This study was begun just before publication of the retrospective review by Sullivan13 of suspected DTI evolution in adult acute care patients, and the results share several similarities. Similar to Sullivan, the initial intent of this study was to describe and understand the characteristics of patients who developed a DTI and the contributing intrinsic and extrinsic factors involved. The long-term intent was to use this knowledge to inform clinical practice and future research. The current retrospective study examined factors associated with the development and outcomes of DTI during a 2-year period. Although no definite intrinsic or extrinsic factors could be directly attributed to the development of DTI, incidence of DTIs was higher in patients with cardiovascular diseases (including hypertension, peripheral and cerebrovascular disease, congestive heart failure) and diabetes mellitus.
In the current cohort of DTIs, (11%) progressed to full-thickness/unstageable at the time of discharge. The majority (131, 73%) were stable or were categorized as sloughing of the epidermis at the time of patient discharge. Twenty-eight (28, 16%) of the DTIs were completely resolved; 69 DTIs (38%) occurred in patients who died at a median of 51 days after the DTI was first identified, 38 (55%) of whom were still hospitalized. Cohorts in this and previously published work13 both had similar patterns of comorbidities, with a high incidence of patients who had cardiac, vascular, and/or renal diseases or diabetes mellitus.
Pre-DTI identification assessment. In 13 (7%) of the 179 DTIs, a skin alteration was documented before the DTI developed, and most of these (8 DTIs) initially showed blanchable erythema. The range of time that erythema was present varied greatly (ie, from 20 hours to 192 hours). For 3 DTIs, the PU was initially identified as Stage 1 and was present for 22 to 29 hours before being documented as a DTI. Two (2) DTIs were initially identified as Stage 2, with 1 present 25 hours before the DTI was documented. In this case, the patient underwent a procedure in which he was positioned over the Stage 2 PU; 48 hours after the procedure, the wound bed became dark purple and nonblanchable based on physical exam by the APRN CNS. Farid et al11 suggested blanchable erythema develops 168 to 336 hours before DTI formation, a range much higher than that of the current study. In the authors’ EHR system, the CNS on the unit was automatically alerted of skin alterations documented in the EHR to trigger the need for further assessment and intervention, which may explain this difference.
Chart information of the patients with the 13 DTIs and pre-existing skin alterations was reviewed to determine the types of diagnostic and surgical procedures associated with injury development. In a pilot study by Honaker et al,16 precipitating events occurred 1 to 5 (mean 2.41) days before DTI skin changes were noted. Therefore, the current study reviewed records for the 5 days before DTI documentation and identified 7 DTIs in patients who had surgical procedures lasting from 30 minutes to 5 hours. For 1 DTI, erythema was present for 168 hours before the DTI was identified, and the patient had undergone 7 diagnostic procedures in the 5 days before the DTI was documented. Another had erythema documented for 49 hours before DTI appearance; this patient had undergone 5 diagnostic procedures within that period of time.
Surgical and procedural considerations. In a surgical environment, DTI prevention involves identifying patients at risk through a skin assessment and reliably implementing prevention strategies. In the inpatient setting in the United States, the Braden Scale is a widely used tool for identifying at-risk surgical patients.17 However, in an OR environment, the preoperative Braden Scale score is inherently skewed because most patients have lost the ability for self-protection and communication. The Scott Triggers tool was developed as a predictive scale developed on evidence-based factors specifically tailored for high-risk perioperative PI or DTI development.17 The Munro Tool for Pressure Ulcer Risk-Assessment Scale for Perioperative Patients was developed as both a communication tool and documentation of risk assessment in each phase of perioperative care.18 The Munro Tool incorporates 15 evidence-based risk factors for the perioperative period. However, reliability and validity testing have not been completed on either of these tools. Good hand-off communication and visual indicators can alert OR staff as to which patients are most at risk because of preoperative instability and diagnostic procedures, as well as specialty knowledge of required positioning and equipment used during the case. If a patient develops a DTI postoperatively, root cause analysis needs to include OR or procedural environment staff, so all involved personnel can examine and possibly improve their practice.19 Although the differences between the outcome groups in the current study were not statistically significant, more postoperative DTIs evolved to full-thickness/unstageable PIs postoperatively (7 DTIs, 35%), and there was a higher incidence of procedures before DTI appearance.
