Frostbite patients may benefit from innovative fluorescence imaging technology

Major advancement allows physicians to visualize blood flow with handheld device at bedside

Physicians at Hennepin Healthcare have a new tool to help make life and limb-saving decisions in patients being evaluated for frostbite injury and other tissue perfusion concerns. Stryker’s SPY-PHI is a hand-held device that was made to be used in a surgical setting to visualize the quality of blood flow in vessels and micro vessels that provide oxygen to organs. HCMC is the first hospital in the state to implement this advanced technology in an acute setting.

“We’ve already realized SPY’s benefits when evaluating exposure patients for frostbite injury,” explains HCMC emergency physician Dr. Thomas Masters. “It may help physicians determine when the use of clot-busting medications is indicated, as well as when it’s not.”

SPY-PHI uses a near-infrared low powered laser light source to stimulate a fluorescent imaging agent that has been injected into the blood stream. The fluorescent agent binds to the proteins in blood and circulates through the body. When stimulated by near infrared light, the protein-bound agent emits a fluorescence signal which enables visualization of blood flowing through vessels and into tissue. The fluorescence is captured by a special camera, is processed and is displayed on a video monitor for the physician to review. Since the agent is bound to blood, where blood goes, it goes. If there is no fluorescence, it can mean that there is compromised blood flow.

“We hope that eventually it may have applications for crush injuries, necrotizing fasciitis, and other types of wounds,” said Dr. Masters.

Unlike traditional bone scans, which can be time-consuming to perform in an emergent situation, SPY technology does not involve ionizing radiation and utilizes a fluorescence imaging agent with a short half-life thus allowing surgeons to repeat perfusion assessment as needed.  

HCMC is a nationally recognized Level I Adult Trauma Center and Level 1 Pediatric Trauma Center with the largest emergency department in Minnesota. It is operated by Hennepin Healthcare System, Inc., a subsidiary corporation of Hennepin County. The comprehensive academic medical center and public teaching hospital and clinic system includes a 484-bed acute care hospital, primary care and specialty clinics located in Minneapolis and surrounding suburban communities, as well as home care and hospice services.

HCMC using real-time blood flow imaging to improve treatment for non-healing wounds

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HCMC is the first in Minnesota to use the LUNA Imaging System

Hennepin County Medical Center’s (HCMC) Center for Wound Healing and its Center for Hyperbaric Medicine are now using fluorescence microangiography – a new technology that can assess blood flow in chronic, non-healing wounds and diabetic foot ulcers. HCMC is the first in Minnesota to use the LUNA™ Imaging System during wound assessment.

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Dr. Thomas Masters

“The results of using LUNA have become so impressive that we can’t imagine caring for wounds without it. It’s quickly become an integral assessment tool,” explains emergency physician Dr. Thomas Masters.

Healthy blood flow or microcirculation is essential to healing wounds that can result from diabetes, a complication from a recent surgery, or even frostbite. Fluorescence microangiography with the LUNA system enables doctors to perform assessment of blood flow to the wound, utilizing real-time information to define treatment plans, optimize patient recovery and reduce the frequency of these complications. Complications from chronic wounds may include necrosis, infection, partial or total limb amputation and the need for repeat surgery.

“We already know that some diabetic and radiation wounds greatly improve when treated with hyperbaric oxygen therapy,” said Dr. Masters. “Having the LUNA diagnostic tool to visualize the results allows us to measure the successful healing process during treatment. Likewise, it can indicate when there’s irrevocable tissue death so unnecessary limb preservation efforts can be avoided.”

Procedures with the LUNA System do not involve the potential safety hazards associated with X-ray procedures and traditional contrast agents. Because the dye that’s used is processed in the liver, kidney function is not affected. This is significant for patients diagnosed with diabetes whose kidney function may be at risk.

“We care for many patients with diabetes who may already have compromised kidney function, so this was a very important factor to us,” said Dr. Masters.

HCMC has the only multi-chamber hyperbaric oxygen facility in the region that’s used for 24/7 emergency treatment of critically ill patients and those with limb or life-threatening infections.

Hyperbaric oxygen has long been recognized as an important adjunctive therapy for chronic medical conditions such as delayed soft tissue radiation injury and Wagner 3 or greater foot ulcers in diabetic patients. For more information, go to www.hennepinhealthcare.org