Pulmonary edema
| Pulmonary edema | |
|---|---|
| Specialty | Pulmonology, cardiology, medical emergency  |
Pulmonary edema (American English), or oedema (British English; both words from the Greek Template:Polytonic), is fluid accumulation in the lungs.[1] It leads to impaired gas exchange and may cause respiratory failure. It is due to either failure of the heart to remove fluid from the lung circulation ("cardiogenic pulmonary edema") or a direct injury to the lung parenchyma ("noncardiogenic pulmonary edema").[2] Treatment depends on the cause, but focuses on maximizing respiratory function and removing the cause.
Signs and symptoms
Symptoms of pulmonary edema include difficulty breathing, coughing up blood, excessive sweating, anxiety, and pale skin. A classic sign of pulmonary edema is the production of pink frothy sputum. If left untreated, it can lead to coma and even death, in general, due to its main complication of hypoxia. If pulmonary edema has been developing gradually, symptoms of fluid overload may be elicited. These include nocturia (frequent urination at night), ankle edema (swelling of the legs, in general, of the "pitting" variety, wherein the skin is slow to return to normal when pressed upon), orthopnea (inability to lie down flat due to breathlessness), and paroxysmal nocturnal dyspnea (episodes of severe sudden breathlessness at night).
Diagnosis
In general, pulmonary edema is suspected due to findings in the medical history, such as previous cardiovascular disease, and physical examination: End-inspiratory crackles (sounds heard at the end of a deep breath) on auscultation are characteristic for pulmonary edema. The presence of a third heart sound (S3) is predictive of cardiogenic pulmonary edema.[2].
In general, blood tests are performed for electrolytes (sodium, potassium) and markers of renal function (creatinine, urea). Liver enzymes, inflammatory markers (usually C-reactive protein) and a complete blood count as well as coagulation studies (PT, aPTT) are typically requested. B-type natriuretic peptide (BNP) is available in many hospitals, sometimes even as a point-of-care test. Low levels of BNP (<100 pg/ml) make a cardiac cause very unlikely.[2]
The diagnosis is confirmed on X-ray of the lungs, which shows increased fluid in the alveolar walls. Kerley B lines, increased vascular filling, pleural effusions, upper lobe diversion (increased blood flow to the higher parts of the lung) may be indicative of cardiogenic pulmonary edema, whereas patchy alveolar infiltrates with air bronchograms are more indicative of noncardiogenic edema[2]
Low oxygen saturation and disturbed arterial blood gas readings may strengthen the diagnosis and provide grounds for various forms of treatment. If urgent echocardiography is available, this may strengthen the diagnosis, as well as identify valvular heart disease. In rare occasions, insertion of a Swan-Ganz catheter may be required to distinguish between the two main forms of pulmonary edema.[2]
Causes
Pulmonary edema is either due to direct damage to the tissue or a result of inadequate functioning of the heart or circulatory system.
When directly or indirectly caused by increased pulmonary blood pressure, pulmonary edema may appear when this pressure increases from the normal 15 mmHg[3] to above 25 mmHg.[4]
Cardiogenic
- Congestive heart failure
- Severe heart attack with left ventricular failure
- Severe arrhythmias (tachycardia/fast heartbeat or bradycardia/slow heartbeat)
- Hypertensive crisis
- Pericardial effusion with tamponade
- Fluid overload, e.g., from kidney failure or intravenous therapy
Non-cardiogenic
May occur after upper airway obstruction, intravenous fluid overload, neurogenic causes (seizures, head trauma, strangulation, electrocution). Can also be seen with ARDS (adult respiratory distress syndrome):
Alveolar
- Inhalation of toxic gases
- Pulmonary contusion, i.e., high-energy trauma
- Aspiration, e.g., gastric fluid or in case of drowning
- Reexpansion, i.e. post [[large volume thoracentesis, resolution of pneumothorax, post decortication, removal of endobronchial obstruction
- Reperfusion injury, i.e. postpulmonary thromboendartectomy or lung transplantation
- Immersion pulmonary edema[5][6]
- Multiple blood transfusions
- Severe infection
Other/unknown
- Multitrauma, e.g., severe car accident
- Neurogenic, e.g., subarachnoid hemorrhage
- Certain types of medication, illicit drug use
- Upper airway obstruction, i.e. negative pressure pulmonary edema[7][8]
- Arteriovenous malformation
- Hantavirus pulmonary syndrome
- Ascent to high altitude occasionally causes high altitude pulmonary edema (HAPE)[9][10]
Management
Focus is initially on maintaining adequate oxygenation. The patient is given high-flow oxygen, noninvasive ventilation (either continuous positive airway pressure (CPAP) or variable positive airway pressure (VPAP)[11][12]) or mechanical ventilation and PEEP in very severe cases.
