Intro to Pulmonary Diagnostics

Question 0

Pulmonary mechanics of inspiration

Answer 0

Intercostal muscles and diaphragm contract Lungs expand Air drawn in

Question 1

What is the only artery in the body that carries deoxygenated blood?

Answer 1

Pulmonary artery

Question 2

Pulmonary mechanics of expiration

Answer 2

Passive process Depends on elastic recoil of lungs

Question 3

Airway obstruction.

Answer 3

Asthma Chronic bronchitis COPD Results in air trapping due to decreased expiratory flow

Question 4

Fingernail clubbing

Answer 4

Many causes including -lung cancer -TB -Cystic Fibrosis -Endocarditis

Question 5

CXR

Answer 5

Common indications -pneumonia -pneumothorax -CHF Noninvasive Low radiation exposure Cost: $200-350

Question 6

Pulmonary function testing

Answer 6

Spirometry -measures volume and speed of airflow on inspiration and expiration. Used to diagnose and assess asthma, COPD, pulmonary fibrosis Noninvasive, safe

Question 7

CT scan of the chest

Answer 7

Used to diagnose -PE -pneumonia -aortic dissection -lung cancer Much higher sensitivity than a CXR Higher radiation (100-400X) Higher cost ($1800)

Question 8

Spiral CT

Answer 8

Continuous, rotating beam Quicker, higher resolution than conventional CT

Question 9

Multirow CT

Answer 9

Latest generation of CT Thinner slices, improved resolution

Question 10

CT for PE

Answer 10

CT is the preferred study to assess for PE because it is highly sensitive and non-invasive

With IV contrast

Look for filling filling defects in pulmonary arteries or branches

Will also show alternate causes of sxs

Question 11

Ventilation/perfusion scan

Answer 11

(V/Q Scan)

Also used to asses for PE when important to reduce radiation exposure or when contrast can’t be administered (renal dz/allergy)

Ventilation: radionuclide inhaled to assess ability of air to reach all parts of lungs

Perfusion: IV radionuclide to assess blood circulation

V/Q Mismatch: where normal airflow, but impaired perfusion

Results can be normal, low probability, intermediate probability, or high probability

Low or intermediate probability cannot r/o PE

Question 12

Pulmonary Angiography

Answer 12

Diagnose PE

Insert catheter under fluoro into pulmonary arteries and inject dye

Invasive, higher risk.

Same sensntivity as CT so has largely been replaced

Question 13

D-Dimer

Answer 13

Fibrin degredation product released by a clot

Elevated with PE, DVT

If pt has low to moderate risk of PE and has normal D-Dimer, can r/o PE

Very sensitive (95%), but not very specific (50%)

False positives with: inflammation, cancer, pregnancy, advanced age, trauma

Question 14

Sputum Culture

Answer 14

Used to identify specific organism causing pneumonia

May be contaminated by oral flora

Question 15

WBC

Answer 15

Often, but not always, elevated with pneumonia

Neither sensitive nor specific

Question 16

Bronchoscopy

Answer 16

Fiberoptic scope to view airways

Search for tumors, foreign bodies, source of hemoptysis

Obtain biopsies

Low risk

Question 17

During a PA CXR, which way does the patient stand?

Answer 17

The rays flow from posterior to anterior, with the anterior chest closest to the film.

Question 18

During a lateral CXR, which way does the patient stand?

Answer 18

With their left side up against the film.

Question 19

AP CXR

Answer 19

Usual portable technique

Heart shadow is magnefied

Often times, the patient is also supine:

DIaphragms are higher, lung volume is decreased

Question 20

Lateral decubitus CXR

Answer 20

Patient lying on side

Useful for detecting pleural effusion

Question 21

Densities

Answer 21

Lead > Mineral > Soft Tissues > Fluid > Fat > Air

Mineral–very dense, appears white

• calcifications, bone

Soft tissues

• muscle, mediastinal structures

Fluid

• Heart, vessels

Fat

• Breasts

Air

• Lungs, gastric bubble, trachea, bronchi

Question 22

CXR Reading Method

Answer 22

Label: pt’s name, age, sex

Orientation: R vs L side

Technique: Penetration, rotation, inspiration

Interpretation

Question 23

Proper penetration

Answer 23

Should barely be able to see outline of vertebral bodies within heart shadow down to diaphragm

Bronchovascular structures should be visible

On lateral films: Vertebral bodies should darken as you move caudally because more air in lower lobes

Question 24

Rotation

Answer 24

Make sure clavicular heads are equal distance from spinous processes Rotated film can distort appearance of heart and mediastinum

Question 25

Inspiration

Answer 25

CXR should be shot at full inspiration Should be able to count 8-10 posterior ribs

Question 26

General things to interpret on CXR

Answer 26

Heart and great vessels Lungs Soft tissues Bones

Question 27

Heart and Great Vessels

Answer 27

Cardiac silhouette normally 1/2 or less of thoracic width on PA Check aortic knob, mediastinal width, SVC

Question 28

Lungs | (CXR Interpretation)

Answer 28

Lung fields: * Infiltrate, atelectasis * Nodules, mass * Pneumothorax Vasculature * Hilar and pulmonary vessels * Peripheral vasculature--seen in lateral 1" of lung, clearer in lower fields on upright films Costophrenic Angle * Pleural effusion blunts angle * Right diaphragm higher than left

Question 29

Soft Tissues

Answer 29

* Breasts * Chest wall * Neck * Mediastinum * trachea should be midline * identify tracheal bifurcation * look for mediastinal widening * hilar mass or lymphadenopathy

Question 30

Bones

Answer 30

Look for lesions or fractures of: clavicles scapulae humeri and shoulder joints ribs spine

Question 31

Silhouette Sign

Answer 31

If a pulmonary opacity is in contact with the heart border, then the heart border will be obscured Commonly seen with **RML** and **left lingular infiltrates**

Question 32

CXR Findings in CHF

Answer 32

Cardiomegaly Cephalization of pulmonary flow Interstitial Edema-lungs whited out Kerley B Lines Fluid in fissures Pulmonary Edema Pleural Effusions-blunted costophrenic angles

Question 33

Cephalization of Pulmonary Flow

Answer 33

Normally pulmonary blood flow is more prominent in dependent areas of lung (near bases) When congested it is also prominent toward head

Question 34

Kerley B Lines

Answer 34

Short, horizontal lines found in lower lung periphery Seen MC'ly in CHF

Question 35

Pneumothorax

Answer 35

Lung space is black, with area where lung is pronounced and shriveled Subtly, a pleural line can be noted where the lung has separated from cavity

Question 36

Tension Pneumothorax

Answer 36

Life-threatening L mediastinal shift, decreased venous return (can kink aorta and vena cava) May rapidly lead to cardiac arrest Needs emergent needle thoracotomy

Question 37

COPD Changes

Answer 37

Diffuse hyperinflation with flattening of diaphragms

Question 38

Atelectasis

Answer 38

Collapse or incomplete expansion of part of the lung Linear or curvilinear increased density on CXR, often associated with volume loss May see elevated diaphragm because lung collapses on itself

Question 39

Solitary Pulmonary Nodule

Answer 39

Can be innocuous or malignant More likely to be benign if calcified Try to compare to previous CXR Consider CT/biopsy to evaluate

Question 40

Pulmonary Mass

Answer 40

Well-defined opacity Suspicious for malignancy