Designing the future in wound care : the role of the nurse practitioner

The nurse practitioner is emerging as a new level and type of health care. Increasing specialisation and advanced educational opportunities in nursing and the inequality in access to health care for sectors of the community have established the conditions under which the nurse practitioner movement has strengthened both nationally and internationally. The boundaries of responsibility for nurses are changing, not only because of increased demands but also because nurses have demonstrated their competence in varied extended and expanded practice roles. The nurse practitioner role reflects the continuing development of the nursing profession and substantially extends the career path for clinical nurses. This paper describes an aspect of a large-scale investigation into the feasibility of the role of the nurse practitioner in the Australian Capital Territory (ACT) health care system. The paper reports on the trial of practice for a wound care nurse practitioner model in a tertiary institution. In the trial the wound care nurse practitioner worked in an extended practice role for 10 months. The nurse practitioner practice was supported, monitored and mentored by a clinical support team. Data were collected relating to a range of outcomes including definition of the scope of practice for the model, description of patient demographics and outcomes and the efficacy of the nurse practitioner service. The findings informed the development of clinical protocols that define the scope of practice and the parameters of the wound care nurse practitioner model and provided information on the efficacy of this model of health care for the tertiary care environment. The findings further suggest that this model brings expert wound care and case management to an at-risk patient population. Recommendations are made relating to ongoing research into the role of the wound care nurse practitioner model in the ACT health care system.

The human dimension of nosocomial wound infection : a study in liminality

Nosocomial wound infection is a disease that has to date been primarily understood through the language of science and biomedicine. This paper reports on findings from a sociological, interpretive study that focused on the experiential dimension of this phenomenon. The illness experience of a nosocomial wound infection is examined within a cultural milieu that values the smooth, untroubled body and alternatively ascribes cultural meaning to a body that has a definable illness. Within this context the person with a chronic wound from nosocomial infection defies normative categorisation and is thus situated outside the patterning of society. The human dimension of nosocomial wound infection includes the private, existential and embodied aspects of living with a chronic, infected wound. This report indicates that the experiential dimension is characterised by an embodied state of liminality. People with this illness live an indeterminate existence that is in-between health and illness, cure and disease. As such they have no recognised place in the medical or social world.

Elevated uric acid correlates with wound severity

Chronic venous leg ulcers are a major health issue and represent an often overlooked area of biomedical research. Nevertheless, it is becoming increasingly evident that new approaches to enhance healing outcomes may arise through better understanding the processes involved in the formation of chronic wounds. We have for the first time shown that the terminal purine catabolite uric acid (UA) is elevated in wound fluid (WF) from chronic venous leg ulcers with relative concentrations correlating with wound chronicity. We have also shown a corresponding depletion in UA precursors, including adenosine, with increased wound severity. Further, we have shown that xanthine oxidase, the only enzyme in humans that catalyses the production of UA in conjunction with a burst of free radicals, is active in chronic WF. Taken together, this provides compelling evidence that xanthine oxidase may play a critical role in the formation of chronic wounds by prolonging the inflammatory process.

Reduced Il17a expression distinguishes a Ly6cloMHCIIhi macrophage population promoting wound healing

Macrophages are the main components of inflammation during skin wound healing. They are critical in wound closure and in excessive inflammation, resulting in defective healing observed in chronic wounds. Given the heterogeneity of macrophage phenotypes and functions, we here hypothesized that different subpopulations of macrophages would have different and sometimes opposing effects on wound healing. Using multimarker flow cytometry and RNA expression array analyses on macrophage subpopulations from wound granulation tissue, we identified a Ly6cloMHCIIhi “noninflammatory” subset that increased both in absolute number and proportion during normal wound healing and was missing in Ob/Ob and MYD88−/− models of delayed healing. We also identified IL17 as the main cytokine distinguishing this population from proinflammatory macrophages and demonstrated that inhibition of IL17 by blocking Ab or in IL17A−/− mice accelerated normal and delayed healing. These findings dissect the complexity of the role and activity of the macrophages during wound inflammation and may contribute to the development of therapeutic approaches to restore healing in chronic wounds.

Wound Management Innovation Cooperative Research Centre - a new model for inter-disciplinary wound research

Wound research is a complex multidimensional activity most effectively conducted by inter-disciplinary teams that connect studies in basic wound biology, devices and biomaterials with clinical practice. These complexities have been recognised in a new initiative through the establishment of an inter-disciplinary wound research centre in Australia; the Wound Management Innovation Cooperative Research Centre (WMI CRC). The centre is funded by the Australian Government's Cooperative Research Centre Program and a consortium of 22 participants and has a resource of US$108 million over 8 years...

