Hyperaemia

Pathogenesis of Pachyvein Formation in Central Serous Chorioretinopathy: A Hydrodynamic Analysis

Objectives: To attain an understanding of pachyvein formation seen with central serous chorioretinopathy (CSC) by measuring the choroidal blood flow (CBF) velocity and to apply the findings to existing hydrodynamic theorems. Methods: Nineteen subjects with monocular CSC (mean age 51.8 ± 12.7 years) were included. Laser speckle flowgraphy measured the mean blur rate (MBR) in the foveal and perifoveal regions, and the findings were applied to the Equation of Continuity (Q = AV) and Bernoulli's theorem (1/2V2 + P/ρ = constant). Results: The mean foveal/perifoveal MBRs in the CSC eyes were 6.4 ± 3.2/9.6 ± 3.2 (p < 0.001). The mean MBRs in the non-CSC eyes were 8.3 ± 3.2/7.9 ± 2.4 (p = 0.37). The significant foveal CBF velocity decrease in CSC eyes occurs because of exudation from the hyperpermeable choriocapillaris. The subsequent decrease in blood volume due to the exudation elicits a decrease in the blood flow velocity in the inferior venules in accordance with the Equation of Continuity. The decrease in the blood flow velocity may result in an elevated blood flow pressure in the inferior venules and veins at the exudation site, in accordance with Bernoulli's theorem. Conclusion: A significant decrease in the foveal MBR may result from exudation from the hyperpermeable macular choriocapillaris. This decreased velocity may elicit a blood pressure elevation that can expand the inferior venules and veins at the exudation site, so-called pachyvein and pachychoroid formation. The application of hydrodynamic theorems to the measurement of ocular blood flow can provide new insights into the understanding of the pathogenesis of chorioretinal disease.

Skeletal Muscle, Skin, and Bone as Three Major Nitrate Reservoirs in Mammals: Chemiluminescence and 15N-Tracer Studies in Yorkshire Pigs

In mammals, nitric oxide (NO) is generated either by the nitric oxide synthase (NOS) enzymes from arginine or by the reduction of nitrate to nitrite by tissue xanthine oxidoreductase (XOR) and the microbiome and further reducing nitrite to NO by XOR or several heme proteins. Previously, we reported that skeletal muscle acts as a large nitrate reservoir in mammals, and this nitrate reservoir is systemically, as well as locally, used to generate nitrite and NO. Here, we report identifying two additional nitrate storage organs-bone and skin. We used bolus of ingested 15N-labeled nitrate to trace its short-term fluxes and distribution among organs. At baseline conditions, the nitrate concentration in femur bone samples was 96 ± 63 nmol/g, scalp skin 56 ± 22 nmol/g, with gluteus muscle at 57 ± 39 nmol/g. In comparison, plasma and liver contained 34 ± 19 nmol/g and 15 ± 5 nmol/g of nitrate, respectively. Three hours after 15N-nitrate ingestion, its concentration significantly increased in all organs, exceeding the baseline levels in plasma, skin, bone, skeletal muscle, and in liver 5-, 2.4-, 2.4-, 2.1-, and 2-fold, respectively. As expected, nitrate reduction into nitrite was highest in liver but also substantial in skin and skeletal muscle, followed by the distribution of 15N-labeled nitrite. We believe that these results underline the major roles played by skeletal muscle, skin, and bone, the three largest organs in mammals, in maintaining NO homeostasis, especially via the nitrate-nitrite-NO pathway.

Using high-resolution imaging to study the impact of the Kalogon wheelchair cushion on blood flow in the gluteal area

AIM OF THE STUDY

This study investigated how the air-bladder offloading mode of the Orbiter by Kalogon wheelchair cushion (Orbiter) affected blood flow in the gluteal region of non-disabled subjects. The hypothesis was that the cushion's offloading mode would improve blood flow, resulting in reduced reactive hyperemia when compared to the static setting, or Loaded Control (LC). Furthermore, the study proposed a technique using a high-resolution image laser speckle contrast system to measure blood flow in the gluteal area.

METHODS

Two procedures were carried out, one with the participant sitting on a cushion in LC, and the second, the cushion was set to offloading mode. Blood flow was measured through data imaging after each procedure. Three trials were performed, starting and ending in different cushion bladders. Customized algorithms were used to select regions of interest on the images for calculations. The Wilcoxon Signed-Rank Test was conducted to compare the offloads and loaded control values of each region of interest. Results were considered significant at α = 0.05.

RESULTS

Ten healthy, non-disabled adults participated in the study, seven females and three males. There were no significant differences among the participants. However, results showed that seven subjects tended to decrease reactive hyperemia in the offload sequence of trial when the last two bladders offloaded were the sacrum followed by the right ischial tuberosity.

CONCLUSIONS

The high-resolution imager showed that the Orbiter Offloads helped reduce reactive hyperemia in seven subjects, potentially improving blood flow. More research is necessary to comprehend the mechanisms of these effects fully.

Development of a method to identify persistent and blanchable redness by skin blotting in mice

Persistent and blanchable redness (PBR) is not currently included in category I pressure injury (PI), which is defined as non-blanchable redness (NBR). However, PBR progresses to PI in a clinical setting. Therefore, it should be clinically managed as category I PI, and a method to distinctly identify PBR is needed. This study aimed to examine whether PI-related biomarkers can distinguish PRB from transient redness (TR) and NBR using skin blotting. TR, PBR, and NBR models were established by the different conditions of dorsal skin compression. Redness observation and skin blotting were performed, and the skin tissue samples were subjected to histological and molecular biological analyses. The vascular endothelial growth factor (Vegf) b, heat shock protein (Hsp) 90aa1, tumour necrosis factor, interleukin (Il) 1b, and Il6 messenger ribonucleic acid levels were significantly different between the three models. The VEGF-A, VEGF-B, IL-1β, and IL-6 protein levels were different between the three models. Although the results of skin blot examinations were inconsistent with those of the expression analysis of tissue, HSP90α and IL-1β are suggested to be potential markers to distinguish PBR from TR and NBR.

Cardiac Rehabilitation Improves Endothelial Function in Coronary Artery Disease Patients

Exercise-based cardiac rehabilitation may be an effective non-pharmacological intervention for improving endothelial function in coronary artery disease patients. Therefore, this systematic review with meta-analysis aimed to (a) estimate the training-induced effect on endothelial and vascular smooth muscle function, assessed by flow-mediated dilation and nitroglycerin-mediated dilation, respectively, in coronary artery disease patients; and to (b) study the influence of potential trial-level variables (i. e. study and intervention characteristics) on the training-induced effect on endothelial and vascular smooth muscle function. Electronic searches were performed in Pubmed, Scopus, and Embase up to February 2021. Random-effects models of standardised mean change were estimated. Heterogeneity analyses were performed by using the Chi ² test and I ² index. Our results showed that exercise-based cardiac rehabilitation significantly enhanced flow-mediated dilation (1.04 [95% confidence interval=0.76 to 1.31]) but did not significantly change nitroglycerin-mediated dilation (0.05 [95% confidence interval=-0.03 to 0.13]). Heterogeneity testing reached statistical significance (p<.001) with high inconsistency for flow-mediated dilation (I ² =92%). Nevertheless, none of the analysed variables influenced the training-induced effect on flow-mediated dilation. Exercise-based cardiac rehabilitation seems to be an effective therapeutic strategy for improving endothelial-dependent dilation in coronary artery disease patients, which may aid in the prevention of cardiovascular events.

