The Impact of Thermal Stress on Cognition and the Use of Cooling Wear for Alleviation-An Explorative Study.

Increased ambient temperatures during the care of severely burned patients are essential for mitigating hypothermia and minimizing the impact of consecutive hypermetabolism. For involved medical staff, those conditions may lead to impaired concentration, possibly negatively affecting optimal patient care. Yet, alleviation strategies are lacking. As a novel coping strategy, cooling wear may be an effective means. This explorative study aimed to investigate the effect of high ambient temperatures on the concentration capacity and cooling wear to alleviate thermal stress. The effects of high ambient temperatures and the additional use of cooling wear on the concentration capacity of medical staff were investigated in six subjects during two simulated burn surgeries. Each individual served as his/her own control undergoing one simulation with and one without cooling wear. Concentration capacity was measured before and after each simulation with a standardized test. The results suggested that high ambient temperatures, as used in burn medicine, negatively affect human concentration capacity. The initial assessment of concentration capacity yielded homogenous values. After heat exposure, subjects wearing cooling wear showed a higher concentration capacity and a lower error rate compared to subjects without cooling wear. Summing up, temperature-related decrements in vigilance and performance among medical personnel may impair the patients' outcome. As an opportunity to withstand thermal stress and improve medical care and safety, cooling wear showed promising results and may be used as a heat alleviator. Burn medicine may particularly benefit from further development and rigorous investigation of cooling strategies.

Personal protective equipment in the COVID-19 pandemic and the use of cooling-wear as alleviator of thermal stress : A pilot study in plastic surgery staff members.

BACKGROUND: High temperatures at workplaces lead to health-related risks and premature exhaustion. The coronavirus disease 2019 (COVID-19) pandemic requires many health professionals to perform under unfavorable conditions. Personal protective equipment (PPE) causes thermal stress and negatively affects performance. PATIENTS, MATERIALS AND METHODS: This pilot project investigated the effects of PPE and additional cooling wear on physiological parameters and concentration of six healthy staff members of the Plastic Surgery Department of the Medical University of Graz, Austria during simulated patient care. In this study two 1­hour cycles with patient care-related tasks with PPE and PPE + cooling-wear, respectively, were conducted. A third cycle with scrubs exclusively served as baseline/negative control. The assessment occurred immediately pre-cycles and post-cycles. RESULTS: Pre-cycle assessments showed no significant differences between the cycles. After PPE cycle, increased physical stress levels and decrements in concentration capacity were observed. Physiological parameters were significantly less affected in the cooling cycle, while concentration capacity slightly increased. CONCLUSION: COVID-19 PPE causes considerable thermal stress, ultimately affecting human performance. As opportunity to withstand thermal stress, and improve patients' and professionals' safety, cooling-wear can be considered relevant. Medical personnel performing in exceptional situations may particularly benefit from further development and investigation of cooling strategies.

A novel human ex-vivo burn model and the local cooling effect of a bacterial nanocellulose-based wound dressing.

BACKGROUND: Burn wound progression is a significant problem as burns initially thought to be superficial can actually become full thickness over time. Cooling is an efficient method to reduce burn wound conversion. However, if the cooling agent is below room temperature, depending on the wound size the patient is at risk of hypothermia. Additionally, tissue perfusion is reduced leading to an aggravation of burn wound progression. We investigated if wound dressings based on non-pre-cooled bacterial nanocellulose (BNC) with a high water content cool a burn just by evaporation and reduce the intradermal damages in the skin. MATERIAL AND METHODS: In a human ex-vivo model, skin explants underwent contact burns using a 100 °C hot steel block. The burned areas were divided into two groups of which one was cooled with a BNC-based wound dressing. Intradermal temperature probes measured temperature in cooled and uncooled burn sites over 24 h. For histological assessments of the burned areas biopsies were taken at different time points. High mobility group box-1 (HMBG1) staining served as marker for cell vitality and necrosis in the different skin layers. RESULTS: Intradermal temperature measurement showed that application of the BNC-based wound dressing reduced temperature significantly in burned skin. This cooling effect resulted in a maximum temperature difference of 6.4 ± 1.9 °C and a significant mean reduction of the area under the curve in the first hour after burn of 62% (p < 0.0001). The histological results showed less necrosis and less dermal-epidermal separation in the cooled areas. The HMGB1 staining revealed more vital cells in the cooled group than in the uncooled group. CONCLUSION: Based on our results, BNC-based wound dressings cool a burn. Intradermal temperature as well as thermal damage of the tissue was reduced. The tested BNC-based wound dressing can be used without pre-cooling to cool a burn as well as to reduce the burn BNC-based wound progression through its evaporation cooling effect.

Delivery of antiseptic solutions by a bacterial cellulose wound dressing: Uptake, release and antibacterial efficacy of octenidine and povidone-iodine.

BACKGROUND: Bacterial nanocellulose (BNC) is considered a promising carrier for various substances and novel approaches using BNC in combination with antiseptics are well documented. However, the difference in the molecular weight of these molecules influences their uptake by and release from BNC. Analysing the diffusion of standard molecules with different weight, e.g. dextrans, offers the possibility to investigate the mobility of various molecules. We aimed to test the use of BNC regarding uptake and release of different standard molecules as well as two commercially available antiseptics for possible applications in future wound dressings. MATERIAL AND METHODS: Diffusion profiles, uptake and release of three FITC-dextran molecules differing in weight as well as octenidine (Octenisept®) and povidone-iodine (Betaisodona®)-based antiseptics were tested with BNC-based wound dressings. Furthermore, the antiseptic efficacy of BNC in combination with antiseptics against Staphylococcus aureus was tested. RESULTS: Uptake and release capacity for FITC-dextran molecules showed a molecular weight-dependent mobility from BNC into an agarose gel. The loading capacity of BNC was also inversely proportional to the molecular weight of the antiseptics. The release test for octenidine showed a sustained and prolonged delivery into a solid matrix, whereas povidone-iodine was released faster. Both antiseptic solutions combined with BNC showed a good dose-dependent efficacy against S. aureus. CONCLUSION: Results obtained from the mobility of FITC-dextran molecules in the BNC matrix could open possible applications for the combination of BNC with other molecules for medical applications. Combination of both tested antiseptics with BNC showed to be an efficient approach to control bacterial infections.

