Suspected Deep Tissue Injury Evaluated by North Carolina WOC Nurses: A Descriptive Study

Risk factors for the development and evolution of deep tissue injuries: A systematic review

AIMS

The aim of this systematic review is to identify the current epidemiological evidence indicating the unique risk factors for deep tissue injury (DTI) compared to grade I-IV pressure injury (PI), the proportion of DTI which evolve rather than resolve and the anatomical distribution of DTI.

METHODS

A systematic literature search was undertaken using the MEDLINE and CINAHL Plus databases using the search terms 'Deep tissue injury OR DTI [Title/abstract]'. A google scholar search was also conducted in addition to hand searches of relevant journals, websites and books which were identified from reference lists in retrieved articles. Only peer-reviewed English language articles published 2009-2021 were included, with full text available online.

RESULTS

The final qualitative analysis included nine articles. These included n = 4 retrospective studies, n = 4 prospective studies and n = 1 animal study.

CONCLUSION

The literature indicates that the majority of DTI occur at the heel and sacrum although in paediatric patients they are mainly associated with medical devices. Most DTI are reported to resolve, with between 9.3 and 27% deteriorating to full thickness tissue loss. Risk factors unique to DTI appear to include anaemia, vasopressor use, haemodialysis and nicotine use although it is unclear if these factors are unique to DTI or are shared with grade I-IV PI. Factors associated with deterioration include cooler skin measured using infrared thermography and negative capillary refill. With 100% of DTI showing positive capillary refill in one study resolving without tissue loss (p = 0.02) suggesting this may be an effective prognostic indicator. More prospective studies are required focusing on establishing causal links between risk factors identified in earlier retrospective studies. Ideally these should use statistically powered samples and sufficient follow up periods allowing DTI outcomes to be reached. Further work is also needed to establish reliable diagnostic criteria for DTI in addition to more studies in the paediatric population.

Use of Thermal Imaging to Identify Deep-Tissue Pressure Injury on Admission Reduces Clinical and Financial Burdens of Hospital-Acquired Pressure Injuries

A deep-tissue pressure injury (DTPI) is a serious type of pressure injury that begins in tissue over bony prominences and can lead to the development of hospital-acquired pressure injuries (HAPIs). Using a commercially available thermal imaging system, study authors documented a total of 12 thermal anomalies in 9 of 114 patients at the time of admission to one of the study institution’s ICUs over a 2-month period. An intensive, proven wound prevention protocol was immediately implemented for each of these patients. Of these 12 anomalies, 2 ultimately manifested as visually identifiable DTPIs. This represented a 60% reduction in the authors' institution’s historical DTPIs/HAPI rate. Because these DTPIs were documented as present on admission using the thermal imaging tool, researchers avoided a revenue loss associated with nonreimbursed costs of care and also estimated financial benefits associated with litigation expenses known to be generated with HAPIs.

Using thermal imaging to document DTPIs when patients present has the potential to significantly reduce expenses associated with pressure injury litigation. The clinical and financial benefits of early documentation of skin surface thermal anomalies in anatomical areas of interest are significant.

Magnetic resonance elastography of skeletal muscle deep tissue injury

The current state-of-the-art diagnosis method for deep tissue injury in muscle, a subcategory of pressure ulcers, is palpation. It is recognized that deep tissue injury is frequently preceded by altered biomechanical properties. A quantitative understanding of the changes in biomechanical properties preceding and during deep tissue injury development is therefore highly desired. In this paper we quantified the spatial-temporal changes in mechanical properties upon damage development and recovery in a rat model of deep tissue injury. Deep tissue injury was induced in nine rats by two hours of sustained deformation of the tibialis anterior muscle. Magnetic resonance elastography (MRE), T₂ -weighted, and T₂ -mapping measurements were performed before, directly after indentation, and at several timepoints during a 14-day follow-up. The results revealed a local hotspot of elevated shear modulus (from 3.30 ± 0.14 kPa before to 4.22 ± 0.90 kPa after) near the center of deformation at Day 0, whereas the T₂ was elevated in a larger area. During recovery there was a clear difference in the time course of the shear modulus and T₂ . Whereas T₂ showed a gradual normalization towards baseline, the shear modulus dropped below baseline from Day 3 up to Day 10 (from 3.29 ± 0.07 kPa before to 2.68 ± 0.23 kPa at Day 10, P < 0.001), followed by a normalization at Day 14. In conclusion, we found an initial increase in shear modulus directly after two hours of damage-inducing deformation, which was followed by decreased shear modulus from Day 3 up to Day 10, and subsequent normalization. The lower shear modulus originates from the moderate to severe degeneration of the muscle. MRE stiffness values were affected in a smaller area as compared with T₂ . Since T₂ elevation is related to edema, distributing along the muscle fibers proximally and distally from the injury, we suggest that MRE is more specific than T₂ for localization of the actual damaged area.

