Pressure Map Technology for Pressure Ulcer Patients: Can We Handle the Truth?

Matthew Q. Pompeo, MD
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WOUNDS. 2013;25(2):34–40.
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  Abstract: Objective. The purpose of this study was to trial new pressure mapping technology for patients with pressure ulcers. Methods. Pressure mapping data was recorded during 3 phases of technology implementation, as nurses became increasingly familiar with pressure mapping technology in a 55-bed, long-term acute care (LTAC) facility in North Texas. Forty-three patients with pressure ulcers were selected for the study. Patients with pressure ulcers, or who were considered at high risk for developing pressure ulcers based on a Braden score of ≤ 12, were selected to utilize a pressure-sensing device system. Results. Turning timeliness improved greatly from the baseline phase to the last phase. The average turning after the 2-hour alarm decreased from 120 minutes to 44 minutes, and the median time to turning decreased from 39 minutes to 17 minutes. If time past 2 hours is considered the most damaging time to tissue, these reductions (average and median) represented 63% and 56% less potential tissue damage. Conclusion. Pressure mapping technology is in its infancy and this paper discusses implications for the future, including barriers to implementation and potential advanced applications. While only changes in nursing practice were measured in this study, the changes observed suggest the technology can be instrumental in reducing hospital-acquired pressure ulcers and improving the healing of pressure wounds in the future.


  Pressure ulcers remain a huge burden, in terms of financial cost to the medical system and the suffering of patients. Despite advances in bed technology and many aspects of wound care from 1993 to 2006, the number of hospitalizations for pressure ulcers reported to Medicare increased 80% despite only 15% more patients.1 Reasons for this persistence involve many factors. One important contributor is that medical advances are postponing death from other causes, thus creating an ever more aged and frail patient population. As more frail patients are becoming more numerous, it is clear providers need more tools in their armamentarium to prevent and treat pressure ulcers. With this in mind, technology that can help facilities reduce pressure wounds is greatly needed.

Methods and Materials

  The pressure-sensing device. The device (The MAP System, Wellsense Inc, Nashville, TN) is a thin mat placed on a mattress that has a color monitor attached. The mat contains thousands of sensors, and is secured to the top of the mattress with straps. These sensors measure pressures through a sensing area measuring 1945 mm x 805 mm. The sensors display specific areas of pressure, and the system provides live feedback to clinicians as they reposition patients. The monitor acts as an educational tool for staff, patients, and family by indicating where the pressure points are located. (Figure 1). It can also assist clinicians in optimal surface selection and detection of malfunctioning mattresses. Figure 2 shows an image from the device monitor of a patient on a bed that was inadvertently deflated, while Figure 3 shows an image from the device monitor of the same patient with the bed properly inflated. Other features include a bed alarm that can be set to sound at the desired interval to alert for turning (the alarms were set for 2 hours for this study).   Description of Implementation of the pressure-sensing device system. The project was implemented in 3 phases from September 2011 through October 2011. The first phase (baseline) spanned a 2-week period designed to capture baseline turning data. During this phase the nurses were given minimal instruction and the monitors were covered from their view. During the second 2-week phase (voluntary learning), the nurses had brief, voluntary in-services with the pressure-sensing device representative to learn about the device, and the monitors were uncovered. During the third phase (mandatory), which lasted 1 month, nurses had mandatory meetings with the director of nursing at the facility as well as the product representatives. This pilot study was designed to measure the changes in nursing behavior in regard to turning patients.   Patients with pressure ulcers, or who were considered at high risk for developing pressure ulcers based on a Braden score of ≤ 12, were selected to utilize the pressure-sensing device system. Overall, 43 patients were mapped during the study.   The pressure-sensing device has 3 components related to pressure reduction and nursing care. The first component is the live image. The image on the monitor allows nurses to see areas of high pressure, which appear in red. The nurses found that, often, minor adjustments would get rid of the high pressure areas, even while keeping the patient in the same position (eg, left lateral or supine). One experienced physical medicine and rehabilitation wound physician commented that the system showed subtle changes often reduced pressure, and the changes were often not what the physician’s experience would have suggested.   When patients and families saw the images from the device, they usually expressed great interest and became advocates for pressure reduction. Occasionally, even nonwound patients, not originally included in the study, would request to have the system. The second component is the alarm, which alerts for turning. The alarm does not monitor for high pressures, but is set at an interval of 90 minutes, 120 minutes, or 180 minutes based on the preference of the facility to perform turning.   The third feature (which is optional) is the recording of the images to allow documentation and review of patient repositioning.