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.

Effect of Vibration on Alleviating Foot Pressure-Induced Ischemia under Occlusive Compression

Objectives

Foot ulcers often occur in people with diabetes because of pressure-induced tissue ischemia. Vibration has been reported to be helpful in alleviating mechanical damage and promoting wound healing. The objective of this study is to explore whether vibration can relieve reactive hyperemia in foot tissue under occlusive compression.

Methods

Thirteen healthy adults participated in the study. Each foot was placed under occlusive compression without or with vibration intervention, which was randomly assigned every other day. The dorsal foot skin blood flow (SBF) was measured pre- and postintervention for each subject in each test. Temporal variations and spectral features of SBF were recorded for comparison.

Results

The results showed that subjects displayed an obvious reactive hyperemia in the foot tissue after pressure occlusion, whereas they displayed a more regular SBF when vibration was applied along with occlusive compression. Moreover, the amplitude of metabolic, neurogenic, and myogenic pathways for SBF was significantly reduced during the hyperemia process when vibration was applied.

Conclusions

This study demonstrated that vibration can effectively reduce the level of hyperemia in foot tissue under occlusive compression and also induce less protective physiological regulatory activities. This is helpful for protecting foot tissue from pressure-induced ischemic injury and foot ulcers.

Responses to an intra-articular lipopolysaccharide challenge following dietary supplementation of Saccharomyces cerevisiae fermentation product in young horses

Dietary intervention may be a valuable strategy to optimize the intra-articular environment in young horses to prolong their performance career. To test the hypothesis that dietary supplementation of a Saccharomyces cerevisiae fermentation product would reduce markers of joint inflammation and increase markers of cartilage metabolism following a single inflammatory insult, Quarter Horse yearlings (mean ± SD; 9 ± 1.0 mo) were balanced by age, sex, body weight (BW), and farm of origin and randomly assigned to the following treatment groups: 1.25% BW/d (dry matter basis) custom-formulated concentrate only (CON; n = 9) or concentrate top-dressed with 21 g/d S. cerevisiae fermentation product (SCFP; n = 10) for 98 d. Horses had ad libitum access to Coastal bermudagrass hay. On day 84, one randomly selected radial carpal joint from each horse was injected with 0.5 ng lipopolysaccharide (LPS) solution. The remaining carpal joint was injected with sterile lactated Ringer’s solution as a contralateral control. Synovial fluid obtained before supplementation (day 0) and on day 84 at preinjection hour 0 and 6, 12, 24, 168, and 336 h postinjection was analyzed for prostaglandin E₂ (PGE₂), carboxypropeptide of type II collagen (CPII), and collagenase cleavage neopeptide (C2C) by commercial assays. Rectal temperature, heart rate, respiration rate, carpal surface temperature, and carpal circumference were recorded prior to each sample collection and for 24 h postinjection. Data were analyzed using linear models with repeated measures. From day 0 to 84, synovial C2C declined (P ≤ 0.01) and the CPII:C2C ratio increased (P ≤ 0.01) in all horses with no effect of diet. In response to intra-articular LPS, synovial PGE₂ increased by hour 6 (P ≤ 0.01) and returned to baseline by hour 336; CPII increased by hour 12, remained elevated through hour 168 (P ≤ 0.01), and returned to baseline by hour 336; and C2C increased by hour 6 (P ≤ 0.01) but did not return to baseline through hour 336 (P ≤ 0.01). Post-intra-articular injection, PGE₂ levels were lower in SCFP than CON horses (P = 0.01) regardless of injection type. Synovial CPII and the CPII:C2C ratio demonstrated stability during the LPS challenge in SCFP compared with CON horses (P ≤ 0.01). Clinical parameters were not influenced by diet but increased in response to repeated arthrocentesis (P ≤ 0.01). Dietary SCFP may favorably modulate intra-articular inflammation following an acute stressor and influence cartilage turnover in young horses.

Preliminary Assessment on the Histological Changes in Juvenile Siganus guttattus (Bloch, 1787) Exposed to Plastic Debris

Plastic debris is ubiquitous in the marine environment and many of this is polyethylene based plastic bags. Its potential effect on marine organisms is still understudied. Hence, this study determined the histological changes induced in the intestine and liver of the juvenile rabbit fish, Siganus guttatus. S. guttatus (N = 150) were sub chronically exposed to plastic bag debris suspensions (0, 0.01, 0.1, 1.0 and 10 mg L^-1) for 10 days. In addition to histological changes, the condition factor (CF) index of the fishes were assessed. Results showed that there was no significant difference in the CF index of the fishes exposed to varying concentrations of plastic suspensions, there was however histological changes in fishes exposed to 10 mg L^-1. The histological changes in the intestine were hyperemia, necrosis, goblet cells hyperplasia, and shortening of the villi. Histological changes in the liver were hyperemic blood vessels and vacuolization. Fishes exposed to 10 mg L^-1 exhibited a higher proximal, distal, liver and total organ index as compared to those unexposed (p < 0.05).

CLEAR - Effect of contact lens materials and designs on the anatomy and physiology of the eye

This paper outlines changes to the ocular surface caused by contact lenses and their degree of clinical significance. Substantial research and development to improve oxygen permeability of rigid and soft contact lenses has meant that in many countries the issues caused by hypoxia to the ocular surface have largely been negated. The ability of contact lenses to change the axial growth characteristics of the globe is being utilised to help reduce the myopia pandemic and several studies and meta-analyses have shown that wearing orthokeratology lenses or soft multifocal contact lenses can reduce axial length growth (and hence myopia). However, effects on blinking, ptosis, the function of Meibomian glands, fluorescein and lissamine green staining of the conjunctiva and cornea, production of lid-parallel conjunctival folds and lid wiper epitheliopathy have received less research attention. Contact lens wear produces a subclinical inflammatory response manifested by increases in the number of dendritiform cells in the conjunctiva, cornea and limbus. Papillary conjunctivitis is also a complication of all types of contact lenses. Changes to wear schedule (daily disposable from overnight wear) or lens materials (hydrogel from SiHy) can reduce papillary conjunctivitis, but the effect of such changes on dendritic cell migration needs further study. These changes may be associated with decreased comfort but confirmatory studies are needed. Contact lenses can affect the sensitivity of the ocular surface to mechanical stimulation, but whether these changes affect comfort requires further investigation. In conclusion, there have been changes to lens materials, design and wear schedules over the past 20+ years that have improved their safety and seen the development of lenses that can reduce the myopia development. However, several changes to the ocular surface still occur and warrant further research effort in order to optimise the lens wearing experience.

