Lecture Notes on Chest X-rays: Atelectasis, Lines, Tubes, Devices, and Surgeries

Learning Objectives

Identify atelectasis and lobar collapse.
Understand mechanisms and etiologies of atelectasis.
Accurately identify lines, tubes, and devices; assess for placement and complications.
Identify evidence of prior cardiac surgery and prosthetic heart valves.

Definition: Loss of lung volume due to collapse of lung tissue.
- Origin of Term: Greek; 'adalectasis' (incomplete) and 'ectasy' (area).
Classification:
- Mechanisms:
  - Obstructive Atelectasis: Airway obstruction, followed by gas resorption.
    - Causes: Tumor, mucus plug, foreign body aspiration, external compression.
  - Nonobstructive Atelectasis: Includes passive, compression, adhesive, and cicatricial subtypes.
    - Passive: Disruption of visceral and parietal pleura (e.g., pleural effusions, pneumothoraces).
    - Compression: Space-occupying lesion compresses lung (e.g., tumors, elevated diaphragm).
    - Adhesive: Diminished surfactant (infant respiratory distress syndrome, ARDS).
    - Cicatricial: Parenchymal scarring (tuberculosis, idiopathic pulmonary fibrosis).
- Radiographic Appearance:
  - Linear or Plate-like: Thin, wide, parallel to diaphragm or perpendicular to pleural surface.
  - Round Atelectasis: Associated with asbestos exposure, may appear as lung mass.
  - Segmental Atelectasis: Entire lung segment collapses, typically requires CT.
  - Lobar Atelectasis: Extreme form, usually from airway obstruction.
    - Radiographic findings: Ipsilateral hemidiaphragm elevation, mediastinal shift, juxtaphrenic peak sign.

Right Upper Lobe: Collapses superiorly and medially.
Right Middle Lobe: Minimal impact, noticeable by volume reduction or shadow over heart on lateral film.
Right Lower Lobe: Collapses posterior medially, wedge-shaped opacity.
Left Upper Lobe: Collapses anteriorly, can be medially or interposed by left lower lobe (Luftsickle sign).
Left Lower Lobe: Collapses posterior medially and inferiorly, triangular opacity.

Central Lines: Intravenous catheters in central veins (IJ, subclavian, femoral).
- PICC Lines: Introduced in peripheral vein to central circulation.
- Optimal placement: Tip at SVC and right atrium junction.
Pulmonary Artery Catheters (Swann-Gans): Advanced to pulmonary circulation.
- Assess position: Tip no more than 3cm from midline.
Endotracheal Tubes: For mechanical ventilation; tip about 5cm above carina.
Nasogastric Tubes: Enter via nares, advance to stomach; confirm by x-ray.
Chest Tubes: Drain effusion/empyema or treat pneumothorax.
Ports: Subcutaneous reservoirs for ongoing chemotherapy.
Telemetry Electrodes: Identifiable by wires.

Pacemakers: Single or dual chamber; generator near shoulder, leads to heart.
- Biventricular Pacemaker: Includes lead to coronary sinus for left ventricle.
ICD (Implantable Cardioverter Defibrillator): For arrhythmias, identifiable by coils.
Atrial Septal Defect Closure Device: Appears as metal flower on x-ray.
Implantable Loop Recorder: Captures arrhythmias.
LVAD (Left Ventricular Assist Device): Supports failing heart.

Pneumothorax: From implantation procedure.
Cardiac Perforation: Lead advanced through myocardium.
Lead Fracture: Occurs near clavicle, first rib.
Twiddler's Syndrome: Patient causes lead displacement by rotating pacemaker.

Sternotomy Wires: Twisted clips seen on x-ray.
Prosthetic Heart Valves: Various types, including mechanical and bioprosthetic.
- Identification of valve position: Aortic vs. Mitral.
Methods to Identify Valve Position:
- Profile on PA film for aortic (end-on) and mitral (on face).
- Apparent blood flow direction.
- Cardiac silhouette bisection method.

Deep Brain Stimulator: For Parkinson's disease treatment, visible on x-ray.
Breast Implants: Unilateral implants may be mistaken for pathology in certain cases.

Importance of accurately assessing chest x-rays for lines, tubes, devices, and surgical evidence.
Next video will provide practice x-rays and review overall approach.