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| {{Infobox_Disease | | {{Infobox_Disease |
| | Name = Pulmonary contusion | | | Name = Pulmonary contusion |
| | Image = Pulmonary contusion CT arrow.jpg | | | Image = Pulmonary contusion CT arrow.jpg |
| | Caption = A [[CT scan]] showing a pulmonary contusion (red arrow) accompanied by a [[rib fracture]] (blue arrow) | | | Caption = A [[CT scan]] showing a pulmonary contusion (red arrow) accompanied by a [[rib fracture]] (blue arrow) |
| | DiseasesDB =
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| | ICD10 = {{ICD10|S|27|3|s|20}}
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| | ICD9 = {{ICD9|861.21}}, {{ICD9|861.31}}
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| | ICDO = <!--n/a-->
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| | OMIM = <!--n/a-->
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| | MedlinePlus =
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| | eMedicineSubj =
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| | eMedicineTopic =
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| | MeshID =
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| }} | | }} |
| {{SI}} | | {{Pulmonary contusion}} |
| {{CMG}} | | {{CMG}} |
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| {{EH}}
| | ==[[Pulmonary contusion overview|Overview]]== |
| | | ==[[Pulmonary contusion historical perspective|Historical Perspective]]== |
| ==Overview==
| | ==[[Pulmonary contusion classification|Classification]]== |
| A '''pulmonary contusion''' (or '''lung contusion''') is a contusion ([[bruise]]) of the [[lung]], caused by [[chest trauma]]. As a result of damage to [[capillary|capillaries]], blood and other fluids accumulate in the lung tissue. The excess fluid interferes with [[gas exchange]], potentially leading to inadequate oxygen levels ([[hypoxia (medical)|hypoxia]]). Unlike [[pulmonary laceration]], another type of lung injury, pulmonary contusion does not involve a cut or tear of the lung tissue.
| | ==[[Pulmonary contusion pathophysiology |Pathophysiology]]== |
| | | ==[[Pulmonary contusion causes|Causes]]== |
| ==Pathophysiology==
| | ==[[Pulmonary contusion differential diagnosis|Differentiating Pulmonary contusion from other Diseases]]== |
| A pulmonary contusion usually is caused by [[blunt trauma]] but also is caused by explosions or a [[shock wave]] associated with [[penetrating trauma]]. With the use of explosives during World Wars I and II, pulmonary contusion resulting from blasts gained recognition. In the 1960s its occurrence began to receive wider recognition in civilians, for whom it is usually caused by traffic accidents. The use of seat belts and airbags reduces the risk to vehicle occupants.
| | ==[[Pulmonary contusion epidemiology and demographics|Epidemiology and Demographics]]== |
| | | ==[[Pulmonary contusion natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| ==Diagnosis==
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| ===Signs and symptoms===
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| Clues from how the injury occurred, [[physical examination]] and [[Chest X-ray|chest radiography]] are used in the diagnosis. Typical signs and symptoms include direct effects of the physical trauma, such as chest pain and [[Hemoptysis|coughing up blood]], as well as signs that the body is not receiving enough oxygen, such as [[cyanosis]]. The contusion frequently heals on its own with supportive care. Often nothing more than supplemental oxygen and close monitoring is needed; however, [[intensive care]] may be required. For example, if breathing is severely compromised, [[mechanical ventilation]] may be required. [[Fluid replacement]] may be needed to ensure adequate blood volume, but fluids are given carefully since [[fluid overload]] can worsen [[pulmonary edema]], which may be lethal.
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| ==Epidemiology==
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| The severity ranges from mild to deadly—small contusions may have little or no impact on the patient's health—yet pulmonary contusion is the most common type of potentially lethal chest trauma. It occurs in 30–75% of severe chest injuries. With an estimated mortality rate of 14–40%, pulmonary contusion plays a key role in determining whether an individual will die or suffer serious ill effects as the result of trauma. Pulmonary contusion is usually accompanied by other injuries. Although associated injuries are often the cause of death, pulmonary contusion is thought to cause death directly in a quarter to half of cases. Children are at especially high risk for the injury because the relative flexibility of their bones prevents the chest wall from absorbing force from an impact, causing it to be transmitted instead to the lung. Pulmonary contusion is associated with complications including [[pneumonia]] and [[acute respiratory distress syndrome]], and it can cause long-term respiratory disability.
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| ==Classification==
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| [[Image:Alveolus diagram.png|thumb|left|The alveoli]]
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| Pulmonary contusion and laceration are injuries to the lung tissue. [[Pulmonary laceration]], in which lung tissue is torn or cut, differs from pulmonary contusion in that the former involves disruption of the [[macroscopic]] architecture of the lung,<ref name="Collins07">{{cite book | author=Collins J, Stern EJ | title=Chest Radiology: The Essentials | isbn=0781763142 | publisher=Lippincott Williams & Wilkins | year= 2007 | page=120 }}</ref> while the latter does not.<ref name="Wicky00"/> When lacerations fill with blood, the result is [[pulmonary hematoma]], a collection of blood within the lung tissue.<ref name="White991">{{cite book | author=Stern EJ, White C | title=Chest Radiology Companion | publisher=Lippincott Williams & Wilkins | location=Hagerstown, MD | year=1999 | pages=103 | isbn=0-397-51732-7 }}</ref> Contusion involves hemorrhage in the [[pulmonary alveolus|alveoli]] (tiny air-filled sacs responsible for absorbing oxygen), but a [[hematoma]] is a discrete clot of blood not interspersed with lung tissue.<ref name="Moore03">{{cite book | chapter=Trauma to the chest wall and lung | author=Livingston DH, Hauser CJ | title=Trauma. Fifth Edition | editor=Moore EE, Feliciano DV, Mattox KL | year=2003 | publisher=McGraw-Hill Professional | isbn=0071370692 | pages=525–528 }}</ref> A collapsed lung can result when the [[pleural cavity]] (the space outside the lung) accumulates blood ([[hemothorax]]) or air ([[pneumothorax]]) or both ([[hemopneumothorax]]). These conditions do not inherently involve damage to the lung tissue itself, but they may be associated with it. Injuries to the chest wall are also distinct from but may be associated with lung injuries. Chest wall injuries include [[rib fracture]]s and [[flail chest]], in which multiple ribs are broken so that a segment of the ribcage is detached from the rest of the chest wall and moves independently.
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| ==Signs and symptoms==
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| Presentation may be subtle; people with mild contusion may have no symptoms at all.<ref name="Costantino06"/> However, pulmonary contusion is frequently associated with [[Medical sign|signs]] (objective indications) and [[symptom]]s (subjective states), including those indicative of the lung injury itself and of accompanying injuries. Because gas exchange is impaired, signs of low blood [[oxygen saturation]], such as low concentrations of oxygen in [[arterial blood gas]] and [[cyanosis]] (bluish color of the skin and mucous membranes) are commonly associated.<ref name="mlr07"/> [[Dyspnea]] (painful breathing or difficulty breathing) is commonly seen,<ref name="mlr07"/> and tolerance for exercise may be lowered.<ref name="Wanek04"/> [[Tachypnea|Rapid breathing]] and [[tachycardia|a rapid heart rate]] are other signs.<ref name="Mick06">{{cite book |author=Mick NW, Peters JR, Egan D, Nadel ES, Walls R, Silvers S| chapter=Chest trauma| title=Blueprints Emergency Medicine. Second edition |publisher=Lippincott Williams & Wilkins|location=Philadelphia, PA |year=2006 |pages=76 |isbn=1-4051-0461-9}}</ref><ref name="Chang04">{{cite book |author=Coyer F, Ramsbotham J |chapter=Respiratory health breakdown |editor= Chang E, Daly J, Eliott D |title=Pathophysiology Applied to Nursing |publisher=Mosby Australia |location=Marrickville, NSW |year=2004 |pages=154–155 |isbn=0-7295-3743-9 }}</ref> With more severe contusions, [[breath sounds]] heard through a stethoscope may be decreased, or [[rales]] (an abnormal crackling sound in the chest accompanying breathing) may be present.<ref name="mlr07"/><ref name="Hood89"/> People with severe contusions may have [[bronchorrhea]] (the production of watery [[sputum]]).<ref name="Gavelli02">{{cite journal | author=Gavelli G, Canini R, Bertaccini P, Battista G, Bnà C, Fattori R | title=Traumatic injuries: Imaging of thoracic injuries | journal=European Radiology | volume=12 | issue=6 | pages=1273–1294 | year=2002 | month=June | pmid=12042932 | doi=10.1007/s00330-002-1439-6 }}</ref> Wheezing and coughing are other signs.<ref name="Yamamoto05">{{cite journal | author=Yamamoto L, Schroeder C, Morley D, Beliveau C | title=Thoracic trauma: The deadly dozen | journal=Critical Care Nursing Quarterly | volume=28 | issue=1 | pages=22–40 | year=2005 | pmid=15732422 }}</ref> [[hemoptysis|Coughing up blood]] or bloody sputum is present in up to half of cases.<ref name="Yamamoto05"/> [[Cardiac output]] (the volume of blood pumped by the heart) may be reduced,<ref name="Gavelli02"/> and [[hypotension]] (low blood pressure) is frequently present.<ref name="mlr07"/> The area of the chest wall near the contusion may be [[tenderness (medicine)|tender]]<ref name="Tovar08"/> or painful due to associated chest wall injury.
