Wound Healing Society 2023 update on guidelines for arterial ulcers.

The Wound Healing Society guidelines for the treatment of arterial insufficiency ulcers were originally published in 2006, with the last update in 2014. These guidelines provided recommendations, along with their respective levels of evidence, on seven categories: diagnosis, surgery, infection control, wound bed preparation, dressings, adjuvant therapy and long-term maintenance. Over the last 9 years, additional literature regarding these aspects of arterial ulcer management has been published. An advisory panel comprised of academicians, clinicians and researchers was chosen to update the 2014 guidelines. Members included vascular surgeons, internists, plastic surgeons, anaesthesiologists, emergency medicine physicians and dermatologists, all with expertise in wound healing. The goal of this article is to evaluate relevant new findings upon which an updated version of the guidelines will be based.

A mathematical model of the use of supplemental oxygen to combat surgical site infection.

Infections are a common complication of any surgery, often requiring a recovery period in hospital. Supplemental oxygen therapy administered during and immediately after surgery is thought to enhance the immune response to bacterial contamination. However, aerobic bacteria thrive in oxygen-rich environments, and so it is unclear whether oxygen has a net positive effect on recovery. Here, we develop a mathematical model of post-surgery infection to investigate the efficacy of supplemental oxygen therapy on surgical-site infections. A 4-species, coupled, set of non-linear partial differential equations that describes the space-time dependence of neutrophils, bacteria, chemoattractant and oxygen is developed and analysed to determine its underlying properties. Through numerical solutions, we quantify the efficacy of different supplemental oxygen regimes on the treatment of surgical site infections in wounds of different initial bacterial load. A sensitivity analysis is performed to investigate the robustness of the predictions to changes in the model parameters. The numerical results are in good agreement with analyses of the associated well-mixed model. Our model findings provide insight into how the nature of the contaminant and its initial density influence bacterial infection dynamics in the surgical wound.

Empiric evidence for a genetic contribution to predisposition to surgical site infection.

The genetics of microbial pathogens have been extensively studied, but there has been little work on human genetic susceptibility to surgical site infection (SSI). We analyzed a large genealogical population database to study the familial contribution to SSI. We analyzed 651 individuals with International Classification of Disease, Ninth Revision codes indicating the presence of SSI. Matched hospital controls were randomly selected from the database based on birth year, sex, and birthplace. The average relatedness of all possible pairs of cases and separately of controls (×1000 sets) was compared empirically. The relative risk (RR) for SSI was estimated by comparing the number of observed affected individuals among the relatives of cases to the number of affected individuals observed among relatives of matched hospital controls. The genealogical index of familiality test for patients with SSI showed significant excess relatedness (p < 0.010); this excess was still observed when close relationships were ignored (p = 0.019). The RR for third-degree relatives of cases was significantly elevated (1.62, p = 0.029). The significant excess relatedness and the significantly elevated RR to distant relatives support a genetic predisposition to acquiring SSI.

High intraoperative inspired oxygen does not increase postoperative supplemental oxygen requirements.

BACKGROUND: Although a high fraction of inspired oxygen (FIO2) could reduce surgical site infection, there is concern it could increase postoperative pulmonary complications, including hypoxemia. Intraoperative positive end-expiratory pressure can improve postoperative pulmonary function. A practical measure of postoperative pulmonary function and the degree of hypoxemia is supplemental oxygen requirement. We performed a double-blind randomized 2 × 2 factorial study on the effects of intraoperative FIO2 0.3 versus more than 0.9 with and without positive end-expiratory pressure on the primary outcome of postoperative supplemental oxygen requirements in patients undergoing lower risk surgery. METHODS: After Institutional Review Board approval and consent, 100 subjects were randomized using computer-generated lists into four treatment groups (intraoperative FIO2 0.3 vs. more than 0.9, with and without 3-5 cm H2O positive end-expiratory pressure). Thirty minutes and 24 h after extubation, supplemental oxygen was discontinued. Arterial oxygen saturation by pulse oximetry was recorded 15 min later. If oxygen saturation decreased to less than 90%, supplemental oxygen was added incrementally to maintain saturation more than 90%. RESULTS: Nearly all subjects required supplemental oxygen in the postanesthesia care unit. Nonparametric Wilcoxon rank sum test demonstrated no statistically significant difference between groups in supplemental oxygen requirements at 45 min and 24 h after tracheal extubation (P = 0.56 and 0.98, respectively). CONCLUSIONS: Use of intraoperative FIO2 more than 0.9 was not associated with increased oxygen requirement, suggesting it does not induce postoperative hypoxemia beyond anesthetic induction and surgery. Therefore, it may be reasonable to use high inspired oxygen in surgical patients with relatively normal pulmonary function.

The effect of hyperbaric oxygen in the enhancement of healing in selected problem wounds.