Markers of human endometrial hypoxia can be detected in vivo and ex vivo during physiological menstruation

STUDY QUESTION

Can markers of human endometrial hypoxia be detected at menstruation in vivo?

SUMMARY ANSWER

Our in vivo data support the presence of hypoxia in menstrual endometrium of women during physiological menstruation.

WHAT IS KNOWN ALREADY

Current evidence from animal models and human in vitro studies suggests endometrial hypoxia is present at menstruation and drives endometrial repair post menses. However, detection of human endometrial hypoxia in vivo remains elusive.

STUDY DESIGN, SIZE, DURATION

We performed a prospective case study of 16 women with normal menstrual bleeding.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Reproductively aged female participants with a regular menstrual cycle underwent objective measurement of their menstrual blood loss using the alkaline haematin method to confirm a loss of <80 ml per cycle. Exclusion criteria were exogenous hormone use, an intrauterine device, endometriosis or fibroids >3 cm. Participants attended for two MRI scans; during days 1-3 of menstruation and the early/mid-secretory phase of their cycle. The MRI protocol included dynamic contrast-enhanced MRI and T2* quantification. At each visit, an endometrial sample was also collected and hypoxia-regulated repair factor mRNA levels (ADM, VEGFA, CXCR4) were quantified by RT-qPCR.

MAIN RESULTS AND THE ROLE OF CHANCE

Women had reduced T2* during menstrual scans versus non-menstrual scans (P = 0.005), consistent with menstrual hypoxia. Plasma flow (Fp) was increased at menstruation compared to the non-menstrual phase (P = 0.0005). Laboratory findings revealed increased ADM, VEGF-A and CXCR4 at menstruation on examination of paired endometrial biopsies from the menstrual and non-menstrual phase (P = 0.008; P = 0.03; P = 0.009). There was a significant correlation between T2* and these ex vivo hypoxic markers (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

This study examined the in vivo detection of endometrial hypoxic markers at specific timepoints in the menstrual cycle in women with a menstrual blood loss <80 ml/cycle and without significant uterine structural abnormalities. Further research is required to determine the presence of endometrial hypoxia in those experiencing abnormal uterine bleeding with and without fibroids/adenomyosis.

WIDER IMPLICATIONS OF THE FINDINGS

Heavy menstrual bleeding (HMB) is a common, debilitating condition. Understanding menstrual physiology may improve therapeutics. To our knowledge, this is the first in vivo data supporting the presence of menstrual hypoxia in the endometrium of women with normal menstrual bleeding. If aberrant in those with HMB, these non-invasive tests may aid diagnosis and facilitate personalized treatments for HMB.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by Wellbeing of Women grant RG1820, Wellcome Trust Fellowship 209589/Z/17/Z and undertaken in the MRC Centre for Reproductive Health, funded by grants G1002033 and MR/N022556/1. H.O.D.C. has clinical research support for laboratory consumables and staff from Bayer AG and provides consultancy advice (but with no personal remuneration) for Bayer AG, PregLem SA, Gedeon Richter, Vifor Pharma UK Ltd, AbbVie Inc; Myovant Sciences GmbH. H.O.D.C. receives royalties from UpToDate for articles on abnormal uterine bleeding.

TRIAL REGISTRATION NUMBER

N/A.

Measles skin rash: Infection of lymphoid and myeloid cells in the dermis precedes viral dissemination to the epidermis

Measles is characterized by fever and a maculopapular skin rash, which is accompanied by immune clearance of measles virus (MV)-infected cells. Histopathological analyses of skin biopsies from humans and non-human primates (NHPs) with measles rash have identified MV-infected keratinocytes and mononuclear cells in the epidermis, around hair follicles and near sebaceous glands. Here, we address the pathogenesis of measles skin rash by combining data from experimentally infected NHPs, ex vivo infection of human skin sheets and in vitro infection of primary human keratinocytes. Analysis of NHP skin samples collected at different time points following MV inoculation demonstrated that infection in the skin precedes onset of rash by several days. MV infection was detected in lymphoid and myeloid cells in the dermis before dissemination to the epidermal leukocytes and keratinocytes. These data were in good concordance with ex vivo MV infections of human skin sheets, in which dermal cells were more targeted than the epidermal cells. To address viral dissemination to the epidermis and to determine whether the dissemination is receptor-dependent, we performed experimental infections of primary keratinocytes collected from healthy donors. These experiments demonstrated that MV infection of keratinocytes is mainly nectin-4-dependent, and differentiated keratinocytes, which express higher levels of nectin-4, are more susceptible to MV infection than proliferating keratinocytes. Based on these data, we propose a model to explain measles skin rash: migrating MV-infected lymphocytes initiate the infection of dermal skin-resident CD150⁺ immune cells. The infection is subsequently disseminated from the dermal papillae to nectin-4⁺ keratinocytes in the basal epidermis. Lateral spread of MV infection is observed in the superficial epidermis, most likely due to the higher level of nectin-4 expression on differentiated keratinocytes. Finally, MV-infected cells are cleared by infiltrating immune cells, causing hyperemia and edema, which give the appearance of morbilliform skin rash.

Several viral infections are associated with skin rash, including parvovirus B19, human herpesvirus type 6, dengue virus and rubella virus. However, the archetype virus infection that leads to skin rash is measles. Although all of these viral exanthemata often appear similar, their pathogenesis is different. In the case of measles, the appearance of skin rash is a sign that the immune system is clearing MV-infected cells from the skin. How the virus reaches the skin and is locally disseminated remains unknown. Here, we combine observations and expertise from pathologists, dermatologists, virologists and immunologists to delineate the pathogenesis of measles skin rash. We show that MV infection of dermal myeloid and lymphoid cells precedes viral dissemination to the epidermal leukocytes and keratinocytes. We speculate that immune-mediated clearance of these infected cells results in hyperemia and edema, explaining the redness of the skin and the slightly elevated spots of the morbilliform rash.