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| Signs and symptoms take time to develop, and as many as half of cases are [[asymptomatic]] at the initial presentation.<ref name="Costantino06">{{cite journal | author=Costantino M, Gosselin MV, Primack SL | title=The ABC's of thoracic trauma imaging | journal=Seminars in Roentgenology | volume=41 | issue=3 | pages=209–225 | year=2006 | month=July | pmid=16849051 | doi=10.1053/j.ro.2006.05.005 }}</ref> The more severe the injury, the more quickly symptoms become apparent. In severe cases, they may occur by three or four hours after the trauma.<ref name="Gavelli02"/> [[Hypoxemia]] (low oxygen concentration in the arterial blood) typically becomes progressively worse over 24–48 hours after injury.<ref name="Fabian07"/> In general, pulmonary contusion tends to worsen slowly over a few days,<ref name="Moore03"/> but it may also cause rapid deterioration.<ref name="mlr07"/>
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| ==Causes== | |
| [[Image:Crushed Saturn.jpg|thumb|left|Motor vehicle accidents are the most common cause of pulmonary contusion.]] | |
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| Pulmonary contusion, which occurs in 25–35% of all blunt chest trauma,<ref name="Moloney08"> | |
| {{
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| cite journal |author=Moloney JT, Fowler SJ, Chang W |title=Anesthetic management of thoracic trauma |journal=Current Opinion in Anaesthesiology |volume=21 |issue=1 |pages=41–46 |year=2008 |month=February |pmid=18195608 |doi=10.1097/ACO.0b013e3282f2aadc }}
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| </ref> is usually caused by the rapid deceleration that results when the moving chest strikes a fixed object.<ref name="Yamamoto05"/> About 70% of cases result from motor vehicle collisions,<ref name="ullman03"/> most often when the chest strikes the inside of the car.<ref name="mlr07"/> Falls,<ref name="ullman03">
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| {{
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| cite journal |author=Ullman EA, Donley LP, Brady WJ |title=Pulmonary trauma emergency department evaluation and management |journal=Emergency Medicine Clinics of North America |volume=21 |issue=2 |pages=291–313 |year=2003 |pmid=12793615 |doi=10.1016/S0733-8627(03)00016-6 }}
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| </ref> assaults,<ref name="Thomas03">
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| {{
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| cite book |author=Haley K, Schenkel K |chapter=Thoracic trauma|editor=Thomas DO, Bernardo LM, Herman B |title=Core curriculum for pediatric emergency nursing |publisher=Jones and Bartlett Publishers |location=Sudbury, Mass |year=2003 |pages=446 |isbn=0-7637-0176-9
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| }}
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| </ref> and sports injuries are other causes.<ref name="France03">
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| {{
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| cite book |title=Introduction to Sports Medicine and Athletic Training |chapter= The chest and abdomen |author=France R| year=2003 |publisher = Thomson Delmar Learning |page=506–507 |isbn=140181199X}}</ref> Pulmonary contusion can also be caused by explosions; the organs most vulnerable to [[blast injury|blast injuries]] are those that contain gas, such as the lungs.<ref name="CohnSM"/> Blast lung is severe pulmonary contusion, bleeding, or [[edema]] with damage to alveoli and blood vessels, or a combination of these.<ref name="Sasser06">
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| {{
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| cite journal |author=Sasser SM, Sattin RW, Hunt RC, Krohmer J |title=Blast lung injury |journal=Prehospital Emergency Care |volume=10 |issue=2 |pages=165–72 |year=2006 |pmid=16531371 |doi=10.1080/10903120500540912 }}</ref> This is the primary cause of death among people who initially survive an explosion.<ref name="Born05">
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| {{
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| cite journal |author=Born CT |title=Blast trauma: The fourth weapon of mass destruction |journal=Scandanavian Journal of Surgery |volume=94 |issue=4 |pages=279–285 |year=2005 |pmid=16425623 |url=http://www.fimnet.fi/sjs/articles/SJS42005-279.pdf |format=PDF}}
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| </ref>
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| In addition to [[blunt trauma]], [[penetrating trauma]] can cause pulmonary contusion.<ref name="Strange02">
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| {{
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| cite book |author= Lucid WA, Taylor TB |chapter=Thoracic trauma| editor=Strange GR |title=Pediatric Emergency Medicine: A Comprehensive Study Guide |publisher=McGraw-Hill, Medical Publishing Division |location=New York |year=2002 |pages=92–100 |isbn=0-07-136979-1
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| }}
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| </ref> Contusion resulting from penetration by a rapidly moving projectile usually surrounds the path along which the projectile traveled through the tissue.<ref name="Karmy02">{{cite book | chapter=Pulmonary contusion | author=Sattler S, Maier RV | editor=Karmy-Jones R, Nathens A, Stern EJ | title=Thoracic Trauma and Critical Care | publisher=Springer | location=Berlin | year=2002 | pages=159–160 and 235–243 | isbn=1-4020-7215-5}}</ref> The pressure wave forces tissue out of the way, creating a temporary [[cavitation|cavity]]; the tissue quickly moves back into place, but it is damaged. Pulmonary contusions that accompany gun and knife wounds are not usually severe enough to have a major effect on outcome;<ref name="White99"/> penetrating trauma causes less widespread lung damage than does blunt trauma.<ref name="ullman03"/> An exception is shotgun wounds, which can seriously damage large areas of lung tissue through a blast injury mechanism.<ref name="White99"/>
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| ==Mechanism== | |
| The physical processes behind pulmonary contusion are poorly understood. However, it is known that lung tissue can be crushed when the chest wall bends inward on impact.<ref name="Hwang96">{{cite journal | author=Hwang JCF, Hanowell LH, Grande CM | title=Peri-operative concerns in thoracic trauma | journal=Baillière's Clinical Anaesthesiology | volume=10 |issue=1 | pages=123–153 | doi=10.1016/S0950-3501(96)80009-2 | date=1996 }}</ref> Three other possible mechanisms have been suggested: the [[inertia]]l effect, the spalling effect, and the implosion effect.