Using Alternative Light Source Technology to Enhance Visual Inspection of the Skin

BACKGROUND

The identification of deep tissue pressure injury (DTPI) in the early stages of evolution presents a challenge, as skin compromise is only visually apparent when evidence of damage reaches its outer layers.

CASE DESCRIPTION

We describe use of an alternative light source (ALS) to enhance visual skin assessment in 3 cases. Case 1 was a 47-year-old African American man with a hyperpigmented inner buttocks and a mixture of partial- and shallow full-thickness skin loss from incontinence-associated dermatitis and friction. Case 2 was a 62-year-old African American woman with a gluteal cleft DTPI. Case 3 was a 57-year-old African American woman with a stage 3 pressure injury of the right buttock.

CONCLUSION

The ALS enabled visualization of skin nuances not visible to the unaided eye. Based on this experience, we conclude that use of an ALS provided additional visual details when compared to traditional visual inspection. We found that as the ALS interplays with skin layers, penetrating and absorbing at differing depths, compromised skin appeared darker and more distinct when compared to adjacent, intact skin. Additional research is needed to determine whether the ALS enables earlier pressure injury detection, timelier and more effective intervention, decreased morbidity, and cost savings.

An advanced magnetic resonance imaging perspective on the etiology of deep tissue injury

Early diagnosis of deep tissue injury remains problematic due to the complicated and multifactorial nature of damage induction and the many processes involved in damage development and recovery. In this paper, we present a comprehensive assessment of deep tissue injury development and remodeling in a rat model by multiparametric magnetic resonance imaging (MRI) and histopathology. The tibialis anterior muscle of rats was subjected to mechanical deformation for 2 h. Multiparametric in vivo MRI, consisting of T2, T2*, mean diffusivity (MD), and angiography measurements, was applied before, during, and directly after indentation as well as at several time points during a 14-day follow-up. MRI readouts were linked to histological analyses of the damaged tissue. The results showed dynamic change in various MRI parameters, reflecting the histopathological status of the tissue during damage induction and repair. Increased T2 corresponded with edema, muscle cell damage, and inflammation. T2* was related to tissue perfusion, hemorrhage, and inflammation. MD increase and decrease was reported on the tissue’s microstructural integrity and reflected muscle degeneration and edema as well as fibrosis. Angiography provided information on blockage of blood flow during deformation. Our results indicate that the effects of a single damage-causing event of only 2 h of deformation were present up to 14 days. The initial tissue response to deformation, as observed by MRI, starts at the edge of the indentation. The quantitative MRI readouts provided distinct and complementary information on the extent, temporal evolution, and microstructural basis of deep tissue injury-related muscle damage.

NEW & NOTEWORTHY We have applied a multiparametric MRI approach linked to histopathology to characterize damage development and remodeling in a rat model of deep tissue injury. Our approach provided several relevant insights in deep tissue injury. Response to damage, as observed by MRI, started at some distance from the deformation. Damage after a single indentation period persisted up to 14 days. The MRI parameters provided distinct and complementary information on the microstructural basis of the damage.

