A 42-year-old healthy man presented to the ED 3 hours after sustaining an injury to the tip of his left index finger from a pressurized washer. He stated that while at work, he had touched the jet nozzle of the washer to “test” its pressure, and had experienced immediate pain in his entire finger as well as blanching in his mid-finger. He took a picture of his finger with his cell phone approximately 5 minutes postinjury, which showed cynanosis at the distal volar pad (Figure 1).
On presentation to the ED, physical examination revealed only an innocuous 1-mm puncture wound to the middle of the volar pad of the distal phalanx of his left index finger, with mild tenderness along the length of the finger but no swelling. The rest of the finger and hand appeared intact with normal color and sensation.
Three weeks after discharge, however, the patient developed pain, diffuse swelling, and purulent drainage from the same injured finger and presented again to the ED. He was immediately taken to the operating room where a broad dissection was performed and drains were placed. Two months later, he reported a complete resolution of the infection and was still working on regaining full functioning of his finger by attending physical therapy.
High-Pressure Injection injuries
Diagnosis
At the time of presentation, most high-pressure injection injuries to the hand appear innocuous but frequently result in severe sequelae, including functional disability and amputation. High-pressure injuries occur when soft tissues are placed in contact or near the opening of a high-pressure device or malfunctioning equipment (eg, pinhole rupture in a hydraulic hose).
While the literature reports that 100 psi or greater is required to break the skin,1 patients presenting to the ED typically report operating machinery shooting between 2,000 and 12,000 psi.2,3 Case-report reviews of patients with high-pressure injection injuries by Schoo et al4 and Hogan and Ruland5 found this type of injury most often occurred in the nondominant hand of male laborers—primarily in the index finger—with 30% to 48% of such injuries resulting in amputation of the digit.
Mechanical and Chemical Injuries
High-pressure injection injuries can be both mechanical as well as chemical. A mechanical high-pressure injury depends upon the magnitude of the injection force, with higher pressures associated with increased dysfunction and incidence of amputation. A chemical-related injury depends upon the duration of exposure and the volume of the material injected.
A high-pressure injury results from a tearing of the soft tissues, with shearing and dissection within and among the tissue plains down the finger and into the palm and proximal tissues.4,6 In this type of injury, there is often direct injury to the neurovascular bundles.
Along with the mechanical aspect of injury, a concurrent chemical injury depends upon the type of material injected (ie, gas or liquid), cytotoxicity, concentration, and inflammatory properties.6 Hogan and Ruland5 described the incidence of amputation associated with injected materials to be greater than 40% with diesel fuel, paint thinner, oil, and paint; 20% to 40% with undercoating, hydraulic fluid, and grease; and 0% with air and water. Oil-based paint injections were associated with a 58% amputation rate comapred to only 6% for latex paints.5
In general, evaluation of high-pressure-related injuries begins with a thorough history to identify the injected material and its attributes, pressure of injection, mechanism of exposure, time elapsed since the event, and the patient’s tetanus immunization status. Interventions include radiographs to evaluate for proximal spread of injected material; tetanus immunization, if required; prophylactic antibiotic therapy7; analgesia; and often emergency surgical consultation. The use of corticosteroid therapy has not been shown to impact the amputation rate or the incidence of infection.5
Type of Injury and Treatment
Wong et al8 developed the following guidelines categorizing the type and recommended treatment of mild, moderate, and severe high-pressure injection injuries:
Mild Injuries. In mild high-pressure injection injuries, patients tend to seek immediate treatment. These types of injuries typically involve oil or water, with a relatively low-pressure exposure, and preserved circulation in the injured area.8 Treatment includes conservative management with an option for surgery.5,8