Blast Injury HARRT 2004

PRIMARY BLAST INJURY Unique to HE explosions Unique to HE explosions Damage sustained as a direct result of the blast wave Damage sustained as a direct result of the blast wave Air-containing structures are the most susceptible: Air-containing structures are the most susceptible: Lungs Lungs G.I. Tract G.I. Tract Ears (tympanic membranes) Ears (tympanic membranes)

PRIMARY BLAST INJURY Damage occurs in 3 ways: Damage occurs in 3 ways: Spalling: Pressure wave moving from an area of high density to one of lower density. Spalling: Pressure wave moving from an area of high density to one of lower density. Results in turbulence at the interface between the 2 areas and a shattering of tissue at the border. Results in turbulence at the interface between the 2 areas and a shattering of tissue at the border. Implosion: Compression of pockets of gas within areas of the body causing them to rebound to a greater volume as the wave passes Implosion: Compression of pockets of gas within areas of the body causing them to rebound to a greater volume as the wave passes Acceleration/Deceleration of different tissues at different rates and speeds Acceleration/Deceleration of different tissues at different rates and speeds

PRIMARY BLAST INJURY:PULMONARY BAROTRAUMA Most common type of fatal blast injury. Most common type of fatal blast injury. Generalized alveolar damage due to spalling effect: Generalized alveolar damage due to spalling effect: Hemorrhage Hemorrhage Edema Edema Parenchymal/pleural lacerations Parenchymal/pleural lacerations A-V fistulas A-V fistulas Acute Gas Embolism (AGE) Acute Gas Embolism (AGE) ARDS ARDS Pulmonary contusions Pulmonary contusions

SECONDARY BLAST INJURY Both HE and LE Explosions Both HE and LE Explosions Damage sustained by the impact of debris energized by the blast. Damage sustained by the impact of debris energized by the blast. Speeds > 1500 mph. Speeds > 1500 mph. One’s thumb in another’s neck. One’s thumb in another’s neck. Due to blast winds. Due to blast winds. Both blunt and penetrating trauma. Both blunt and penetrating trauma. Responsible for majority of casualties. Responsible for majority of casualties. e.g. Oklahoma City: wounds due to glass shards. e.g. Oklahoma City: wounds due to glass shards. Pipe bombs Pipe bombs

PHYSICAL EXAM A,B,Cs A,B,Cs LUNGS LUNGS Contusion, pneumothorax Contusion, pneumothorax Dyspnea Dyspnea Chest pain Chest pain Hemoptysis Hemoptysis Rales, rhonchi Rales, rhonchi Cyanosis Cyanosis Respiratory S&S may occur later. Respiratory S&S may occur later.

PHYSICAL EXAM G.I. TRACT G.I. TRACT Principally colon & stomach. Principally colon & stomach. Occult Occult May require repeat exams May require repeat exams Pain, nausea, vomiting, rectal bleeding, testicular pain. Pain, nausea, vomiting, rectal bleeding, testicular pain. Especially in closed- space/underwater blasts Especially in closed- space/underwater blasts Leibovici, ‘99: No such injuries found in open-air bombings in his series. Leibovici, ‘99: No such injuries found in open-air bombings in his series.