Sunday, May 26, 2013

BLAST INJURIES: ESSENTIAL FACTS


In lieu of recent events, I contemplated doing a post on this completely myself, but the more I read, the more I realized that it would be re-inventing the wheel on my part as there are EXCELLENT resources out there on this topic. Below you will find one of the best, down and dirty reviews on BLAST injuries, their treatment, monitoring, and disposition courtesy of the CDC. It is a fairly long review, so feel free to browse through it, read only parts of it, and share it away. I modified this slightly by highlighting the key points with my own comments after them.

Any EMS, public safety or medical personnel need to be aware of at least the following basics when dealing with blast patients:

1) Key Concepts:

- Bombs and explosions can cause unique patterns of injury seldom seen outside combat
- Expect HALF of all initial casualties to seek medical care over a ONE-HOUR period
- Most severely injured arrive AFTER the less injured, who bypass EMS triage and go directly to the closest hospitals
- Predominant injuries involve multiple penetrating injuries and blunt trauma
- Explosions in confined spaces (buildings, large vehicles, mines) and/or structural collapse are associated with GREATER morbidity and mortality
- Primary blast injuries in survivors are predominantly seen in confined space explosions
- Repeatedly examine and assess patients exposed to a blast
- All bomb events have the potential for chemical and/or radiological contamination
- Triage and life saving procedures should never be delayed because of the possibility of radioactive contamination of the victim; the RISK OF EXPOSURE to caregivers is SMALL
- Universal precautions effectively protect against radiological secondary contamination of first responders and first receivers... this means that you need to wear it!
- For those with injuries resulting in nonintact skin or mucous membrane exposure, hepatitis B immunization (within 7 days) and age-appropriate tetanus toxoid vaccine (if not current)

2) Blast Injuries:

- PRIMARY: Injury from over-pressurization force (blast wave) impacting the body surface resulting in:
TM rupture, pulmonary damage and air embolization, hollow viscus injury

- SECONDARY: Injury from projectiles (bomb fragments, flying debris) resulting in:
Penetrating trauma, fragmentation injuries, blunt trauma

- TERTIARY: Injuries from displacement of victim by the blast wind resulting in:
Blunt/penetrating trauma, fractures and traumatic amputations

- QUATERNARY: All other injuries from the blast:
Crush injuries, burns, asphyxia, toxic exposures, exacerbations of chronic illness

PRIMARY BLAST INJURY:

1) Lung Injury:

-Signs usually present at time of initial evaluation, but MAY BE DELAYED up to 48 hrs
- Reported to be more common in patients with skull fractures, >10% BSA burns, and penetrating injury to the head or torso
- Varies from scattered petechiae (pin-point hemorrhages of the skin) to confluent hemorrhages
- Suspect in anyone with dyspnea, cough, hemoptysis, or chest pain following blast
- CXR: “butterfly” pattern
- High flow O2 sufficient to prevent hypoxemia via NRB mask, CPAP, or ET tube
- Fluid management similar to pulmonary contusion; ensure tissue perfusion but avoid volume overload
- Endotracheal intubation for massive hemoptysis, impending airway compromise or respiratory failure... common sense here, if you suspect airway deterioration of the pt, then tube them while you still can!
- Consider selective bronchial intubation for significant air leaks or massive hemoptysis
- Positive pressure may risk alveolar rupture or air embolism
- Prompt decompression for clinical evidence of pneumothorax or hemothorax... remember it is better to decompress if you suspect a tension PTX than NOT... if the pt turned out to have a HEMOthorax, then you will only get blood back! That is OK, put a stopcock on it, and move on, at least you now know the cause of their hemodynamic collapse!!!
- Consider prophylactic chest tube before general anesthesia or air transport... this is CRITICAL for those of you working in smaller outlying hospitals to which patients may show up for INITIAL stabilization... if you are a flight crew or an EMS transport agency picking this patient up, make sure this is done!
- Air embolism can present as stroke, MI, acute abdomen, blindness, deafness, spinal cord injury, claudication
- High flow O2; prone, semi-left lateral, or left lateral position
- Consider transfer for hyperbaric O2 therapy... know where your hyperbaric hospitals are, many cities only have ONE or none!

2) Abdominal Injury:

- Gas-filled structures most vulnerable (esp. colon)
- Bowel perforation, hemorrhage (small petechiae to large hematomas), mesenteric shear injuries, solid organ lacerations, and testicular rupture
- Suspect in anyone with abdominal pain, nausea, vomiting, hematemesis, rectal pain, tenesmus, testicular pain, unexplained hypovolemia
- Clinical signs can be initially subtle until acute abdomen or sepsis is advanced

3) Ear Injury:

- Tympanic membrane MOST COMMON PRIMARY BLAST INJURY!
- Signs of ear injury usually evident on presentation (hearing loss, tinnitus, otalgia, vertigo, bleeding from external canal, otorrhea)

4) Other Injury:

- Traumatic amputation of any limb is a marker for multi-system injuries... this may seem common sense, but we all too often TUNNEL VISION on these injuries due to their graphic & horrifying nature... throw a tourniquet, and move on with your primary assessment! Once you stop the external bleeding, it is the other stuff that will kill them... PTX, head injury with increased ICP, internal bleeding, perforated organs, etc... don't forget that!
- Concussions are common and easily overlooked
- Consider delayed primary closure for grossly contaminated wounds, and assess tetanus immunization status
- Compartment syndrome, rhabdomyolysis, and acute renal failure are associated with structural collapse, prolonged extrication, severe burns, and some poisonings
- Consider possibility of exposure to inhaled toxins (CO, CN, MetHgb) in both industrial and terrorist explosions
- Significant percentage of survivors will have serious eye injuries

DISPOSITION:

- No definitive guidelines for observation, admission, or discharge
- Discharge decisions will also depend upon associated injuries
- Admit 2nd and 3rd trimester pregnancies for monitoring
- Close follow-up of wounds, head injury, eye, ear, and stress-related complaints
- Patients with ear injury may have tinnitus or deafness; communications and instructions may need to be written

Please see the full resource text for further info at:
http://emergency.cdc.gov/HAN/han00346.asp

I would like to thank the CDC website and Epocrates for this detailed summary.

Stay safe!

AS ALWAYS I TRY TO ENSURE THE ACCURACY OF MY MATERIAL, BUT MISTAKES HAPPEN AS I AM HUMAN. IT IS YOUR DUTY TO DOUBLE CHECK ALL INFO, PARTICULARLY THAT FOUND ON THE INTERNET. PLEASE FOLLOW YOUR LOCAL PROTOCOLS BUT DO NOT DISREGARD YOUR COMMON SENSE.

~EMSDoc911

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