When circulatory causes have led to pulmonary edema, treatment with intravenous nitrates (glyceryl trinitrate), and loop diuretics, such as furosemide or bumetanide, is the mainstay of therapy. These improve both preload and afterload, and aid in improving cardiac function.
Sildenafil is used as a preventative treatment for altitude-induced pulmonary edema[13][14], although the mechanism of action is not known.[citation needed] While this effect has only recently been discovered, sildenafil is already becoming an accepted treatment for this condition, in particular in situations where the standard treatment of rapid descent has been delayed for some reason.[15]
References
- ^ "pulmonary edema" at Dorland's Medical Dictionary
- ^ a b c d e Ware LB, Matthay MA. Acute pulmonary edema. N Engl J Med 2005;353:2788-96. PMID 16382065.
- ^ What Is Pulmonary Hypertension? From Diseases and Conditions Index (DCI). National Heart, Lung, and Blood Institute. Last updated September 2008. Retrieved on 6 April, 2009.
- ^ Chapter 41, page 210 in: Cardiology secrets By Olivia Vynn Adair Edition: 2, illustrated Published by Elsevier Health Sciences, 2001 ISBN 1560534206, 9781560534204
- ^ Hampson NB, Dunford RG (1997). "Pulmonary edema of scuba divers". Undersea Hyperb Med. 24 (1): 29–33. PMID 9068153. Retrieved 2008-09-04.
- ^ Cochard G, Arvieux J, Lacour JM, Madouas G, Mongredien H, Arvieux CC (2005). "Pulmonary edema in scuba divers: recurrence and fatal outcome". Undersea Hyperb Med. 32 (1): 39–44. PMID 15796313. Retrieved 2008-09-04.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Fremont RD, Kallet RH, Matthay MA, Ware LB (2007). "Postobstructive pulmonary edema: a case for hydrostatic mechanisms". Chest. 131 (6): 1742–6. doi:10.1378/chest.06-2934. PMC 2783608. PMID 17413051. Retrieved 2008-09-04.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Chuang YC, Wang CH, Lin YS (2007). "Negative pressure pulmonary edema: report of three cases and review of the literature". Eur Arch Otorhinolaryngol. 264 (9): 1113–6. doi:10.1007/s00405-007-0379-9. PMID 17598119.
{{cite journal}}:|access-date=requires|url=(help); Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Luks AM (2008). "Do we have a "best practice" for treating high altitude pulmonary edema?". High Alt. Med. Biol. 9 (2): 111–4. doi:10.1089/ham.2008.1017. PMID 18578641.
{{cite journal}}:|access-date=requires|url=(help) - ^ Bates, M (2007). "High altitude pulmonary edema". Altitude Physiology Expeditions. Retrieved 2008-09-04.
- ^ Masip J, Roque M, Sánchez B, Fernández R, Subirana M, Expósito JA (2005). "Noninvasive ventilation in acute cardiogenic pulmonary edema: systematic review and meta-analysis". JAMA. 294 (24): 3124–30. doi:10.1001/jama.294.24.3124. PMID 16380593.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Peter JV, Moran JL, Phillips-Hughes J, Graham P, Bersten AD (2006). "Effect of non-invasive positive pressure ventilation (NIPPV) on mortality in patients with acute cardiogenic pulmonary oedema: a meta-analysis". Lancet. 367 (9517): 1155–63. doi:10.1016/S0140-6736(06)68506-1. PMID 16616558.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Richalet JP, Gratadour P, Robach P; et al. (2005). "Sildenafil inhibits altitude-induced hypoxemia and pulmonary hypertension". Am. J. Respir. Crit. Care Med. 171 (3): 275–81. doi:10.1164/rccm.200406-804OC. PMID 15516532.
{{cite journal}}: Explicit use of et al. in:|author=(help)CS1 maint: multiple names: authors list (link) - ^ Perimenis P (2005). "Sildenafil for the treatment of altitude-induced hypoxaemia". Expert Opin Pharmacother. 6 (5): 835–7. doi:10.1517/14656566.6.5.835. PMID 15934909.
- ^ Fagenholz PJ, Gutman JA, Murray AF, Harris NS (2007). "Treatment of high altitude pulmonary edema at 4240 m in Nepal". High Alt. Med. Biol. 8 (2): 139–46. doi:10.1089/ham.2007.3055. PMID 17584008.
{{cite journal}}: CS1 maint: multiple names: authors list (link)
See also
External links
- HeartFailureMatters.org Animation showing How Heart Failure causes Fluid Accumulation - Created by the European Heart Failure Association