special subjects
High Pressure Injection Injuries
Introduction
High-pressure injection (HPI) injuries are rare injuries that occur when substances are accidentally injected by industrial equipment under pressure high enough to breach the skin. The injected substance often causes extensive tissue damage . Diagnosis is clinical; evaluation requires x-rays. Treatment is surgical, sometimes including amputation. High-pressure injection (HPI) injuries are usually work-related but occasionally involve hobbyists or home repair projects. HPI injuries are rare, even though the use of high-pressure injection apparatus and activities involving the injection of various industrial fluids under high pressure are common industrial processes. These fluids include paints, air, solvents, gasoline, hydraulic fluid, grease, and water. Accidental injection of industrial fluid via an HPI apparatus has serious and often limb-threatening consequences for workers. Pressure can be as high as 10,000 pounds per square inch (69,000 kilopascals) with velocities up to 400 mph (644 km/hour), which can cause direct and sometimes severe tissue damage. Also, the injected fluid disperses throughout the subcutaneous tissues, often along lines of low resistance, specifically often the neurovascular structures. Many injected fluids are irritating and cause a significant foreign body reaction if allowed to remain in the tissue. Infection rates depend on the substance injected, degree of tissue damage, and the body part involved. Patients should be frequently re-evaluated because the risk for infection following these injuries is high. Most HPI injuries occur in the nondominant hand of male workers with an average age of 36. 