pulm diagnostics

Question 1

why order PFTs

Answer 1

Differentiate cause of patient’s dyspnea/cough symptoms
Response to bronchodilators/treatment
Differentiate between Restrictive and Obstructive pulmonary defects
Preoperative

Question 2

PFT c/i

Answer 2

Pain with deep breathing
Uncooperative patients
Recent MI or unstable angina
Thoracic or abdominal aneurysm
Recent surgery

Question 3

FVC

Answer 3

The amount of air that can be forcefully expelled from a maximally inflated lung
Independent risk factor for early death in COPD patients if ↓
↓ in obstructive
↓ ↓ in restrictive

Question 4

FEV1

Answer 4

the amount of air expelled in the first second of the FVC
↓ in obstructive
Total FEV₁ is ↓ in restrictive, but if you took it as a percentage of the ↓ FVC, it I proportionally normal. [FEV₁/FVC = normal]

Question 5

TV

Answer 5

amount of air that goes in and out with normal respirations

Question 6

obstructive lung disease

Answer 6

FEV₁ (more decreased) and FVC both ↓
These patients are really slow at getting the air out
increased compliance
COPD
Asthma
Bronchiectasis

Question 7

restrictive lung disease

Answer 7

FVC really ↓; FEV₁ also ↓ but with a normal ratio
Can get air out quick; just don’t have that much to start with
decreased compliance
Pneumonia
Pulmonary Fibrosis
Connective Tissue Diseases
Acute Respiratory Distress Syndrome
Pulmonary Vascular Disease

Question 8

FEV1/FVC

Answer 8

this ratio is usually <0.70 in obstructive lung disease
This ratio is usually NORMAL (0.75-0.85) in normal lungs and in restrictive lung disease

Question 9

PFT prep

Answer 9

No bronchodilators for 6 hours before test
No smoking for 6 hours before test
Measure height/weight to ensure predicted normal values are accurate

Question 10

peak flow

Answer 10

measures how fast or slow you can blow air out of your lungs (equal to FEV1)
Can have patient record baseline at home regularly until baseline is established OR can use expected baseline
BEST approach is to have patients measure baseline at home
Can also use online calculator (MDCALC)
Safe for discharge home if Peak flow is 60-80% of expected after treatment
mild=<70%
moderate=40-69%
severe=<40%

Question 11

thoracentesis

Answer 11

Insertion of needle into the pleural space for removal of fluid

Diagnostic Indications:
Analyze fluid to determine etiology of effusion

Needle is placed through chest wall, into the fluid contained in the pleural cavity. One-way valve allows fluid to be aspirated when syringe plunger is pulled back

Therapeutic Indications:
Relieve pain and dyspnea

Usually only if accumulations > 1 liter

Lateral decubitus CXR: > 1 cm distance to fluid level from chest wall

Question 12

empyema

Answer 12

purulent
clear at top after centrifuge

Question 13

chylous

Answer 13

milk after centrifuge
pearly appearance

Usually due problem with lymphatic drainage of the pleural space

Damaged during surgery
Local pressure due to tumor

Question 14

bloody

Answer 14

trauma
malignancy
infection
PE w/ infarction
infections

Question 15

transudative

Answer 15

straw-colored

Usually due to a systemic process
Usually layers out on CXR
Often bilateral

Leakage of fluid from intact capillaries due to vascular pressure changes or underlying problem with low protein

CHF – most common
Cirrhosis
Nephrotic syndrome
Hypoproteinemia
PE

Question 16

exudative

Answer 16

thicker
yellow

Pleural fluid protein/serum protein ratio > 0.5

Pleural fluid LDH/serum LDH ratio > 0.6

Pleural fluid LDH > 2/3 upper limit of normal for serum LDH

Usually due to a local process
Often loculated, doesn’t layer on CXR
Often unilateral

Release of fluid due leaky blood vessels from the underlying process

Inflammatory
Infectious conditions
Neoplastic conditions
Trauma
PE

Most common are pneumonia and cancer