It can first appear as a minor cut: an annoyance, rather than a serious issue. High-pressure equipment carries an inherent risk of accidents, and it’s easy to treat an innocuous-looking injury as a routine battle scar in an industry where so many work with their hands on a daily basis.
In reality, though, contractors should respond to high-pressure injection injuries as if they were shot with a liquid bullet — and to avoid dire consequences, such as amputation, time is of the essence.
“These injuries initially produce little pain and do not appear severe,” said Dr. Ryan Wermeling, a plastic surgery resident at the University of Kentucky and a specialist in high-pressure injection injuries to the hand. “But early recognition is one of the most important factors in managing the condition.”
Grease guns, airless spray guns, diesel injectors, paint guns, concrete guns, and plastic injectors are all possible sources for injection injuries, where the injector pierces the skin and underlying tissues. This causes material to be embedded deep within the body, making it a challenge to clean or disinfect the area. As such, the prognosis varies based on the substance injected.
“Injuries involving substances that contain organic solvents have a much worse prognosis than those involving substances that are more inert,” Wermeling explained. “Oil-based paint and paint thinner [are] considered the worst offenders. They have an amputation rate of over 50 percent.” Substances such as grease, diesel, air, and water can be less damaging.
No matter the substance, the most controllable variable is time. Wermeling notes that the amputation rate for severe injection injuries involving oil-based paint or thinner is close to 60 percent if the time between injury and debridement exceeds six hours. But if dealt with in under six hours, the amputation rate falls below 40 percent.
How Injection Injuries Happen
According to Rory S. McLaren, director of the Fluid Power Safety Institute, the typical age range of an injection-injury patient is between 21 and 59, with 36 as the average. McLaren says research shows most injuries occur to those working at a new job for less than six months, presumably due to a lack of equipment familiarity.
The most common injection site is the non-dominant hand, on which the thumb, index, and middle fingers are often injured. The tip of the non-dominant index finger is the most reported location. “This is because the device is most often held in the dominant hand while the device is being worked on, or in the case of a paint spray gun, the nozzle is being adjusted by the other hand,” McLaren said.
Injection injuries typically occur at a pressure of between 2,000 and 10,000 psi (13.8‒68.9 MPa) of velocity, McLaren said. That far exceeds the threshold of the mere 100 psi (0.7 MPa) needed to puncture the skin. Because of that pressure, the injected fluid can travel a significant distance from the initial wound — thus leading to widespread tissue damage.
As a whole, high-pressure injections occur in about 1 of every 600 cases of hospital-reported hand injuries, McLaren said. People most at risk are those who work near hydraulic-powered machinery. However, it is possible to simply be in the wrong place at the wrong time.
Initially, the point of entry and possibly exit can look very small, McLaren said. It may not bleed, and the patient may not complain of pain — just numbness or increased pressure. But over time, the location will become increasingly irritated.
As Wermeling explained, the prognosis improves if surgical debridement — the removal of damaged tissue and foreign material — is performed within six hours. Unfortunately, research shows the average time between an injection injury and emergency department treatment is eight hours, McLaren said.
“Victims may return to work for some time,” Wermeling said.
Injuries with oil-based paint, paint thinner, or other organic solvents often produce severe pain only within hours, according to Wermeling. This help victims get to treatment faster, but the downside is those substances are more toxic. Meanwhile, grease or diesel injections may produce very few initial symptoms. In fact, Wermeling says there have been reports of victims of those injections delaying treatment for months — at which time an intense chronic inflammatory reaction can develop.
“A high-pressure injection injury of the hand is an emergency,” Wermeling said, adding that a trip to a hospital emergency room — not urgent care or a general physician — is essential. “We recommend that the patient be taken to surgery as quickly as possible.”
Before the procedure, given under anesthesia, medical personnel will check for any signs of life-threatening trauma or systemic reactions. Patients can help doctors by providing information on the velocity of the injection machine and the Safety Data Sheet (SDS) for the substance.
Beyond debridement, Wermeling explains that awareness is crucial. He says emergency room staff should inform patients of the amputation risk and the likelihood of functional loss, thereby stressing motivation and cooperation in rehabilitation exercises.
Even if amputation is avoided, other complications can include infection and chronic pain in the affected area — sometimes making it too stiff to be usable. As a result, rehabilitation programs, such as physical therapy, are key to restoring as much use as possible.
The good news is that injection injuries are preventable.
For example, Graco, a spray equipment manufacturer, has a checklist of items to prevent injection injuries. The list asks users to stay clear of high-pressure fluid streams and sprays; never remove protective devices such as spray gun tip guards; use only flushing practices outlined in the instruction manual; never try to stop leaks with a hand or body part; always use the spray gun trigger safety when not spraying; and not to feel for leaks using hands or a rag.
Additionally, Graco implores users to observe listed pressure-relief procedures and not to exceed the working pressure ratings of components, which can cause over-pressurized equipment and the unexpected rupture of a sprayer part, leading to a release. The company also advises paying special attention to all high-pressure equipment and inspecting for any excessive wear, damage, or ill-fitting connections.
Meanwhile, the U.S. Centers for Disease Control and Prevention (CDC) offers tips for avoiding injection injuries involving pressure washers. These include not pointing a high-pressure device toward yourself or others; not attempting to push or move objects with spray; and using only approved, grounded outlets and extension cords.
Other popular suggestions include wearing basic personal protective equipment (PPE), such as gloves and goggles, and following all instructions from the equipment manufacturer and the coating or solvent manufacturer. The American Association of Poison Control Centers also has a 24-hour hotline at (800) 222-1222 that offers free, confidential medical advice for poison exposure questions.
Safety should be your number one concern on any project. Taking the time to prevent injection injuries now might keep you healthy in the long run.
This feature is part of a special anniversary series in 2017 in which CoatingsPro reflects on and updates the magazine’s most-read digital stories. To see the original article, please click here.