9/4/2014 Blast Injuries Objectives • An Overview of the Effects of Blast Injuries at the • Describe the basic physics, mechanisms of injury, and Medical Level pathophysiology of blast injury • List the four types or categories of blast injuries • List the factors associated with increased risk of Presented by: Jay Wuerker, EMT-P primary blast injury EMS Instructor II Objectives…cont. Why? • Recognize the key diagnostic indicators of serious • Combat primary blast injury • Terrorism • State the most common cause of death following an • Accidents explosion Combat: Iraq & Afghanistan Terrorism: USS Cole 1 9/4/2014 Terrorism: ??? Terrorism • Bombings are clearly the most common cause of casualties in terrorist incidents. • Recent terrorism has shown increasing numbers of suicidal bombers wearing or driving the explosive device • A poor man’s guided missile! Boston Marathon April 15, 2013 Pressure cooker device • Pressure cooker device (2), form of an IED • “Inspire” magazine Summer 2010, “Make a Bomb in • Same type of device used in Mumbai train bombings the Kitchen of your Mom”, by “The AQ chef”. in 2006 and Time Square car bomb attempt in 2010 • Al-Qaeda publication article on the step by step • Often packed with nails, ball bearings and other small process for making a Pressure cooker bomb. metal objects Boston Marathon Results • Three killed, 264 wounded – many with amputations, scene described as a war zone • One Police officer killed in shoot out with bomber suspect Dzhokhar Tsarnaev 2 9/4/2014 Not in Wisconsin? • Steve Preisler - aka “Uncle Fester” , from Green Bay , graduated from Marquette University in 1981 with a degree in Chemistry and Biology. • Many books, including “Secrets of Methamphetamine Manufacture” and “Home Workshop Explosives” • Has a website MacGyver Bombs MacGyver Bombs cont. • Park High school – October 2, 2012 • Chemicals used include Drain or Toilet bowl cleaners, • Plastic bottle – soda or water (different sizes) Calcium Hypochlorite or such items as Dry Ice • Use combination of a strong acid or base and things • Injury from blast effects and chemical that may cause like aluminum foil to create a gas that causes the burns or respiratory injury container to explode • Felony in many states New Threats September 11, 2014 • ISIS – Islamic State of Iraq and Syria • ? • Estimated 100 US citizens belong to ISIS • 6000 missing foreign nationals on student visas in the US • Times Square and Las Vegas 3 9/4/2014 Accidents Accidents Grain elevator Fireworks Plant Explosion First… A Little Theory Morton Thiokol …What Is An Explosive? Destroyed in Seconds – Chemical Plant Explosion • There are four types… • High explosive • http://youtu.be/_KuGizBjDXo • Low explosives • Fuel-Air explosives • Nuclear Explosives We won’t talk about nuclear explosions… Explosives High Order Explosives “HE” • Nitroglycerine • High order • Dynamite • Detonation • TNT – the “classic” • Blast wave formation (supersonic) • PETN – ‘det’ cord. • Low order • Deflagration • C-4 – familiar to all military • No blast wave formation (always subsonic) • Semtex (Warsaw pact version of C-4) • ANFO • Ammonium nitrate, fuel oil mixture 4 9/4/2014 High Order Explosives Low Order Explosives “HE” (Propellants) • When a high explosive detonates, it is converted • Gunpowder instantaneously into a gas at high pressure and • Nitrocellulose temperature. • Smokeless powder • (This is also is a high explosive under certain • The expansion of these gases creates the blast wave. conditions) • Brisance is the shattering effect of the blast wave • Match heads • Multiple other compounds • Abnormal explosion of a high order explosive may occur Deflagration Fuel-Air Explosives Low-Order Explosive Combustion (Thermobaric Weapons) • Neither a high explosive nor a low order explosive • Has features of both • Most often has deflagration • May have supersonic detonation • May have much longer, broader blast wave than high explosive Deflagration is very rapid burning…. The speed is increased by confinement Thermobaric Weapons Fuel-Air Mixtures Fuel-Air Mixtures (not just military explosives) • Particularly effective in enclosed spaces • Fireball and blast can travel around corners • Blast waves are intensified when reflected by walls and other surfaces. • Grain/dust explosions • Optimized to produce heat and blast • BLEVE • Secondary effects through flying fragments • Toxic detonation gases • Boiling Liquid Expanding • Anoxia Vapor Explosion • Slow escape of natural or LP gas 5 9/4/2014 IED IED (A very, very bad terminology) Has many shapes • Improvised Explosive Device • ANY device that doesn’t have a military issue number…somewhere • Ranges from • crude match-head pipe bombs Low explosive • Experimental professional munitions that don’t yet have issue