Morning Report

Morning Report: 5/7/2013

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Today’s Morning Report is courtesy of Dr. Joshi!

 

Blast Injuries:  NEJM 2005

 

DePalma RG, Burris DG, Champion HR, Hodgson MJ. Blast Injuries. NEJM. 2005 Mar 31;352(13):1335-42. PMID: 15800229.

 

How to categorize Injuries:

Few bombings in the US –

  • 1995 Okalahoma bombing killed 168, injured 518
  • 2004 Madrid train bombing
  • Iraq
  • Israel

 

Problem – improvised explosive devices are often loaded with metallic objects to cause penetrating injuries in crowded areas.

 

Types of Bombs:  Conventional, Enhanced-Blast

Conventional

  • Conventional bombs generate blast wave that spreads from point source
  • Blast wave has two parts:  (physics is nonlinear and complex)
    • 1.  Shock wave of high pressure
    • 2.  Blast wind aka air in motion

***  Blast wave damage decreases exponentially the further away you are, but there is a reversal of wind back toward the blast and UNDERPRESSURIZATION.

Underpressurization – causes organ damage

 

Enhanced-Blast Explosive Devices – significantly greater energy dissipated

  • MORE DAMAGE
    • Primary Blast – disseminates explosive and then triggers it to cause a SECOND explosion
      • Therefore, the high pressure wave generated radiates to a MUCH larger area
      • Therefore, prolonging the overpressurization phase
  • Greater proportion of primary blast injuries than conventional devices

 

TIP:  Blast injuries should be suspected in any pt regardless of the distance the pt was from the blast center and regardless of visible signs of injury.

 

Types of Blast Injuries:

1 – Different effect of pressure

2 – Effects of projectiles

3 – Effect of Structural damage and being thrown by wind

4 – Burns, asphyxia, exposure to toxic inhalants

 

Primary Blast Injuries – Barotrauma :  over or underpressurization

  • Mostly organs that are air-filled and airfluid levels
  • TM membrane, pulmonary damage, air embolis, repture of hollow viscus
  • Increase in pressure of 5psi is enough to reputure TM
  • TM neurapraxia – deafness, tinnitus, vertigo
  • 56-76 psi needed to damage other organs
  • Therefore, if no rupture of TM, then other organs likely fine regarding primary injury
  • Lungs:  pneumo, hemo, subq emphysema, pulm edema, air emboli
  • Colon:  most common hollow viscous perforated; mesenteric ischemia
  • Eye:  rupture of globe, serous retinitis, hyphema
  • Brain:  LOC, TBI

 

Secondary Blast Injuries – Projectiles / Explosives

  • Penetrating wounds
    • Primary fragments – come from the explosive itself
    • Secondary fragments – come from the explosion, ie broken glass from windows

 

Tertiary Blast Injuries –Structure and Wind

  • Blast can cause structural damage and fragmentation of buildings/vehicles
  • Crush Syndrome – metabolic derangement resulting from damage to muscle leads to renal failure
  • Compartment Syndrome – damaged edematous muscle in inelastic sheath; don’t forget the abdomen
  • Pts trapped for many hours to days may die from the crush and compartment syndromes
  • Thrown into other objects by wind

 

Quaternary Blast Injuries- explosion related injuries from persisting conditions

  • Burns, problems related to if you are on anticoagulation, or if you are pregnant, toxins
  • Ex. Resp illness related to 9-11 bombings

 

General Concepts:

  • Injuries in closed areas like buildings or buses will have more victims with primary injury than in open areas (Israel bus bomb vs. air bomb)
  • Injuries are BIPHASIC (high immediate deaths, followed by low early and late mortality rates)
  • Triage:  “greatest good for the greatest number”
  • Goal – find critically ill with CORRECTABLE conditions among the many people with minor injuries
  • Up to 28% of blast survivors may have serious eye injuries
  • The care of a child is more resource intensive than the care of an adult
  • During pregnancy, direct injury of the fetus is said to be uncommon, due to amniotic fluid, but the attachment to the placenta is at risk and could lead to placental abruption (high density uterine wall and low density placental medium).
The views expressed on this blog are the author's own and do not reflect the views of their employer. Please read our full disclaimer here. Any references to clinical cases refer to patients treated at a virtual hospital, Janus General Hospital.
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Jay Khadpe MD

Editor in Chief of "The Original Kings of County" Assistant Professor of Emergency Medicine Assistant Residency Director SUNY Downstate / Kings County Hospital
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