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
- Failing heart > pulm edema > stress response > incr afterload
- 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[1]
- 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 generous PEEP and diuretics
Differential Diagnosis
Acute dyspnea
Emergent
- Pulmonary
- Airway obstruction
- Anaphylaxis
- Angioedema
- Aspiration
- Asthma
- Cor pulmonale
- Inhalation exposure
- Noncardiogenic pulmonary edema
- Pneumonia
- Pneumocystis Pneumonia (PCP)
- Pulmonary embolism
- Pulmonary hypertension
- Tension pneumothorax
- Idiopathic pulmonary fibrosis acute exacerbation
- Cystic fibrosis exacerbation
- Cardiac
- Other Associated with Normal/↑ Respiratory Effort
- Other Associated with ↓ Respiratory Effort
Non-Emergent
- ALS
- Ascites
- Uncorrected ASD
- Congenital heart disease
- COPD exacerbation
- Fever
- Hyperventilation
- Interstitial lung disease
- Neoplasm
- Obesity
- Panic attack
- Pleural effusion
- Polymyositis
- Porphyria
- Pregnancy
- Rib fracture
- Spontaneous pneumothorax
- Thyroid Disease
- URI
Treatment
- CPAP/BiPAP with PEEP 6-8; titrate up to PEEP of 10-12
- Nitroglycerin
- Dosing Options
- Sublingual 0.4 mg q5min
- Nitropaste (better bioavailability than oral Nitroglycerin)
- Intravenous: 0.1mcg/kg/min - 5mcg/kg/min
- Dosing Options
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
- Morphine is no longer recommended do to increased morbidity
See Also
References
- ↑ Bhaskar B, Fraser JF. Negative pressure pulmonary edema revisited: Pathophysiology and review of management. Saudi J Anaesth. 2011 Jul-Sep; 5(3): 308–313.