High Pressure Injection Wound

Aka: High Pressure Injection Wound, High Pressure Injection Injury, Spray Gun Injection Injury

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II. Epidemiology

  1. Accounts for 1 in 600 hand injuries
  2. Most common in young male laborers working with paint, automotive grease, solvents, diesel oil

III. 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)
    1. Injection substances are delivered at speeds approaching 400 mph
    2. By comparison, even forces as low as 100 psi are strong enough to break through skin
  3. Injected materials typically spread broadly
    1. Spread along planes of least resistance
      1. Neurovascular bundles
      2. Tendon sheaths
      3. Hand compartments
    2. Results in direct injury, local ischemia, chemical inflammation and Granulomatous reaction
    3. Risk of vascular necrosis and local soft tissue necrosis
    4. Also sets the stage for secondary infection

IV. 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 (50%)
    1. Organic solvents (paint thinner, paint and oil-based products, diesel fuel, jet fuel, oil)
    2. Water or air injections are not associated with amputations
  4. References
    1. Hogan (2006) J Orthop Trauma 20(7): 503-11 [PubMed]

V. History

  1. Time of injury
    1. Delayed presentation is common (mean 9 hours after injury)
    2. Delays (esp. >6 to 10 hours) are associated with high amputation and infection rates
  2. Offending tool
    1. Obtain information regarding the pressure gun and pressure delivered
  3. Injected substance
    1. Clean water and air are considered lower risk injection injuries
    2. Paint is associated with large inflammatory responses and high amputation rates
    3. Grease is associated with less inflammatory response and lower amputation rates

VI. Symptoms

  1. Non-dominant index finger most commonly affected
  2. Initial injury appears relatively mild
  3. Patient develops numbness, burning or pain over time

VII. Signs

  1. Deceptively small entry wound despite severe subcutaneous damage
  2. With toxic injections, injury site becomes pale, edematous and very tender to palpation
  3. Perform a complete extremity exam (and obtain serial exams during evaluation)
    1. Examine the "joint above, joint below, circulation, motor function and Sensation, skin and compartments"
    2. Neuromuscular exam
    3. Tendon exams in flexion and extension at each joint
    4. Consider Compartment Pressures

VIII. Labs: Agent injected has risk of hepatotoxicity and nephrotoxicity

  1. Liver Function Tests
  2. Blood Urea Nitrogen (BUN)
  3. Serum Creatinine

IX. Imaging

  1. XRay
    1. May demonstrate radiopaque substance
    2. Subcutaneous Emphysema may be present
  2. CT Extremity
    1. Consider in non-diagnostic XRay

X. Management

  1. High risk injury!
    1. Initial findings may be underwhelming despite being a limb-threatening injury
    2. Small punctures may hide an extensive degree of forthcoming tissue destruction
  2. Immediate surgical Consultation (e.g. hand surgery)
    1. Emergent surgical intervention is per surgeon's discretion
    2. Most injection injuries require surgical management (>50%)
      1. Early surgical decompression, irrigation and Debridement of caustic injections
      2. Worse outcomes are associated with surgical delay >6 hours after injury
      3. Serial Debridement may be needed as tissue viability evolves over first 48-72 hours
      4. Delayed closure, skin grafts, flap reconstruction or amputation may be needed
    3. Injection injuries (water and air only) without Compartment Syndrome may not require surgery
      1. Grease, hydraulic fluid, diesel fuel and solvents require emergent operative irrigation and Debridement
  3. Poison control Consultation (if indicated by substance injected)
  4. General measures
    1. Tetanus Prophylaxis
    2. Elevate the affected extremity
    3. Splint and immobilize the affected limb
    4. Broad-spectrum empiric Antibiotics
    5. ParenteralAntibiotics
    6. Leave wounds open
  5. Avoid measures that results in decreased perfusion (excessive swelling and vasospasm)
    1. Avoid Digital Blocks
    2. Avoid local ice
    3. Avoid compressive dressings

XI. Complications

  1. Compartment Syndrome
  2. Limb Amputation (approaches 30%)
  3. Pyogenic Flexor Tensynovitis
    1. Staphylococcus Aureus is most common
  4. Common longterm complications of the affected extremity (may impact employment and Disability)
    1. Chronic stiffness, pain and cold intolerance
    2. Motor weakness and sensory deficits
  5. Other rare delayed complications
    1. Oleogranuloma
    2. Fibrohistiocytic tumor
    3. Squamous Cell Carcinoma

XII. Course

  1. Predictors of worse functional outcome
    1. Digital ischemia at presentation
    2. Tendon sheath involvement
    3. Proximal spread of injected material
    4. Delayed presentation or surgery delay (>6 hours after injury)
  2. Amputation Incidence
    1. Organic solvent and oil-based paint injections are associated with higher amputation rates
      1. Grease injuries are associated with lower amputation rates
    2. Most high pressure washers provide >2000 psi at the nozzle (which may be >10x higher than rated psi)
      1. Amputation rate: 50% if injection psi >2000
      2. Amputation rate: <40% if injection psi <2000
  3. Longterm functional rehabilitation is typically required after acute management
    1. Hand therapy
    2. Physical therapy
    3. Occupational therapy

XIII. References

  1. Hori (2015) Crit Dec Emerg Med 29(3): 2-7
  2. Kiel (2023) Crit Dec Emerg Med 37(11): 18-9
  3. Murphy (2026) Crit Dec Emerg Med 40(8): 25-6
  4. Hogan (2006) J Orthop Trauma 20(7): 503-11 [PubMed]
  5. Vasilevski (2000) Am J Emerg Med 18:820-4 [PubMed]

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