Author Question: During endotracheal intubation, the endotracheal tube is attached to a capnometer. During the ... (Read 117 times)

newbem · **on:** Jul 16, 2018

During endotracheal intubation, the endotracheal tube is attached to a capnometer. During the intubation procedure, the therapist observes the capnogram displayed below. How should the therapist interpret this finding?

A. The ET tube has entered the trachea.
B. The ET tube is present in the esophagus.
C. The right mainstem bronchus has been intubated.
D. This finding is a common artifact that presents during CPR.

Question 2

The pressure, flow, and volume waveforms illustrated below were obtained from a patient with COPD being mechanically ventilated with pressure-controlled ventilation (PC-CMV). Where along any of these tracings can the influence of volume compressed in the patient's breathing circuit be noticed?

A. the slight pressure elevation situated at the front end of the pressure plateau
B. the gap along the baseline between the two upward deflections on the volume tracing
C. the initial downward spike located along the flow waveform
D. the abrupt drop-off down toward the baseline on the flow tracing

samiel-sayed · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: A
A. Correct response: The fact that the capnogram tracing abruptly spiked from 0 exhaled CO2 to around 3 CO2 indicates that the endotracheal tube has entered the patient's trachea. Actually, with adequate perfusion and ventilation, one would expect to see an exhaled CO2 percent between 4.5 to 5.0.
B. Incorrect response: If the endotracheal tube was placed into the esophagus, the capnogram would continue to read essentially 0 exhaled CO2. The capnogram would effectively demonstrate a flat line superimposed on the baseline. The first half of the drawing indicates esophageal intubation.
C. Incorrect response: If the therapist had intubated the right mainstem bronchus instead of the trachea, the capnogram would still indicate the tracing shown with this question because CO2 from the right lung would be detected by the capnometer. A portable AP chest x-ray must be performed to confirm the location of the tip of the endotracheal tube.
D. Incorrect response: See explanation A.

Answer to Question 2

ANS: C
A. Incorrect response: See explanation C.
B. Incorrect response: See explanation C.
C. Correct response: The initial downward deflection on the flow-time tracing indicates the volume of gas compressed in the ventilator circuit at the end of inspiration. When inspiration ends, the compressed volume exits the ventilator breathing circuit rapidly. In fact, this volume is expelled more rapidly from the circuit than the patient's own exhaled volume. This sudden flow of gas leaving the breathing circuit causes an initial steep decline in along the flow tracing, followed by a gradual tapering of flow to zero.
D. Incorrect response: See explanation C.