Cardiovascular Magnetic Resonance Imaging: Identifying the Effects of Cancer Therapy

The era of modern oncology incorporates an ever-evolving personalized approach to hematological malignancies and solid tumors. As a result, patient survival rates have, in part, substantially improved, depending on the specific type of underlying malignancy. However, systemic therapies may come along with potential cardiotoxic effects resulting in heart failure with increased morbidity and mortality. Ultimately, patients may survive their malignancy but die as a result of cancer treatment. Cardiovascular magnetic resonance imaging has long been in use for the assessment of function and tissue characteristics in patients with various nonischemic cardiac diseases. Besides an introductory overview on the general definition of cardiotoxicity including potential underlying mechanisms, this review provides insight into the application of various cardiovascular magnetic resonance imaging techniques in the setting of cancer therapy-related cardiac and vascular toxicity. Early identification of cardiotoxic effects may allow for on-time therapy adjustment and/or cardioprotective measures to avoid subsequent long-term heart failure with increased mortality.

Wheelchair Tilt-in-Space and Recline Functions: Influence on Sitting Interface Pressure and Ischial Blood Flow in an Elderly Population

Pressure ulcers (PUs) result from localised injury to the skin and underlying tissue and usually occur over a bony prominence as a result of pressure, often in combination with shear forces. Both pressure magnitude and duration are thought to be key risk factors in the occurrence of PUs, thus exposing wheelchair-bound subjects to high risk of PU development. As a result, wheelchairs that incorporate tilt-in-space and recline functions are routinely prescribed to redistribute pressure away from their ischial tuberosities. The goal of this study was to analyse the role of full-body tilt and recline angles in governing sitting interface pressure and blood circulation parameters in elderly subjects and thereby investigate the efficacy of tilt-in-space wheelchairs for aiding pressure relief activity. Sitting interface pressure and ischial blood flow parameters were examined in 20 healthy elderly subjects while seated in a tilt-in-space and recline wheelchair. Five different angles of seat tilt (5°, 15°, 25°, 35°, and 45°) were assessed in combination with three different angles of backrest recline (5°, 15°, and 30°). The results of the study show that when compared to the upright reference posture, every position (except 15°T/5°R) resulted in a significant decrease in sitting interface pressure. Ischial blood flow also showed significant increases at four different positions (45°T/15°R, 15°T/30°R, 35°T/30°R, and 45°T/30°R) but only at larger tilt-in-space and recline angles. The results therefore suggest that small tilt-in-space and recline angles are indeed able to reduce sitting interface pressures, whereas changes in ischial blood flow only occur at larger angles. In the literature, cell deformation is thought to be dominant over tissue ischemia in the development of tissue necrosis and PUs. Therefore, together with our findings it can be concluded that frequently undertaking small adjustments in tilt-in-space and recline angle might be important for preventing cell deformation and any associated cell necrosis. Larger angles of tilt-in-space and recline seem to support blood flow returning to the tissues, which is likely to play a positive role in healing damaged tissue.

Using Multiscale Entropy to Assess the Efficacy of Local Cooling on Reactive Hyperemia in People with a Spinal Cord Injury

Pressure ulcers are one of the most common complications of a spinal cord injury (SCI). Prolonged unrelieved pressure is thought to be the primary causative factor resulting in tissue ischemia and eventually pressure ulcers. Previous studies suggested that local cooling reduces skin ischemia of the compressed soft tissues based on smaller hyperemic responses. However, the effect of local cooling on nonlinear properties of skin blood flow (SBF) during hyperemia is unknown. In this study, 10 wheelchair users with SCI and 10 able-bodied (AB) controls underwent three experimental protocols, each of which included a 10-min period as baseline, a 20-min intervention period, and a 20-min period for recovering SBF. SBF was measured using a laser Doppler flowmetry. During the intervention period, a pressure of 60 mmHg was applied to the sacral skin, while three skin temperature settings were tested, including no temperature change, a decrease by 10 °C, and an increase by 10 °C, respectively. A multiscale entropy (MSE) method was employed to quantify the degree of regularity of blood flow oscillations (BFO) associated with the SBF control mechanisms during baseline and reactive hyperemia. The results showed that under pressure with cooling, skin BFO both in people with SCI and AB controls were more regular at multiple time scales during hyperemia compared to baseline, whereas under pressure with no temperature change and particularly pressure with heating, BFO were more irregular during hyperemia compared to baseline. Moreover, the results of surrogate tests indicated that changes in the degree of regularity of BFO from baseline to hyperemia were only partially attributed to changes in relative amplitudes of endothelial, neurogenic, and myogenic components of BFO. These findings support the use of MSE to assess the efficacy of local cooling on reactive hyperemia and assess the degree of skin ischemia in people with SCI.

Reducing the Risk for Pressure Injury During Combat Evacuation

BACKGROUND

Combat casualties undergoing aeromedical evacuation are at increased risk for pressure injuries. The risk factors pressure and shear are potentially modifiable via solutions appropriate for en route care.

OBJECTIVES

To compare transcutaneous oxygen levels and skin temperatures in healthy participants under offloaded (side lying) and loaded (supine or supine with 30° backrest elevation) under 4 conditions: control (no intervention), Mepilex sacral and heel dressings, LiquiCell pad, and Mepilex plus LiquiCell.

METHODS

Participants were randomly assigned to 4 groups according to ideal body weight. Backrest positions were randomized. Transcutaneous oxygen level and temperature were measured on the sacrum and the heel; skin interface pressure was measured with an XSensor pressure imaging system. Measurements were obtained for 5 minutes at baseline (offloaded), 40 minutes with participants supine, and 15 minutes offloaded.

RESULTS

In the 40 healthy participants, interface pressure, transcutaneous oxygen level, and skin temperature did not differ between the 4 groups. Peak interface pressures were approximately 43 mm Hg for the sacrum and 50 mm Hg for the heel. Sacral transcutaneous oxygen level differed significantly between unloaded (mean, 79 mm Hg; SD, 16.5) and loaded (mean, 57 mm Hg; SD, 25.2) conditions (P < .001) in a flat position (mean, 85.2 mm Hg; SD, 13.6) and with 30° backrest elevation (mean, 66.7 mm Hg; SD, 24.2) conditions (P < .001). Results for the heels and the sacrum were similar. Sacral skin temperature increased significantly across time (approximately 1.0°C).

CONCLUSIONS

The intervention strategies did not differ in prevention of pressure injuries.

