Certified Registered Nurse Anesthetist (CRNA) Practice Exam

Which are the only "fail safe" signs for the correct placement of an endotracheal tube?

1. Visual confirmation of tube placement

2. Persistence of appropriate levels of end-tidal carbon dioxide

3. Palpation of the cuff in the trachea

4. Presence of breath sounds bilaterally

The correct answer is: Persistence of appropriate levels of end-tidal carbon dioxide

The identification of the persistence of appropriate levels of end-tidal carbon dioxide is considered a "fail safe" sign for verifying correct endotracheal tube placement. When an endotracheal tube is positioned correctly within the trachea, it allows for the proper exchange of gases between the lungs and the environment. The presence of carbon dioxide in the exhaled breath indicates that the tube is effectively situated where it can access the alveoli for adequate ventilation. The measurement of end-tidal carbon dioxide is a reliable indicator, as it not only confirms the position of the tube within the trachea but also reflects the patient's respiratory status. This is particularly critical in assessing their ventilation, as any significant changes or absence of carbon dioxide can suggest displacement or misplacement of the tube, prompting necessary interventions. While visual confirmation of tube placement, palpation of the cuff in the trachea, and presence of breath sounds bilaterally are important checks in the intubation process, they do not provide as definitive a measure of proper placement as the continuous monitoring of end-tidal carbon dioxide. Each of these methods has limitations: visual confirmation may be ambiguous, palpation could lead to misinterpretation based on anatomical variations, and the presence of breath sounds