Problem wounds represent a significant and growing challenge to our healthcare system. The incidence and prevalence of these wounds are increasing in the population, resulting in growing utilization of healthcare resources and dollars expended. Venous leg ulcers represent the most common lower-extremity wound seen in ambulatory wound care centers, with recurrences frequent and outcomes often less than satisfactory. Pressure ulcers are common in patients in long-term institutional care settings adding significant increases in cost, disability and liability. Foot ulcers in patients with diabetes contribute to more than half of lower-extremity amputations in the United States in a group at risk, representing only 3 percent of the population. In response to this challenge, specialized programs have emerged designed to identify and manage these patients, using standardized protocols and a variety of new technologies to improve outcomes. Hyperbaric oxygen treatment (HBO2T) has been increasingly utilized in an adjunctive role in the care of many of these patients, coinciding with optimized patient and local wound care.

Quantitative tissue oxygen measurement in multiple organs using 19F MRI in a rat model.

Measurement of individual organ tissue oxygen levels can provide information to help evaluate and optimize medical interventions in many areas including wound healing, resuscitation strategies, and cancer therapeutics. Echo planar (19) F MRI has previously focused on tumor oxygen measurement at low oxygen levels (pO(2)) <30 mmHg. It uses the linear relationship between spin-lattice relaxation rate (R(1)) of hexafluorobenzene (HFB) and pO(2). The feasibility of this technique for a wider range of pO(2) values and individual organ tissue pO(2) measurement was investigated in a rat model. Spin-lattice relaxation times (T(1) = 1/R(1)) of hexafluorobenzene were measured using (19) F saturation recovery echo planar imaging. Initial in vitro studies validated the linear relationship between R(1) and pO(2) from 0 to 760 mmHg oxygen partial pressure at 25, 37, and 41°C at 7 Tesla for hexafluorobenzene. In vivo experiments measured rat tissue oxygen (ptO2) levels of brain, kidney, liver, gut, muscle, and skin during inhalation of both 30 and 100% oxygen. All organ ptO(2) values significantly increased with hyperoxia (P < 0.001). This study demonstrates that (19) F MRI of hexafluorobenzene offers a feasible tool to measure regional ptO2 in vivo, and that hyperoxia significantly increases ptO2 of multiple organs in a rat model.

High oxygen partial pressure decreases anemia-induced heart rate increase equivalent to transfusion.

BACKGROUND: Anemia is associated with morbidity and mortality and frequently leads to transfusion of erythrocytes. The authors sought to directly compare the effect of high inspired oxygen fraction versus transfusion of erythrocytes on the anemia-induced increased heart rate (HR) in humans undergoing experimental acute isovolemic anemia. METHODS: The authors combined HR data from healthy subjects undergoing experimental isovolemic anemia in seven studies performed by the group. HR changes associated with breathing 100% oxygen by nonrebreathing facemask versus transfusion of erythrocytes at their nadir hemoglobin concentration of 5 g/dl were examined. Data were analyzed using a mixed-effects model. RESULTS: HR had an inverse linear relationship to hemoglobin concentration with a mean increase of 3.9 beats per min per gram of hemoglobin (beats/min/g hemoglobin) decrease (95% CI, 3.7-4.1 beats/min/g hemoglobin), P < 0.0001. Return of autologous erythrocytes significantly decreased HR by 5.3 beats/min/g hemoglobin (95% CI, 3.8-6.8 beats/min/g hemoglobin) increase, P < 0.0001. HR at nadir hemoglobin of 5.6 g/dl (95% CI, 5.5-5.7 g/dl) when breathing air (91.4 beats/min; 95% CI, 87.6-95.2 beats/min) was reduced by breathing 100% oxygen (83.0 beats/min; 95% CI, 79.0-87.0 beats/min), P < 0.0001. The HR at hemoglobin 5.6 g/dl when breathing oxygen was equivalent to the HR at hemoglobin 8.9 g/dl when breathing air. CONCLUSIONS: High arterial oxygen partial pressure reverses the heart rate response to anemia, probably because of its usability rather than its effect on total oxygen content. The benefit of high arterial oxygen partial pressure has significant potential clinical implications for the acute treatment of anemia and results of transfusion trials.

Changes in heel skin temperature under pressure in hip surgery patients.

