Basic Chest X-Ray Interpretation

Different tissues in our body absorb X-rays at different extents:

– Bone- high absorption (white)

– Tissue- somewhere in the middle absorption (grey)

– Air- low absorption (black)

Systematic CXR Interpretation

• IDENTIFICATION

• TECHNIQUE

• INTERPRETATION

Systematic CXR Interpretation

• IDENTIFICATION

– Correct patient

– Correct date & time

– Correct examination• Right vs. Left side (gastric bubble)• Comparison film.

Systematic CXR Interpretation

• IDENTIFICATION

• TECHNIQUE

• INTERPRETATION

• TECHNIQUE

– Complete exam

• All views

• Entire anatomical area included.

Systematic CXR Interpretation

TECHNIQUE, cont.– Projection or Quality of the film:

• First determine is the film a PA or AP view.

• PA- the x-rays penetrate through the back of the patient on to the film.

• AP-the x-rays penetrate through the front of the patient on to the film.

The width of heart & mediastinum larger on AP film.

• All x-rays in the ICU are portable and are AP view

Systematic CXR Interpretation

TECHNIQUE, cont.

― Position

• Erect.

• Supine.

• Lateral position.

Systematic CXR Interpretation

Systematic CXR Interpretation• TECHNIQUE, cont.

– Penetration• Over-penetrated dark films can

obscure subtle pathologies.

• Under-penetrated white films may given impression of diffuse increased density.

Is the film over or under penetrated?

• If under penetrated you will not be able to see the thoracic vertebrae.

• TECHNIQUE, cont.

― Adequacy (full Inspiration)• Normal, erect, inspiratory CXR shows

9.5-10.5 posterior ribs.• Less inspiration appears diffusely

denser• Diaphragms elevated causing heart &

mediastinum to appear enlarged.

Systematic CXR Interpretation

Systematic CXR Interpretation

• TECHNIQUE, cont.

―Rotation• Determine by observing the equal

distance between the medial clavicular head and the spinous process of the thoracic vertebral body.

Systematic CXR Interpretation

• IDENTIFICATION

• TECHNIQUE

• INTERPRETATION

INTERPRETATION Extraneous material

Contrast Lines, tubes, clips All properly located?

Bones Fracture, dislocation Mineralization

Soft tissues Asymmetry Calcifications

Systematic CXR Interpretation

INTERPRETATION Diaphragms & Below

Free air Dilated bowel Abnormal position

Lung fields & mediastinum Asymmetry , central mediastinum Consolidation (opacity), nodule or

lesion Vascular marking.

Heart Size & shape Cardiothoracic ratio

Systematic CXR Interpretation

CONSOLIDATION

CONSOLIDATION

Congestive Heart Failure

TENSION PNEUMOTHORAX

Air under the diaphragm

ARTERIAL BLOOD GAS

Arterial Blood Gas

Definition

• Blood gases is a measurement of how much oxygen (O2) and carbon dioxide (CO2) is in your blood.

• It also determines the acidity (pH) of your blood.

Arterial Blood Gas

Why the Test is Performed ?

To evaluate respiratory diseases and conditions that affect the lungs.

It helps determine the effectiveness of oxygen therapy.

Arterial Blood GasHow the Test is Performed? Usually, blood is taken from an artery.

The blood may be collected from the radial artery in the wrist, the femoral artery in the groin, or the brachial artery in the arm.

May test circulation to the hand before taking a sample of blood from the wrist area.

Insert a small needle through the skin into the artery

(You can use (anesthesia) applied to the site before the test begins).

How the Test is Performed

In rare cases, blood from a vein may be used.

After the blood is taken, pressure is applied to the site for a few minutes to stop the bleeding.

Watch the site for signs of bleeding or circulation problems.

The sample must be quickly sent to a laboratory for analysis to ensure accurate results.

Arterial Blood Gas

How to Prepare for the Test

There is no special preparation.

If you are on oxygen therapy, the oxygen concentration must remain constant for 20 minutes before the test.

Arterial Blood Gas

How the Test Will Feel

You may feel brief cramping or throbbing at the puncture site

Arterial Blood Gas

Risks There is very little risk when the

procedure is done correctly.

Veins and arteries vary in size from one patient to another and from one side of the body to the other.

Taking blood from some people may be more difficult than from others.

Arterial Blood Gas

Other risks associated with this test may include:

Bleeding at the puncture site Blood flow problems at puncture site (rare) Bruising at the puncture site Delayed bleeding at the puncture site Fainting or feeling light-headed Hematoma (blood accumulating under the skin) Infection (a slight risk any time the skin is

broken)

Arterial Blood Gas

Arterial Blood Gas