Treatments and NFLU therapy. No discernible pattern of dressings used on DTIs, either before or after the DTI, was identified, although silicone-border dressings were used most frequently (37, 95%); these dressings were used before DTI occurrence in 20 DTIs. Use of specialty beds increased after DTIs appeared, with the greatest increased use in the group with resolved outcomes (P = .002). The only specialty bed used that showed significance between DTI outcome groups was a powered, multizoned, low-air-loss mattress system (10/9/3; P = .005) compared with (partial) high-air-loss mattress (1/8/3; P = 0.45).
DTI has been shown in a review of the literature by Berlowitz and Brienza20 to result from tissue distortion related to vertical and shear forces; in addition, the review by Stekelenburg et al21 and the rat model study by Cui et al22 demonstrated that compression of the blood supply, impaired lymphatic function of the tissues, and reperfusion injury also can be factors. Several investigators including Peirce et al (rat model)23 and Oomens et al24,25 and Agam and Gefen26 (biomedical engineering models) showed damage from oxygen-derived free radicals released during reperfusion can cause inflammatory and cytotoxic effects on the tissues, rendering muscle tissue more susceptible to this damage than the skin. NLFU provided at 40 kHz has been shown by multiple investigators27-31 to improve healing by decreasing proinflammatory cytokines, increasing vascular endothelial growth factors and improving microcirculation. In retrospective studies by Honaker et al31 and Thomas,32 an average of 10 to 12 sessions were required to produce a 75% to 100% resolution rate of DTIs. During the time frame covered by this study, NLFU was used for patients who did not have measurable signs of healing with standard treatments including dressings, specialty beds, and turn/reposition programs. The mean number of sessions for the NLFU group in the current series was 9.9, but 33% of the patients had 5 or fewer sessions because the DTI resolved or the patient was discharged or died. To achieve the best outcomes with NLFU, the intervention should be started as soon as the DTI is identified. In the current study, the average delay between DTI identification and NLFU initiation was 2 days, but in 9 DTIs (16%), there were delays ≥5 days.
Unlike the results of the prospective randomized controlled trial by Prather et al27 and a quasi-experimental study by McCormack and Hobbs33 that showed improved healing of partial-thickness injuries, the outcomes for the current cohort of DTIs that received NLFU were not better than those who did not. Several confounding factors were more prevalent in the NLFU-treated group, such as longer LOS (47 days vs 38 days), vasopressor use following DTI identification (38% vs 23%), and mechanical ventilation (50% vs 25%).
Although no specific patient acuity data were collected, the NLFU-treated group of DTIs were in patients who had a higher acuity of illness, because death occurred in 28% of the NLFU group within 1 month of discharge and in 70% of those patients, death occurred on the day of discharge or 2 to 3 days later.
HOB elevation. Since the introduction of guidelines for the prevention of ventilator-associated pneumonia, clinicians have had to weigh competing patient care priorities with regard to HOB elevation. Guidelines for ventilator-associated pneumonia34,35 recommend a HOB elevation between 30˚ and 45˚, and NPUAP guidelines recommend a HOB elevation of <30˚.36,37
A feasibility study by Schallom et al35 found reduced oral secretion volumes and reflux at higher HOB elevations without pressure-related tissue injuries. However, the 11 patients who completed the Schallom study35 all were on low-air-loss mattresses, and the study period was only 48 hours. In the current study, ventilator support was found to be a significant factor for PU development. This conflict in perceived priorities related to HOB elevation could be addressed with a more frequent turn-reposition program and use of specialty mattresses, such as those with low-air-loss, pressure-redistributing, or shear-reduction features.
LOS. In the current study, hospital LOS ranged from 4 to 258 days, with a median of 23 days, and ICU LOS ranged from 1–173 days with a median of 12 days. DTIs that were resolved at discharge had the longest ICU and hospital LOS, as well as the latest onset of DTI following admission. Most patients who had an extended LOS were awaiting transplant or dependent on supportive technology, such as extracorporeal membrane oxygenation or left ventricular assist devices. The authors’ analysis of DTI outcomes was limited to the status at hospital discharge, so although 131 DTIs (73%) were considered stable (not worsening) or improving (skin intact, discoloration fading), the ultimate DTI outcome was unknown. A total of 12 DTIs that resolved before discharge were device-related; the extended LOS due to more severe illness most likely allowed time for complete resolution.
