PFT
Normal Values:
FEV1
TLC
FEV/TLC
Flow volume loops
Airway Obstructions
Fixed Airway Obstruction:
- e.g. tumor
Variable extrathoracic: - restrictive only on inhalation (e.g. vocal cord paralysis)
COPD
emphysema (parenchymal disease) and/or chronic bronchitis (small airways)
usually a mix of both clinically
Pulmonary Hypertension
Diagnostic Criteria: mPAP>20mmHg
Most common cause: group 2
Effusions
Effusion is exudative if one of the following are met:
- Pleural fluid-to-serum protein ratio > 0.5
- Pleural fluid-to-serum LDH ratio > 0.6
- Pleural fluid LDH > 0.67 (i.e. two-thirds) the upper limits of the laboratory’s normal serum LDH
Otherwise: Transudative
How to remember:
- fluid/serum
| Pleural Effusion | Pneumothorax | Consolidative Pneumonia | |
|---|---|---|---|
| Ausculation | decreased/absent | decreased/absent | adventitious |
| Percussion | dull | hyperresonant | dull |
| Tactile Fremitus | decreased/absent | decreased/absent | increased |
| Whispered Pectoriloquy | absent | absent | increased |
| Egophony | absent | absent | present (E→A) |
Interstitial Lung Disease
Features:
- Poor exercise tolerance / low O2 stores
- end point is irreversible fibrosis
- trajectories differ; protect from pulmonary insults (vaccines!)
Idiopathic Pulmonary Fibrosis
- honeycombing, starts in bases
- dry crackles
Sarcoidosis
- **multisystem granulomatous disease with a fairly stereotyped clinical pattern.
- Diagnostic: noncaseating granulomas on biopsy
Most common features:
- Bilateral hilar lymphadenopathy (most classic finding)
- Pulmonary involvement (dry cough, dyspnea, interstitial infiltrates)
- Erythema nodosum (tender red nodules on shins)
- Anterior uveitis (eye pain, photophobia, blurred vision)
- Hypercalcemia (↑ vitamin D activation by granulomas)
Pneumoconiosis
| Disease | Exposure | Key finding | Big complication |
|---|---|---|---|
| Silicosis | Sand, mining, glass | Upper lobe fibrosis + eggshell hilar nodes | ↑ TB risk |
| Coal worker pneumoconiosis | Coal mining | Upper lobe “black lung” nodules | Progressive massive fibrosis |
| Asbestosis | Shipyards, insulation | Lower lobe fibrosis + pleural plaques | Mesothelioma / lung cancer |
ARDS
- refractory hypoxia
- acid-base abnormalities
- respiratory alkslosis
- metabolic acidosis
Berlin definition
Hyaline Membrane Disease
- lack of surfactant in newborns
Risks
- <28 weeks
Signs:
- tachypnea / cyanosis / grunting
Treatment: - O2
- CPAP
- Surfactant administration
Obstructive Sleep Apnea
OSA vs OHS