Explosives and Pulmonary Blast Injuries

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Explosives and Pulmonary Blast Injuries

• Pulmonary Pathophysiology/
• Management
• Dr. Monte J. Gagliardi, CCEMT/P

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Full Measure of Devotion
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Bomb
Any container filled with explosive material
whose explosion is triggered by a clock or other
timing device
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High Order Explosives

• Detonate Quickly
• Fill Space with High Pressure Gasses
• Supersonic overpressurization shock wave
• Positive Blast Wave (gt700 tons of Press.)
• Negative Blast Wave (forms a vacuum)
• TNT, C-4, Semtex, NTG, Dynamite, Ammonium nitrate
  fuel oil

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Low Order Explosives

• Subsonic Explosion
• Overpressureization Wave
• Energy released more slowly
• Pipe Bombs, Gun Powder, Pure Petroleum Based Bombs

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Improvised Explosive Devices (IEDs)

• Usually custom made
• Any number of designs and explosives
• Conventional (Chemical Explosives)
• Dispersives (Chemicals and/or projectiles)

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C4 explosives
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Type of Explosion and Injurity Severity
Kluger,Y., Isr Med Assoc J. 20035A235-240
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Mortality, Morbidity, Hospital Resource
Utilization vs Other Trauma

• Immediate Mortality gt 29
• Inhospital Mortality (6.2 vs 3)
• Increased surgical interventions (53)
• Longer hospital stays (20 gt 14 days)
• Younger age groups

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Explosive Effects

• Blast Pressure Wave
• Fragmentation Effects
• Blast Wind
• Incendiary Thermal Effect
• Secondary Blast Pressure

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Injuries Associated with Early Mortality

• Multiple Trauma
• Head Trauma
• Thoracic Injury
• Abdominal Injury
• Effective Triage is Crucial

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Explosion Pressure Wave

• Patients Location relative to explosion
• Intensity declines rapidly over distance
• Person 10 feet vs. 20 feet
• Blast waves reflected off solid surface
• 50 will suffer pulmonary injury with blast
  pressures of 50-15- psi. Greater than 200 psi is
  fatal.

Stein, M. Medical Consequences of Terrorism.
Surg Clin North Am. 1999 791537-1552
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Primary Blast Injury

• C4 explosions pressures of over 4 million pounds
  per square inch
• Since air is compressible and water is not gas
  containing organs most susceptible ie lungs,
  bowel, middle ear

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Pulmonary Barotrauma

• Most common fatal injury
• Pulmonary contusion
• Systemic air embolism
• Thrombosis
• ARDS
• DIC

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Primary Blast Lung Injury (BLI)

• Highest Mortality and Morbitiy (10-20 of all
  fatalities)
• Chest Trauma (32 of injuries)
• BLI in 42 of victims in confined space bombings
  and 10 open air

Blast Lung Injury what clnicians need to know
CDC.gov , 10/2005
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BLI

• Pressure wave travels through the border between
  air, alveoli and blood vessels
• Pneumothorax, Pulmonary Contusion
• Alveolar hemorrhages
• Blood in the septae
• Air in the blood vessels
• Alveolar venous fistulas
• Systemic air embolism

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BLI Severity Score
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BLI Butterfly pattern of pulmonary infiltrates
and contusions
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BLI

• The degree of hemorrhage determines the degree of
  respiratory insufficiency
• Hemoptysis and Barotrauma are common signs
• Also, pneumomediastinum and subcutaneous emphysema

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BLI
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BLI Signs and Symptoms

• Symptoms
• Cough, Dyspnea, Chest Pain
• Signs
• Hypoxia, cyanosis, apnea, wheezing, decreased
  breath sounds, Hypotensio

Air Emboli can develop rapidly in these patients
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Arterial Gas Embolism
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Arterial Gas Embolism

• Avoid PPV and PEEP if possible gt risk of
  pulmonary alveolar rupture and gtformation of air
  emboli
• Hyperbaric oxygen is definitive Tx
• High flow 02 and left lateral recumbent
• Unilateral lung ventilation may be required

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BLI Treatments

• Supplemental High flow oxygen
• Endotracheal intubation prn
• Ventilation difficulty may require limited peak
  inspiratory pressures (lt40 cm H20)
• Volume controlled ventilation
• Permissive hypercapnia
• Chest tubes for pneumothoraces

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BLI Management

• Positive Pressure Ventilation Most
• High frequency jet ventilation
• Independent Lung ventilation
• Extracorpeal membrane oxygenation

Pizov, et. al. BLI from Explosion on Civilian
Bus, Chest, 1999, 115 165-172
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Are we Ready?
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BLI Wrap up

• Respiratory difficulty and hypoxia
• Complicated by pneumothoraces and air embolism
• Patients with variety of symptoms
• Tachypnea, chest pain, cough, wheeze, hemoptysis,
  lt lung sounds
• High flow 02, PPV prn, permissive hypercapnia,
  judicious fluids