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
Systematic CXR 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
• 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.
Systematic CXR Interpretation
•
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
•
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
Systematic CXR 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
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 Gas
How 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).
Arterial Blood Gas
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:






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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