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| *In the '''inertial effect''', the lighter alveolar tissue is sheared from the heavier [[hilum of lung|hilar]] structures, an effect similar to [[diffuse axonal injury]] in head injury.<ref name="Costantino06"/> It results from the fact that different tissues have different densities, and therefore different rates of acceleration or deceleration.<ref name="Hood89">
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| {{
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| cite book |author=Boyd AD|chapter=Lung injuries|editor= Hood RM, Boyd AD, Culliford AT |title=Thoracic Trauma |publisher=Saunders |location=Philadelphia |year=1989 |pages=153–155 |isbn=0-7216-2353-0
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| }}
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| </ref>
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| *In the '''spalling effect''', lung tissue bursts or is sheared where a shock wave meets the lung tissue, at interfaces between gas and liquid.<ref name="CohnSM"/> The alveolar walls form such a gas-liquid interface with the air in the alveoli.<ref name="Costantino06"/><ref name="Allen96">
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| {{
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| cite journal |author=Allen GS, Coates NE |title=Pulmonary contusion: A collective review |journal=The American Surgeon |volume=62 |issue=11 |pages=895–900 |year=1996 |month=November |pmid=8895709
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| }}
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| </ref> The spalling effect occurs in areas with large differences in density; particles of the denser tissue are spalled (thrown) into the less dense particles.<ref name="Maxson02">
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| {{
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| cite journal |author=Maxson TR |title=Management of pediatric trauma: Blast victims in a mass casualty incident |journal= Clinical Pediatric Emergency Medicine |volume= 3|issue=4 |pages=256–261 |year=2002 |doi= 10.1016/S1522-8401(02)90038-8
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| }}
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| </ref>
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| *The '''implosion effect''' occurs when a pressure wave passes through a tissue containing bubbles of gas: the bubbles first implode, then rebound and expand beyond their original volume.<ref name="Bridges06">
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| {{
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| cite journal |author=Bridges EJ |title=Blast injuries: From triage to critical care |journal=Critical Care Nursing Clinics of North America |volume=18 |issue=3 |pages=333–348 |year=2006 |month=September |pmid=16962455 |doi=10.1016/j.ccell.2006.05.005
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| }}
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| </ref> The air bubbles cause many tiny explosions, resulting in tissue damage;<ref name="Bridges06"/> the overexpansion of gas bubbles stretches and tears alveoli.<ref name="Matthay05"/><ref name="AllenCox98">
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| {{
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| cite journal |author=Allen GS, Cox CS |title=Pulmonary contusion in children: Diagnosis and management |journal=Southern Medical Journal |volume=91 |issue=12 |pages=1099–1106 |year=1998 |month=December |pmid=9853720
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| }}
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| </ref> This effect is thought to occur microscopically when the pressure in the airways increases sharply.<ref name="Hwang96">
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| {{
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| cite journal |author= Hwang JCF, Hanowell LH, Grande CM |title=Peri-operative concerns in thoracic trauma |journal= Baillière's Clinical Anaesthesiology |volume = 10 |issue = 1 |page=123–153 |doi= doi:10.1016/S0950-3501(96)80009-2 | date=1996
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| }}
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| </ref>
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| Contusion usually occurs on the lung directly under the site of impact, but, as with [[traumatic brain injury]], a [[Coup contrecoup injury|contrecoup]] contusion may occur at the site opposite the impact as well.<ref name="Karmy02"/> A blow to the front of the chest may cause contusion on the back of the lungs because a shock wave travels through the chest and hits the curved back of the chest wall; this reflects the energy onto the back of the lungs, concentrating it. (A similar mechanism may occur at the front of the lungs when the back is struck.)<ref name="AllenCox98"/>
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| The amount of energy transferred to the lung is determined in a large part by the compliance (flexibility) of the chest wall.<ref name="Karmy02"/> Children's chests are more flexible because their ribs are more elastic and there is less [[ossification]] of their intercostal [[cartilage]].<ref name="Tovar08"/> Therefore, their chest walls bend, absorbing less of the force and transmitting more of it to the underlying organs.<ref name="Tovar08"/><ref name="Sartorelli04">
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| {{
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| cite journal |author=Sartorelli KH, Vane DW |title=The diagnosis and management of children with blunt injury of the chest |journal=Seminars in Pediatric Surgery |volume=13 |issue=2 |pages=98–105 |year=2004 |month=May |pmid=15362279 |doi=doi:10.1053/j.sempedsurg.2004.01.005
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| }}
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| </ref> An adult's more bony chest wall absorbs more of the force itself rather than transmitting it.<ref name="Sartorelli04"/> Thus children commonly get pulmonary contusions without fractures overlying them, while elderly people are more likely to suffer fractures than contusions.<ref name="Fabian07">{{cite book |author=Peitzman AB, Rhoades M, Schwab CW, Yealy DM, Fabian TC |title=The Trauma Manual: Trauma and Acute Care Surgery (Spiral Manual Series). Third Edition |publisher=Lippincott Williams & Wilkins |location=Hagerstown, MD |year=2007 |pages= 223 |isbn=0-7817-6275-8}} </ref><ref name="Karmy02"/> One study found that pulmonary contusions were accompanied by fractures 62% of the time in children and 80% of the time in adults.<ref name="AllenCox98"/>
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| ==Pathophysiology==
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| [[Image:Fluid-filled alveolus.png|thumb|left|Normally, oxygen and carbon dioxide diffuse across the capillary and alveolar membranes and the interstitial space (top). Fluid impairs this diffusion, resulting in less oxygenated blood (bottom).]]
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| Pulmonary contusion results in bleeding and fluid leakage into lung tissue, which can become stiffened and lose its normal elasticity. The water content of the lung increases over the first 72 hours after injury, potentially leading to frank [[pulmonary edema]] in more serious cases.<ref name="CohnSM"/> As a result of these and other pathological processes, pulmonary contusion progresses over time and can cause hypoxia (insufficient oxygen). | |
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| ===Bleeding and edema===
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| In contusions, torn [[capillary|capillaries]] leak fluid into the tissues around them.<ref name="Fleisher06">{{cite book |chapter=Thoracic trauma |editor=Fleisher GR, Ludwig S, Henretig FM, Ruddy RM, Silverman BK |title=Textbook of Pediatric Emergency Medicine |publisher=Lippincott Williams & Wilkins |location=Hagerstown, MD |year=2006 |pages=1434–1441 |isbn=0-7817-5074-1}}</ref> The membrane between alveoli and capillaries is torn; damage to this [[Alveolar-capillary barrier|capillary–alveolar membrane]] and small blood vessels causes blood and fluids to leak into the alveoli and the [[interstitial space]] (the space surrounding cells) of the lung.<ref name="Gavelli02"/> With more severe trauma, there is a greater amount of edema, bleeding, and tearing of the alveoli.<ref name="ullman03"/> Pulmonary contusion is characterized by [[hemorrhage|microhemorrhage]]s (tiny bleeds) that occur when the [[alveoli]] are traumatically separated from airway structures and blood vessels.<ref name="Karmy02"/> Blood initially collects in the interstitial space, and then edema occurs by an hour or two after injury.<ref name="Matthay05"/> An area of bleeding in the contused lung is commonly surrounded by an area of edema.<ref name="Karmy02"/> In normal [[gas exchange]], [[carbon dioxide]] [[diffusion|diffuses]] across the [[endothelium]] of the capillaries, the interstitial space, and across the alveolar epithelium; oxygen diffuses in the other direction. Fluid accumulation interferes with gas exchange,<ref name="Bailey06">{{cite book | author=Bailey BJ, Johnson JT, Newlands SD, Calhoun KS, Deskin RW | title=Head and Neck Surgery—Otolaryngology | publisher=Lippincott Williams & Wilkins | location=Hagerstown, MD | year=2006 | page=929 | isbn=0-7817-5561-1 }}</ref> and can cause the alveoli to fill with proteins and collapse due to edema and bleeding.<ref name="Karmy02"/> The larger the area of the injury, the more severe respiratory compromise will be.<ref name="ullman03"/>
