Pulmonary edema

Background

• Cardiogenic vs Non-Cardiogenic (ARDS/Altitude/Neurogenic)
• Mechanism of Cardiogenic
  • Failing heart > pulm edema > stress response > incr afterload
    • Incr afterload > incr pulm edema
• Pts often intravascularly depleted; avoid diuretics!

Diagnosis

• Crackles
• Respiratory distress

Specific types

• Negative pressure pulmonary edema
  • Forced inspiration against obstructed airway causes large negative intrathoracic pressure, leading to pulmonary edema
  • Mostly due to postoperative laryngospasm, sudden drops in PEEP (high PEEP to manual BVM), trauma such as hanging, strangulation, foreign bodies, etc.
  • Diagnosis
    • Hypoxemia (may be sudden and large - beware "fake" or "not real" SpO2), stridor, retractions, accessory muscle use, crackles/wheezes
    • CXR shows diffuse interstitial and alveolar infiltrates
    • CT shows preferential central/nondependent distribution of edema (as opposed to other forms of pulmonary edema)
  • Treatment
    • Relieve airway obstruction
    • Vent with PEEP and diuretics

Treatment

1. CPAP/BiPAP with PEEP 6-8; titrate up to PEEP of 10-12
2. Nitroglycerin
   1. Dosing Options
      1. Sublingual 0.4 mg q5min
      2. Nitropaste (better bioavailability than oral Nitroglycerin)
      3. Intravenous: 0.1mcg/kg/min - 5mcg/kg/min

Generally start IV Nitroglycerin 50mcg/min and titrate rapidly (150mcg/min or higher)to symptom relief

• If NTG fails to reduce BP consider nitroprusside (reduces both preload and afterload) or ACE-inhibitiors (preload reducer)
• After pt improves titrate down NTG as enaliprilat (0.625 - 1.25mg IV) or captopril are started

See Also

• Congestive Heart Failure (CHF)
• Acute Respiratory Distress Syndrome

Source

Tintinalli

EMCrit Podcast 1