OBJECTIVE: The aim of the study was to examine the effect of external pressure of the bed surface on heel skin temperature in adults in the first 3 days after hip surgery. DESIGN: A quasi-experimental study in a prospective, within-subjects, repeated-measures design. SETTING: This study was performed at 2 acute-care hospitals. PARTICIPANTS: Eighteen subjects (9 men and 9 women) with a mean age of 58.3 (±16.1) years were recruited after hip surgery at the 2 hospitals. METHODS: Temperature sensors were placed on the plantar surface of each foot, close to the heels. Measures were taken when the heels were (1) suspended above the bed surface for 20 minutes (preload), (2) on the bed surface for 15 minutes (loading), and (3) suspended again above the bed surface for 15 minutes (unloading). MAIN OUTCOME MEASURES: Heel skin temperature and demographic data. RESULTS: Heel temperature increased during loading and unloading in both legs on postoperative days 1 (P = .003) and 3 (P = .04) but not on postoperative day 2. Heel temperature in the nonoperative leg decreased in the first 3 minutes of unloading on postoperative days 2 (P = .02) and 3 (P = .01). CONCLUSION: Heel temperature increased with loading and unloading on postoperative days 1 and 3. Upon immediate unloading, hyperemic response was present only in the nonoperative leg. Keeping the heels off the bed surface at all times may avoid heel skin temperature changes and prevent tissue damage. Further research is needed to identify the mechanisms that explain the effect of external pressure on heel temperature.

"The Adjunct Faculty Are Our Lifeblood" An Institution's Response to Deliver Value to Volunteer Community Faculty.

BACKGROUND AND OBJECTIVES: Because of the importance of and increasing competition for unpaid community faculty's time, we qualitatively evaluated the adjunct community faculty experience in order to identify mechanisms to improve the recruitment, training, and retention of these faculty members. METHODS: The authors captured community faculty and key stakeholder opinion through interviews, focus groups, and a survey to elucidate their perspective of roles, responsibilities, facilitators, and barriers for providing quality teaching and learning experiences. After evaluating the data, we created an impact/effort matrix to guide suggested changes. RESULTS: Key medical education stakeholders reported adjunct community faculty members were critical to delivery of the medical school curriculum and shared methods and barriers for retaining members. Adjunct community faculty focus groups revealed two major themes: (1) personal experience and motivation, and (2) individual advantages and institutional barriers that influence being a faculty member. The survey and impact/effort matrix led to interventions including an Office of Community Faculty to implement recruitment and retention programs and provide more comprehensive oversight, a clinical scheduling hub, improved access to specialists for community faculty, and awards to recognize the critical contributions of community faculty members. CONCLUSIONS: As competition for community placements increases, including community faculty voices to inform action is an effective investment that enables an institution to direct resources towards interventions that maximize their support and engagement. Including community faculty perspectives also increases faculty's ability to participate in training the next generation of physicians.

Representation of women plenary speakers at the American Academy of Neurology Annual Meeting.

OBJECTIVE: To determine whether women have been equitably represented among plenary speakers at the American Academy of Neurology (AAN) Annual Meeting by counting and categorizing speakers and comparing outcomes to AAN membership and US neurology workforce data. METHODS: Lists of plenary speakers between 1958 and 2019 (62 years) were obtained from the AAN. The primary outcome measures were numbers and proportions of men and women in aggregate and among physicians. RESULTS: We identified 635 plenary speakers, including 148 (23.3%) women. Specifically, women made up 14.6% (19 of 130) of presidential and 25.5% (129 of 505) of nonpresidential plenary session speakers. The inclusion of women plenary speakers was meaningfully higher (h = 0.33; difference 14.9%; 95% confidence interval 4.2%-26.7%) for nonphysicians (27 of 74 [36.5%]) than physicians (121 of 561 [21.6%]). Although at zero levels for Annual Meetings held between 1958 and 1990 and at mostly low but varying levels thereafter, the representation of women and women physicians has been at or above their proportions in the AAN membership and US neurology workforce since 2017. Comparison of representation by plenary session name revealed an unequal distribution of women, with women physicians concentrated in the Sidney Carter Award in Child Neurology presidential session. CONCLUSION: Historically and recently, women and women physicians were underrepresented among AAN plenary speakers. As the AAN has taken active steps to address equity, women have been included in more representative proportions overall. However, notable gaps remain, especially in specific prestigious plenary sessions, and further research is needed to determine causality.

Transforming The Medical Device Industry: Road Map To A Circular Economy.

A circular economy involves maintaining manufactured products in circulation, distributing resource and environmental costs over time and with repeated use. In a linear supply chain, manufactured products are used once and discarded. In high-income nations, health care systems increasingly rely on linear supply chains composed of single-use disposable medical devices. This has resulted in increased health care expenditures and health care-generated waste and pollution, with associated public health damage. It has also caused the supply chain to be vulnerable to disruption and demand fluctuations. Transformation of the medical device industry to a more circular economy would advance the goal of providing increasingly complex care in a low-emissions future. Barriers to circularity include perceptions regarding infection prevention, behaviors of device consumers and manufacturers, and regulatory structures that encourage the proliferation of disposable medical devices. Complementary policy- and market-driven solutions are needed to encourage systemic transformation.