Dated: Sunday, 22nd NOVEMBER 2009

Title: HIGH PRESSURE INJECTION INJURIES

Key Features of High Pressure Injection Injuries:

The entrance site from HPI injuries is often deceptively small leading to an underestimation of the severity of the injury. The injury is usually initially painless, and the individual may continue to work and not seek immediate treatment. Within a few hours of injury, fever, lymphadenitis (swelling of the local lymph nodes), extreme pain and inability to move the affected

appendage usually develop. High pressure injection injuries are genuine medical emergencies, no matter how benign the initial appearance. Immediate specialist surgical treatment is required no matter how seemingly benign the injury is. Physicians commonly underestimate the severity of these injuries, resulting in inappropriate early discharge from hospital and/or critical delays

in treatment. The injected material acts as a projectile. It is important that the treating physician looks for both entrance and exit wounds. Most frequently, the site of injury is a small puncture wound on the terminal segment of the index finger of the non-dominant hand. The average age of the patient at injury is 28.4 years, with an age range of 16-47 years. The left hand is twice as likely to be damaged as the right hand. A common explanation for this being that inexperienced workers clean the

end of a pressure gun with the tip of a finger.

Key Features of High Pressure Injection Injuries:

Can occur with virtually any liquid, vapour or gas that is used at pressures > or = 50 – 100 psi including: Greases, Solvents, Hydraulic Fluids, Gas Oils (particularly Diesel Oils), Paints & Other Coatings, Steam, Compressed Air, Other Compressed Gases or Propellants & can also occur with Solids e.g. Sand Blasting.

Prognosis of High Pressure Injection Injuries:

Even with expert medical treatment, amputation rates range from 16-55% for HPI injuries. Permanent disability is the usual outcome, particularly when the hand or fingers are involved.

SAFETY ALERT #379

WHICH PROGRESSES TO A BIG INJURY!

THAT OFTEN PROGRESSES TO A BAD OUTCOME EVEN WITH TREATMENT!

INITIALLY THERE IS A SMALL HOLE!

Chemical Properties of the Injected Material have a Considerable Effect on Clinical Injury:

Viscous substances - dispersion in the tissues is less marked than with more fluid materials. These substances primarily affect the nerves and blood vessels in the affected area leading to severe injuries.

Low viscosity materials disperse more readily into the soft tissues but often produce extensive inflammation. Injection pressure is also reported to be a factor in the extent of injury. Solvents (hydrocarbon solvents, chemsols) are associated with extensive damage and may cause lipid dissolution and destruction of

tissues, even when not injected under high pressure. Solvents produce the most severe inflammatory responses, leading to high amputation rates. Grease has been shown to be associated with oleogranulomata formation (a reaction to foreign bodies), fistula formation, fibrosis, and poor

functional outcomes.

Implications:

All hydrocarbon (and probably chemsols) solvents except the pentanes are used in high pressure applications – SDS should contain a warning phrase regarding high pressure injection injury.

All substances should be checked for high pressure applications and a warning phrase should be included in the SDS where appropriate. SDS updates are a lower priority but high impact process.