Evaluation of conjugated linoleic acid supplementation on markers of joint inflammation and cartilage metabolism in young horses challenged with lipopolysaccharide

Seventeen yearling Quarter Horses were used in a randomized complete block design for a 56-d trial to determine ability of dietary CLA to mitigate joint inflammation and alter cartilage turnover following an inflammatory insult. Horses were blocked by age, sex, and BW, and randomly assigned to dietary treatments consisting of commercial concentrate offered at 1% BW (as-fed) supplemented with either 1% soybean oil (CON; n = 6), 0.5% soybean oil and 0.5% CLA (LOW; n = 5; 55% purity; Lutalin, BASF Corp., Florham Park, NJ), or 1% CLA (HIGH; n = 6) top-dressed daily. Horses were fed individually every 12 h and offered 1% BW (as-fed) coastal bermudagrass (Cynodon dactylon) hay daily. This study was performed in 2 phases: phase I (d 0 to d 41) determined incorporation of CLA into plasma and synovial fluid; phase II (d 42 to d 56) evaluated potential of CLA to mitigate intra-articular inflammation and alter cartilage metabolism. Blood and synovial fluid were collected at 7- and 14-d intervals, respectively, to determine fatty acid concentrations. On d 42, carpal joints within each horse were randomly assigned to receive intra-articular injections of 0.5 ng lipopolysaccharide (LPS) derived from Escherichia coli 055:B5 or sterile lactated Ringer's solution. Synovial fluid samples were obtained at preinjection h 0 and 6, 12, 24, 168, and 336 h postinjection, and analyzed for prostaglandin E2 (PGE2), carboxypeptide of type II collagen (CPII), and collagenase cleavage neopeptide (C2C). Data were analyzed using PROC MIXED procedure of SAS. Horses receiving the CON diet had undetectable levels of CLA for the duration of the study. A quadratic dose response was observed in concentrations of CLA in plasma and synovial fluid (P < 0.01). A negative quadratic dose response was observed for plasma arachidonic acid (20:4) with a reduction in concentration to d 14 in HIGH horses (P = 0.04). Synovial fluid 20:4 tended to decrease in horses receiving the HIGH diet (P = 0.06). Post LPS injection, synovial PGE2 was not affected by dietary treatment (P = 0.15). Synovial C2C was lower in HIGH horses (P = 0.05), and synovial CPII tended to be greater in LOW horses than HIGH and CON horses (P = 0.10). In conclusion, dietary CLA incorporated into plasma and synovial fluid prior to LPS challenge. Dietary CLA did not influence inflammation; however, there was a reduction in cartilage degradation and an increase in cartilage regeneration.

Trends of reactive hyperaemia responses to repetitive loading on skin tissue of rats - Implications for pressure ulcer prevention

Tissue recovery is important in preventing tissue deterioration, which is induced by pressure and may lead to pressure ulcers (PU). Reactive hyperaemia (RH) is an indicator used to identify people at risk of PU. In this study, the effect of different recovery times on RH trend is investigated during repetitive loading. Twenty-one male Sprague-Dawley rats (seven per group), with body weight of 385-485 g, were categorised into three groups and subjected to different recovery times with three repetitive loading cycles. The first, second, and third groups were subjected to short (3 min), moderate (10 min), and prolonged (40 min) recovery, respectively, while fixed loading time and pressure (10 min and 50 mmHg, respectively). Peak hyperaemia was measured in the three cycles to determine trends associated with different recovery times. Three RH trends (increasing, decreasing, and inconsistent) were observed. As the recovery time is increased (3 min vs. 10 min vs. 40 min), the number of samples with increasing RH trend decreases (57% vs. 29% vs. 14%) and the number of samples with inconsistent RH trend increases (29% vs. 57% vs. 72%). All groups consists of one sample with decreasing RH trend (14%). Results confirm that different recovery times affect the RH trend during repetitive loading. The RH trend may be used to determine the sufficient recovery time of an individual to avoid PU development.

The effect of pressure and shear on tissue viability of human skin in relation to the development of pressure ulcers: a systematic review

Pressure ulcers are a significant problem in health care, due to high costs and large impact on patients' life. In general, pressure ulcers develop as tissue viability decreases due to prolonged mechanical loading. The relation between load and tissue viability is highly influenced by individual characteristics. It is proposed that measurements of skin blood flow regulation could provide good assessment of the risk for pressure ulcer development, as skin blood flow is essential for tissue viability. . Therefore, the aim of this systematic review is to gain insight in the relation between mechanical load and the response of the skin and underlying tissue to this loading measured in-vivo with non-invasive techniques. A systematic literature search was performed to identify articles analysing the relation between mechanical load (pressure and/or shear) and tissue viability measured in-vivo. Two independent reviewers scored the methodological quality of the 22 included studies. Methodological information as well as tissue viability parameters during load application and after load removal were extracted from the included articles and used in a meta-analysis. Pressure results in a decrease in skin blood flow parameters, compared to baseline; showing a larger decrease with higher magnitudes of load. The steepness of the decrease is mostly dependent on the anatomical location. After load removal the magnitude of the post-reactive hyperaemic peak is related to the magnitude of pressure. Lastly, shear in addition to pressure, shows an additional negative effect, but the effect is less apparent than pressure on skin viability.

A new method to evaluate the effects of shear on the skin

Currently, pressure ulcer preventive strategies focus mainly on pressure redistribution. Little attention is paid to reduce the harmful effects of shear-force, because little is known about pathophysiological aspects of shear-force. Even today, no method to measure the effects of shear-force on the skin is available. Therefore, the aim of this study was to investigate the response to shear-forces in terms of analyzing a noninvasive biomarker and reactive hyperemic parameter measured at the skin of healthy participants. A physical model was developed to produce a combination of pressure and shear or pressure alone on the skin. Ten healthy male participants were included and pressure (3.9 kPa) and a combined loading of pressure and shear (2.4 kPa + 14.5 N) was applied at the volar aspect of the forearms for 15 and 30 minutes. A Sebutape sample was used to collect IL-1α and total protein (TP) noninvasively. The reactive hyperemic parameter was derived from a laser Doppler flowmeter. The increase in IL-1α/TP-ratio after a combined loading of pressure and shear for 30 minutes of 6.2 ± 2.5 was significantly higher compared with all other test conditions (p < 0.05). The increase in cutaneous blood cell flux was already significantly higher when a combined loading of pressure and shear was applied for 15 minutes compared with pressure alone. These results shows that the IL-1α/TP-ratio and cutaneous blood cell flux can be used as robust measures of the effect of shear-force on skin in humans. Therefore, this model can be used to evaluate materials aimed at the reduction of shear.

Pressure ulcers: Current understanding and newer modalities of treatment

This article reviews the mechanism, symptoms, causes, severity, diagnosis, prevention and present recommendations for surgical as well as non-surgical management of pressure ulcers. Particular focus has been placed on the current understandings and the newer modalities for the treatment of pressure ulcers. The paper also covers the role of nutrition and pressure-release devices such as cushions and mattresses as a part of the treatment algorithm for preventing and quick healing process of these wounds. Pressure ulcers develop primarily from pressure and shear; are progressive in nature and most frequently found in bedridden, chair bound or immobile people. They often develop in people who have been hospitalised for a long time generally for a different problem and increase the overall time as well as cost of hospitalisation that have detrimental effects on patient's quality of life. Loss of sensation compounds the problem manifold, and failure of reactive hyperaemia cycle of the pressure prone area remains the most important aetiopathology. Pressure ulcers are largely preventable in nature, and their management depends on their severity. The available literature about severity of pressure ulcers, their classification and medical care protocols have been described in this paper. The present treatment options include various approaches of cleaning the wound, debridement, optimised dressings, role of antibiotics and reconstructive surgery. The newer treatment options such as negative pressure wound therapy, hyperbaric oxygen therapy, cell therapy have been discussed, and the advantages and disadvantages of current and newer methods have also been described.

