High Pressure Injection Wound

Aka: High Pressure Injection Wound, Spray Gun Injection Injury

1. Background
   1. Associated with occupational paint or spray gun use
   2. Nozzle pressures are very high (up to 10,000 psi, much higher than rated psi)
   3. Injected materials typically spread broadly
      1. Spread along neurovascular bundles, tendon sheaths and hand compartments
      2. Results in direct injury, local ischemia, chemical inflammation and granulomatous reaction
      3. Also sets the stage for secondary infection
2. Risk Factors: Amputation
   1. High pressure >1000 psi (43% versus 19% with low pressure injections)
   2. Delay to operating room >6 hours (58% versus 38% with earlier surgery)
   3. Injected solvents are at highest risk of amputation
      1. Organic solvents (paint thinner, paint and oil-based products)
      2. Water or air injections are not associated with amputations
   4. References
      1. Hogan (2006) J Orthop Trauma 20(7): 503-11 [PubMed]
3. Symptoms
   1. Non-dominant index finger most commonly affected
   2. Patient develops numbness, burning or pain over time
4. Signs
   1. Deceptively small entry wound despite severe subcutaneous damage
5. Labs: Agent injected has risk of hepatotoxicity and nephrotoxicity
   1. Liver Function Tests
   2. Blood Urea Nitrogen (BUN)
   3. Serum Creatinine
6. Management
   1. Immediate surgical Consultation
      1. Emergent surgical intervention is per surgeon's discretion
      2. Most injection injuries require surgical management
      3. Injection injuries (water and air only) without Compartment Syndrome may not require surgery
   2. Poison control Consultation (if indicated by substance injected)
   3. High risk injury!
   4. General measures
      1. Tetanus prophylaxis
      2. Elevate the affected extremity
      3. Broad-spectrum empiric antibiotics
      4. Parenteral antibiotics
      5. Leave wounds open
   5. Avoid measures that results in decreased perfusion (excessive swelling and vasospasm)
      1. Avoid Digital Blocks
      2. Avoid local ice
7. Complications
   1. Pyogenic Flexor Tensynovitis
      1. Staphylococcus aureus is most common
8. Course
   1. Precaution
      1. Most high pressure washers provide >2000 psi at the nozzle (which may be >10x higher than rated psi)
   2. Amputation Incidence
      1. Amputation rate: 50% if injection psi >2000
      2. Amputation rate: <40% if injection psi <2000
9. References
   1. Hori (2015) Crit Dec Emerg Med 29(3): 2-7
   2. Vasilevski (2000) Am J Emerg Med 18:820-4 [PubMed]