Blast injuries - emergency medicine revision
Overview
Blast injuries produce a complex, multisystem pattern of trauma from the blast wave itself and from secondary effects (projectiles, body displacement, thermal/chemical exposures and structural collapse).
In the emergency department, treat suspected blast victims as major‑trauma patients and maintain a high index of suspicion for occult primary‑blast injuries (lungs, middle ear, hollow viscera, brain, and arterial gas embolism).
Use national major‑trauma and resuscitation guidance for initial assessment and for mass‑casualty organisation (NICE NG39/NG40; Resuscitation Council special‑circumstances guidance).
Basic physics and pathophysiology
An explosion generates a rapidly expanding gas front that creates a high‑pressure overpressure wave followed by a negative phase as air rebounds. Two mechanical effects are clinically important:
- Stress (longitudinal) waves: act at tissue-gas interfaces (for example alveoli, bowel, middle ear), causing spalling, implosion and micro‑ or macroscopic haemorrhage.
- Shear (transverse) waves: produce differential acceleration and tearing at tissue attachment sites, contributing to blunt soft‑tissue and skeletal injury.
Primary blast injury (PBI) results from the pressure wave acting directly on tissues. Secondary, tertiary and quaternary injuries result from debris, body displacement and other explosion consequences.
Classification (practical)
- Primary: direct barotrauma from the blast wave - classically affects lungs (primary blast lung), middle ear (tympanic membrane rupture), hollow viscera, eye and CNS (concussive injury).