Lecture 1: Diagnostic & Therapeutic Skills

Question 1

At what age is PFT indicated?

Answer 1

5 and older.

Question 2

What is acrocyanosis?

Answer 2

Cyanosis of the extremities

Question 3

What kind of condition is PFT usually tested in?

Answer 3

• Chronic lung conditions with respiratory symptoms.
• Rib fracture

Generally not for things like pneumonia.

Can be done for things like a rib fracture, which are acute but can impair pulmonary function as a secondary complication.

Question 4

What is a normal total lung capacity? (TLC)

Answer 4

6L

Question 5

How are lung reserve volumes calculated?

Answer 5

IRV: Air inspired ABOVE the tidal volume.
ERV: Air exhaled BELOW the tidal volume.

Neither calculation includes tidal volume itself.

Question 6

What is spirometry generally indicated for?

Answer 6

• Diagnosis/monitoring of lung/neuromuscular disease.
• Preventing post-surgical pulmonary complications.

Encourages people to take deep breath to prevent alveolar collapse.

Question 7

What people should avoid spirometry?

Answer 7

• Recent abdominal/intracranial/eye surgery or pneumothorax
• Aneurysms
• Unstable angina/recent MI
• Acute severe asthma, acute respiratory distress, active TB

Mimics valsalva, which can open abdominal wounds or increase ICP.

Question 8

What is a normal FEV1/FVC ratio?

Answer 8

70% or more.

Less than 0.7 generally implies COPD.

Normal implies normal or restrictive lung disease.

Question 9

What is gold standard testing for PFTs? Indication?

Answer 9

Plethysmography

Decreased FVC on spirometry.

Question 10

Why is plethysmography used?

Answer 10

Measures TLC because the chamber is enclosed and the residual lung volume can be measured as well.

Question 11

Define obstructive vs restrictive lung disease.

Answer 11

• Obstructive: Difficulty EXHALING air.
• Restrictive: Difficulty INHALING air.

Question 12

For an adult, what increases imply a positive response to bronchodilator therapy? Child?

Answer 12

• Increases in FEV1 > 12%
• Increases in FVC > 0.2L

Both must be present.

5-18: Does not require FVC change.

Question 13

How do flow volume loops differ between obstructive and restrictive lung disease?

Answer 13

• Obstructive: expiration flow rate should be LOW. Inspiration is partially impaired.
• Restrictive: Inspiration flow rate should be LOW. Expiration is partially impaired. Impaired TLC.

Question 14

What factor is restrictive lung disease graded by?

Answer 14

TLC

Question 15

What factor is obstructive lung disease graded by?

Answer 15

FEV1

Question 16

How is diffusing capacity measured? (DLco)

Answer 16

Inhalation of carbon monoxide and tracer. Amount exhaled = did not diffuse.

Example: 15% exhaled = 85% diffusing capacity.

Question 17

What is the most sensitive PFT?

Answer 17

DLco

Question 18

What is considered a passing 6MWT?

Answer 18

Flat surface walking for 6 minutes at 95%+ pulse ox with 1200-2300 ft walked.

Question 19

What is peak flow used for?

Answer 19

Monitoring asthmatic’s peak expiratory flow rate to determine asthma control.

Non-invasive, simple, at home.

Question 20

Why is ETCO2 preferred over O2 sats?

Answer 20

ETCO2 will rise almost 1 minute prior to O2 drop, which can signal hypoxia sooner.

Question 21

What are the 4 phases of a CO2 waveform?

Answer 21

1. Dead space ventilation
2. Ascending phase (exhalation)
3. Alveolar phase (uniform exhalation)
4. Inspiration (inhaling)

Question 22

What does elevated ETCO2 imply?

Answer 22

Hypercapnia.

Implies hypoventilation.

Question 23

How is an asthmatic’s CO2 waveform altered?

Answer 23

Rounded part in ascending phase and an upward sloping alveolar plateau.

Shark-fin deformity

Question 24

When are sputum cultures indicated for pneumonia?

Answer 24

• IP admission for pneumonia
• OP failure of empiric ABX for pneumonia

Question 25

What is the primary disadvantage of CT scanning?

Answer 25

Radiation exposure is much higher with a CT than with a single XR. | mSv ## Footnote Example: CXR: 0.1 mSv (10 days of natural radiation) CT Chest: 7 mSv (2 years of natural radiation)

Question 26

What food allergy should be checked prior to contrast injection?

Answer 26

Seafood/shellfish because iodine is often a contrast agent.

Question 27

What is the difference between a CTA and a CT Chest with contrast?

Answer 27

CTA only highlights vascular structures. CT Chest with contrast will show both tissue and vascular structures.

Question 28

When is a VQ scan indicated?

Answer 28

R/o PE when CT is contraindicated. | AKA CT is PREFERRED first-line test. ## Footnote It is not more sensitive. It is primarily in pregnant patients.

Question 29

What exactly does a VQ scan measure?

Answer 29

Detects poor blood flow in pulmonary vasculature (perfusion) and uneven air distribution (ventilation).

Question 30

Describe the VQ scan procedure.

Answer 30

1. Inhalation of radioactive material to image airflow in lungs. (ventilation) 2. Injection of radioactive material to assess vasculature. (perfusion)

Question 31

What would a VQ scan look like for a suspected PE?

Answer 31

Question 32

What is the main pitfall of a VQ scan?

Answer 32

Unable to identify a blood clot. It simply reveals that blood flow is impaired in general.

Question 33

Describe the 3 types of abnormal VQ scans.

Answer 33

1. Abnormal ventilation, normal perfusion: COPD or asthma. 2. Normal ventilation, abnormal perfusion: PE. 3. Abnormal ventilation, abnormal perfusion: Any of above + pneumonia.

Question 34

What are the biggest risks with a VQ scan?

Answer 34

* Radioactive breastmilk for 24 hours. * Allergic reaction: MC urticaria

Question 35

What is the definitive/gold standard test for acute PE?

Answer 35

Pulmonary angiography. | Invasive test, not indicated first-line.

Question 36

What does a negative pulmonary angiography indicate?

Answer 36

Excludes clinically relevant PEs.

Question 37

When is pulmonary angiography indicated over CTA?

Answer 37

* Nondiagnostic CTA. * Gold standard for PE. ## Footnote Otherwise, CTA is preferred.

Question 38

What are the two types of bronchoscopes and the differences?

Answer 38

* Flexible: MC, using procedural sedation. * Rigid: using general anesthesia

Question 39

When is bronchoscopy indicated?

Answer 39

* Evaluation and removal of airway foreign bodies * Diagnosing and staging bronchogenic carcinoma * Hemoptysis * Pulmonary infections * Transbronchial lung biopsy * Bronchoalveolar lavage

Question 40

What is the main contraindication to bronchoscopy?

Answer 40

Severe bronchospasms or bleeding diathesis. | Diathesis = tendency to suffer from a medical condition.