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| ===Consolidation and collapse===
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| Pulmonary contusion can cause parts of the lung to [[consolidation (medicine)|consolidate]], alveoli to collapse, and [[atelectasis]] (partial or total lung collapse) to occur.<ref name="Keough01">{{cite journal |author=Keough V, Pudelek B |title=Blunt chest trauma: Review of selected pulmonary injuries focusing on pulmonary contusion |journal=AACN Clinical Issues |volume=12 |issue=2 |pages=270–281 |year=2001 |pmid=11759554}}</ref> Consolidation occurs when the parts of the lung that are normally filled with air fill with material from the pathological condition, such as blood.<ref name="Pryor98">{{cite book |author=Collins CD, Hansell DM |chapter=Thoracic imaging |editor=Pryor JA, Webber BR| title=Physiotherapy for Respiratory and Cardiac Problems |publisher=Churchill Livingstone |location=Edinburgh |year=1998 |pages= 35 |isbn=0-443-05841-5}}</ref> Over a period of hours after the injury, the alveoli in the injured area thicken and may become consolidated.<ref name="Karmy02"/> A decrease in the amount of [[surfactant]] produced also contributes to the collapse and consolidation of alveoli;<ref name="Moloney08"/> inactivation of surfactant increases their [[surface tension]].<ref name="AllenCox98"/> Reduced production of surfactant can also occur in surrounding tissue that was not originally injured.<ref name="Hwang96"/>
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| [[Inflammation]] of the lungs, which can result when components of blood enter the tissue due to contusion, can also cause parts of the lung to collapse. [[Macrophage]]s, [[neutrophils]], and other [[White blood cell|inflammatory cell]]s and blood components can enter the lung tissue and release factors that lead to inflammation, increasing the likelihood of respiratory failure.<ref name="Klein02"/> In response to inflammation, excess [[mucus]] is produced, potentially plugging parts of the lung and leading to their collapse.<ref name="Karmy02"/> Even when only one side of the chest is injured, inflammation may also affect the other lung.<ref name="Klein02"/> Uninjured lung tissue may develop edema, thickening of the septa of the alveoli, and other changes.<ref name="Bastos08"/> If this inflammation is severe enough, it can lead to dysfunction of the lungs like that seen in acute respiratory distress syndrome.<ref name="Sutyak07"/>
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| ===Ventilation/perfusion mismatch=== | |
| Normally, the [[Ventilation/perfusion ratio|ratio of ventilation to perfusion]] is about one-to-one; the volume of air entering the alveoli ([[ventilation (physiology)|ventilation]]) is about equal to that of blood in the capillaries around them ([[perfusion]]).<ref name="Prentice94">
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| {{
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| cite journal |author=Prentice D, Ahrens T |title=Pulmonary complications of trauma |journal=Critical Care Nursing Quarterly |volume=17 |issue=2 |pages=24–33 |year=1994 |month=August |pmid=8055358
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| }}
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| </ref> This ratio is reduced in pulmonary contusion; fluid-filled alveoli cannot fill with air, oxygen does not fully saturate the [[hemoglobin]], and the blood leaves the lung without being fully oxygenated.<ref name="Gwinnutt03">
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| {{
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| cite book |author=Kishen R, Lomas G |chapter=Thoracic trauma |editor=Gwinnutt CL, Driscoll P |title=Trauma Resuscitation: The Team Approach |publisher=Informa Healthcare |year=2003 |isbn=1-85996-009-X |pages=55–64
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| }}
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| </ref> Insufficient inflation of the lungs, which can result from inadequate mechanical ventilation or an associated injury such as flail chest, can also contribute to the ventilation/perfusion mismatch.<ref name="AllenCox98"/> As the mismatch between ventilation and perfusion grows, blood oxygen saturation is reduced.<ref name="Gwinnutt03"/> Pulmonary hypoxic vasoconstriction, in which blood vessels near the hypoxic alveoli [[vasoconstriction|constrict]] (narrow their diameter) in response to the lowered oxygen levels, can occur in pulmonary contusion.<ref name="Allen96"/> The [[vascular resistance]] increases in the contused part of the lung, leading to a decrease in the amount of blood that flows into it,<ref name="Bastos08"/> directing blood to better-ventilated areas.<ref name="Allen96"/> Although reducing blood flow to the unventilated alveoli is a way to compensate for the fact that blood passing unventilated alveoli is not oxygenated,<ref name="Allen96"/> the oxygenation of the blood remains lower than normal.<ref name="Prentice94"/> If it is severe enough, the hypoxemia resulting from fluid in the alveoli cannot be corrected just by giving supplemental oxygen; this problem is the cause of a large portion of the fatalities that result from trauma.<ref name="Gwinnutt03"/>
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| ==Diagnosis== | | ==Diagnosis== |
| | [[Pulmonary contusion history and symptoms|History and Symptoms]] | [[Pulmonary contusion physical examination|Physical Examination]] | [[Pulmonary contusion laboratory findings|Laboratory Findings]] | [[Pulmonary contusion chest x ray|Chest X Ray]] | [[Pulmonary contusion CT|CT]] | [[Pulmonary contusion other diagnostic studies|Other Diagnostic Studies]] |
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| To diagnose pulmonary contusion, health professionals use clues from a physical examination, information about the event that caused the injury, and [[radiography]].<ref name="ullman03"/> Laboratory findings may also be used; for example, arterial blood gasses may show insufficient oxygen and excessive carbon dioxide even in someone receiving supplemental oxygen.<ref name="Keough01"/> However, blood gas levels may show no abnormality early in the course of pulmonary contusion.<ref name="Strange02"/>
| | ==Treatment== |
| | | [[Pulmonary contusion medical therapy|Medical Therapy]] | [[Pulmonary contusion surgery|Surgery]] | [[Pulmonary contusion future or investigational therapies|Future or Investigational Therapies]] |
| ===X-ray=== | |
| [[Image:Pulmonary contusion.jpg|thumb|right|A chest X-ray showing right sided pulmonary contusion associated with rib fractures and [[subcutaneous emphysema]]]] | |
| [[Chest X-ray]] is the most common method used for diagnosis,<ref name="Klein02"/> and may be used to confirm a diagnosis already made using [[medical sign|clinical signs]].<ref name="CohnSM">{{cite journal |author=Cohn SM |title=Pulmonary contusion: Review of the clinical entity |journal=Journal of Trauma |volume=42 |issue=5 |pages=973–979 |year=1997 |pmid=9191684}}</ref> Consolidated areas appear white on an X-ray film.<ref name="Fish03">
| |
| {{
| |
| cite book |author=Fish RM |chapter=Diagnosis and treatment of blast injury |editor=Fish RM, Geddes LA, Babbs CF |title=Medical and Bioengineering Aspects of Electrical Injuries |publisher=Lawyers & Judges Publishing |location=Tucson, AZ |year=2003 |pages=55 |isbn=1-930056-08-7
| |
| }}
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| </ref> Contusion is not typically restricted by the anatomical boundaries of the lobes or segments of the lung.<ref name="Allen96"/><ref name="Johnson08"/><ref name="Strife02">{{cite book |author=Donnelly LF |chapter=CT of Acute pulmonary infection/trauma |editor=Strife JL, Lucaya J |title=Pediatric Chest Imaging: Chest Imaging in Infants and Children |publisher=Springer |location=Berlin |year=2002 |pages=123 |isbn=3-540-43557-3}}</ref> The X-ray appearance of pulmonary contusion is similar to that of [[Pulmonary aspiration|aspiration]],<ref name="Sartorelli04"/> and the presence of [[hemothorax]] or [[pneumothorax]] may obscure the contusion on a radiograph.<ref name="White99"/> Signs of contusion that progress after 48 hours post-injury are likely to be actually due to aspiration, pneumonia, or ARDS.<ref name="Hood89"/>
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| Although chest radiography is an important part of the diagnosis, it is often not sensitive enough to detect the condition early after the injury.<ref name="Keough01"/> In a third of cases, pulmonary contusion is not visible on the first chest radiograph performed.<ref name="Wanek04">{{cite journal |author=Wanek S, Mayberry JC |title=Blunt thoracic trauma: Flail chest, pulmonary contusion, and blast injury |journal=Critical Care Clinics |volume=20 |issue=1 |pages=71–81 |year=2004 |month=January |pmid=14979330 |doi=10.1016/S0749-0704(03)00098-8 }}</ref> It takes an average of six hours for the characteristic white regions to show up on a chest X-ray, and the contusion may not become apparent for 48 hours.<ref name="Wanek04"/><ref name="Allen96"/><ref name="Johnson08"/> When a pulmonary contusion is apparent in an X-ray, it suggests that the trauma to the chest was severe and that a CT scan might reveal other injuries that were missed with X-ray.<ref name="Wicky00">{{cite journal |author=Wicky S, Wintermark M, Schnyder P, Capasso P, Denys A |title=Imaging of blunt chest trauma |journal=European Radiology |volume=10 |issue=10 |pages=1524–1538 |year=2000 |pmid=11044920 }}</ref>
