high pressure fluids can cause initially innocuous injury but devastating delayed injuries
Epidemiology
most common in laborers in industry using high pressure sprays or hydraulics such as paint, automotive grease, solvents and diesel oil
Pathophysiology
a fluid spray at over 100psi pressure is sufficient to pass through the skin
many sprays are 3,000-10,000psi and the fluid is travelling at up to ~600kph and the force can be equivalent to a 1 ton press falling from 25cm
the injection of fluid dissects the soft tissues along lines of least resistance (including along neurovascular bundles)
injury can arise from:
direct pressure injury which may cause vascular occlusion and subsequent tissue necrosis
chemical irritation
secondary inflammatory response
secondary infection
Clinical features
often have a benign looking entry wound which is initially relatively painless
if the injury is substantive, there will be delayed onset of oedema, tense tissues, pallor and cold which may then result in necrosis
Diagnosis
Xray - may show extend of radio-opaque material
otherwise it is clinical
Mx
tetanus prophylaxis
limb elevation
parenteral antibiotics for gram-negative and gram-positive coverage
monitor for compartment syndrome
avoid digital blocks and ice to prevent decreased perfusion
contact plastic surgery early as most cases need emergent surgical debridement to remove foreign bodies, irrigate and debride necrotic tissue (this may need to be repeated in 24-72hrs)
approx. half of “non-operative, conservatively managed” cases will need surgery 1)
if surgery is delayed > 10hrs, rate of amputation increases
~half of finger injuries will need amputation
amputation rates approach 50% with organic solvents, oil-based paint, paint thinner, diesel fuel, jet fuel, or oil