Last updated:
May 14, 2008
Years published: 1989, 1993, 1995, 1996, 1999, 2003, 2004, 2017
NORD gratefully acknowledges Joshua M. Diamond, MD MSCE, Associate Medical Director, Lung Transplantation Program, and Assistant Professor of Medicine, Hospital of the University of Pennsylvania, Section of Advanced Lung Disease/Lung Transplant, for assistance in the preparation of this report.
Acute respiratory distress syndrome (ARDS) is a type of severe, acute lung dysfunction affecting all or most of both lungs that occurs as a result of illness or injury. Although it is sometimes called adult respiratory distress syndrome, it may also affect children. ARDS is a buildup of fluid in the small air sacs (alveoli) in the lungs. This makes it difficult for oxygen to get into the bloodstream. Major symptoms may include breathing difficulties (dyspnea), rapid breathing (tachypnea), excessively deep and rapid breathing (hyperventilation) and insufficient levels of oxygen in the circulating blood (hypoxemia). ARDS may develop in conjunction with widespread infection in the body (sepsis) or as a result of pneumonia, trauma, shock, severe burns, aspiration of food into the lung, multiple blood transfusions, and inhalation of toxic fumes, among other things. It usually develops within 24 to 48 hours after the original illness or injury and is considered a medical emergency. It may progress to involvement of other organs.
Typically, ARDS develops within 24 to 48 hours of the original illness or injury. It may become a life-threatening condition characterized by inflammation of the lungs, which may begin in one lung but eventually affects both, and leads to damage to the air sacs (alveoli) and surrounding small blood vessels. The damaged alveoli close down or fill up with fluid (lung edema), thereby losing their ability to oxygenate the blood and eliminate carbon dioxide. Patients experience increasingly severe respiratory distress, associated with decreasing oxygen levels in arterial blood and tissues.
With the fluid buildup, the lungs become heavy, stiff, and unable to expand properly. Most patients require mechanical ventilation because of respiratory failure. The disorder may also be accompanied or followed by impairment of other vital functions, including cardiovascular, renal, hepatic, hematologic, and neurologic functions. Involvement of other organs in addition to the lungs may lead to a condition sometimes called multi-organ dysfunction syndrome.
The person with ARDS may initially appear agitated as a result of breathing difficulty (rapid breathing or shortness of breath), but later may become lethargic and or even comatose. The patient may appear pale, and the hands and feet may have a bluish-gray tone because of the diminished level of oxygen in the blood
Typically, ARDS develops within 24 to 48 hours of the original illness or injury. It may become a life-threatening condition characterized by inflammation of the lungs, which may begin in one lung but eventually affects both, and leads to damage to the air sacs (alveoli) and surrounding small blood vessels. The damaged alveoli close down or fill up with fluid (lung edema), thereby losing their ability to oxygenate the blood and eliminate carbon dioxide. Patients experience increasingly severe respiratory distress, associated with decreasing oxygen levels in arterial blood and tissues.
With the fluid buildup, the lungs become heavy, stiff, and unable to expand properly. Most patients require mechanical ventilation because of respiratory failure. The disorder may also be accompanied or followed by impairment of other vital functions, including cardiovascular, renal, hepatic, hematologic, and neurologic functions. Involvement of other organs in addition to the lungs may lead to a condition sometimes called multi-organ dysfunction syndrome.
The person with ARDS may initially appear agitated as a result of breathing difficulty (rapid breathing or shortness of breath), but later may become lethargic and or even comatose. The patient may appear pale, and the hands and feet may have a bluish-gray tone because of the diminished level of oxygen in the blood
The incidence of ARDS varies widely, due to the different definitions of the disease, as well as demographic, cultural, and healthcare system related differences across countries. Acute respiratory distress syndrome can affect persons of any age who suffer acute injury or illness affecting the lungs. The incidence increases with age, ranging from 16 affected individuals per 100,000 persons aged 15-19 to 306 affected individuals per 100,000 persons between the ages of 75 and 84. There is no difference in the incidence between male and females when ARDS is associated with sepsis and most other causes. However, the incidence is slightly higher among females when trauma is the underlying cause leading to ARDS.
Despite our improving understanding of ARDS over the last 20 years, the in hospital mortality for this condition still remains 40-50%, with the majority of deaths occurring within the first few weeks of disease onset.
The diagnosis is based on the presence of respiratory distress accompanied by low levels of oxygen in the blood and the presence of known risk factors such as sepsis, pneumonia, or trauma. Chest x-rays will show fluid filling spaces that should be filled with air. The presence of fluid in the air sacs and the “wet” breathing sounds sometimes made by patients may suggest congestive heart failure but a medical examination will often distinguish between that condition and ARDS.
Treatment
Standard therapy consists of mechanical ventilation, supplemental oxygen, prone positioning, use of paralytics, fluid management and a technique called positive end expiratory pressure (PEEP) to help push the fluid out of air sacs. These are combined with continuing treatment of the original illness or injury.
Because people with ARDS are less able to fight lung infections, they may develop bacterial pneumonia during the course of the illness. Antibiotics are given to fight infection. Also, supportive treatment such as intravenous fluid or food may be needed. If other organ systems become involved, measures may be needed to support those organs.
The introduction into standard practice of a recent recommendation to use smaller “tidal volumes” (the volume of each individual breath delivered by the ventilator) has resulted in improved survival outcomes. Earlier, ventilators were set to deliver 12 ml per kg of body weight. Now only 6 ml per kg of body weight are delivered. In addition, limiting the pressure delivered to the lung (driving pressure and plateau pressure) improves patient survival.
