By Frank Aviles Jr, PT, CWS, FACCWS, CLT-LANA, ALM, AWCC, MAPWCA
The influence of infrared technology is but one link that today’s comprehensive wound care teams can trace back to this country’s space exploration.
What Are Some Recent Technological Advances in Wound Care?
Wound care has made significant and exciting progress over the years. We have moved from a passive wound bed approach to an active, strategic, individualized wound and periwound approach with the help of technological advancements. Interestingly, some of the technology in use today, such as infrared thermometers and other thermal infrared devices that collect and monitor data, were developed from the National Aeronautics and Space Administration space program. This type of technology is also being used to measure land surface temperatures in two thermal bands to detect heat.
How Technological Advancements in Wound Care Mirror the Space Race
There are several philosophical parallels to the type of collaboration that occurred during the height of the “Space Race” of the 1960s and what constitutes today’s multidiscipline wound care program. Perhaps the most parallel is “failure is not an option,” a phrase associated with Gene Kranz. Kranz is an aerospace engineer who is among those credited with helping the Apollo 13 mission’s success in the sense that lives were saved despite troubling circumstances.
Evolving Wound Care Collaboration
Why Don’t Chronic Wounds Progress Past the Inflammatory Phase?
It doesn’t take a search on Google to know that chronic wounds do not progress if they remain in the inflammatory phase of healing. At one point, we had to rely on “retinal scans,” which Dr. William Ball, a surgeon I continue to collaborate with, describes as “putting your eye on the wound to accurately perform an assessment.” In a field where time is always of the essence, understanding what causes wounds to remain inflamed and addressing the wound promptly can change the course of the healing trajectory. The longer a wound remains open, the more likely it is that infection and amputation will be factors during treatment.
How Infrared Technology Is Used to Detect Pressure Injuries Before They Happen
Years ago, I was approached by industry with an opportunity to use long-wave infrared thermography (LWIT) for detecting pressure injuries before their occurrence. Even though LWIT was being utilized only for detecting injuries based on the cooler aspect of the spectrum, I wanted to learn more about the technology’s ability to assess inflammatory conditions.1 I was intrigued and began implementing LWIT immediately in my practice across the continuum of care while realizing that my practice would be changed forever. I am now able to assess what I’ve coined “thermal energy” radiated from the human body as a result of metabolic active processes, or the lack thereof, based on a scale.
Concurrently, another opportunity presented itself with the use of a near-infrared spectroscopy device that provides information on tissue oxygenation, total hemoglobin, total deoxyhemoglobin, and total oxyhemoglobin.2 The device also complements LWIT in making real-time clinical decisions. The findings for those approaches will be published in a future article.
These two technologies continue to change how I look at wounds, not only by improving my assessments, treatment validation, and intervention selection, but also by providing images to determine whether there’s increased thermal energy (inflammation) or decreased thermal energy (moving away from inflammation or even hypoperfusion).3-5
Again, this collaboration is one that would have, at one time, been unimaginable.
What Is the Electromagnetic Spectrum?
Figure 1. The Visible Light Spectrum
The electromagnetic spectrum is important as we learn about infrared, and it is defined as the range of all types of electromagnetic radiation. This spectrum varies in characteristics, such as frequencies, wavelengths, and photon energies. They travel at speeds similar to light, but their characteristics vary in ranges. The types of radiation and wavelengths include:
- Radio waves - >1mm
- Microwaves: mm to 25µm
- Infrared: 25µm to 2.5µm
- Near-infrared: 2.5µm to 750nm
- Visible: 750nm to 400nm
- Ultraviolet: 400nm to 1nm
- X-rays: 1nm to 1pm
The human eye can view light that is part of the visible light spectrum, wavelengths that range from approximately 400 to 750 nm. However, wavelengths on either extreme of the visible spectrum are not visible to the human eye.
When visible light travels through a prism, the wavelengths separate into the colors of the rainbow. The color red has the longest wavelength, and purple has the shortest. Objects that are cooler will have longer wavelengths, whereas hotter items will have shorter wavelengths in this visible spectrum.
Outside of the visible spectrum, as in the case of infrared light, we must utilize a special camera to see wavelengths. This imaging system interprets various wavelengths of infrared light and displays them as colors (Figure 2). When using the special camera, heat is orange and red, whereas cooler areas are blue or purple. The camera’s imaging displays the wavelengths this way for easy interpretation, although when considering the true wavelengths of visible color, it’s important to understand that visible light is the opposite. The camera displays temperature by using conventional associations of color with temperature rather than how a wavelength’s color actually manifests. Readability is important for ease of use of infrared technology, so a clinician can observe an image and easily identify the temperature of the body in the image.
Figure 2. Infrared light
How Infrared Can Be Used in Wound Care Assessments
This technology is being used in clinical practice, not as a diagnostic device but as an effective preventative intervention, complementing assessments, validating interventions, and assisting in the selection of treatments promptly based on LWIT findings.
Figure 3 shows an image and a photograph taken of a patient. On the left is a photograph of the area being imaged. The software can measure wounds. The key between both images show a color scale based on degrees Celsius. Areas above 0 indicate an increase in thermal energy, whereas below 0 indicate a decrease in thermal energy. On the right side is a thermal image of the area being captured. Previous studies indicated a normal thermographic range level of +1.1 to −1.1, as illustrated in Figure 3.
Figure 3. Normal Thermographic Image
The literature tells us that we often admit patients to the hospital to treat cellulitis with antibiotics. A study found that 28% of the patients were incorrectly diagnosed with lower-limb cellulitis, and venous stasis dermatitis was the culprit in 37% of cases.6
Figure 4A illustrate a patient who had stasis dermatitis confirmed with no increase in thermal energy, whereas Figure 4B confirmed increased levels of thermal energy, thus validating the extent of the problem. The patient in Figure 4B was thought to be improving based on visual inspection; however, thermal imaging validated that this assumption was not correct.