  The pressure-sensing device system showed that in the baseline time period, the average turning time was 120 minutes after the 2-hour alarm had sounded, or every 4 hours. This post-alarm turn time improved slightly to 105 minutes during the initial learning phase, and further improved to an average of 44 minutes after the mandatory learning phase (Graph 1). Between phases 1 and 2, the average time between the sounding of the alarm and the actual turning of the patient was reduced, while the median time was not, indicating that in this trial, the ability to see the live image or have the alarm sound did not necessarily translate into getting the staff into the rooms more consistently for turning.   How much could this technology reduce damaging pressure to vulnerable tissue? One way to consider this would be to assume that tissue load at some point becomes irreversible (”damaging time”). While this interval to “damaging time” is variable for every patient and depends on many factors, it occurs for most patients at some time after 2 hours.2   If the delay in turning past 2 hours is considered the “damaging time,” this reduction from 120 minutes to 44 minutes represents a 63% reduction of the damaging time to tissue (Graph 2). For the median times in minutes, it produced a 22-minute reduction, which is a reduction of 22/39 = 56% of damaging time.   Longer-term studies will be required to ascertain the actual benefits of this technology.

Additional Findings

  Two patients developed hospital-acquired wounds during the baseline phase of the trial. In both cases the recordings from the pressure-sensing device were reviewed, and showed the affected body parts had not been repositioned for long periods of time. These case reviews were part of the mandatory in-service during the third implementation phase.   The knowledge that turning time was being recorded had a direct effect on the nursing staff’s adherence to turning schedules. During the second and third implementation phases, no hospital-acquired ulcers occurred, although it is not expected that the pressure-sensing device system alone will completely eliminate hospital-acquired pressure ulcers.   In this pilot study, the mere presence of the map and monitor did not yield significant improvement in turning timeliness. The improvement only occurred when it was clear that the hospital was capable of, and fully engaged in, using the information from the system.


  The idea of “skin failure,” similar to heart or kidney failure, is credible, and the concept attempts to destigmatize the development of pressure wounds.3 Nevertheless, most practitioners believe the majority of pressure ulcers are preventable.4 Pressure ulcers by definition do not develop without pressure extensive enough to irreversibly damage tissue. Tissue injury requires adequate pressure over a critical time period to damage the tissue. The higher the pressure, the shorter the critical time period.5 Theoretically, there are 3 major mechanisms to prevent pressure-induced tissue injury:     1) Reduce interface pressure to a level that will not occlude capillary flow. This is the mechanism of many specialty surfaces, such as low air loss beds that allow the body to immerse and thereby distribute pressure over a larger area and reduce pressure.     2) Turn patient at frequent enough intervals so that even if the capillary blood flow is compromised to the areas in contact with the surface, no one area of tissue is affected long enough to suffer irreversible damage. For any particular pressure ulcer, if the patient can be positioned so that the ulcer and area around it are not touching the bed, the interface pressure to that area goes to zero and the area is maximally perfused.     3) Use alternating mattress systems that essentially redistribute pressure by moving areas of supporting pressure under the patient. Pressure can be further distributed by continuing to turn the patient. This type of system will usually, and necessarily, have high zones of pressure in the areas supporting the patient, but can be safe due to the frequent redistribution.   The pressure-sensing device system used in this study works to maximize the benefits of mechanisms 1 and 2. The live mapping allows clinicians to visualize and minimize areas of high pressure, while the alarm system provides notification at times when turning should occur and the recording can quantitate pressure relief. For pressure ulcer wounds, pressure relief is the “medicine,” and yet it is a medicine that is neither quantitated nor convincingly recorded. This technology is like a medication administration record for pressure ulcers in that it quantitates the medication dosage and administration—in this case, the amount of time a wound is offloaded and the times at which the offloading occurred.   This is in sharp distinction to the checklists for turning currently in use. In the author’s experience, the systems in place usually fall short in delivering the “standard of care” of turning every 2 hours. While nurses may not always have time to turn patients every 2 hours, the author has observed them being instructed to document that the turns occurred on checklists.   This technology offers objective, verifiable evidence that the wound treatment occurred, which turning checklists do not.   Perhaps the biggest hurdle to the implementation of technology such as this is whether facilities will choose to embrace the accountability the system can impose; more specifically, whether facilities will overcome the fear that the data could be used for litigious purposes. Bedside devices that will raise accountability will only increase, which makes this an opportune time for the medical community to begin a discussion. Perhaps there could be allowances to encourage facilities that use and actively manage such a system for some legal protection, such as immunity from its admission into evidence if the facility systemically uses the data to improve care; discounts related to insurance; or limits to the liability that could be incurred.   Alternatively, facilities can simply opt out of the recording feature until a policy is in place in regard to potential legal ramifications. To achieve maximum benefit from the system, however, the nursing staff needs to understand its ability to record data. This study illustrated that showing the nursing staff recordings made by the system during mandatory training is an important component of encouraging compliance with turning protocols and maximizing the benefit of the system. This feature could be demonstrated whether or not the facility plans to use the recording feature.   Without the recording function that makes it possible to see when patients are actually turned, the alarm function of the pressure-sensing devices serves no more purpose than a simple timer. In the baseline phase, the alarms essentially acted like a simple timer, and with nurses mostly unaware of the recording, effectiveness was limited. The improvements over the next 2 phases (especially phase 3) demonstrate that what the system offers over a simple timer is accountability. These findings suggest nursing accountability is what directly results in adherence to the turning protocol and the potential for improved patient outcomes.   The system can be configured to match the needs of the facility both in terms of the alarm intervals and the recording feature. At a minimum, the live images from the pressure-sensing device can be used to help with repositioning patients, and the system alarm can sound at appropriate intervals to remind clinicians to turn the patients and record no data. However, the technology has much more to offer if recording is enabled. For instance, wound specialists may want to look at turning frequency for the previous 24 hours, much as they would review vital signs, labs, or medication records. If pain is the 5th vital sign,6,7 turning and pressure reduction may be the new 6th vital sign for patients with existing pressure wounds.   Caregivers could receive a morning report, not only on the amount of turning for the previous 24 hours, but also on the quality of the turning in getting wound areas totally off the bed. This technology could also better-align scarce resources for patients truly in need of high levels of care. Turning schedules could be personalized based on patient criteria as determined by the pressure-sensing device. To realize these advances, more analytic automation of the systems is necessary and is ongoing. The predictive potential will only be realized, however, after the systems are in use for large numbers of patients and their clinical variables and outcomes are able to be analyzed.   Limitations of pressure-sensing device system and use in alternating mattresses. One potential criticism of the current system is that is does not allow airflow. In this clinical pilot trial the authors did not restrict its use from any pressure wound patients, but for patients who are very excoriated, the potential benefits will need to be considered against the need for air flow.   For alternating systems, the images from the device need to be interpreted with less emphasis on the amount of high pressure, and more emphasis on the change over time, for particular skin areas. Conceivably, the technology could direct the alternating functions of a “smart mattress,” but whether that would be more beneficial than straight alternating cycles remains to be seen. Even with alternating mattresses, getting the wound area completely off the mattress is the best way to offload, which means patients should still be turned whenever possible.   In the author’s experience, with any specialty bed, and alternating beds in particular, there can be a consistently false belief among a low percentage of nurses that turning is no longer needed.   When this technology is applied to alternating systems, it may be more important that the software still monitor turning rather than direct air baffle flow. After all, the alternating beds can already be set to automatically alternate pressure, but achieving regular turning is never as easy as pushing a button.   How much could this technology reduce hospital-acquired ulcers (or improve healing?) This study was not designed to answer those questions because the time frame was too short. However it is interesting to consider what outcomes might arise from such changes in nursing practice.


