Blast injury: Difference between revisions

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==Background==
==Background==
{| class="wikitable sortable"
*Primary blast wave increased in closed space - detonation in corner has potential to increase blast yield to 8x
*Recent enhanced-blast weapons (EBW) disperses gas before explosion - larger blast wave with lower pressure amplitude that diffuses around corners
 
===Spalling Effect===
''Due to blast pressure forces, injuries are to organs with air-fluid interfaces (spalling effect)''
*TMs
*Alveoli
*GI tract
 
===Situational Examples===
*Military - young healthy soldiers with body armor reducing thoracic/abdominal injuries but significant groin and lower extremity injuries
*Civilian - children to elderly, higher rates of penetrating thoracic/abdominal injury
 
===Injury Classifications===
{|class="wikitable"
|+ Classification
|+ Classification
|-
|-
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! scope="col" | '''Example'''
! scope="col" | '''Example'''
|-
|-
| Primary||Direct effect from shockwave||Sheer and stress forces||TM rupture, Ocular Injury, concussion, blast lung
| Primary||Direct effect from shockwave||Sheer and stress forces||[[TM rupture]], Ocular Injury, [[concussion]], blast lung
|-
|-
| Secondary||Impact of fragments|Penetrating trauma, amps, lacs||
| Secondary||Impact of fragments||Penetrating trauma, amps, lacs||
|-
|-
| Tertiary ||Blast propels body or large object into body||Crush and blunt trauma||Similar to MVC, Fractures, Pneumothorax, Hemopneumothorax
| Tertiary ||Blast propels body or large object into body||[[Crush injury]] and blunt trauma||Similar to MVC: Fractures, [[Pneumothorax]], Hemopneumothorax
|-
|-
| Quaternary ||Environmental||Burns, Toxins, Weather||
| Quaternary ||Environmental||Burns, Toxins, Weather||
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|}
|}


*Injuries to organs with air-fluid interfaces (spalling effect)
 
**TMs
{{Department of navy blast effects}}
**Alveoli
**GI tract
*Military - young healthy soldiers with body armor reducing thoracic/abdominal injuries
*Civilian - children to elderly, higher rates of penetrating thoracic/abdominal injury
*Primary blast wave increased in closed space - detonation in corner has potential to increase blast yield to 8x
*Recent enhanced-blast weapons (EBW) disperses gas before explosion - larger blast wave with lower pressure amplitude that diffuses around corners


==Clinical Features==
==Clinical Features==
*Penetrating and blunt injuries, burns, amputations
===Pulmonary===
*Markers of severe blast injury
*Blast lung is the most common fatal primary blast injury (PBI)
**> 10% TBSA burn
*[[Pulmonary contusion]]
**Skull, facial fx
*[[Pneumomediastinum]] due to alveolar rupture - [[pneumothorax]], subcutaneous emphysema, [[pneumopericardium]], pneumoretroperitoneum, pneumoperitoneum, [[air embolus]]
**Penetrating injury to head or thorax
*Thrombosis, [[DIC]], [[ARDS]]
**Traumatic amputations
===HEENT===
*Primary blast injuries most likely to cause pulmonary, acoustic/head, thoracic trauma
*[[TM rupture]] most common - not a marker of PBI severity or prognosis
**Pulmonary is most common fatal PBI
*Hemotympanum
***Pulmonary contusion
*Ossicle injury
***Pneumomediastinum due to alveolar rupture - PTX, subQ emphysema, pneumopericardium, pneumoretroperitoneum, pneumoperitoneum, air embolus
*Direct [[ocular Trauma|ophthalmic injury]], [[foreign bodies]], or ophthalmic artery [[air embolus]]
***Thrombosis, DIC, ARDS
 
**Acoustic/head
===Thoracic===
***TM rupture most common - not a marker of PBI severity or prognosis
*[[shock|Cardiovascular collapse]] (within seconds)
***Hemotympanum
*[[Hypotension]] due to impaired reflex that increases SVR
***Ossicle injury
 
***Direct ophthalmic injury, FBs, or ophthalmic artery air embolus
===Infectious Disease===
**Thoracic - immediate effects
***CV collapse (within seconds)
***Decreased BP due to impaired reflex that increases SVR
*Transmission of disease due to penetrating trauma is rare but possible with HIV, HCV, HBV
*Transmission of disease due to penetrating trauma is rare but possible with HIV, HCV, HBV


==Workup==
===Musculoskeletal===
*CXR, CT chest
*[[Amputation]]s
*FAST, comprehensive CT
*[[Burns]]
 
===Markers of severe blast injury===
*> 10% [[TBSA]] burn
*Skull, facial fracture
*Penetrating injury to head or thorax
*Traumatic amputations
 
==Differential Diagnosis==
{{MCI types}}
 
==Evaluation==
[[File:Massive right hemothorax.jpg|thumb|[[CXR]] with large right sided hemothorax (and widened mediastinum).]]
*[[CXR]] - butterfly distribution, bilateral patchy infiltrates
*CT chest
*[[FAST]], comprehensive CT
*Repeat clinical abdominal exams looking for peritonitis - X-rays, US, CT insensitive except in perforation
*Repeat clinical abdominal exams looking for peritonitis - X-rays, US, CT insensitive except in perforation
*Initial CT head may not be enough - may require MRI for DAI
*Initial [[CT head]] may not be enough - may require [[MRI]] for DAI
*Labs
*Labs
**Consider HbCO and electrolytes
**Consider carboxyhemoglobin and electrolytes
**Screening UA for significant explosions
**Screening [[UA]] for significant explosions
**Burn labs (rhabdomyolysis, compartment syndrome, severe burns)
**[[Burn]] labs ([[rhabdomyolysis]], [[compartment syndrome]], severe [[burns]])
**DIC labs (PT, aPTT, CBC, D-dimer, thrombin time, fibrinogen)
**[[DIC]] labs (PT, aPTT, CBC, D-dimer, thrombin time, fibrinogen)
**White phosphorous labs (hypocalcemia, hyperphosphatemia)
**[[White phosphorus]] labs ([[hypocalcemia]], [[hyperphosphatemia]], LFTs)
 