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| ===Computed tomography===
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| [[Image:Pulmonary contusion pseudocyst CT.jpg|right|thumb|A chest CT scan revealing pulmonary contusions, pneumothorax, and [[pseudocyst]]s]] | |
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| [[Computed tomography]] (CT scanning) is a more sensitive test for pulmonary contusion,<ref name="mlr07"/><ref name="Fleisher06"/> and it can identify [[abdominal trauma|abdominal]], chest, or other injuries that accompany the contusion.<ref name="Bastos08"/> In one study, chest X-ray detected pulmonary contusions in 16.3% of people with serious blunt trauma, while CT detected them in 31.2% of the same people.<ref name="Keel07">
| |
| {{
| |
| cite journal |author=Keel M, Meier C |title=Chest injuries - what is new? |journal=Current Opinion in Critical Care |volume=13 |issue=6 |pages=674–679 |year=2007 |month=December |pmid=17975389 |doi=10.1097/MCC.0b013e3282f1fe71 }}
| |
| </ref> Unlike X-ray, CT scanning can detect the contusion almost immediately after the injury.<ref name="Johnson08"/> However, in both X-ray and CT a contusion may become more visible over the first 24–48 hours after trauma as bleeding and edema into lung tissues progress.<ref name="MillerLA06">
| |
| {{
| |
| cite journal |author=Miller LA |title=Chest wall, lung, and pleural space trauma |journal=Radiologic Clinics of North America|volume=44 |issue=2 |pages=213–224, viii |year=2006 |month=March |pmid=16500204 |doi=10.1016/j.rcl.2005.10.006
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| }}
| |
| </ref> CT scanning also helps determine the size of a contusion, which is useful in determining whether a patient needs mechanical ventilation; a larger volume of contused lung on CT scan is associated with an increased likelihood that ventilation will be needed.<ref name="Johnson08"/> CT scans also help differentiate between contusion and [[pulmonary hematoma]], which may be difficult to tell apart otherwise.<ref name="Shields04">{{cite book |author=Grueber GM, Prabhakar G, Shields TW |editor=Shields TW |chapter= Blunt and penetrating injuries of the chest wall, pleura, and lungs |title=General Thoracic Surgery |publisher=Lippincott Williams & Wilkins |location=Philadelphia, PA |year=2005 |pages= 959 |isbn=0-7817-3889-X }}</ref> However, pulmonary contusions that are visible on CT but not chest X-ray are usually not severe enough to affect outcome or treatment.<ref name="Klein02"/>
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|
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|
| (Images shown below courtesy of RadsWiki)
| | ==Case Studies== |
| | | [[Pulmonary contusion case study one|Case #1]] |
| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Pulmonary-contusions-001.jpg|CT image demonstrates bilateral pulmonary contusions
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| Image:Pulmonary-contusions-002.jpg|CT image demonstrates bilateral pulmonary contusions
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| </gallery>
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| </div>
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| ==Prevention==
| |
| Prevention of pulmonary contusion is similar to that of other chest trauma. Airbags in combination with seat belts can protect vehicle occupants by preventing the chest from striking the interior of the vehicle during a collision, and by distributing forces involved in the crash more evenly across the body.<ref name="mlr07"/> However, in rare cases, an airbag causes pulmonary contusion in a person who is not properly positioned when it deploys.<ref name="Caudle07">{{cite journal |author=Caudle JM, Hawkes R, Howes DW, Brison RJ |title=Airbag pneumonitis: A report and discussion of a new clinical entity |journal=CJEM |volume=9 |issue=6 |pages=470–473 |year=2007 |month=November |pmid=18072996}}</ref> Child restraints such as carseats protect children in vehicle collisions from pulmonary contusion.<ref name="Cullen01"/> Equipment exists for use in some sports to prevent chest and lung injury; for example, in softball the catcher is equipped with a chest protector.<ref name="Pfeiffer07"/> Athletes who do not wear such equipment, such as basketball players, can be trained to protect their chests from impacts.<ref name="Pfeiffer07">{{cite book |author=Pfeiffer RP, Mangus BC |title=Concepts of Athletic Training |publisher=Jones and Bartlett Publishers |location=Boston |year=2007 |pages=200 |isbn=0-7637-4949-4 }}</ref> Protective garments can also prevent pulmonary contusion in explosions.<ref name="Cooper96"/> Although traditional body armor made from rigid plates or other heavy materials protects from projectiles generated by a blast, it does not protect against pulmonary contusion, because it does not prevent the blast's shock wave from being transferred to the lung.<ref name="Cooper96"/> Special body armor has been designed for military personnel at high risk for blast injuries; these garments can prevent a shock wave from being propagated across the chest wall to the lung, and thus protect wearers from blast lung injuries.<ref name="Cooper96"/> These garments alternate layers of materials with high and low [[acoustic impedance]] (the product of a material's density and a wave's velocity through it) in order to "decouple" the blast wave, preventing its propagation into the tissues.<ref name="Cooper96">{{cite journal |author=Cooper GJ |title=Protection of the lung from blast overpressure by thoracic stress wave decouplers |journal=Journal of Trauma |volume=40 |issue=Supplement 3 |pages=S105–110 |year=1996 |month=March |pmid=8606389}}</ref>
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| ==Treatment ==
| |
| | |
| No treatment is known to speed the healing of a pulmonary contusion; the main care is supportive.<ref name="Sutyak07"/> Attempts are made to discover injuries accompanying the contusion,<ref name="CohnSM"/> to prevent additional injury, and to provide supportive care while waiting for the contusion to heal.<ref name="Sutyak07"/> Monitoring, including keeping track of [[fluid balance]], respiratory function, and oxygen saturation using [[pulse oximetry]] is also required as the patient's condition may progressively worsen.<ref name="Pryor981">
| |
| {{
| |
| cite book |author=Ridley SC |chapter=Surgery for adults |editor= Pryor JA, Webber BR|title=Physiotherapy for Respiratory and Cardiac Problems |publisher=Churchill Livingstone |location=Edinburgh |year=1998 |pages= 316 |isbn=0-443-05841-5
| |
| }}
| |
| </ref> Monitoring for complications such as [[pneumonia]] and acute respiratory distress syndrome is of critical importance.<ref name="Ruddy05">
| |
| {{
| |
| cite journal |author=Ruddy RM |title=Trauma and the paediatric lung |journal=Paediatric Respiratory Reviews |volume=6 |issue=1 |pages=61–67 |year=2005 |month=March |pmid=15698818 |doi=10.1016/j.prrv.2004.11.006
| |
| }}
| |
| </ref> Treatment aims to prevent [[respiratory failure]] and to ensure adequate blood [[oxygenation]].<ref name="Moloney08"/><ref name="Strange02"/> Supplemental oxygen can be given and it may be warmed and humidified.<ref name="Gwinnutt03"/> When the contusion does not respond to other treatments, extracorporeal membranous oxygenation may be used, pumping blood from the body into a machine that oxygenates it and removes carbon dioxide prior to pumping it back in.<ref name="Pettiford07"/>
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| ===Ventilation===
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| [[Positive pressure ventilation]], in which air is forced into the lungs, is needed when oxygenation is significantly impaired. [[Non-invasive (medical)|Noninvasive]] positive pressure ventilation including [[continuous positive airway pressure]] (CPAP) and bi-level positive airway pressure (BiPAP), may be used to improve oxygenation and treat atelectasis.<ref name="Sutyak07"/> In both, air is blown into the airways at a prescribed pressure via a mask fitted tightly to the face; in BiPAP the pressure changes between inhalation and exhalation, while in CPAP the pressure is the same during both.<ref name="Sutyak07"/> Noninvasive ventilation has advantages over [[invasive (medical)|invasive]] methods because it does not carry the risk of infection that intubation does, and it allows normal coughing, swallowing, and speech.<ref name="Sutyak07"/> However, the technique may cause complications; it may force air into the stomach or cause aspiration of stomach contents, especially when level of consciousness is decreased.<ref name="Moore03"/>
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| [[Image:VIP Bird2.jpg|left|thumb|[[mechanical ventilator|Mechanical ventilation]] may be required if pulmonary contusion causes inadequate oxygenation.]]