  This pilot study demonstrated the potential improved care that may be possible using a pressure-sensing device system technology. The current technology is likely to become much more sophisticated as it matures, and at this point it is hard to predict how it will best be utilized.   Measuring pressure relief for patients with pressure ulcers is so obvious it is hard to imagine it will not eventually be part of mandated quality initiatives. It will be important that the wound community be involved in shaping the most appropriate use of this technology, and to do this, the systems must be used and evaluated to discover how they best contribute to improving patient care and outcomes. Hopefully the wound community will be the leaders in defining the terms of the use of this technology rather than having it defined for them.


1. Agency for Healthcare Research and Quality (H-CUP): Statistical Brief # 64. Hospitalization Related to Pressure Ulcers among Adults 18 Years and Older, 2006. Accessed January 18, 2013. 2. Reswick J, Rodgers J. Experience at Rancho Los Amigos Hospital with Devices and Techniques to Prevent Pressure Sores. In: Bedsore Biomechanics, Kennedy, Cowden & Scales (Eds .), Baltimore : University Park Press, 301-310, 1976. 3. Langemo D, Brown G. Skin fails too: acute, chronic and end-stage skin failure. Adv Skin Wound Care

. 2006;19(4): 206-211. 4. Black JM, Edsberg LE, Baharestani MM, et al. Pressure ulcers: avoidable or unavoidable? Results of the National Pressure Ulcer Advisory Panel Consensus Conference. Ostomy Wound Manage. 2011;57(2):24-37. 5. Bergstom N. Patients at risk for pressure ulcers and evidenced-based care for pressure ulcer prevention. In: Bader D, Bouten CVC, Colin DC, Oomens CWJ, eds. Pressure Ulcer Research: Current and Future Perspectives. Heidelberg, Germany. Springer Publishing, 2010: 35-50. 6. American Pain Society Quality of Care Committee. Quality improvement guidelines for the treatment of acute pain and cancer pain. JAMA. 1995;274(23):1874-1880. 7. US Department of Veterans Affairs. Pain as the 5th Vital Sign Toolkit. Accessed January 29, 2013. The author is from private practice, Dallas, TX. Address correspondence to: Matthew Q. Pompeo, MD 4106 Lorinser Lane Dallas, TX 75220 Disclosure: The author discloses no financial relationship with the manufacturer of the device tested in this study.


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