==Management==
*[[Chest tube]] for significant [[hemothorax]] and/or [[pneumothorax]]
*[[pRBCs]] and [[FFP]] in 1:1 ratio with platelets for hemodynamically unstable patients
*[[TM rupture]] - initial treatment supportive and enough for 75% with spontaneous healing; operative repair may be necessary for others
*Operative exploration for [[peritonitis]]
*[[Air embolus]] (rare) - isolate air in apex of LV by placing patient in left decubitus, head down, feet up position
 
==Disposition==
*Ambulatory patient with normal TM evaluation at low risk for occult blast injury - discharge with precautions
*All others require admission


==Treatment==
==See Also==
*pRBCs and FFP in 1:1 ratio with platelets for hemodynamically unstable pts
*[[Explosions]]
*TM rupture - initial Tx supportive and enough for 75% with spontaneous healing; operative repair may be necessary for others
*[[Wound ballistics]]
*Operative exploration for peritonitis
*Air embolus (rare) - isolate air in apex of LV by placing pt in left decubitus, head down, feet up position


==References==
==References==
#Pennardt A, Lavonas EJ, Danzl D, Talavera F, Levy DB, Halamka JD. Blast Injuries. eMedicine Medscape Review. Last updated Apr 21, 2014. http://emedicine.medscape.com/article/822587-overview#showall
<references/>
#Yeh DD, Schecter WP. Primary blast injuries - An updated concise review. World J Surg (2012). 36:966-972.
#Ritenour AE, Baskin TW. Primary blast injury: Update on diagnosis and treatment. Crit Care Med 2008; 36[Suppl.]:S311-S317.


[[Category:EMS]]
[[Category:Trauma]]
[[Category:Trauma]]

Latest revision as of 20:13, 17 April 2024

Background

  • Primary blast wave increased in closed space - detonation in corner has potential to increase blast yield to 8x
  • Recent enhanced-blast weapons (EBW) disperses gas before explosion - larger blast wave with lower pressure amplitude that diffuses around corners

Spalling Effect

Due to blast pressure forces, injuries are to organs with air-fluid interfaces (spalling effect)

  • TMs
  • Alveoli
  • GI tract

Situational Examples

  • Military - young healthy soldiers with body armor reducing thoracic/abdominal injuries but significant groin and lower extremity injuries
  • Civilian - children to elderly, higher rates of penetrating thoracic/abdominal injury

Injury Classifications

Classification
Blast Type Injury Cause Injuries Example
Primary Direct effect from shockwave Sheer and stress forces TM rupture, Ocular Injury, concussion, blast lung
Secondary Impact of fragments Penetrating trauma, amps, lacs
Tertiary Blast propels body or large object into body Crush injury and blunt trauma Similar to MVC: Fractures, Pneumothorax, Hemopneumothorax
Quaternary Environmental Burns, Toxins, Weather
Quinary Bodily absorption of contaminates Hypermetabolic state


Effects based on blast pressure[1]

Potential Injury Pressure (PSI) Structural Effects
Loss of balance/temporary ear damage 0.5-3 psi Glass shatters; facade fails
Slight chance of eardrum rupture 5-6 psi Cinderblock shatters; steel structures fail; containers collapse; utility poles fail
50% chance of eardrum rupture 15 psi Structural failure of typical construction
Lung collapse/damage 30 psi Reinforced construction failure
Fatal injuries 100 + psi* Structural failure

Clinical Features

Pulmonary

HEENT

Thoracic

Infectious Disease

  • Transmission of disease due to penetrating trauma is rare but possible with HIV, HCV, HBV

Musculoskeletal

Markers of severe blast injury

  • > 10% TBSA burn
  • Skull, facial fracture
  • Penetrating injury to head or thorax
  • Traumatic amputations

Differential Diagnosis

Mass casualty incident

Evaluation

CXR with large right sided hemothorax (and widened mediastinum).

Management

  • Chest tube for significant hemothorax and/or pneumothorax
  • pRBCs and FFP in 1:1 ratio with platelets for hemodynamically unstable patients
  • TM rupture - initial treatment supportive and enough for 75% with spontaneous healing; operative repair may be necessary for others
  • Operative exploration for peritonitis
  • Air embolus (rare) - isolate air in apex of LV by placing patient in left decubitus, head down, feet up position

Disposition

  • Ambulatory patient with normal TM evaluation at low risk for occult blast injury - discharge with precautions
  • All others require admission

See Also

References

  1. ↑ Terrorism Handbook for Operational Responders by Armando Bevalacqua and Richard Stilp (1998) and the Department of the Navy EODB 60 A-1-1-4 (2001) “Table A-1 http://www.fema.gov/pdf/plan/prevent/rms/428/fema428_ch4.pdf
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