A 28-year-old female patient is intubated for status asthmaticus. After 4 hours, the team notices asymmetrical breath sounds with decreased air entry on the right side. The endotracheal tube position is suspected to be malpositioned. Which investigation should be performed first to confirm right mainstem intubation?
A. Immediate fiber-optic bronchoscopy
B. Computed tomography of the thorax
C. Portable chest X-ray with tube position marker
D. Transesophageal echocardiography
Explanation
Investigation of Choice for Suspected Mainstem Intubation
Clinical Scenario
Asymmetrical breath sounds with unilateral decreased air entry in an intubated patient is classic for right mainstem intubation. The investigation must:
Portable chest X-ray with a radiopaque tube position marker is the standard initial investigation for suspected endotracheal tube malposition. It directly visualizes tube position relative to the carina and mainstem bronchi.
High-YieldNEET PG
Chest X-ray allows:
1.
Measurement of tube tip distance from the carina (normal: 3–5 cm above carina)
2.
Confirmation of right vs. left mainstem intubation
3.
Identification of other complications (aspiration, pneumothorax, atelectasis)
4.
Rapid bedside availability
Diagnostic Criteria on Chest X-ray
Table
Finding
Interpretation
Tube tip 3–5 cm above carina
Correct position
Tube tip < 2 cm from carina
Risk of cuff herniation
Tube tip in right mainstem
Right mainstem intubation (common)
Tube tip in left mainstem
Left mainstem intubation (rare, difficult)
Asymmetrical lung inflation
Suggests mainstem intubation
Clinical Pearl
Right mainstem intubation is more common than left because the right mainstem bronchus is more vertical and in line with the trachea. Asymmetrical breath sounds with right-sided decrease should prompt immediate CXR confirmation and tube withdrawal by 1–2 cm.
Mnemonic
TUBE — Tip position, Under 3 cm risk, Bronchus intubation, Examine clinically first
Warning
Do not rely on clinical examination alone (asymmetrical breath sounds) to diagnose mainstem intubation; some patients with right mainstem intubation may have deceptively symmetrical sounds due to transmitted breath sounds. CXR confirmation is mandatory.
When to Proceed to FOB
Fiber-optic bronchoscopy is reserved for:
Inability to obtain adequate CXR (e.g., portable film too poor quality)
Suspected tube obstruction or kinking (not just malposition)
