Doctor123.org

Noncardiogenic Pulmonary Edema, Emergency Medicine

Basics

Description

- 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

- 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.

  • 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 HgOften apparent from the clinical circumstancesThe concentration of protein in the alveolar fluid is identical to that of the intravascular space in patients with NCPECephalad redistribution of blood flow, pulmonary effusions, and cardiomegaly are usually not present
  • Adult respiratory distress syndrome:Clinical presentation caused by permeability pulmonary edemaAssociated 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:SepsisPneumoniaNonthoracic traumaInhaled toxinsDisseminated 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 failureLower-extremity swellingCardiomegaly

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 ventilationDecreases work of breathingUse low tidal volumes of 6 " “8mL/kg to reduce barotrauma to the lungsInitially 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)