Figure 4. A, Mild-level increase in thermal energy noted caused by stasis dermatitis
Figure 4. B. High-level increase of thermal energy consistent with cellulitis. Note the larger extent of area involved captured on thermal image compared with the actual picture.
While utilizing this device in the wound care clinic, in the emergency department, in the operating room, and in acute care units, it was evident that this device helped to determine whether the extremity was in danger based on the level of metabolic activity. Figure 5 shows a patient who had high levels of thermal energy.
Figure 5. Patient being treated for an infection. According to visual assessment, redness significantly decreased from the previous assessment, but the image indicates a larger problem: positive for gas gangrene.
How Infrared Technology Helps Identify Pressure Injuries in Patients With Darker-Pigmented Skin
The literature also states that clinicians will not accurately recognize the level of inflammation, especially in darker-pigmented patients, and this limitation can have a detrimental effect on care. It has been documented that failure to identify early signs of pressure damage can lead to worsening pressure-related conditions.7 Rosen et al in 20068 found that darker-pigmented patients were more likely to have stage 2 to 4 pressure injuries than White patients, a finding suggesting that failure to recognize this damage leads darker-pigmented patients to develop more severe tissue damage. There have been suggestions on how to improve visual assessments. With this technology, clinicians can determine whether there’s decreased thermal energy or hypoperfusion or whether there’s an active inflammatory process in darker-pigmented patients.
Figure 6 demonstrates a heel on a darker pigmented patient with decreased thermal energy or hypoperfusion, whereas Figure 7 demonstrates a picture of a darker-pigmented patient with difficulty assessing redness. The infrared image indicates a serious inflammatory reaction, which was infection. The use of this technology helped the patient in Figure 7 with limb salvage procedures based on this bedside, real-time image.
Figure 6. Note the heel demonstrating a decrease in thermal energy consistent with a possible pressure injury.
Figure 7. High level of thermal energy consistent with severe infection
Patients who are at the end of life have also demonstrated a consistent thermal image pattern.
Infrared technology also allows clinicians to verify whether treatments are progressing along the healing cascade. As a chronic wound moves out of the inflammatory phase and into the proliferative phase, the expectation is that clinical signs of inflammation will decrease as the body continues to repair the injured tissue. Figure 8 demonstrates serial images after the initiation of antibiotics.
Figure 8. Pre- and post-treatment intervention
The use of technology continues to improve the delivery and timeliness of care provided to patients. The ability to recognize conditions sooner, in real time, leads to improved outcomes. We can use and implement this technology across the continuum to help assessments, validate interventions, and predict or prevent conditions that may have a deeper physiological impact.
Clinicians can utilize this technology as a valuable adjunct to assessments when looking at acute infections, chronic infections, limb-threatening infections, hypoperfusion, the existence of nonviable tissue, end-of-life patterns, surgical-site infections or incisions that will dehisce, and much more. With further research in the use of infrared in wound care, this mode of wound imaging may solve many of the issues posed by retinal scans. Much like the space race, innovations in wound care are accelerating. Hopefully, clinicians will be able to prevent and heal wounds that seem as impossible as reaching the moon.
- Aviles F. Advances in wound care technology: what we see is what we get… and more. Today’s Wound Clinic. 2021;15(9). hmpgloballearningnetwork.com
- Aviles F. Ischial tuberosity pressure injury with inflammation and poorly oxygenated tissue. case study. Kent Imaging Case-Studies. 2021. Accessed May 26, 2022. Aviles_PressureInjury_MM22006-15.pdf. In:https://www.kentimaging.com/case-studies 3. Aviles F. You ain’t seen nothing yet: detection of inflammation by measuring metabolic activity with long-wave infrared thermography. Poster presented at The Symposium of Advanced Wound Care Fall 2021; October 29-31, 2021; Las Vegas, NV.
- Aviles F. Utilizing long wave infrared thermography to detect inflammatory changes in clinical practice. Poster to be presented at WOCNext; June 5-8, 2022; Fort Worth, TX.
- Aviles F, Bulitt P. Utilizing long-wave infrared thermography (LWIT) to visualize the sharp debridement inflammatory process. Poster presented at The Symposium of Advanced Wound Care Spring 2021; May 10-14, 2021; Virtual.
- David CV, Chira S, Eells SJ, et al. Diagnostic accuracy in patients admitted to hospitals with cellulitis. Dermatol Online J. 2011;17(3):1. Published 2011 Mar 15.
- Aviles F. Long-wave infrared thermography in subclinical inflammatory conditions in dark complexioned individuals. Poster to be presented at The Symposium of Advanced Wound Care Fall 2022; October 14-16, 2022; Las Vegas, NV.
- Rosen J, Mittal V, Delgenholtz H et al (2006) Ability, incentives and management feedback: organisational change to reduce pressure ulcers in a nursing home. J Am Med Dir Assoc 7(3): 141–6
About the Author
Frank Aviles Jr. is currently the Wound Care Clinical Coordinator at Natchitoches Regional Medical Center (NRMC) overseeing and assisting with wound care practices across the continuum of care. Frank is also a wound care consultant for Louisiana Extended Care Hospital Natchitoches and LHC group, wound care/lymphedema instructor & advisor for the Academy of Lymphatic Studies, and an educator/lymphedema therapist/consultant for Cane River Therapy Services.
The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, HMP Global, its affiliates, or subsidiary companies