Basics
Description
- Noncardiogenic pulmonary edema (NCPE) occurs secondary to accumulation of excess fluid and protein into the alveoli from factors other than increased pulmonary capillary pressure >18 mm Hg
- Permeability pulmonary edema:
- Functional disruption of the capillary " “alveolar membrane allows protein and fluid to move freely from the intravascular space into the alveolar space
- Pulmonary parenchymal changes are similar to CHF
- Concomitant CHF may occur in up to 20% of patients with acute respiratory distress syndrome (ARDS)
- Distinction between NCPE and CHF:
- Pulmonary capillary pressure ≤18 mm Hg
- Often apparent from the clinical circumstances
- The concentration of protein in the alveolar fluid is identical to that of the intravascular space in patients with NCPE
- Cephalad redistribution of blood flow, pulmonary effusions, and cardiomegaly are usually not present
- Adult respiratory distress syndrome:
- Clinical presentation caused by permeability pulmonary edema
- Associated with severe physiologic impairment
- Typically, onset of the edema is within 1 " “2 hr of the noxious insult.
- ¢ ˆ ¼250,000 cases occur each year in US
Etiology
- ARDS is the #1 cause:
- Caused by:
- Sepsis
- Pneumonia
- Nonthoracic trauma
- Inhaled toxins
- Disseminated intravascular coagulation (DIC)
- Radiation pneumonitis
- High-altitude pulmonary edema (HAPE) neurogenic pulmonary edema
- Narcotic overdose
- Pulmonary embolus
- Eclampsia
- Transfusion-related acute lung injury (TRALI)
- Re-expansion of a collapsed lung in patient with a pneumothorax
- Salicylate intoxication
- Inhaled cocaine use
- Near drowning
- HCTZ
- Uremia
- S/p cardiopulmonary bypass; especially if patient taking amiodarone
Diagnosis
Signs and Symptoms
- Shortness of breath
- Fatigue
- Weakness
- Cough
- Malaise
Physical Exam
- Scattered rhonchi and rales
- Hypoxia
- Dyspnea
- Tachypnea
- Accessory muscle use
- Tachycardia
- Pink, frothy sputum
- You will not see the stigmata of left- and right-sided heart failure
- Lower-extremity swelling
- Cardiomegaly
Essential Workup
- History and physical is usually enough to distinguish between cardiogenic and NCPE
- The CXR is essential in confirming the diagnosis and in assessing severity.
Diagnosis Tests & Interpretation
Lab
General lab abnormalities are not specific to NCPE. ‚
Imaging
CXR: ‚
- Initially can be normal
- Classic butterfly pattern of pulmonary edema
- Lack of cardiomegaly
Diagnostic Procedures/Surgery
Pulmonary artery catheter: ‚
- Pulmonary capillary wedge pressures normal or near-normal in contrast to elevated pressures with cardiogenic pulmonary edema
Differential Diagnosis
- Cardiogenic pulmonary edema
- Diffuse alveolar hemorrhage
- Diffuse dissemination of cancer such as with lymphoma or leukemia
- Chronic obstructive pulmonary disease exacerbation
- Pulmonary embolus
- Restrictive lung disease
- Pneumonia
Treatment
Pre-Hospital
- Patent airway
- Adequate oxygenation
- Cautions:
- Patients will typically not respond to usual measures to treat CHF.
Initial Stabilization/Therapy
- Supplemental oxygen (nasal cannula or nonrebreather)
- IV catheter
- Continuous cardiac monitor
- Continuous pulse oximetry
Ed Treatment/Procedures
- The treatment of NCPE is to treat underlying cause and give supportive care.
- Diuretics are not used.
- Noninvasive ventilatory support (BiPAP, CPAP) may be used if available and patient not in respiratory distress:
- If oxygenation or ventilation not improving with noninvasive, intubation is required
- Endotracheal intubation is often necessary:
- Improves oxygenation and ventilation
- Decreases work of breathing
- Use low tidal volumes of 6 " “8mL/kg to reduce barotrauma to the lungs
- Initially place on 100% O2:
- Measure PO2 and decrease FIO2 accordingly.
- Positive end-expiratory pressure (PEEP) of 5 " “10 cm H2O
- Steroids and cyclooxygenase inhibitors have not been proven effective.
- If at high altitude and concerned for HAPE, have the patient descend in elevation or put them in a hyperbaric chamber.
- Nifedipine is adjunctive therapy to O2 and descent.
Follow-Up
Disposition
Admission Criteria
All symptomatic patients should be admitted to ICU: ‚
- Symptoms may worsen at any point for up to 3 days after noxious insult.
Discharge Criteria
Asymptomatic patients (especially narcotic overdose, HAPE, or aspiration): ‚
- Observe in ED for 6 " “12 hr and then discharge with close follow-up scheduled if no evidence of pulmonary edema is present and adequate oxygenation is demonstrated.
Followup Recommendations
Patients, when discharged from the hospital, should seek medical follow-up within 48 hr. ‚
Pearls and Pitfalls
- Utilizing diuretics in the acute setting may worsen patient condition.
- Failure to distinguish between cardiogenic and noncardiogenic etiologies is a pitfall as treatment is different.
Additional Reading
- Fagenholz ‚ PJ, Gutman ‚ JA, Murray ‚ AF, et al. Treatment of high altitude pulmonary edema at 4240 m in Nepal. High Alt Med Biol. 2007;8(2):139 " “146.
- Putensen ‚ C, Theuerkauf ‚ N, Zinserling ‚ J, et al. Meta-analysis: Ventilation strategies and outcomes of the acute respiratory distress syndrome and acute lung injury. Ann Intern Med. 2009;151:566 " “576.
- Sigillito ‚ RJ, DeBlieux ‚ PM. Respiratory failure. In: Wolfson ‚ AB, Hendey ‚ GW, Ling ‚ LJ, et al., eds. Harwood-Nuss ' Clinical Practice of Emergency Medicine. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005.
- Ware ‚ LB, Matthay ‚ MA. Clinical practice. Acute pulmonary edema. N Engl J Med. 2005;353:2788 " “2796.
Codes
ICD9
- 506.4 Chronic respiratory conditions due to fumes and vapors
- 508.1 Chronic and other pulmonary manifestations due to radiation
- 508.9 Respiratory conditions due to unspecified external agent
- 993.2 Other and unspecified effects of high altitude
- 508.8 Respiratory conditions due to other specified external agents
- 994.1 Drowning and nonfatal submersion
ICD10
- J68.1 Pulmonary edema due to chemicals, gases, fumes and vapors
- J70.0 Acute pulmonary manifestations due to radiation
- J70.9 Respiratory conditions due to unspecified external agent
- T70.29XA Other effects of high altitude, initial encounter
- J70.8 Respiratory conditions due to oth external agents
- T75.1XXA Unsp effects of drowning and nonfatal submersion, init
SNOMED
- 95437004 Non-cardiogenic pulmonary edema (disorder)
- 286964001 Radiation respiratory disease (disorder)
- 10519008 Acute pulmonary edema due to fumes AND/OR vapors (disorder)
- 233707008 High altitude pulmonary edema (disorder)
- 233709006 toxic pulmonary edema (disorder)