comparison of confirmation techniques and devices
Section snippets
Direct laryngoscopy
Looking to see whether the endotracheal tube is going through the vocal cords is one of the best ways to determine the location of the tube and is considered the “primary” method of verification.3, 7 However, copious amounts of blood or secretions in the line of sight can make direct visualization quite difficult. Anatomic irregularities, such as a large tongue, prominent teeth, or a short, thick neck, can further interfere with direct visualization, especially when cervical stabilization must
“Gurgling” over the epigastrium
Some recent publications suggest that listening over the epigastrium is the first step after placing the endotracheal tube.7, 8 This method may provide a convincing indication of esophageal placement, but it does not provide positive verification of tracheal placement.3, 8, 9
Auscultating breath sounds
Listening for breath sounds to verify tube placement has limitations, especially when the patient is an infant or a small child. In these patients, referred breath sounds can be heard throughout the chest, even with
End-tidal CO2 detection and monitoring
CO2, a byproduct of cellular metabolism, is transported in the venous blood to the lungs, where it is eliminated during the expiratory phase of breathing. EtCO2 refers to the amount of CO2 present at the end of exhalation and indicates the adequacy of ventilation, perfusion, and gas exchange in the lungs. The normal range for EtCO2 is 35 to 45 mm Hg.
EtCO2 detection and monitoring can be used for both initial and ongoing verification of endotracheal tube placement, as well as for the assessment
Colorimetric EtCO2 detection devices
Colorimetric EtCO2 devices change color in the presence of exhaled CO2. The key to using these EtCO2 detection devices successfully with patients of all ages and sizes is to allow adequate exhalation time so that the detector can change colors. In many cases, this means checking for a definitive color change after 6 ventilations.
The EasyCap (for adults) and Pedi-Cap (for infants and children) have variable color changes and a numeric scale showing the EtCO2 levels (Figure 3). The color change
Limitations with colorimetric devices
Colorimetric EtCO2 detectors are extremely reliable as long as the patient is alive and has a perfusing cardiac rhythm and the device remains uncontaminated. In cases of limited pulmonary perfusion, very little CO2 gets to the lungs to be exhaled and the adapter may not change color quickly if it changes at all. However, although it is less reliable, one can usually expect a color change in properly ventilated patients who have a nonperfusing rhythm but who are receiving adequate CPR.3, 11, 14,
References (17)
Verification of endotracheal tube position
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Optimizing Oxygenation in the Mechanically Ventilated Patient: Nursing Practice Implications
2016, Critical Care Nursing Clinics of North AmericaCitation Excerpt :This assessment includes ensuring that the airway is secured properly and verifying the airway insertion length.17 Strategies used to verify ETT placement include use of end-tidal carbon dioxide monitoring with capnometry and capnography.20 Both capnometry and capnography have been found to be reliable methods of verification in addition to radiological examination via chest radiograph.21
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