Topical application of haemoglobin: a safety study.

OBJECTIVE: Ischaemia is one of the biggest problems in wound healing. It causes chronic wounds and also prevents normal wound healing because the tissue is oxygen deprived. Most oxygen-supplying therapies are only feasible in a clinical setting, but topical haemoglobin applications, such as Granulox, can be used in a non-clinical setting. For home application, the haemoglobin solution is sprayed topically onto the wound using a pressurised ready-to-use device with a bag-on-valve system. Although this system does not mix product and propellant, the risk of product inhalation by the patient, user or bystanders has to be minimised. This safety study aimed to determine particle size and product concentration in the surroundings after application to determine if there is a risk that product particles enter the respiratory tract. METHODS: Measurements were performed using a laser scattered light photometer and a Scanning Mobility Particle Sizer (SMPS)-Spectrometer at different distances from the measuring devices to determine the inhalation risk for a possible user, patient and bystander. At all measuring points the amount of particles, their size and the formation of dust were measured. RESULTS: No nanoparticles or dust were created during the application of the haemoglobin spray. The concentrations of the measured particles are below the allowed limits defined by Austrian law. CONCLUSION: There is no risk of inhaling nanoparticles or being exposed to harmful concentrations of larger particles of the tested product. All the product's ingredients can be degraded and excreted by the human body through natural pathways.

Uptake of PHMB in a bacterial nanocellulose-based wound dressing: A feasible clinical procedure.

BACKGROUND: With the increase of antimicrobial resistance in recent decades, other methods of preventing and fighting infections must be considered. Burn patients, whose wound areas are often extensive, are especially prone to wound infections. The loading of bacterial nanocellulose (BNC) with antiseptics has already been successfully performed but unfortunately, the described procedure is time-consuming and thus not applicable in a clinical emergency setting. Therefore, a clinically feasible approach was established. MATERIAL AND METHODS: Sheets of BNC-based wound dressings were placed into antiseptic solutions containing PHMB (Prontosan® and LAVANID® 2) and were left to soak for up to two hours. At different time points, samples were analysed for their concentration of PHMB and antiseptic efficacy. RESULTS: Within 30min, clinically relevant concentrations of PHMB were achieved in the BNC-based wound dressing. The 30-min PHMB uptake for Prontosan® and LAVANID® 2 resulted in concentrations of 0.05% and 0.019%, respectively. Samples from the PHMB loaded dressing showed a dose dependent antiseptic efficacy for Staphylococcus aureus. CONCLUSION: This experiment showed that the loading of BNC-based wound dressings with PHMB-containing antiseptics was achieved by a simple and quick procedure. According to studies a PHMB concentration of 0.001% can already inhibits all bacterial growth, indicating that the concentrations of PHMB in the BNC-based wound dressings after 30min are higher than the minimal inhibitory concentration and the antiseptic efficacy after 120min loading analysed by an standardized bacterial disk diffusion assay was shown to be comparable to the clinically used Suprasorb® X+PHMB wound dressing.

What can we learn from sonication results of breast implants?

BACKGROUND: Different research groups have identified microorganisms on breast implants by sonication with significant correlation to the rate of capsular contracture. This substantiated the hypothesis of an infectious etiology of capsular contracture. However, no clinical consequence has been drawn from these results yet. Aim of this study was to review sonication results from breast implants and to evaluate the current preoperative antibiotic regime for breast-implant surgery. METHODS: We compared breast implant sonication culture results from published reports and our own database. Current perioperative antibiotic recommendations were compared with the susceptibility profile of the found organisms. RESULTS: We found Coagulase-negative staphylococci and Propionibacteria to be the main group of microorganism found by sonication on explanted breast implants. Most guidelines recommend cephalosporins for preoperative antibiotical prophylaxis for breast-implant surgery. CONCLUSION: There is a discrepancy between antibiotic activity of commonly used antibiotics for preoperative prophylaxis of surgical site infections, and microorganisms found by sonication on breast implants, suspected to trigger the formation of capsular contracture. A targeted antibiotic prophylaxis for breast implant surgery with glycopeptides (e.g. Vancomycin) should be considered for the prevention of capsular contracture.

Susceptibility of Austrian Clinical Klebsiella and Enterobacter Isolates Linked to Patient-Related Data.

The aim of the study was to analyze the antimicrobial susceptibility of Austrian clinical Klebsiella sp. and Enterobacter sp. isolates linked to patient-related data over a time period from 1998 to 2014. The main findings of this study were (i) a marked difference of antibiotic susceptibility rates between different infection sites for both Klebsiella sp. and Enterobacter sp., (ii) significantly greater percentages of resistant isolates among both Klebsiella sp. and Enterobacter sp. in male patients compared to female patients and (iii) significantly greater percentages of resistant isolates among both Klebsiella sp. and Enterobacter sp. from hospital-derived samples compared to samples from the community. In conclusion, our statistical data analysis clearly indicated a strong association of patient-related data and Klebsiella sp. and Enterobacter sp. susceptibility profiles.