Severe blunt muscle trauma in rats: only marginal hypoxia in the injured area

Background

After severe muscle trauma, hypoxia due to microvascular perfusion failure is generally believed to further increase local injury and to impair healing. However, detailed analysis of hypoxia at the cellular level is missing. Therefore, in the present work, spectroscopic measurements of microvascular blood flow and O₂ supply were combined with immunological detection of hypoxic cells to estimate O₂ conditions within the injured muscle area.

Materials and Methods

Severe blunt muscle trauma was induced in the right Musculus gastrocnemius of male Wistar rats by a standardized “weight-drop” device. Microvascular blood flow, relative hemoglobin amount, and hemoglobin O₂ saturation were determined by laser Doppler and white-light spectroscopy. Hypoxic cells were detected by histologic evaluation of covalent binding of pimonidazole and expression of HIF-1α.

Results

Directly after trauma and until the end of experiment (480 minutes), microvascular blood flow and relative hemoglobin amount were clearly increased. In contrast to blood flow and relative hemoglobin amount, there was no immediate but a delayed increase of microvascular hemoglobin O₂ saturation. Pimonidazole immunostaining revealed a hypoxic fraction (percentage area of pimonidazole-labelled muscle cells within the injured area) between 8 to 3%. There was almost no HIF-1α expression detectable in the muscle cells under each condition studied.

Conclusions

In the early phase (up to 8 hours) after severe blunt muscle trauma, the overall microvascular perfusion of the injured area and thus its O₂ supply is clearly increased. This increased O₂ supply is obviously sufficient to ensure normoxic (or even hyperoxic) conditions in the vast majority of the cells.

Understanding the medical markers of elder abuse and neglect: physical examination findings

A specific foundation of knowledge is important for evaluating potential abuse from physical findings in the older adult. The standard physical examination is a foundation for detecting many types of abuse. An understanding of traumatic injuries, including patterns of injury, is important for health care providers, and inclusion of elder abuse in the differential diagnosis of patient care is essential. One must possess the skills needed to piece the history, including functional capabilities, and physical findings together. Armed with this skill set, health care providers will develop the confidence needed to identify and intervene in cases of elder abuse.

The Effects of Different Lying Positions on Interface Pressure, Skin Temperature, and Tissue Blood Flow in Nursing Home Residents

Background:

Although repositioning is considered an important intervention to prevent pressure ulcers, tissue response during loading in different lying positions has not been adequately explored.

Aim:

To compare the effects of different lying positions on interface pressure, skin temperature, and tissue blood flow in nursing home residents.

Method:

From May 2011 to August 2012, interface pressure, skin temperature, and blood flow at three tissue depths were measured for 1 hr over the sacrum in 30° supine tilt and 0° supine positions and over the trochanter major in 30° lateral and 90° lateral positions in 25 residents aged 65 years or older. Measurement of interface pressure was accomplished using a pneumatic pressure transmitter connected to a digital manometer, skin temperature using a temperature sensor, and blood flow using photoplethysmography and laser Doppler flowmetry.

Results:

Interface pressure was significantly higher in the 0° supine and 90° lateral positions than in 30° supine tilt and 30° lateral positions. The mean skin temperature increased from baseline in all positions. Blood flow was significantly higher in the 30° supine tilt position compared to the other positions. A hyperemic response in the post pressure period was seen at almost all tissue depths and positions.

Conclusion:

The 30° supine tilt position generated less interface pressure and allowed greater tissue perfusion, suggesting that this position is the most beneficial.

Objective evaluation by reflectance spectrophotometry can be of clinical value for the verification of blanching/non blanching erythema in the sacral area

Early detection of non blanching erythema (pressure ulcer category I) is necessary to prevent any further skin damage. An objective method to discriminate between blanching/non blanching erythema is presently not available. The purpose of this investigation was to explore if a non invasive objective method could differentiate between blanching/non blanching erythema in the sacral area of patients undergoing hip fracture surgery. Seventy-eight patients were included. The sacral area of all patients was assessed using (i) conventional finger-press test and (ii) digital reading of the erythema index assessed with reflectance spectrophotometry. The patients were examined at admission and during 5 days postsurgery. Reflectance spectrophotometry measurements proved able to discriminate between blanching/non blanching erythema. The reliability, quantified by the intra-class correlation coefficient, was excellent between repeated measurements over the measurement period, varying between 0·82 and 0·96, and a significant change was recorded in the areas from day 1 to day 5 (P < 0·0001). The value from the reference point did not show any significant changes over the same period (P = 0·32). An objective method proven to identify early pressure damage to tissue can be a valuable tool in clinical practice.

Never say never: a descriptive study of hospital-acquired pressure ulcers in a hospital setting

PURPOSE

The purposes of this study were to describe the characteristics of patients who experienced hospital-acquired pressure ulcers (HAPUs); explore risk factors with these patients, including comorbid conditions; and describe risk-reduction measures in patients who developed HAPUs.

SUBJECTS AND SETTING

Eighty-two patients with at least 1 HAPU were identified at an urban Midwestern trauma center over 1 year.

DESIGN

A prospective study was conducted that included chart review and patient assessment.

METHODS

Assessment criteria for the data collection form were obtained from the literature. The novel instrument was designed to capture intrinsic conditions, for example, medical diagnoses; extrinsic conditions, such as microclimate factors; and organ failure. Characteristics of all patients with at least 1 HAPU were collected by a certified wound care nurse. Data were analyzed using descriptive statistics.

RESULTS

Most patients who developed HAPUs were ill enough to require extended hospital stays and discharged to extended care facilities. All patients with HAPUs had multiple risk factors, categorized as intrinsic, extrinsic, or organ failures, yet nearly one-quarter were identified by current standards as "low-risk." Many of the measured variables are well-established risk factors, but several were comorbid diagnoses that are not assessed on the Braden Scale for Pressure Sore Risk. Eighty percent of subjects had 6 or more risk factors associated with an increased risk for PU development (mean = 9.2). Two-thirds of the sample group experienced failure of at least 1 organ system. Data on the use of 5 preventive interventions was tallied. A vast majority of patients (84.1%) were using 4 or 5 (mean = 4.3, SD = 1.0) of the interventions prior to the occurrence of the HAPU.

CONCLUSION

Current risk assessment methods do not assess organ failures and the effect of multiple comorbid associated with HAPU occurrence. Current risk prevention methods may not be sufficient to prevent HAPUs in all patients.

