The clinical and thermographical evaluation of pressure sores

Accuracy of ultrasound, thermography and subepidermal moisture in predicting pressure ulcers: a systematic review

OBJECTIVE

Our aims were to: establish the clinical significance of ultrasound, thermography, photography and subepidermal moisture (SEM) measurement; determine the accuracy of ultrasound, thermography, photography and SEM measurement in detecting skin/tissue damage; determine the relative accuracy of one of these assessment methods over another; make recommendations for practice pertaining to assessment of early skin/tissue damage.

METHOD

The following databases, Cochrane Wounds Group Specialised Register, The Cochrane Central Register of Controlled Trials, Ovid MEDLINE, Ovid EMBASE, Elsevier version, EBSCO CINAHL, ClinicalTrials.gov , WHO International Clinical Trials Registry (ICTR) and The EU Clinical Trials Register were searched for terms including; thermography, ultrasound, subepidermal moisture, photograph and pressure ulcer.

RESULTS

We identified four SEM, one thermography and five ultrasound studies for inclusion in this review. Data analysis indicated that photography was not a method which allowed for the early prediction of PU presence. SEM values increased with increasing tissue damage, with the sacrum and the heels being the most common anatomical locations for the development of erythema and stage I PUs. Thermography identified temperature changes in tissues and skin that may give an indication of early PU development; however the data were not sufficiently robust. Ultrasound detected pockets of fluid/oedema at different levels of the skin that were comparable with tissue damage. Thus, SEM and ultrasound were the best methods for allowing a more accurate assessment of early skin/tissue damage. Using the EBL Critical Appraisal Tool the overall validities of the studies varied between 33.3-55.6%, meaning that there is potential for bias within all the included studies. All of the studies were situated at level IV, V and VII of the evidence pyramid. Although the methodological quality of the studies warrants consideration, these studies showed the potential that SEM and ultrasound have in early PU detection.

CONCLUSION

SEM and ultrasound are promising in the detection and prediction of early tissue damage and PU presence. However, these methods should be further studied to clarify their potential for use more widely in PU prevention strategies.

Noninvasive imaging technologies for cutaneous wound assessment: A review

The ability to phenotype wounds for the purposes of assessing severity, healing potential and treatment is an important function of evidence-based medicine. A variety of optical technologies are currently in development for noninvasive wound assessment. To varying extents, these optical technologies have the potential to supplement traditional clinical wound evaluation and research, by providing detailed information regarding skin components imperceptible to visual inspection. These assessments are achieved through quantitative optical analysis of tissue characteristics including blood flow, collagen remodeling, hemoglobin content, inflammation, temperature, vascular structure, and water content. Technologies that have, to this date, been applied to wound assessment include: near infrared imaging, thermal imaging, optical coherence tomography, orthogonal polarization spectral imaging, fluorescence imaging, laser Doppler imaging, microscopy, spatial frequency domain imaging, photoacoustic detection, and spectral/hyperspectral imaging. We present a review of the technologies in use or development for these purposes with three aims: (1) providing basic explanations of imaging technology concepts, (2) reviewing the wound imaging literature, and (3) providing insight into areas for further application and exploration. Noninvasive imaging is a promising advancement in wound assessment and all technologies require further validation.

Combination of thermographic and ultrasonographic assessments for early detection of deep tissue injury

Early detection and intervention of deep tissue injury are important to lead good outcome. Although the efficiency of ultrasonographic assessment of deep tissue injury has been reported previously, it requires a certain level of skill for accurate assessment. In this study, we present an investigation of the combination of thermographic and ultrasonographic assessments for early detection of deep tissue injury. We retrospectively reviewed 28 early-stage pressure ulcers (21 patients) presenting at the University of Tokyo Hospital between April 2009 and February 2010, surveying the associated thermographic and ultrasonographic findings. The wound temperature patterns were divided into low, even and high compared with the surrounding skin. Ultrasonographic findings were classified into unclear layer structure, hypoechoic lesion, discontinuous fascia and heterogeneous hypoechoic area. All 13 ulcers that were associated with low temperature showed good outcome; three ulcers had even temperatures and 12 ulcers showed high temperature on thermographic assessment. The two deep tissue injuries were rated high on thermographic assessment and showed heterogeneous hypoechoic area findings on ultrasonographic assessment. No non-deep tissue injury lesion was associated with these two findings simultaneously. The combination of thermographic and ultrasonographic assessments is expected to increase the accuracy of the early detection of deep tissue injuries.