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| People with signs of inadequate [[respiration (physiology)|respiration]] or oxygenation may need to be [[intubation|intubated]]<ref name="Wanek04"/> and [[ventilator|mechanically ventilated]].<ref name="Yamamoto05"/> Mechanical ventilation aims to reduce pulmonary edema and increase oxygenation.<ref name="Allen96"/> Ventilation can reopen collapsed alveoli, but it is harmful for them to be repeatedly opened, and positive pressure ventilation can also damage the lung by overinflating it.<ref name="Dueck06">
| |
| {{
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| cite journal |author=Dueck R |title=Alveolar recruitment versus hyperinflation: A balancing act |journal=Current Opinion in Anaesthesiology |volume=19 |issue=6 |pages=650–654 |year=2006 |month=December |pmid=17093370 |doi=10.1097/ACO.0b013e328011015d
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| }}
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| </ref> Intubation is normally reserved for when respiratory problems occur,<ref name="Wanek04"/> but most significant contusions do require intubation, and it may be done early in anticipation of this need.<ref name="Moore03"/> People with pulmonary contusion who are especially likely to need ventilation include those with prior severe [[lung disease]] or kidney problems; the elderly; those with a lowered level of consciousness; those with low blood oxygen or high carbon dioxide levels; and those who are going to be operated on and need [[anesthesia]].<ref name="Gwinnutt03"/>
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| Pulmonary contusion or its complications such as acute respiratory distress syndrome may cause lungs to lose [[pulmonary compliance|compliance]] (stiffen), so higher pressures may be needed to give normal amounts of air<ref name="Moore03"/> and oxygenate the blood adequately.<ref name="Fleisher06"/> [[Positive end-expiratory pressure]] (PEEP), which delivers air at a given pressure at the end of the expiratory cycle, can reduce edema and keep alveoli from collapsing.<ref name="Tovar08"> | |
| {{
| |
| cite journal |author=Tovar JA |title=The lung and pediatric trauma |journal=Seminars in Pediatric Surgery |volume=17 |issue=1 |pages=53–59 |year=2008 |pmid=18158142 |doi=10.1053/j.sempedsurg.2007.10.008
| |
| }}
| |
| </ref> PEEP is considered necessary with mechanical ventilation; however, if the pressure is too great it can expand the size of the contusion<ref name="ullman03"/> and injure the lung.<ref name="Sutyak07"/> When the compliance of the injured lung differs significantly from that of the uninjured one, the lungs can be ventilated independently with two ventilators in order to deliver air at different pressures; this helps avoid injury from overinflation while providing adequate ventilation.<ref name="Anantham05">
| |
| {{
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| cite journal |author=Anantham D, Jagadesan R, Tiew PE |title=Clinical review: Independent lung ventilation in critical care |journal=Critical Care |volume=9 |issue=6 |pages=594–600 |year=2005 |pmid=16356244 |pmc=1414047 |doi=10.1186/cc3827 |url=http://ccforum.com/content/9/6/594
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| }}
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| </ref>
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| ===Fluid therapy===
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| The administration of [[fluid resuscitation|fluid therapy]] in individuals with pulmonary contusion is controversial.<ref name="Gwinnutt03"/> Excessive fluid in the circulatory system ([[hypervolemia]]) can worsen [[hypoxia (medical)|hypoxia]] because it can cause fluid leakage from injured capillaries (pulmonary edema), which are more permeable than normal.<ref name="AllenCox98"/><ref name="Johnson08"/> However, low blood volume ([[hypovolemia]]) resulting from insufficient fluid has an even worse impact, potentially causing [[hypovolemic shock]]; for people who have lost large amounts of blood, fluid resuscitation is necessary.<ref name="Gwinnutt03"/> A lot of the evidence supporting the idea that fluids should be withheld from people with pulmonary contusion came from animal studies, not [[clinical trial]]s with humans; human studies have had conflicting findings on whether fluid resuscitation worsens the condition.<ref name="CohnSM"/> For people who do require large amounts of [[intravenous]] fluid, a [[catheter]] may be placed in the [[pulmonary artery]] to measure the pressure within it.<ref name="mlr07"/> Measuring pulmonary artery pressure allows the clinician to give enough fluids to prevent shock without exacerbating edema.<ref name="Smith98">
| |
| {{
| |
| cite book |author=Smith M, Ball V |Chapter=Thoracic trauma |title=Cardiovascular/respiratory physiotherapy |publisher=Mosby |location=St. Louis |year=1998 |pages=221 |isbn=0-7234-2595-7
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| }}
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| </ref> [[Diuretic]]s, drugs that increase urine output to reduce excessive fluid in the system, can be used when fluid overload does occur.<ref name="KarmyJurk04"/> [[Furosemide]], a diuretic used in the treatment of pulmonary contusion, also relaxes the [[smooth muscle]] in the veins of the lungs, thereby decreasing pulmonary [[vascular resistance|venous resistance]] and reducing the pressure in the pulmonary capillaries.<ref name="Johnson08"/>
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| ===Supportive care===
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| Retaining secretions in the airways can worsen hypoxia<ref name="Danne03">
| |
| {{
| |
| cite book |chapter=Airway control |author = Danne PD, Hunter M, MacKillop ADF |title=Trauma. Fifth Edition |editor=Moore EE, Feliciano DV, Mattox KL |year= 2003 |publisher= McGraw-Hill Professional | isbn= 0071370692 |pages=183
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| }}
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| </ref> and lead to infections.<ref name="Moore03"/> Thus, an important part of treatment is [[pulmonary toilet]], the use of suction, deep breathing, coughing, and other methods to remove material such as mucus and blood from the airways.<ref name="Wanek04"/> [[Chest physiotherapy|Chest physical therapy]] makes use of techniques such as breathing exercises, stimulation of coughing, suctioning, percussion, movement, vibration, and drainage to rid the lungs of secretions, increase oxygenation, and expand collapsed parts of the lungs.<ref name="Ciesla96">{{cite journal | author=Ciesla ND | title=Chest physical therapy for patients in the intensive care unit | journal=Physical Therapy | volume=76 | issue=6 | pages=609–625 | year=1996 | month=June | pmid=8650276 | format=PDF | url=http://www.ptjournal.org/cgi/pmidlookup?view=long&pmid=8650276 }}</ref> People with pulmonary contusion, especially those who do not respond well to other treatments, may be positioned with the uninjured lung lower than the injured one to improve oxygenation.<ref name="Johnson08"/> Inadequate pulmonary toilet can result in pneumonia.<ref name="Prentice94"/> People who do develop infections are given antibiotics.<ref name="ullman03"/> No studies have yet shown a benefit of using antibiotics as a preventative measure before infection occurs, although some doctors do recommend prophylactic antibiotic use even without scientific evidence of its benefit.<ref name="Tovar08"/> However, this can cause the development of [[antibiotic resistance|antibiotic resistant]] strains of bacteria, so giving antibiotics without a clear need is normally discouraged.<ref name="CohnSM"/> For people who are at especially high risk of developing infections, the [[sputum]] can be [[Microbiological culture|culture]]d to test for the presence of infection-causing bacteria; when they are present, antibiotics are used.<ref name="Allen96"/>
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| Pain control is another means to facilitate the elimination of secretions. A chest wall injury can make coughing painful, increasing the likelihood that secretions will accumulate in the airways.<ref name="Moore031"/> Chest injuries also contribute to [[hypoventilation]] (inadequate breathing) because the chest wall movement involved in breathing adequately is painful.<ref name="Moore031">{{cite book | chapter=Trauma to the chest wall and lung | author = Livingston DH, Hauser CJ | title=Trauma. Fifth Edition | editor=Moore EE, Feliciano DV, Mattox KL | year= 2003 | publisher= McGraw-Hill Professional | isbn= 0071370692 | pages=515 }}</ref><ref name="Lawrence06">{{cite book | author=Dolich MO, Chipman JG| chapter=Trauma | editor =Lawrence P, Bell, RH, Dayton MT, Mohammed MAA | title=Essentials of General Surgery | publisher=Lippincott Williams & Wilkins | location=Hagerstown, MD | year=2006 | pages=191–192 | isbn=0-7817-5003-2 }}</ref> Insufficient expansion of the chest may lead to [[atelectasis]], further reducing oxygenation of the blood.<ref name="Keough01"/> [[Analgesic]]s (pain medications) can be given to reduce pain.<ref name="Yamamoto05"/> Injection of anesthetics into nerves in the chest wall, called [[nerve block]]ade, is another approach to pain management; this does not depress respiration the way some pain medications can.<ref name="AllenCox98"/>
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| ==Prognosis==
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| [[Image:Healed pulmonary contusion.JPG|right|thumb|This CT scan, taken 22 days after pulmonary contusion with major chest trauma, shows that the contusion has completely resolved.<ref name="Guen07">{{cite journal | author=Le Guen M, Beigelman C, Bouhemad B, Wenjïe Y, Marmion F, Rouby JJ | title=Chest computed tomography with multiplanar reformatted images for diagnosing traumatic bronchial rupture: A case report | journal=Critical Care | volume=11 | issue=5 | pages=R94 | year=2007 | pmid=17767714 | doi=10.1186/cc6109 | url=http://ccforum.com/content/11/5/R94 }}</ref>]]
