# After an intubated client is repositioned, oxygen saturation falls and chest expansion becomes unequal. Waveform capnography continues, and a suction catheter passes without resistance. Click the part of the tube shown that best explains these findings.

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=581184&lang=en  
> language: en  
> subject: Physiological Adaptation  
> category: PA

## Question

After an intubated client is repositioned, oxygen saturation falls and chest expansion becomes unequal. Waveform capnography continues, and a suction catheter passes without resistance. Click the part of the tube shown that best explains these findings.

![](https://mymerci.kr/data/nclex/hotspot/regen_20260908_2350/HSR521.svg)

## Explanation

D shows the distal tip beyond the carina in a main bronchus, directing ventilation predominantly to one lung.

## In-depth explanation

Quick answer
D. D shows the distal tip beyond the carina in a main bronchus, directing ventilation predominantly to one lung.
Why this is the best choice
Persistent exhaled carbon dioxide supports airway rather than esophageal placement but does not establish appropriate depth. A patent tube can still extend too far. The depicted distal tip passes the bifurcation; its depth, not an obstruction at the connector or cuff, explains unequal expansion.
Clinical picture
The observations are fictional teaching data. Apply the stated context; the selected feature does not by itself replace a complete bedside assessment.
Memory hook
Airway placement and correct depth are separate checks.
Decision rule
Airway placement and correct depth are separate checks.
Why the other regions do not fit
A is the external connector and appears continuous. B is the cuff in the trachea above the bifurcation. C is the anatomical fork itself. D is the tube component positioned beyond that fork.
**Sources**
- An endotracheal tube extending into a main bronchus can cause asymmetric ventilation and requires correction.

## Key concepts

- **Endotracheal tube depth despite persistent capnography** — Airway placement and correct depth are separate checks.
- **Comparison with context** — Ongoing capnography can falsely reassure the learner even though tube depth is wrong.

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