W11. Lectures 9-11 CVP

What are chest radiographs primarily used for?

They are the predominant diagnostic test used to identify anatomic abnormalities and pathologic processes in the chest.

What is another name for a radiograph?

A roentgenogram.

What are the main objects seen on a chest radiograph?

Air, fat, water, tissues, and bone.

How do air and bone appear on a chest radiograph?

Air appears dark, while bone appears white.

What are the 2 standard views in a routine chest radiograph?

PA and left lateral views.

What are some other chest radiograph views besides PA and lateral?

Decubitus, lordotic, oblique, and bedside AP views.

How do X-rays create an image of internal structures?

They use high-energy photons, with dense structures blocking photons and appearing white, while less dense areas let photons pass and appear dark.

Why do lungs usually appear dark on a chest X-ray?

Because they are filled with air, which allows more photons to pass through.

What does the ABCDEFG checklist help with in chest X-ray interpretation?

It provides a systematic approach to evaluating the image.

In the ABCDEFG approach, what does A stand for?

Assessment and Air.

What should be checked first under Assessment on a chest X-ray?

Patient ID, date, and study type.

How do you check for patient rotation on a chest X-ray?

The medial clavicles should be equidistant from the spinous processes.

How do you judge adequate inspiration on a chest X-ray?

About 9-11 posterior ribs should be visible.

How do you judge adequate penetration on a chest X-ray?

Pulmonary vessels should be visible all the way to the lung edges.

What does “extra air” mean on a chest X-ray?

Air present where it should not be.

What should be ruled out if extra air is seen on a chest X-ray?

Pneumothorax, pneumoperitoneum, and tracheal deviation.

In the ABCDEFG approach, what does B stand for?

Bones and Body Wall.

What should be checked under Bones and Body Wall on a chest X-ray?

The clavicles, all 12 pairs of ribs for fractures, and the soft tissues for swelling or masses.

In the ABCDEFG approach, what does C stand for?

Cardiac silhouette.

What is the normal size limit for the cardiac silhouette on a chest X-ray?

The heart should be less than 50% of the total chest width.

On a chest radiograph, where is the right atrium seen?

On the film’s left side.

On a chest radiograph, where is the left ventricle seen?

On the film’s right side.

In the ABCDEFG approach, what does D stand for?

Diaphragm.

What is the normal appearance of the diaphragms on a chest X-ray?

They should be symmetric and curved, with the right typically slightly higher than the left.

What should the costophrenic angles look like on a normal chest X-ray?

They should be sharp.

In the ABCDEFG approach, what does E stand for?

Equipment and Effusions.

What should be checked when evaluating equipment on a chest X-ray?

Where it is relative to other structures and whether it is in the correct functional position.

Where should an endotracheal tube tip be located on a chest X-ray?

More than 2 cm above the carina.

Where should an NG tube be located on a chest X-ray?

In the stomach.

How do pleural effusions commonly appear on a chest X-ray?

As fluid that blunts the costophrenic angles.

In the ABCDEFG approach, what does F stand for?

Fields, meaning the lungs.

What should the lung fields look like on a normal chest X-ray?

They should be symmetric, without haziness, white dots, or blotches.

What can lighter areas or opacities in the lung fields indicate?

Blood, pus, or water.

In the ABCDEFG approach, what does G stand for?

Great vessels.

Which great vessels should be checked on a chest X-ray?

The aorta, pulmonary artery, superior vena cava, and inferior vena cava.

How wide should the aorta normally appear compared with the thoracic spine?

It should be just wider than the T-spine.

What can deviation in the great vessels suggest?

Congenital abnormality or disease.

What were the practice pathologies listed in these notes for chest X-ray interpretation?

Right middle lobe pulmonary fibrosis, pneumonia, and rapid clearance of CHF.

How does CT compare with chest radiography?

CT is more sensitive than chest X-ray.

What is CT especially good for in chest imaging?

Localizing disease and detecting occult pneumothorax.

What is the basic principle behind MRI?

It involves the interaction of stimulated hydrogen nuclei with a strong magnetic field.

What is MRI mainly indicated for in chest imaging?

Evaluation of chest wall processes.

When might MRI be used after an abnormal chest radiograph?

When the chest radiograph shows a nodule or mass.

What is bronchography?

A study that uses contrast to evaluate bronchial anatomy and gross pathologic changes in the bronchial wall and lumen.

What does bronchography allow clinicians to study?

Normal and variant bronchial anatomy and gross pathologic changes.

What is a V/Q scan?

A nuclear imaging test that measures the ventilation/perfusion ratio.

What is the normal average V/Q ratio?

About 0.80.

What is the main clinical use of a V/Q scan?

Diagnosing pulmonary embolism.

What does a V/Q scan require?

Radioactive isotopes.

Which radioactive isotopes are mentioned for V/Q scanning?

Technetium and xenon.

In one sentence, how do dense structures appear on chest X-ray?

Dense structures such as bone appear white because they block more photons.

In one sentence, how do low-density structures appear on chest X-ray?