The pathogenesis of skin wounds due to pressure

Wounds due to pressure arise in areas of anoxic necrosis. Blood is excluded from the skin by pressures in excess of the mean capillary pressure. In addition, trauma initiates haemostatic mechanisms which increase the extent of the vascular occlusion owing to the fact that endothelial cell retraction occurs and platelet thrombosis takes place. Endogenous factors potentiate this reaction in the base of the sore and the surrounding skin, Junctional complexes can be stabilised in animals by means of a single dose of ACTH in gelatine solvent administered four hours before operation and a marked diminution in the incidence of pressure sores occurs. Clinical trials are in progress in which the drug is administered to elderly patients prior to orthopaedic surgery. The extent of the vascular occlusion as well as the concomitant increase in tissue perfusion associated with wound healing can be determined thermographically and radiometrically. Three types of sore can be identified, each with a different prognosis. A non-intrusive technique is available which provides considerable assistance to those concerned with the management of patients with pressure sores.

Pelvic movement and interface pressure distribution during manual wheelchair propulsion

OBJECTIVE

To investigate the movement of the ischial tuberosities and the redistribution of interface pressure during manual wheelchair propulsion.

DESIGN

Measurement of ischial tuberosity positions and comparison with corresponding position of the zones of peak pressure by using independent samples t tests. Analysis of variance was used to compare peak and average pressures under static and dynamic conditions.

SETTING

Human locomotion laboratory.

PARTICIPANTS

Ten subjects with spinal cord injury (SCI) and 10 individuals with no disabilities.

INTERVENTIONS

Manual wheelchair propulsion on a stationary wheelchair ergometer at the subject's maximum propulsion speed.

MAIN OUTCOME MEASURES

Seat interface pressure and the 3-dimensional position of the pelvis were measured with a pressure mat and an optical motion analysis system.

RESULTS

During wheelchair sprinting, the ischia were located at 19.2+/-11.7 mm behind the corresponding peak pressure locations. The anteroposterior rocking of the pelvis was 11.2 degrees and 5.2 degrees for the normal and SCI group, respectively. The average interface pressure over the ischial tuberosity area was lower under dynamic conditions. It was also observed in the SCI group that there was a concentration of high-pressure gradients around the peak pressure areas of the buttock during dynamic propulsion.

CONCLUSION

Peak pressure locations did not concur exactly with the ischial tuberosities during propulsion. The movements of the ischial bone and the cyclic loading imposed on the tissue underneath the ischial tuberosities during dynamic conditions may have implications for the etiology of decubitus ulcers.

Drug-based prevention of pressure-sores

A double-blind clinical trial was carried out in 85 patients undergoing surgery to the upper shaft of the femur and to the hip-joint. In the control series, 27% developed pressure-sores before discharge from hospital. In the group in which 80 I.U. of corticotrophin (A.C.T.H.) in gelatin solvent was administered, only 12% developed pressure-sores. 19% of the patients with fractures to the upper shaft of the femur developed sores because accurate timing was not always possible. Prevention was complete in the case of total-hip replacement which is an elective procedure where A.C.T.H. can be administered at the right time to prevent disruptive damage to the microcirculation. It is suggested that the administration of A.C.T.H. should form part of the management of all high-risk surgical situations.

Collagenase in the treatment of dermal and decubitus ulcers

The current management of decubitus ulcers, factors in wound healing and the role of enzymes in treatment are discussed. The therapeutic benefits of collagenase (Santyl) ointment in 21 patients are described, supplemented by serial color photographs. Statistical evidence is provided for the conclusion that collagenase ointment is an excellent adjunct to therapy.