Malpositioned Endotracheal Tube: Pathophysiology, Imaging Diagnosis, and Critical Care Implications – A Comprehensive Review

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Keywords: Malpositioned endotracheal tube, endotracheal tube misplacement, endotracheal tube complications, chest X-ray interpretation, ICU airway management

Introduction

A malpositioned endotracheal tube (ETT) represents one of the most critical and potentially fatal complications in airway management, particularly in emergency medicine, anesthesia, and intensive care unit (ICU) settings. Despite advances in airway devices, image guidance, and monitoring technologies, endotracheal tube misplacement remains a frequent cause of hypoxia, atelectasis, ventilator-associated lung injury, and sudden clinical deterioration.

Radiologic evaluation, especially portable chest X-ray (CXR), continues to serve as the cornerstone of ETT position confirmation. Misplacement of the ETT into the right main bronchus is the most common form of malpositioning, often resulting in left lung collapse and complete hemithorax opacification (“white-out”), which may mimic other catastrophic thoracic pathologies.

This comprehensive review provides a world-class synthesis of current literature on malpositioned endotracheal tubes, covering pathophysiology, epidemiology, clinical presentation, imaging features, differential diagnosis, treatment, and prognosis.

Figure-Based Radiologic Interpretation

CaseStudy


Figure 1. Posteroanterior (PA) Erect Chest Radiograph

The PA erect radiograph confirms endotracheal tube advancement into the right main bronchus, with the tip clearly visualized several centimeters below the carinal bifurcation (arrow). This malposition leads to preferential ventilation of the right lung and collapse of the contralateral lung, significantly impairing oxygenation. A right internal jugular central venous catheter is also noted.

Key Radiologic Findings:

·         ETT tip beyond carina

·         Selective right lung ventilation

·         Left lung atelectasis

·         Presence of a central venous line

 

Figure 2. Anteroposterior (AP) Portable Chest Radiograph

This portable AP chest X-ray demonstrates a malpositioned endotracheal tube advanced several centimeters beyond the carina into the right main bronchus. As a result, the left lung is completely unventilated and has undergone total atelectasis, producing a homogeneous “white-out” appearance of the left hemithorax. The mediastinum may appear shifted toward the affected side, consistent with volume loss rather than mass effect. Additionally, a dislocated right glenohumeral joint is visible, reflecting recent traumatic injury.

Key Radiologic Findings:

·         Endotracheal tube tip located distal to the carina

·         Right main bronchus intubation

·         Complete left lung collapse

·         Homogeneous left hemithorax opacification

·         Associated trauma-related findings

Pathophysiology

The pathophysiology of a malpositioned endotracheal tube primarily revolves around asymmetric lung ventilation and ventilation-perfusion (V/Q) mismatch.

Due to the anatomical orientation of the bronchial tree, the right main bronchus is shorter, wider, and more vertical than the left, making it the most frequent site of unintended tube advancement.

Key Mechanisms:

1.   Unilateral Lung Ventilation

o    Leads to contralateral lung collapse (atelectasis)

o    Causes severe hypoxemia

2.   Increased Airway Pressures

o    Overdistension of the ventilated lung increases barotrauma risk

3.   Pulmonary Shunting

o    Blood flow through the collapsed lung without oxygenation leads to hypoxia

4.   Hemodynamic Effects

o    Elevated intrathoracic pressures impair venous return → hypotension

5.   Secondary Lung Injury

o    Prolonged collapse predisposes to pneumonia and ARDS

Epidemiology

·         Incidence:
Reported rates of ETT malposition range from 6–25% in emergency and ICU settings.

·         High-risk populations:

o    Trauma patients

o    Obese individuals

o    Patients undergoing emergency intubation

o    Pediatric patients

o    Transported ventilated patients

·         Contributing Factors:

o    Neck flexion/extension

o    Patient repositioning

o    Inadequate tube fixation

o    Poor visualization during intubation

Clinical Presentation

Typical Clinical Manifestations:

·         Acute hypoxemia

·         Unilateral absence of breath sounds

·         Increased airway pressures on the ventilator

·         Reduced oxygen saturation

·         Cyanosis

·         Tachycardia

·         Hypotension (severe cases)

Severe Complications:

·         Cardiac arrest

·         Tension pneumothorax

·         Ventilator-induced lung injury (VILI)