Mutual enlightenment : augmenting human factors research in surgical robotics

This discussion has outlined a theoretical and pragmatic framework to demonstrate that future research involving the analysis of human performance in surgical should encourage the use of phenomenology to enhance the knowledge base of this area of study. Merging experiential (first-person) and experimental (third-person) methods may possibly help improve research designs and analyses in the investigation of robotics in surgical performance. By relying solely on third-person techniques, the current methodology and interpretation used to analyze human performance in surgical robotics is limited. Recent advances in cognitive science and psychology have also recognized this limitation and have now begun to shift to neurophenomenology. Finally, discussion on recent robotics research presented here demonstrates the potential phenomenology holds for augmenting the methodological and analysis techniques currently used by researchers of human performance in surgical robotics.

Health service pathways for patients with chronic leg ulcers : identifying effective pathways for facilitation of evidence based wound care

Background: Chronic leg ulcers cause long term ill-health for older adults and the condition places a significant burden on health service resources. Although evidence on effective management of the condition is available, a significant evidence-practice gap is known to exist, with many suggested reasons e.g. multiple care providers, costs of care and treatments. This study aimed to identify effective health service pathways of care which facilitated evidence-based management of chronic leg ulcers. Methods: A sample of 70 patients presenting with a lower limb leg or foot ulcer at specialist wound clinics in Queensland, Australia were recruited for an observational study and survey. Retrospective data were collected on demographics, health, medical history, treatments, costs and health service pathways in the previous 12 months. Prospective data were collected on health service pathways, pain, functional ability, quality of life, treatments, wound healing and recurrence outcomes for 24 weeks from admission. Results: Retrospective data indicated that evidence based guidelines were poorly implemented prior to admission to the study, e.g. only 31% of participants with a lower limb ulcer had an ABPI or duplex assessment in the previous 12 months. On average, participants accessed care 2–3 times/week for 17 weeks from multiple health service providers in the twelve months before admission to the study clinics. Following admission to specialist wound clinics, participants accessed care on average once per week for 12 weeks from a smaller range of providers. The median ulcer duration on admission to the study was 22 weeks (range 2–728 weeks). Following admission to wound clinics, implementation of key indicators of evidence based care increased (p<0.001) and Kaplan-Meier survival analysis found the median time to healing was 12 weeks (95% CI 9.3–14.7). Implementation of evidence based care was significantly related to improved healing outcomes (p<0.001). Conclusions: This study highlights the complexities involved in accessing expertise and evidence based wound care for adults with chronic leg or foot ulcers. Results demonstrate that access to wound management expertise can promote streamlined health services and evidence based wound care, leading to efficient use of health resources and improved health.

Functional monoecy due to delayed anther dehiscence : a novel mechanism in pseuduvaria mulgraveana (annonaceae)

Unlike most genera in the early-divergent angiosperm family Annonaceae, Pseuduvaria exhibits a diversity of floral sex expression. Most species are structurally andromonoecious (or possibly androdioecious), although the hermaphroditic flowers have been inferred to be functionally pistillate, with sterile staminodes. Pseuduvaria presents an ideal model for investigating the evolution of floral sex in early-divergent angiosperms, although detailed empirical studies are currently lacking. The phenology and pollination ecology of the Australian endemic species Pseuduvaria mulgraveana are studied in detail, including evaluations of floral scent chemistry, pollen viability, and floral visitors. Results showed that the flowers are pollinated by small diurnal nitidulid beetles and are protogynous. Pollen from both hermaphroditic and staminate flowers are shown to be equally viable. The structurally hermaphroditic flowers are nevertheless functionally pistillate as anther dehiscence is delayed until after petal abscission and hence after the departure of pollinators. This mechanism to achieve functional unisexuality of flowers has not previously been reported in angiosperms. It is known that protogyny is widespread amongst early-divergent angiosperms, including the Annonaceae, and is effective in preventing autogamy. Delayed anther dehiscence represents a further elaboration of this, and is effective in preventing geitonogamy since very few sexually mature flowers occur simultaneously in an individual. We highlight the necessity for field-based empirical interpretations of functional floral sex expression prior to evaluations of evolutionary processes.

Numerical techniques for simulating a fractional mathematical model of epidermal wound healing

A number of mathematical models investigating certain aspects of the complicated process of wound healing are reported in the literature in recent years. However, effective numerical methods and supporting error analysis for the fractional equations which describe the process of wound healing are still limited. In this paper, we consider the numerical simulation of a fractional mathematical model of epidermal wound healing (FMM-EWH), which is based on the coupled advection-diffusion equations for cell and chemical concentration in a polar coordinate system. The space fractional derivatives are defined in the Left and Right Riemann-Liouville sense. Fractional orders in the advection and diffusion terms belong to the intervals (0, 1) or (1, 2], respectively. Some numerical techniques will be used. Firstly, the coupled advection-diffusion equations are decoupled to a single space fractional advection-diffusion equation in a polar coordinate system. Secondly, we propose a new implicit difference method for simulating this equation by using the equivalent of Riemann-Liouville and Grünwald-Letnikov fractional derivative definitions. Thirdly, its stability and convergence are discussed, respectively. Finally, some numerical results are given to demonstrate the theoretical analysis.