numbers Often high explosives Issued Munitions …can be part of an IED Roadside IED… 155 mm Artillery shells linked with detonation cord Injuries From Blast Blast Effects Definitions • Primary • The direct effect of the blast • Secondary • Due to projectiles from the blast • Tertiary • The victim is thrown by the blast wind • Quaternary • All other effects – burns, building collapse, etc. 6 9/4/2014 Primary Blast Injury Primary Blast Injury • Primary Blast Injury (PBI) is caused directly by the • Compression of surrounding air or water sudden increase in air pressure after an explosion • Differential pressures at interfaces • Blast wave or shock front that travels faster than the speed • Differential pressures in tissues of sound • Organ distortion • Tensile strength of the tissue is exceeded • How will this injure tissue??? • Tissue tearing Variables Affecting Severity Variables Affecting Severity Primary Blast Injury Primary Blast Injury • "Blast Environment" is a very important • Distance is the most important factor determining the extent of injuries. • Intensity varies by the third power of the distance… • Nearby structures may either act as a shield or • Double the distance from the explosion and may reflect the blast wave onto a casualty. reduce the injury by a factor of 8 • Confined environment increases damage • The most effective way to minimize injury • Foxhole or shelter is a confined environment from primary blast injury is to increase the • Inside the bus is bad… distance from the center of the explosion (stand-off distance) • Orientation of body relative to blast wave – end-on orientation minimizes injury Variables Affecting Severity Blast Inside of a Closed Space Reflected Primary Blast Injury Blast Waves • A blast wave that is reflected can create • Peak of the initial positive wave a peak pressure 10X greater than that • Overpressure >60-80 PSI potentially lethal of the incident wave. • Duration of the overpressure • Blast waves inside buildings are repeatedly • Longer is bad – See thermobaric weapons reflected creating a “complex blast wave” • Medium in which it travels • Marked increase in injuries related to primary blast effects when explosion • Water is a special case occurs in a closed space 7 9/4/2014 Primary Blast Injury Primary Blast Injury • Organs most sensitive to blast effects are air filled (damage is produced at the • Direct trauma interface between air and water) • Amputations • middle ear: ear drum rupture @ 5 psi • Death • the respiratory system – • lungs and bronchi: lung damage at 15 psi • Hollow organ damage • upper airways (trachea, pharynx and larynx) • Ear • nasal passages and sinuses • the bowels. • Lung • LD is around 50 psi. • GI tract 50 • Air embolism is 1o cause of sudden death due to blast Primary Blast Injury Primary Blast Injury Traumatic Amputation • Blast wave creates stress wave through skin and muscles • Stress wave shatters solid bone • Landmines • Expanding gases enter and expand tissues while ripping off distal part Death Amputation Primary Blast Injury Primary Blast Injury Pulmonary Injury Pulmonary Injury • Hemorrhage: • Blood vessels stretched and torn • Pulmonary contusion causing • Hemoptysis pulmonary • Hemothorax contusion • Escape of Air: • Pneumothorax • Interstitial • Pneumomediastinum hemorrhage with • Pulmonary pseudocyst oxygen diffusion Bruises on lungs produced problems • Arterial gas embolism (AGE) when primary blast wave • Apnea rapidly accelerates ribs into underlying lung tissue 8 9/4/2014 Primary Blast Injury Primary Blast Injury Pulmonary Injury Pulmonary Injury • Respiratory difficulty • With exertion • Signs of blast lung are usually present at • At rest !! the time of the initial evaluation. • Asymmetrically or patchy • Presentation may be delayed by 48 hours. decreased breath sounds Blood • In one series, all patient with blast lung required or inspiratory crackles & ventilation support within 6 hours of presentation • Decreased SaO2 on ambient air Fluids • All were in enclosed space (bus bomb) or 100% oxygen therapy in • Pulmonary infiltrates on lungs • Wheezing or SOB on arrival should be chest radiograph presumed to be blast lung Primary Blast Injury Primary Blast Injury Pulmonary Injury Brain Injury • Alveoli disrupted • Concussion • Pneumothorax • Tension pneumothorax • TBI • Asymmetrically decreased • Arterial gas embolism breath sounds • Signs and symptoms include headache, fatigue, poor • Tracheal deviation concentration, lethargy, anxiety, and insomnia • JVD • Shock if enough pressure in hemithorax to cause mediastinal shift (tension pneumothorax) Primary Blast Injury Primary Blast Injury Arterial Gas Embolism Ear Injury • Arterial gas embolism (AGE) – [air bubbles enter blood stream • Middle ear: and travel to brain and/or