Based on 2 concepts
- Increased hydrostatic pressure
- Decreased oncotic pressure
- Upright films will detect effusions >400mL
- Lateral decubitus films will detect as little as 50mL of fluid
- Order: cell count, gram stain, culture, pH, protein, LDH
Exudate vs transudate - use Light's Criteria
- Treat the underlying pathology!
- Avoid large volume taps (>1L) if CHF, renal or hepatic pathology
- Unstable - septic shock, tension hydropneumothorax
- If tapping:
- Avoid NV bundle
- Have patient lean over table
- Use ultrasound
- When to tap:
- Typically, these patients will not need a tap or tube in the ED.
- If patients have persistent hypoxia in spite of other interventions, consider tap.
- Severe respiratory failure.
Rare - air embolism, sheared catheter loss