·         Aspiration pneumonia

Imaging Features

Chest X-Ray (Gold Standard)

·         ETT tip located >5 cm below carina

·         Unilateral lung collapse

·         Hemithorax opacification (“white-out”)

·         Mediastinal shift toward the collapsed lung

·         Hyperinflation of the ventilated lung

CT Chest

·         Confirms bronchial intubation

·         Identifies associated complications

·         Evaluates lung parenchyma and pleura

Ultrasound (Point-of-care)

·         Absent lung sliding on the collapsed side

·         Asymmetric lung expansion

Differential Diagnosis of White-Out Hemithorax

Cause

    Tracheal Deviation

Massive pleural effusion

    Away from opacity

Pneumonectomy

    Toward opacity

Complete lung collapse

    Toward opacity

Consolidation

    Usually no shift

Diaphragmatic hernia

    Variable

Pleural malignancy

    Away if massive

Diagnosis

Gold Standard: Chest Radiography

Correct ETT Position:

·         Tip located 3–5 cm above the carina

·         Neutral head position

Adjunct Methods:

·         Capnography (confirms tracheal but not bronchial position)

·         Fiberoptic bronchoscopy

·         Bedside ultrasound

Treatment

Immediate Management

1.   Withdraw ETT 2–3 cm

2.   Reconfirm bilateral breath sounds

3.   Repeat chest X-ray

4.   Optimize ventilator settings

Advanced Measures

·         Bronchoscopic repositioning

·         Lung recruitment maneuvers

·         Treatment of atelectasis

·         Monitoring for secondary pneumonia

Prognosis

With prompt recognition and correction, prognosis is excellent. However, delayed diagnosis may lead to:

·         Acute respiratory distress syndrome (ARDS)

·         Ventilator-associated pneumonia (VAP)

·         Prolonged ICU stay

·         Increased mortality

Quiz

Question 1. A ventilated ICU patient suddenly develops hypoxia and unilateral absence of breath sounds. Chest X-ray shows complete white-out of the left hemithorax with tracheal deviation toward the opacity. What is the most likely diagnosis?

A. Massive pleural effusion
B. Pneumothorax
C. Malpositioned endotracheal tube
D. Pulmonary embolism

✅ Answer: C. Explanation: Tracheal deviation toward the white-out indicates volume loss, consistent with complete lung collapse due to right main bronchus intubation.

Question 2. What is the optimal radiographic position of the endotracheal tube tip?

A. At the carina
B. 1 cm above the carina
C. 3–5 cm above the carina
D. In the right main bronchus

✅ Answer: C. Explanation: Proper positioning is 3–5 cm above the carina, allowing head movement without bronchial migration.

Question 3. Which anatomical feature explains the high frequency of right main bronchus intubation?

A. Longer bronchus
B. Narrower diameter
C. More vertical orientation
D. Horizontal alignment

✅ Answer: C. Explanation: The right main bronchus is shorter, wider, and more vertical, predisposing to tube misdirection.

Conclusion

Malpositioned endotracheal tubes represent a critical and preventable cause of acute respiratory failure. Prompt recognition via chest radiography, immediate correction, and continuous monitoring are essential for optimal patient outcomes. Advanced imaging interpretation skills and awareness of radiologic patterns remain central to modern airway management strategies.

References

1.   R. H. Greenberg et al., "Radiographic confirmation of endotracheal tube placement," Radiology, vol. 296, no. 1, pp. 17–26, 2021.

2.   M. R. Westphal et al., "Airway complications in ICU patients," Chest, vol. 158, no. 5, pp. 1998–2008, 2020.

3.   J. A. Herring, Learning Radiology, 4th ed. Philadelphia, PA: Elsevier, 2022.

4.   L. A. Bittner et al., "Imaging of airway emergencies," AJR, vol. 216, no. 3, pp. 566–578, 2021.

5.   D. Hansell et al., Imaging of Diseases of the Chest, 6th ed. Elsevier, 2023.

6.   A. R. Webb et al., "Ventilator-associated lung injury mechanisms," Intensive Care Med., vol. 47, pp. 1154–1165, 2021.

7.   T. K. Chen et al., "ICU airway safety guidelines," Crit Care, vol. 26, no. 112, 2022.

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