Devices. In a presentation to the 2012 NPUAP Bi-Annual Conference, Baharestani38 noted that PUs caused by medical devices have increased in recent years. Medical device-related PUs are defined by the NPUAP1 as resulting “from the use of devices designed and applied for diagnostic and therapeutic purposes. The resultant pressure ulcer generally conforms to the pattern or shape of the device.” A secondary analysis of medical center data39 has shown medical devices create pressure against the skin, and the microclimate is altered as a result of humidity and heat between the device and the skin. This combination makes PUs more likely to occur after device use. To prevent these injuries, health care facilities have put policies in place to ensure medical devices are removed or repositioned in a timely manner; when a device is used, the NPUAP recommends that it be cushioned and the skin under a medical device inspected at least daily unless medically contraindicated and more often in patients with localized or generalized edema, and that staff be educated on use of medical devices.39
Of the 179 DTIs in the current study, 41 (23%) were related to medical devices. The device most likely to cause a DTI was a long-stretch compression wrap (Deluxe LF elastic bandage; Hartmann Inc, Rock Hill, SC) applied to the lower extremities. Wraps accounted for 15 (38%) of the DTIs caused by medical devices. As a result of this finding, the authors changed practice to use of short-stretch wraps (Rosidal K; Lohmann & Rauscher, Milwaukee, WI) for ambulatory patients and long-stretch wraps for nonambulatory patients. Cotton or foam padding was applied before wrap use to protect bony prominences and tendons from focused pressure. Casts and splints accounted for 8 (18%) of the device-related DTIs.
Other medical devices that caused DTIs in this study included cervical spine collars (3, 7%), cast/splint (5, 12%), respiratory devices (5, 12%), braces (5, 13%), boots (2, 5%), sequential compression devices (1, 2%), slings (1, 2%), and oscillating beds (3, 7%). In their prospective study, Coyer et al40 found ICU patients who developed a device-related DTI had an average of 8.6 medical devices placed. Endotracheal tubes and nasogastric tubes caused the highest number of DTIs in their study.
In the current study, 27 (68%) of the DTIs caused by medical devices occurred in the ICU setting and of those 11(49%) were caused by long-stretch wraps. A unique situation arises when patients are unconscious and require a cast or splint. If a patient cannot communicate that the cast or splint is causing additional pain, a PU may be more likely to occur. In rare cases the authors have experienced, removing the splint or cast routinely can place the patient at risk for further complications, such as worsening an unstable fracture.
Incontinence. According to a systematic review41 and a prospective analysis,42 fecal and urinary incontinence usually do not cause DTIs, but they have been associated with PUs because of the weakening of the skin’s ability to tolerate shear/friction, moisture, caustic drainage, and bacteria.37,38Gefen43 used mathematical and computational modelling to demonstrate the effects of wetness-related friction on shear loads, with resulting reduced strength of wet skin. In a systematic review and meta-analysis of incontinence-associated dermatitis and moisture as risk factors for PU development, Beeckman et al41 found significant associations between both urinary incontinence alone and double incontinence and PU development. In the current sample cohort, a low incidence of urinary incontinence was noted because patients were either continent or had an indwelling urinary catheter. However, patients with DTIs had an higher incidence of fecal incontinence in all outcome categories, ranging from 60% to 84%, with the highest percentage in the full-thickness/unstageable group.
Braden subscale scores. No statistical difference was found between the 3 condition-at-discharge groups in total Braden score 1, 2, and 3 days before DTI appearance. Each group’s total scores placed them in the high-risk category (12–14), with slightly lower scores in the group that developed full-thickness/unstageable DTI. The Braden nutrition subscale score was the only subscale that showed a significant difference between groups before DTI development, with the lowest scores found in the group that developed full-thickness PUs.
Although the prospective, quasi-experimental repeated measures study by Serpa and Santos44 did not find the Braden nutrition subscale score to be predictive for PU development in hospitalized patients, the current authors were not surprised to observe that DTIs progressed to full-thickness injuries and were associated with the lowest scores. A minimal downward trend was noted in other subscale scores from 72 to 24 hours before DTI, but the trend seemed to be consistent with an increasing acuity of illness and intensity of therapy and care, which may have been associated with decreased mobility and increased tissue distortion.