Subepidermal moisture detection of heel pressure injury: The pressure ulcer detection study outcomes

We examined subepidermal moisture (SEM) and visual skin assessment of heel pressure injury (PrI) among 417 nursing home residents in 19 facilities over 16 weeks. Participants were older (mean age 77 years), 58% were female, over half were ethnic minorities (29% African American, 12% Asian American, 21% Hispanic), and at risk for PrI (mean Braden Scale Risk score = 15.6). Blinded concurrent visual assessments and SEM measurements were obtained at heels weekly. Visual skin damage was categorised as normal, erythema, stage 1 PrI, deep tissue injury (DTI) or stage 2 or greater PrI. PrI incidence was 76%. Off-loading occurred with pillows (76% of residents) rather than heel boots (21%) and often for those with DTI (91%). Subepidermal moisture was measured with a device where higher readings indicate greater moisture (range: 0-70 tissue dielectric constant), with normal skin values significantly different from values in the presence of skin damage. Subepidermal moisture was associated with concurrent damage and damage 1 week later in generalised multinomial logistic models adjusting for age, diabetes and function. Subepidermal moisture detected DTI and differentiated those that resolved, remained and deteriorated over 16 weeks. Subepidermal moisture may be an objective method for detecting PrI.

Defining Unstageable Pressure Ulcers as Full-Thickness Wounds: Are These Wounds Being Misclassified?

PURPOSE

The purpose of this study was to describe the evolution of unstageable pressure ulcers (PUs) over time to determine if their healing trajectory is consistent with full- or partial-thickness wounds.

DESIGN

Retrospective review of electronic medical record and a clinical PU database.

SUBJECTS AND SETTINGS

Patients with hospital-acquired, unstageable PUs were evaluated. Subjects were cared for at a level 1 trauma/burn center and safety net hospital in the Pacific Northwest between November 2007 and March 2011.

METHODS

Electronic medical records and a clinical PU database for 194 unstageable PUs were examined. The PU database is managed by certified wound care nurses; it includes data on all verified hospital-acquired PUs since 2007. The unit of analysis for this study was the individual PU site.

RESULTS

Of the initial 194 unstageable PUs identified, 120 were excluded due to lack of data needed to address research questions. Out of the 74 unstageable PUs that remained in the study, approximately one-third (33.8%) were found to follow a healing trajectory consistent with partial-thickness wounds.

CONCLUSION

Findings indicate that while approximately two-thirds of unstageable PUs demonstrate healing trajectories consistent with full-thickness wounds, slightly more than a third follow a trajectory consistent with partial-thickness wounds. Additional research is needed to clarify the healing trajectories of unstageable PUs and to determine whether the current definition for unstageable PUs is adequate.

A MRI-Compatible Combined Mechanical Loading and MR Elastography Setup to Study Deformation-Induced Skeletal Muscle Damage in Rats

Deformation of skeletal muscle in the proximity of bony structures may lead to deep tissue injury category of pressure ulcers. Changes in mechanical properties have been proposed as a risk factor in the development of deep tissue injury and may be useful as a diagnostic tool for early detection. MRE allows for the estimation of mechanical properties of soft tissue through analysis of shear wave data. The shear waves originate from vibrations induced by an external actuator placed on the tissue surface. In this study a combined Magnetic Resonance (MR) compatible indentation and MR Elastography (MRE) setup is presented to study mechanical properties associated with deep tissue injury in rats. The proposed setup allows for MRE investigations combined with damage-inducing large strain indentation of the Tibialis Anterior muscle in the rat hind leg inside a small animal MR scanner. An alginate cast allowed proper fixation of the animal leg with anatomical perfect fit, provided boundary condition information for FEA and provided good susceptibility matching. MR Elastography data could be recorded for the Tibialis Anterior muscle prior to, during, and after indentation. A decaying shear wave with an average amplitude of approximately 2 μm propagated in the whole muscle. MRE elastograms representing local tissue shear storage modulus G_d showed significant increased mean values due to damage-inducing indentation (from 4.2 ± 0.1 kPa before to 5.1 ± 0.6 kPa after, p<0.05). The proposed setup enables controlled deformation under MRI-guidance, monitoring of the wound development by MRI, and quantification of tissue mechanical properties by MRE. We expect that improved knowledge of changes in soft tissue mechanical properties due to deep tissue injury, will provide new insights in the etiology of deep tissue injuries, skeletal muscle damage and other related muscle pathologies.