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| Pulmonary contusion usually resolves itself<ref name="Strange02"/> without causing permanent complications;<ref name="Collins07">{{cite book | author=Collins J, Stern EJ | title=Chest Radiology: The Essentials | isbn=0781763142 | publisher=Lippincott Williams & Wilkins | year=2007 | pages=120 }}</ref> however it may also have long-term ill effects on respiratory function.<ref name="Bastos08"/><ref name="CohnZieg96">{{cite journal | author=Cohn SM, Zieg PM | title=Experimental pulmonary contusion: Review of the literature and description of a new porcine model | journal=Journal of Trauma | volume=41 | issue=3 | pages=565–571 | year=1996 | month=September | pmid=8810987 }}</ref> Most contusions resolve in five to seven days after the injury.<ref name="Collins07"/> Signs detectable by radiography are usually gone within 10 days after the injury—when they are not, other conditions, such as pneumonia, are the likely cause.<ref name="Allen96"/> Chronic lung disease correlates with the size of the contusion and can interfere with an individual's ability to return to work.<ref name="Karmy02"/> [[Fibrosis]] of the lungs can occur, resulting in [[dyspnea]] (shortness of breath), low blood oxygenation, and reduced [[functional residual capacity]] for as long as six years after the injury.<ref name="Bastos08"/> As late as four years post-injury, decreased functional residual capacity has been found in most pulmonary contusion patients studied.<ref name="Johnson08"/> During the six months after pulmonary contusion, up to 90% of people suffer difficulty breathing.<ref name="Allen96"/><ref name="Johnson08"/> In some cases, dyspnea persists for an indefinite period.<ref name="Wanek04"/> Contusion can also permanently reduce the compliance of the lungs.<ref name="O'Leary07">{{cite book | author=Heck HA, Levitzky MG | chapter=The respiratory system | editor=O'Leary JP, Tabuenca A, Capote LR | title=The The Physiologic Basis of Surgery | publisher=Lippincott Williams & Wilkins | location=Hagerstown, MD | year=2007 | pages=463 | isbn=0-7817-7138-2 }}</ref>
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| ===Complications===
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| Pulmonary contusion can result in respiratory failure—about half of such cases occur within a few hours of the initial trauma.<ref name="Johnson08"/> Other severe complications, including infections and [[acute respiratory distress syndrome]] ([[ARDS]]) occur in up to half of cases.<ref name="AllenCox98"/> Elderly people and those who have heart, lung, or kidney disease prior to the injury are more likely to stay longer in hospital and have complications from the injury. Complications occur in 55% of people with heart or lung disease and 13% of those without.<ref name="Klein02"/> Of people with pulmonary contusion alone, 17% develop ARDS, while 78% of people with at least two additional injuries develop the condition.<ref name="mlr07"/> A larger contusion is associated with an increased risk. In one study, 82% of people with 20% or more of the lung volume affected developed ARDS, while only 22% of people with less than 20% did so.<ref name="Wanek04"/>
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| [[Image:AARDS X-ray cropped.jpg|thumb|left|A chest X-ray showing acute respiratory distress syndrome]]
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| Pneumonia, another potential complication, develops in as many as 20% of people with pulmonary contusion.<ref name="Tovar08"/> Contused lungs are less able to remove bacteria than uninjured lungs, predisposing them to infection.<ref name="Fry07">{{cite book | author=Fry DE | chapter=Surgical infection | editor=O'Leary JP, Tabuenca A, Capote LR | title=The Physiologic Basis of Surgery | publisher=Lippincott Williams & Wilkins | location=Hagerstown, MD | year=2007 |pages=241 |isbn=0-7817-7138-2 }}</ref> Intubation and mechanical ventilation further increase the risk of developing pneumonia; the tube is passed through the nose or mouth into the airways, potentially tracking bacteria from the mouth or sinuses into them.<ref name="Sutyak07"/> Also, intubation prevents coughing, which would clear bacteria-laden secretions from the airways, and secretions pool near the tube's cuff and allow bacteria to grow.<ref name="Sutyak07"/> The sooner the [[endotracheal tube]] is removed, the lower the risk of pneumonia, but if it is removed too early and has to be put back in, the risk of pneumonia rises.<ref name="Sutyak07"/> People who are at risk for [[pulmonary aspiration]] (e.g. those with lowered level of consciousness due to head injuries) are especially likely to get pneumonia.<ref name="Sutyak07"/> As with ARDS, the chances of developing pneumonia increase with the size of the contusion.<ref name="Wanek04"/> Children and adults have been found to have similar rates of complication with pneumonia and ARDS.<ref name="AllenCox98"/>
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| ==Epidemiology==
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| Pulmonary contusion is found in 30–75% of severe cases of chest injury, making it the most common serious injury to occur in association with [[thorax|thoracic]] trauma.<ref name="mlr07">
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| {{
| |
| cite journal |author=Miller DL, Mansour KA |title=Blunt traumatic lung injuries |journal=Thoracic Surgery Clinics |volume=17 |issue=1 |pages=57–61 |year=2007 |pmid=17650697 |doi= 10.1016/j.thorsurg.2007.03.017
| |
| }}
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| </ref> Of people who have multiple injuries with an [[injury severity score]] of over 15, pulmonary contusion occurs in about 17%.<ref name="CohnSM"/> It is difficult to determine the death rate ([[mortality rate|mortality]]) because pulmonary contusion rarely occurs by itself.<ref name="ullman03"/> Usually, deaths of people with pulmonary contusion result from other injuries, commonly traumatic brain injury.<ref name="Karmy02"/> It is controversial whether pulmonary contusion with [[flail chest]] is a major factor in mortality on its own or whether it merely contributes to mortality in people with multiple injuries.<ref name="EAST06"/> The mortality rate of pulmonary contusion is estimated to range from 14–40%, depending on the severity of the contusion itself and on associated injuries.<ref name="Gavelli02"/> When the contusions are small, they do not normally increase the chance of death or poor outcome for people with blunt chest trauma; however, these chances increase with the size of the contusion.<ref name="Klein02"/> One study found that 35% of people with multiple significant injuries including pulmonary contusion die.<ref name="ullman03"/> In another study, 11% of people with pulmonary contusion alone died, while the number rose to 22% in those with additional injuries.<ref name="mlr07"/> An accompanying flail chest increases the [[disability|morbidity]] and mortality to more than twice that of pulmonary contusion alone.<ref name="Johnson08"/> Pulmonary contusion is thought to be the direct cause of death in a quarter to a half of people with [[polytrauma]] who die.<ref name="KarmyJurk04"/>
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| Pulmonary contusion is the most common cause of death among vehicle occupants involved in accidents,<ref>{{cite book | author=Milroy CM, Clark JC | chapter=Injuries and deaths in vehicle occupants |editor=Mason JK, Purdue BN |title=The Pathology of Trauma |publisher=Arnold |year=2000 |pages=10 |isbn=0-340-69189-1 }}</ref> and it is thought to contribute significantly in about a quarter of deaths resulting from vehicle collisions.<ref name="White99"/> As vehicle use has increased, so has the number of auto accidents, and with it the number of chest injuries.<ref name="Sutyak07"/> However an increase in the number of airbags installed in modern cars may be decreasing the incidence of pulmonary contusion.<ref name="mlr07"/> Use of child restraint systems has brought the approximate incidence of pulmonary contusion in children in vehicle accidents from 22% to 10%.<ref name="Cullen01">
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| {{
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| cite journal |author=Cullen ML |title=Pulmonary and respiratory complications of pediatric trauma |journal=Respiratory Care Clinics of North America |volume=7 |issue=1 |pages=59–77 |year=2001 |month=March |pmid=11584805
| |
| }}
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| </ref>
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| Since their chest walls are more flexible, children are more vulnerable to pulmonary contusion than adults are,<ref name="Strange02"/> and it is more common in children than in adults for that reason.<ref name="Matthay05">
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| {{cite book | chapter=Thoracic trauma, surgery, and perioperative management |editor=Matthay RA, George RB, Light RJ, Matthay MA |title=Chest Medicine: Essentials of Pulmonary and Critical Care Medicine |publisher=Lippincott Williams & Wilkins |location=Hagerstown, MD |year=2005 |pages=578 |isbn=0-7817-5273-6 }}</ref> Children in forceful impacts suffer twice as many pulmonary contusions as adults with similar injury mechanisms, yet have proportionately fewer rib fractures.<ref name="Tovar08"/> Pulmonary contusion has been found in 53% of children with significant chest injuries (those requiring hospitalization).<ref name="Nakayama">{{cite journal | last=Nakayama | first=DK | coauthors=Ramenofsky ML, Rowe MI | title=Chest injuries in childhood | journal=Annals of Surgery | volume=210 | issue=6 | pages=770–775 | date=December 1989 | url=http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1357870&blobtype=pdf | pmid=2589889 }}</ref> The rates of certain types of injury mechanisms differ between children and adults; for example, children are more often hit by cars when they are pedestrians.<ref name="AllenCox98"/> Differences in the bodies of children and adults also lead to different manifestations of pulmonary contusion and associated injuries; for example, children have less body mass, so the same force is more likely to lead to trauma to multiple body systems.<ref name="AllenCox98"/> Some differences in children's physiology might be advantageous (for example they are less likely to have other medical conditions), and thus they have been predicted to have a better outcome.<ref name="AllenCoxDif97">
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| {{cite journal |author=Allen GS, Cox CS, Moore FA, Duke JH, Andrassy RJ |title=Pulmonary contusion: Are children different? |journal=Journal of the American College of Surgeons |volume=185 |issue=3 |pages=229–233 |year=1997 |month=September |pmid=9291398 }}</ref> However, despite these differences, children with pulmonary contusion have similar mortality rates to adults.<ref name="AllenCox98"/>