Patient-specific and surgical characteristics in the development of pressure ulcers

BACKGROUND

Implementation of the ruling on the Inpatient Prospective Payment System by the Centers for Medicare and Medicaid has challenged nurses to focus on the prevention of pressure ulcers. Despite years of research, pressure ulcers are still one of the most common complications experienced by patients in health care facilities.

OBJECTIVE

To examine the relationship between patients' characteristics (age, sex, body mass index, history of diabetes, and Braden Scale score at admission) and care characteristics (total operating room time, multiple surgeries, and vasopressor use) and the development of pressure ulcers.

METHODS

In a cohort study, data from the electronic medical records of 3225 surgical patients admitted to a Midwest hospital, from November 2008 to August 2009 were analyzed statistically to determine predictors of pressure ulcers.

RESULTS

A total of 12% of patients (n = 383) had at least 1 pressure ulcer develop during their hospitalization. According to logistic regression analysis, scores on the Braden Scale at admission (P < .001), low body mass index (P < .001), number of vasopressors (P = .03), multiple surgeries during the admission (P < .001), total surgery time (P < .001), and risk for mortality (P < .001) were significant predictors of pressure ulcers.

CONCLUSION

Scores on the Braden Scale at admission can be used to identify patients at increased risk for pressure ulcers. For other high-risk factors, such as low body mass index and long operative procedures, appropriate clinical interventions to manage these conditions can help prevent pressure ulcers.

Development of intelligent model to determine favorable wheelchair tilt and recline angles for people with spinal cord injury

Machine-learning techniques have found widespread applications in bioinformatics. Such techniques provide invaluable insight on understanding the complex biomedical mechanisms and predicting the optimal individualized intervention for patients. In our case, we are particularly interested in developing an individualized clinical guideline on wheelchair tilt and recline usage for people with spinal cord injury (SCI). The current clinical practice suggests uniform settings to all patients. However, our previous study revealed that the response of skin blood flow to wheelchair tilt and recline settings varied largely among patients. Our finding suggests that an individualized setting is needed for people with SCI to maximally utilize the residual neurological function to reduce pressure ulcer risk. In order to achieve this goal, we intend to develop an intelligent model to determine the favorable wheelchair usage to reduce pressure ulcers risk for wheelchair users with SCI. In this study, we use artificial neural networks (ANNs) to construct an intelligent model that can predict whether a given tilt and recline setting will be favorable to people with SCI based on neurological functions and SCI injury history. Our results indicate that the intelligent model significantly outperforms the traditional statistical approach in accurately classifying favorable wheelchair tilt and recline settings. To the best of our knowledge, this is the first study using intelligent models to predict the favorable wheelchair tilt and recline angles. Our methods demonstrate the feasibility of using ANN to develop individualized wheelchair tilt and recline guidance for people with SCI.

Effect of wheelchair tilt-in-space and recline angles on skin perfusion over the ischial tuberosity in people with spinal cord injury

OBJECTIVE

To investigate the efficacy of wheelchair tilt-in-space and recline on enhancing skin perfusion over the ischial tuberosity in wheelchair users with spinal cord injury (SCI).

DESIGN

Repeated-measures, intervention, and outcomes-measure design.

SETTING

A university research laboratory.

PARTICIPANTS

Wheelchair users with SCI (N=11; 9 men, 2 women; mean ± SD age, 37.7±14.2y; body mass index, 24.7±2.6kg/m(2); duration of injury, 8.1±7.5y).

INTERVENTIONS

Protocols (N=6) of various wheelchair tilt-in-space and recline angles were randomly assigned to participants. Each protocol consisted of a 5-minute sitting-induced ischemic period and a 5-minute wheelchair tilt-in-space and recline pressure-relieving period. Participants sat in a position without tilt or recline for 5 minutes and then sat in 1 of 6 wheelchair tilted and reclined positions, including (1) 15° tilt-in-space and 100° recline, (2) 25° tilt-in-space and 100° recline, (3) 35° tilt-in-space and 100° recline, (4) 15° tilt-in-space and 120° recline, (5) 25° tilt-in-space and 120° recline, and (6) 35° tilt-in-space and 120° recline. A 5-minute washout period (at 35° tilt-in-space and 120° recline) was allowed between protocols.

MAIN OUTCOME MEASURES

Laser Doppler flowmetry was used to measure skin perfusion over the ischial tuberosity in response to changes in body positions caused by performing wheelchair tilt-in-space and recline. Skin perfusion response to wheelchair tilt-in-space and recline was normalized to skin perfusion of the upright seated position (no tilt/recline).

RESULTS

Combined with 100° recline, wheelchair tilt-in-space at 35° resulted in a significant increase in skin perfusion compared with the upright seated position (no tilt/recline; P<.05), whereas there was no significant increase in skin perfusion at 15° and 25° tilt-in-space (not significant). Combined with 120° recline, wheelchair tilt-in-space at 15°, 25°, and 35° showed a significant increase in skin perfusion compared with the upright seated position (P<.05).

CONCLUSIONS

Our results indicate that wheelchair tilt-in-space should be at least 35° for enhancing skin perfusion over the ischial tuberosity when combined with recline at 100° and should be at least 25° when combined with recline at 120°. Although smaller angles of wheelchair tilt-in-space and recline are preferred by wheelchair users for functional purposes, wheelchair tilt-in-space less than 25° and recline less than 100° may not be sufficient for effective pressure reduction for enhancing skin perfusion over the ischial tuberosity in people with SCI.

Perfusion of the skin of the buttocks in paraplegic and tetraplegic patients, and in healthy subjects after a short and long load

In patients with spinal cord injuries (n=8) and healthy controls (n=8) the hyperaemic response in the buttock skin after sitting on a hard surface was studied using a laser Doppler perfusion imager. They sat for three minutes (short load), or 15 minutes (long load). An exponential mathematical function was used to compare the mean perfusion during the observed interval. The results showed that preloading perfusion is significantly higher among patients than healthy subjects. In both groups, the microcirculation of the skin increased significantly after loading, and peak perfusion was significantly lower after the short load. The mean perfusion was higher among the patients after both loadings, which suggests that there was stronger ischaemic provocation. The main outcome was that there was a dose-response relation between duration of loading and intensity of reactive hyperaemia, and that patients with spinal cord injuries have greater perfusion before and after loading than healthy controls.

Risk factors for gastrointestinal complications in aspirin users: review of clinical and experimental data

This paper reviews recent clinical evidence that suggests that aspirin prophylaxis against cardiac and cerebral vascular ischemia is associated with significant gastrointestinal complications. The clinical and experimental evidence to confirm the role of risk factors of concomitant use of nonsteroidal anti-inflammatory drugs (NSAID), tobacco cigarette smoking, and alcohol consumption are discussed. The limitations of long-term acid suppression treatment for the prevention of these complications are considered. Future experimental studies to guide the clinical approach to develop novel and potentially cost-effective management strategies are discussed.