Several trials are currently ongoing evaluating experimental therapies for ARDS, including human mesenchymal stem cells and extracorporeal membrane oxygenation (ECMO).
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: [email protected]
For information about clinical trials sponsored by private sources, contact: www.centerwatch.com
For more information about clinical trials conducted in Europe, contact: https://www.clinicaltrialsregister.eu
JOURNAL ARTICLES
Villar J, Blanco J, Kacmarek RM. Current incidence and outcome of the acute respiratory distress syndrome. Curr Opin Crit Care. 2016 Feb;22(1):1-6.
Amato MB1, Meade MO, Slutsky AS, Brochard L, Costa EL, Schoenfeld DA, Stewart TE, Briel M, Talmor D, Mercat A, Richard JC, Carvalho CR, Brower RG. Driving pressure and survival in the acute respiratory distress syndrome. N Engl J Med. 2015 Feb 19;372(8):747-55.
Villar J, Sulemanji D, Kacmarek RM. The acute respiratory distress syndrome: incidence and mortality, has it changed? Curr Opin Cirt Care. 2014 Feb;20(1):3-9.
Guérin C, Reignier J, Richard JC, Beuret P, Gacouin A, Boulain T, Mercier E, Badet M, Mercat A, Baudin O, Clavel M, Chatellier D, Jaber S, Rosselli S, Mancebo J, Sirodot M, Hilbert G, Bengler C, Richecoeur J, Gainnier M, Bayle F, Bourdin G, Leray V, Girard R, Baboi L, Ayzac L; PROSEVA Study Group. Prone positioning in severe acute respiratory distress syndrome. N Engl J Med. 2013 June 5;368(23):2159-68.
Alhazzani W, Alshahrani M, Jaeschke R, Forel JM, Papazian L, Sevransky J, Meade MO. Neuromuscular blocking agents in acute respiratory distress syndrome: a systematic review and meta-analysis of randomized controlled trials. Crit Care. 2013 Mar 11;17(2):R43.
Papazian L, Forel JM, Gacouin A, Penot-Ragon C, Perrin G, Loundou A, Jaber S, Arnal JM, Perez D, Seghboyan JM, Constantin JM, Courant P, Lefrant JY, Guérin C, Prat G, Morange S, Roch A; ACURASYS Study Investigators. Neuromuscular blockers in early acute respiratory distress syndrome. N Engl J Med. 2010 Sep 16;363(12):1107-16.
Villar J1, Blanco J, Añón JM, Santos-Bouza A, Blanch L, Ambrós A, Gandía F, Carriedo D, Mosteiro F, Basaldúa S, Fernández RL, Kacmarek RM; ALIEN Network. The ALIEN study: incidence and outcome of acute respiratory distress syndrome in the era of lung protective ventilation. Intensive Care Med. 2011 Dec;37(12):1932-41.
Steinbrook R. How best to ventilate? Trial design and patient safety in studies of the acute respiratory distress syndrome. N Eng J Med. 2003;348:1393-1401.
Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. The Acute Respiratory Distress Syndrome Network. N Engl J Med. 2000 May 4:342(18):1301-8.
Said SI, Dickman KG. Pathways of inflammation and cell death in the lung: modulation by vasoactive intestinal peptide. Reg Pept. 2000;93:21-29.
Bernard GR. Efficacy and safety of recombinant human activated protein C for severe sepsis. N Eng J Med. 2000;344:699-709.
Tobin MJ. Culmination of an era in research on the actue respiratory distress syndrome. N Engl J Med. 2000;342:1360-61.
Ware LB, Marthay MA. The acute respiratory distress syndrome. N Engl J Med. 2000;342:1334-39.
Hudson LD, et al. Protective ventilation for patients with acute respiratory distress syndrome. N Eng J Med.1998;338:385-7.
Amato MBP, et al. Effect of a protective-ventilation strategy on mortality in the acute respiratory distress syndrome. N Eng J Med.1998;338:347-54.
Weg JG, et al. The relation of pneumothorax and other air leaks to mortality in the acute respiratory distress syndrome. N Eng J Med.1998;338:341-6.
Beal AL, Cerra FB. Multiple organ failure syndrome in the 1990s: systemic inflammatory response and organ dysfunction. JAMA 1994;271:226-33.
Villar J, Slutsky AS. The incidence of the adult respiratory distress syndrome. Am Rev Respir Dis 1989;140:814-16.
INTERNET
Harman Eloise M. Acute Respiratory Distress Syndrome. Medscape. Last Update August 11, 2016. https://emedicine.medscape.com/article/165139-overview#a5. Accessed November 28, 2016
ARDS. American Lung Association. Last Update April 1, 2016. https://www.lung.org/lung-health-and-diseases/lung-diseases-lookup/ards/learn-about-ards.html. Accessed November 28, 2016.
Hadjiliadis Denis. Acute respiratory distress syndrome. Medline Plus. Last Update November 19, 2015. https://medlineplus.gov/ency/article/000103.htm. Accessed November 28, 2016.
Acute respiratory distress syndrome. Genetic and Rare Diseases Information Center (GARD). Last Update 5/17/2012. https://rarediseases.info.nih.gov/diseases/5698/acute-respiratory-distress-syndrome. Accessed November 28, 2016.
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