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| ===Associated injuries===
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| [[Image:Pneumothorax hemothorax pneumomediastinum contusion.JPG|right|thumb|Severe pulmonary contusion with pneumothorax and hemothorax following severe chest trauma<ref name="Konijn08">{{cite journal |author=Konijn AJ, Egbers PH, Kuiper MA |title=Pneumopericardium should be considered with electrocardiogram changes after blunt chest trauma: a case report |journal=J Med Case Reports |volume=2 |issue= |pages=100 |year=2008 |pmid=18394149 |pmc=2323010 |doi=10.1186/1752-1947-2-100 |url=http://www.jmedicalcasereports.com/content/2/1/100}}</ref>]]
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| A large amount of force is required to cause pulmonary contusion; a person injured with such force is likely to have other types of injuries as well,<ref name="Strange02"/> and pulmonary contusion can be used to gauge the severity of trauma.<ref name="White99">
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| {{
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| cite book |author=Stern EJ, White C |title=Chest Radiology Companion |publisher=Lippincott Williams & Wilkins |location=Hagerstown, MD |year=1999 |pages=80 |isbn=0-397-51732-7
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| }}
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| </ref> Up to three quarters of cases are accompanied by other chest injuries,<ref name="Sutyak07">
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| {{
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| cite journal |author=Sutyak JP, Wohltmann CD, Larson J |title=Pulmonary contusions and critical care management in thoracic trauma |journal=Thoracic Surgical Clinics |volume=17 |issue=1 |pages=11–23 |year=2007 |pmid=17650693 |doi=10.1016/j.thorsurg.2007.02.001 |url=
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| }}
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| </ref> the most common of these being hemothorax and pneumothorax.<ref name="Klein02">
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| {{
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| cite journal |author=Klein Y, Cohn SM, Proctor KG |title=Lung contusion: Pathophysiology and management |journal=Current Opinion in Anaesthesiology |volume=15 |issue=1 |pages=65–68 |year=2002 |month=February |pmid=17019186 |url=http://www.co-anesthesiology.com/pt/re/coanes/pdfhandler.00001503-200202000-00010.pdf|format=PDF }}
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| </ref> Flail chest is usually associated with pulmonary contusion,<ref name="Allen96"/><ref name="Johnson08"/> and the contusion, rather than the chest wall injury, is often the main cause of respiratory failure in people with these injuries.<ref name="Dohert05">
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| {{
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| cite book |author= Hemmila MR, Wahl WL |chapter= Management of the injured patient |editor=Doherty GM |title=Current Surgical Diagnosis and Treatment |publisher=McGraw-Hill Medical |year=2005 |pages= 214 |isbn=0-07-142315-X
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| }}
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| </ref> Other indications of [[Thorax|thoracic]] trauma may be associated, including [[sternal fracture|fracture of the sternum]] and bruising of the chest wall.<ref name="Lawrence06"/> Over half of fractures of the [[scapula]] are associated with pulmonary contusion.<ref name="Allen96"/> The contusion is frequently found underlying fracture sites.<ref name="Keough01"/> When accompanied by a fracture, it is usually concentrated into a specific location—the contusion is more diffuse when there is no fracture.<ref name="AllenCox98"/><ref name="Johnson08">{{cite journal |author=Johnson SB |title=Tracheobronchial injury |journal= Seminars in Thoracic and Cardiovascular Surgery |volume=20 |issue=1 |pages=52–57 |year= 2008 |pmid=18420127 |doi=10.1053/j.semtcvs.2007.09.001 |url=}}</ref> [[Pulmonary laceration]]s may result from the same blunt or penetrating forces that cause pulmonary contusion.<ref name="mlr07"/> Lacerations can result in pulmonary hematomas; these are reported to develop in 4–11% of pulmonary contusions.<ref name="mlr07"/>
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| ==History ==
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| In 1761, the Italian anatomist [[Giovanni Battista Morgagni]] was first to describe a lung injury that was not accompanied by injury to the chest wall overlying it.<ref name="CohnSM"/> The French military surgeon [[Guillaume Dupuytren]] is thought to have coined the term ''pulmonary contusion'' in the 19th century.<ref name="KarmyJurk04">
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| {{
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| cite journal |author=Karmy-Jones R, Jurkovich GJ |title=Blunt chest trauma |journal=Current Problems in Surgery |volume=41 |issue=3 |pages=211–380 |year=2004 |month=March |pmid=15097979 |doi=10.1016/j.cpsurg.2003.12.004
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| }}
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| </ref> However, it was not until the early 20th century that pulmonary contusion and its clinical significance began to receive wide recognition.<ref name="EAST06">
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| {{
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| cite web |author=EAST practice management workgroup for pulmonary contusion - flail chest: Simon B, Ebert J, Bokhari F, Capella J, Emhoff T, Hayward T, ''et al'' |date=2006| title= Practice management guide for Pulmonary contusion - flail chest | publisher =The Eastern Association for the Surgery of Trauma |url =http://www.east.org/tpg/pulmcontflailchest.pdf |format=PDF|accessdate=2008-06-18
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| }}
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| </ref> With the use of explosives during World War I came many casualties with no external signs of chest injury but with significant bleeding in the lungs.<ref name="EAST06"/> Studies of World War I injuries by D.R. Hooker showed that pulmonary contusion was an important part of the concussive injury that results from explosions.<ref name="EAST06"/>
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| [[Image:Morgagni portrait.jpg|thumb|left|Giovanni Battista Morgagni, credited with having first described lung trauma without chest wall trauma]]
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| Pulmonary contusion received further attention during World War II, when the bombings of Britain caused blast injuries and associated respiratory problems in both soldiers and civilians.<ref name="CohnSM"/> Also during this time, studies with animals placed at varying distances from a blast showed that protective gear could prevent lung injuries.<ref name="CohnZieg96"/> These findings suggested that an impact to the outside of the chest wall was responsible for the internal lesions.<ref name="CohnZieg96"/> In 1945, Buford and Burbank described what they called "wet lung", in which the lungs accumulated fluid and were simultaneously less able to remove it.<ref name="CohnSM"/> They attributed the respiratory failure often seen in blunt chest trauma in part to excessive fluid resuscitation, and the question of whether and how much to administer fluids has remained controversial ever since.<ref name="CohnSM"/>
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| During the Vietnam War, combat again provided the opportunity for study of pulmonary contusion; research during this conflict played an important role in the development of the modern understanding of its treatment.<ref name="CohnSM"/> The condition also began to be more widely recognized in a non-combat context in the 1960s, and symptoms and typical findings with imaging techniques such as X-ray were described.<ref name="CohnSM"/> Before the 1960s, it was believed that the respiratory insufficiency seen in flail chest was due to "paradoxical motion" of the flail segment of the chest wall (the flail segment moves in the opposite direction as the chest wall during respiration), so treatment was aimed at managing the chest wall injury, not the pulmonary contusion.<ref name="Pettiford07">
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| {{
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| cite journal |author=Pettiford BL, Luketich JD, Landreneau RJ |title=The management of flail chest |journal=Thoracic Surgery Clinics |volume=17 |issue=1 |pages=25–33 |year=2007 |month=February |pmid=17650694 |url=
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| }}
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| </ref> For example, [[positive pressure ventilation]] was used to stabilize the flail segment from within the chest.<ref name="Sutyak07"/> It was first proposed in 1965 that this respiratory insufficiency is most often due to injury of the lung rather than to the chest wall,<ref name="CohnSM"/> and a group led by J.K. Trinkle confirmed this hypothesis in 1975.<ref name="Bastos08">
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| {{
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| cite journal |author=Bastos R, Calhoon JH, Baisden CE |title=Flail chest and pulmonary contusion |journal=Seminars in Thoracic and Cardiovascular Surgery |volume=20 |issue=1 |pages=39–45 |year=2008 |pmid=18420125 |doi=10.1053/j.semtcvs.2008.01.004 |url=
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| }}
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| </ref> Hence the modern treatment prioritizes the management of pulmonary contusion.<ref name="EAST06"/> Animal studies performed in the late 1960s and 1970s shed light on the pathophysiological processes involved in pulmonary contusion.<ref name="CohnZieg96"/>
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| ==References==
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| {{reflist|2}}
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| ==External links==
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| *National Guideline Clearinghouse. [http://www.guideline.gov/summary/summary.aspx?doc_id=10167 Practice management guideline for pulmonary contusion - flail chest]
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| {{Chest trauma}}
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