Low-density structures such as air-filled lungs appear dark because they allow more photons through.

What bedside chest X-ray view is often used for hospitalized patients who cannot stand?

AP view at bedside.

Why is a systematic approach like ABCDEFG important in chest X-ray reading?

It helps ensure important abnormalities are not missed.

What might blunting of the costophrenic angles suggest?

Pleural effusion.

What might tracheal deviation on chest X-ray suggest?

Extra air, pressure changes, or other chest pathology.

Why is image quality important before interpreting a chest X-ray?

Poor rotation, poor inspiration, or poor penetration can make the film misleading.

What is the key heart size rule on chest radiograph?

The cardiac silhouette should be less than half the width of the chest.

Which hemidiaphragm is usually higher on a normal chest X-ray?

The right hemidiaphragm.

What kind of abnormalities might haziness or blotches in the lungs represent?

Infiltrates or opacities from fluid, blood, or pus.

If the vessels cannot be seen to the lung edges, what image quality issue should you suspect?

Poor penetration.

If fewer than 9 posterior ribs are visible, what image quality issue should you suspect?

Inadequate inspiration.

If the clavicles are not equidistant from the spinous processes, what image quality issue should you suspect?

Rotation.

What makes CT better than chest X-ray for occult pneumothorax?

CT is more sensitive and can detect abnormalities that a chest X-ray may miss.

What type of chest problem is MRI especially helpful for?

Chest wall processes and evaluation of nodules or masses seen on radiograph.

In one sentence, what is the main purpose of bronchography?

To evaluate bronchial anatomy and pathologic changes in the bronchial wall and lumen using contrast.

In one sentence, what is the main purpose of a V/Q scan?

To assess ventilation-perfusion mismatch, most commonly when pulmonary embolism is suspected.

What does ECMO stand for?

Extracorporeal Membrane Oxygenation.

What does “extracorporeal” mean in ECMO?

It means the process occurs outside the body.

What is the core function of an ECMO machine?

It acts like a pair of lungs by removing blood from the patient, adding oxygen, removing carbon dioxide, and returning oxygenated blood.

What four basic things does ECMO do to the blood?

It removes blood, adds oxygen, removes carbon dioxide, and returns oxygenated blood to the patient.

Which type of ECMO is most common?

Veno-venous (VV) ECMO.

When was VV ECMO originally popularized?

In the 1970s.

What patient group first commonly used VV ECMO?

Neonates, especially premature babies with poor lung function.

Why were neonates a major early use for VV ECMO?

Because the lungs are the last organs to fully develop before birth, so premature babies may have poor lung function.

In VV ECMO, where is blood taken from and where is it returned?

Blood is taken from a vein and returned to a vein.

What must a patient have for VV ECMO to work?

A working heart.

Why must the heart still work in VV ECMO?

Because VV ECMO only bypasses the lungs, not the heart.

What happened to neonatal survival rates with VV ECMO?

Survival improved from about 20% to nearly 80%.

What is the main modern adult use of VV ECMO?

ARDS and other forms of respiratory failure.

What is the main goal of VV ECMO in adults?

To give the lungs a break so the underlying pulmonary problem can heal.

What usually happens to patients after VV ECMO supports their lungs?

They are gradually weaned off as native lung function returns.

What does VA ECMO stand for?

Veno-arterial ECMO.

In VA ECMO, where is blood taken from and where is it returned?

Blood is taken from a vein and returned to an artery.

What kind of support does VA ECMO provide?

Both respiratory and circulatory support.

Why does VA ECMO support the heart?

Because oxygenated blood is returned to the arterial system under pressure, helping circulation.

Which type of ECMO is most relevant in ACLS and cardiac arrest situations?

VA ECMO.

What is the key difference between VV and VA ECMO?

VV ECMO supports the lungs only, while VA ECMO supports both the heart and lungs.

Which ECMO type is used for lung support only?

VV ECMO.

Which ECMO type is used for both heart and lung support?

VA ECMO.

What is the main current criterion for considering ECMO in emergency settings?

The presence of an underlying cause that is reversible.

Are there firm national criteria yet for ECMO use in cardiac arrest?

No, not yet.

What does ECMO “buy time” for?

It buys time for clinicians to fix the underlying problem and restore native function.

What is required to run ECMO in emergency situations?

A dedicated ECMO machine and a specialized team ready to act immediately.

What are “ECMO alerts”?

A possible future system where hospitals activate ECMO responses like stroke or heart alerts for arrests not responding to standard treatment.

Why is ECMO considered an evolving field in emergency care?

Because its use in settings like cardiac arrest is still developing and national criteria are not firmly established.

In one sentence, what does VV ECMO do?

VV ECMO bypasses the lungs to provide respiratory support only.

In one sentence, what does VA ECMO do?

VA ECMO bypasses the lungs and also supports circulation, providing both heart and lung support.

What type of ECMO would be more appropriate for isolated severe respiratory failure with a functioning heart?

VV ECMO.

What type of ECMO would be more appropriate for cardiac arrest or combined heart-lung failure?

VA ECMO.