Pressure ulcers: e-learning to improve classification by nurses and nursing students

AIMS AND OBJECTIVES

To detect problems when classifying pressure ulcers and to examine whether an e-learning program is able to increase the classification skills of qualified nurses and nursing students.

BACKGROUND

Both the distinction between pressure ulcer grades and the differentiation between moisture lesions is difficult. Misclassification and incorrect identification of the lesions results in inadequate preventive and therapeutic measures. Education and training are important for spreading evidence-based insights about this topic.

DESIGN

Repeated measure design, consisting of one pretest and three posttests.

METHODS

The experimental intervention consisted of a one-hour session during which the participants independently went over an e-learning program. The control intervention consisted of a one-hour lecture. Both interventions had the same learning contents. A convenience sample of 212 qualified nurses and 214 final-year nursing students was randomly assigned to an experimental-and a control group.

RESULTS

In the pretest, the classification skills were low. After the intervention, these skills improved significantly in both groups. The nursing students achieved better results when using the e-learning program. Among the qualified nurses, there was no difference between the learning methods. Although the classification skills decreased in the posttests, they did not drop under the level of the pretest.

CONCLUSION

The actual classification system does not provide the necessary information about the severity of a pressure ulcer. The differential diagnosis between a moisture lesion was complicated. The classification skills of the qualified nurses and nursing students increased by both learning methods. Repetition remains, however, necessary.

RELEVANCE TO CLINICAL PRACTICE

Both instruction methods are adequate to acquire the knowledge about the differences between moisture lesions and pressure ulcers. E-learning allows studying in one's own time and place, and could therefore be very suitable for repetition of the training. How to organise this training could be a subject for further research.

Clinical effectiveness of a low-tech versus high-tech pressure-redistributing mattress

OBJECTIVE

To compare the effectiveness of a high-specification foam mattress (control) with a high-tech (Duo2, Hill Rom) alternating/continuous low-pressure mattress (treatment) in the prevention of pressure ulceration. The study also evaluated if there is a difference in performance between the two working modalities (alternating and continuous low pressure) of the high-tech mattress in a comparable sample of patients.

METHOD

Thirty-three patients were observed for two weeks in the control group. In the treatment group, 86 patients were randomised to receive alternating low pressure and 84 continuous low pressure. Incidence of pressure ulcers in both arms was recorded. Student's t-test was used to compare all Braden scores, and the chi-square test and Fisher's exact test to evaluate differences between groups.

RESULTS

There was a high difference in the number of new pressure ulcers in the control group when compared with the treatment group. There was no difference in performance between the alternating and continuous low-pressure modes. However, the sample size is too small to prove or disprove a statistically significant difference between the two modalities.

CONCLUSION

The high-tech mattress was markedly more effective than the high-specification foam mattress in preventing the onset of pressure ulcers. Initial data suggest that the use of alternating or continuous low pressure made little or no difference to the results.

Role of diabetic microvascular disease in the development of foot wounds

The influence of microvascular changes in diabetic foot tissue breakdown is not fully known. Research on the role of vascular mediators in diabetes and their effect on the microvasculature may help to create a more unified theory.

Assessing risk and preventing pressure ulcers in patients with cancer

OBJECTIVE

To identify risk factors for pressure ulcers that may place the patient with cancer at higher risk. The role of nursing to provide pressure ulcer preventive measures will be discussed.

DATA SOURCES

Current research and published literature

CONCLUSION

Research suggests that comprehensive prevention programs are effective in reducing pressure ulcer incidence rates and can be cost-effective. Comprehensive pressure ulcer prevention guidelines include risk assessment, skin care, offloading, and nutrition. Immobility places patients with cancer at greater risk.

IMPLICATIONS FOR NURSING PRACTICE

Nurses are at the forefront of predicting patients at risk for pressure ulcers and working with the multidisciplinary team to implement a pressure ulcer preventive program. There remains a dearth of research related to pressure ulcers and cancer. Research in this area is strongly suggested.

Reliability of the European Pressure Ulcer Advisory Panel classification system

AIM

This paper reports a study examining the interrater and intrarater reliability of classifying pressure ulcers according to the European Pressure Ulcer Advisory Panel classification system when using photographs of pressure ulcers and incontinence lesions.

BACKGROUND

Pressure ulcer classification is an essential tool for assessing ulcers and their severity and determining which preventive or therapeutic action is needed. Many classification systems are described in the literature. There are only a limited number of studies that evaluate the interrater reliability of pressure ulcer grading scales. The intrarater reliability is seldom studied.

METHODS

The study consisted of two phases. In the first phase 56 photographs, together with a random selection of nine photographs from the same set, were presented to 473 nurses. In the second phase, the 56 photographs were presented twice to 86 other nurses with an interval of one month and in a different order. All the nurses were familiar with the European Pressure Ulcer Advisory Panel classification. They did not receive any additional training on classification, and were asked to classify the lesions as normal skin, blanchable erythema, pressure ulcers (four grades, European Pressure Ulcer Advisory Panel classification) or incontinence lesions.

RESULTS

In the first phase, the multirater-Kappa for the 473 participating nurses was 0.37 (P < 0.001). Non-blanchable erythema was often confused with blanchable erythema and incontinence lesions. Also incontinence lesions were frequently not correctly classified. The intrarater agreement was low (kappa = 0.38). In the second phase, the interrater agreement was not significantly different in both sessions. The intrarater agreement was 0.52.

CONCLUSION

Both the interrater and intrarater reliability of the European Pressure Ulcer Advisory Panel classification of lesion photographs by nurses was very low. Differentiation between pressure ulcers and incontinence lesions seems to be difficult.

Perfusion confusion

We would like to congratulate Janine Jones on her paper on pressure ulcer prevention devices, published in October 2005, which clearly illustrates the complexity surrounding equipment selection.

Perioperative analgesia: a factor in the development of heel pressure ulcers?

This article presents the incidence of heel pressure ulcers after an elective hip or a knee replacement. The majority of patients in the authors' institute receive either a neuraxial block (epidural and/or spinal) or peripheral nerve blocks (femoral and sciatic), depending on the anaesthetist's and surgeon's preference, and the patient's physical status. The past few years have seen increasing use of peripheral nerve blocks for knee replacement surgery. Patients with either the central or peripheral nerve blockade are at an increased risk of developing heel pressure ulcers. This article describes the experience at a tertiary referral centre and, in particular, highlights the risk of developing heel ulcers in patients receiving peripheral nerve blocks. Medical and nursing staff looking after these patients should be made aware of this complication and appropriate measures should be taken to prevent this avoidable complication.

Evaluation of pressure ulcer prevention devices: a critical review of the literature

There is a wide range of pressure ulcer prevention devices, but little guidance on clinical and cost-effectiveness. This paper reviews the literature and demonstrates that approaches to evaluation are clinically and experimentally flawed.