Establishment and characterisation of an open mini-thoracotomy surgical approach to an ovine thoracic spine fusion model

Background A large animal model is required for assessment of minimally invasive, tissue engineering based approaches to thoracic spine fusion, with relevance to deformity correction surgery for human adolescent idiopathic scoliosis. Here we develop a novel open mini–thoracotomy approach in an ovine model of thoracic interbody fusion which allows assessment of various fusion constructs, with a focus on novel, tissue engineering based interventions. Methods The open mini-thoracotomy surgical approach was developed through a series of mock surgeries, and then applied in a live sheep study. Customized scaffolds were manufactured to conform with intervertebral disc space clearances required of the study. Twelve male Merino sheep aged 4 to 6 years and weighing 35 – 45 kg underwent the abovementioned procedure and were divided into two groups of six sheep at survival timelines of 6 and 12 months. Each sheep underwent a 3-level discectomy (T6/7, T8/9 and T10/11) with randomly allocated implantation of a different graft substitute at each of the three levels; (i) polycaprolactone (PCL) based scaffold plus 0.54μg rhBMP-2, (ii) PCL-based scaffold alone or (iii) autograft. The sheep were closely monitored post- operatively for signs of pain (i.e. gait abnormalities/ teeth gnawing/ social isolation). Fusion assessments were conducted post-sacrifice using Computed Tomography and hard-tissue histology. All scientific work was undertaken in accordance with the study protocol has been approved by the Institute's committee on animal research. Results. All twelve sheep were successfully operated on and reached the allotted survival timelines, thereby demonstrating the feasibility of the surgical procedure and post-operative care. There were no significant complications and during the post-operative period the animals did not exhibit marked signs of distress according to the described assessment criteria. Computed Tomographic scanning demonstrated higher fusion grades in the rhBMP-2 plus PCL-based scaffold group in comparison to either PCL-based scaffold alone or autograft. These results were supported by histological evaluation of the respective groups. Conclusion. This novel open mini-thoracotomy surgical approach to the ovine thoracic spine represents a safe surgical method which can reproducibly form the platform for research into various spine tissue engineered constructs (TEC) and their fusion promoting properties.

Investigating epidermogenesis in a human skin equivalent model

Skin is the largest, and arguably, the most important organ of the body. It is a complex and multi-dimensional tissue, thus making it essentially impossible to fully model in vitro in conventional 2-dimensional culture systems. In view of this, rodents or pigs are utilised to study wound healing therapeutics or to investigate the biological effects of treatments on skin. However, there are many differences between the wound healing processes in rodents compared to humans (contraction vs. re-epithelialisation) and there are also ethical issues associated with animal testing for scientific research. Therefore, the development of skin equivalent (HSE) models from surgical discard human skin has become an important area of research. The studies in this thesis compare, for the first time, native human skin and the epidermogenesis process in a HSE model. The HSE was reported to be a comparable model for human skin in terms of expression and localisation of key epidermal cell markers. This validated HSE model was utilised to study the potential wound healing therapeutic, hyperbaric oxygen (HBO) therapy. There is a significant body of evidence suggesting that lack of cutaneous oxygen results in and potentiates the chronic, non-healing wound environment. Although the evidence is anecdotal, HBO therapy has displayed positive effects on re-oxygenation of chronic wounds and the clinical outcomes suggest that HBO treatment may be beneficial. Therefore, the HSE was subjected to a daily clinical HBO regime and assessed in terms of keratinocyte migration, proliferation, differentiation and epidermal thickening. HBO treatment was observed to increase epidermal thickness, in particular stratum corneum thickening, but it did not alter the expression or localisation of standard epidermal cell markers. In order to elucidate the mechanistic changes occurring in response to HBO treatment in the HSE model, gene microarrays were performed, followed by qRT-PCR of select genes which were differentially regulated in response to HBO treatment. The biological diversity of the HSEs created from individual skin donors, however, overrode the differences in gene expression between treatment groups. Network analysis of functional changes in the HSE model revealed general trends consistent with normal skin growth and maturation. As a more robust and longer term study of these molecular changes, protein localisation and expression was investigated in sections from the HSEs undergoing epidermogenesis in response to HBO treatment. These proteins were CDCP1, Metallothionein, Kallikrein (KLK) 1 and KLK7 and early growth response 1. While the protein expression within the HSE models exposed to HBO treatment were not consistent in all HSEs derived from all skin donors, this is the first study to detect and compare both KLK1 and CDCP1 protein expression in both a HSE model and native human skin. Furthermore, this is the first study to provide such an in depth analysis of the effect of HBO treatment on a HSE model. The data presented in this thesis, demonstrates high levels of variation between individuals and their response to HBO treatment, consistent with the clinical variation that is currently observed.