Kinetics of isoflurane and sevoflurane in a unidirectional displacement flow and the relevance to anesthetic gas exposure by operating room personnel.

International guidelines recommend the use of ventilation systems in operating rooms to reduce the concentration of potentially hazardous substances such as anesthetic gases. The exhaust air grilles of these systems are typically located in the lower corners of the operating room and pick up two-thirds of the air volume, whereas the final third is taken from near the ceiling, which guarantees an optimal perfusion of the operating room with a sterile filtered air supply. However, this setup is also employed because anesthetic gases have a higher molecular weight than the components of air and should pool on the floor if movement is kept to a minimum and if a ventilation system with a unidirectional displacement flow is employed. However, this anticipated pooling of volatile anesthetics at the floor level has never been proven. Thus, we herein investigated the flow behaviors of isoflurane, sevoflurane, and carbon dioxide (for comparison) in a measuring chamber sized 2.46 × 1.85 × 5.40 m with a velocity of 0.3 m/sec and a degree of turbulence <20%. Gas concentrations were measured at 1,728 measuring positions throughout the measuring chamber, and the flow behaviors of isoflurane and sevoflurane were found to be similar, with an overlap of 90%. The largest spread of both gases was 55 cm at 5.4 m from the emission source. Interestingly, neither isoflurane nor sevoflurane was detected at floor level, but a continuous cone-like spreading was observed due to gravity. In contrast, carbon dioxide accumulated at floor level in the form of a gas cloud. Thus, floor level exhaust ventilation systems are likely unsuitable for the collection and removal of anesthetic gases from operating rooms.

Efficiencies and noise levels of portable surgical smoke evacuation systems.

Surgical smoke resulting from electrocauterization is a health risk for operating room personnel. The U.S. National Institute for Occupational Safety and Health recommends the use of local exhaust ventilation such as a portable smoke evacuation system to reduce surgical smoke, but its efficiency has never been assessed under experimental conditions. In this study, particle filtration efficiencies of five commercially available smoke evacuation systems were investigated in a model operating room. Two cutting angles, the devices' suction capacities, three unidirectional displacement flow rates, and the noise exposures were considered. Results demonstrated that portable smoke evacuation systems reduce surgical smoke up to 99% under optimal conditions. A cutting angle of 45°, the device's maximum suction capacity, and a unidirectional displacement flow rate of 10,500 m³/hr were advantageous. Sound levels ranged between 51-69 dBA and exceeded recommended threshold limits, if used with medium or maximum suction capacity. Hence, portable smoke evacuation systems are beneficial and are recommended. However, a combination with general unidirectional room ventilation and a strict limitation of the use of electrocauterization is strongly advised.

[Design of a clinical study to demonstrate the therapeutic benefit of another wound treatment product]. / Konzeption einer klinischen Studie zum Nachweis des therapeutischen Nutzens eines sonstigen Produktes zur Wundbehandlung.

BACKGROUND: Due to new legal requirements, a patient-relevant benefit for other wound treatment products (sPW) must be demonstrated through clinical studies if reimbursement at the expense of the statutory health insurance is sought in the non-inpatient sector. METHOD: An interdisciplinary group with expertise in clinical wound care has developed general recommendations for the design of suitable studies. In addition to regulatory documents, previous studies that have already been recognized as proof of benefit in other areas served as a basis. RESULTS: Randomized controlled trials that cover at least the most common types of chronic wounds (arterial, venous, diabetic or pressure sore) are recommended as the best method for gathering evidence. Despite the heterogeneous etiology of chronic wounds, the results should also be transferable to other wound types. The test intervention does not usually consist of the sPW alone, but of a combined wound treatment that follows a treatment plan that is as clearly defined as possible. In the comparison group, all wound treatment options (besides the sPW) must also be available and used according to a similar predefined treatment plan. Depending on the intended purpose and treatment goal, complete wound closure should, if possible, be recorded as the cardinal - although not always as the primary - endpoint. In justified cases, e.g. in the case of intermediate use as part of phase-appropriate wound therapy for chronic wounds, a significant reduction in the wound area can also be considered for benefit assessment. Quality of life (e.g. pain) can also justify a benefit and can therefore be recorded as a primary outcome parameter in clinical trials. The duration of the clinical trial should be adapted to the central endpoints, the medical or nursing goal of wound care and the intended purpose of the sPW. A benefit does not always arise from microbiological, physiological, laboratory or histological parameters or imaging findings.

[Abdominal aortic aneurysms-open vs. endovascular treatment : Decision-making from the perspective of the vascular surgeon]. / Abdominelles Aortenaneurysma ­ offene vs. endovaskuläre Therapie : Entscheidungshilfe aus Sicht des Gefäßchirurgen.

CLINICAL/METHODICAL ISSUE: In the last 20 years, the treatment of abdominal aortic aneurysms has essentially evolved from surgical to minimally invasive endovascular treatment. ACHIEVEMENTS: There are still a number of clinical situations that make surgical intervention useful or even necessary. This underlines the importance of interdisciplinary vascular centers for the treatment of complex aortic pathologies and their sequelae. PRACTICAL RECOMMENDATIONS: In the following article, the arguments for the choice of procedure for the treatment of infrarenal aortic aneurysms are discussed and the recommendations of various guidelines are compared.

Towards User-Oriented Recommendations for Local Therapy of Leg and Foot Ulcers-An Update of a S3-German Guideline.

BACKGROUND: The German S3- guideline on local therapy of leg ulcers and diabetic foot ulcers is in the process of being updated. Major goals are to improve the guidelines' applicability and to take steps towards a living guideline according to current methodological standards. The aim of this article is to describe the main measures to achieve these goals. METHODS: The context of the guideline in the field of local wound care and the stakeholder requirements are briefly described. Based on a derived framework, the project team adjusted the methods for the guideline. RESULTS: Main adjustments are more specific inclusion criteria, online consensus meetings and the use of an authoring and publication platform to provide information in a multi-layered format. A new set of practice-oriented key questions were defined by the guideline panel to foster the formulation of action-oriented recommendations. CONCLUSIONS: The set of new key questions addressing practical problems and patients' preferences as well as the adjustments made to improve not only the guidelines' applicability, but also the feasibility of the further dynamic updating processes in the sense of a living guideline, should be steps in the right direction.

Local treatment of chronic wounds: in patients with peripheral vascular disease, chronic venous insufficiency, and diabetes.

BACKGROUND: A chronic wound is defined as an area where the skin is not intact that fails to heal within eight weeks. Such wounds usually develop on the lower limbs as a complication of diabetes, venous insufficiency, or inadequate arterial perfusion. Most of the roughly 45,000 limb amputations performed in Germany each year are necessitated by non-healing chronic wounds. METHODS: In the development of this S3 guideline, a systematic search was performed that yielded 4998 references including 38 randomized, controlled trials and 26 systematic reviews, which were used as the basis for the recommendations and statements made in the guideline. Twelve member societies of the umbrella Association of Scientific Medical Societies in Germany (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften, AWMF), as well as the German Association of Nursing Science (Deutsche Gesellschaft für Pflegewissenschaft, and patient representatives participated in the consensus rounds in which the guideline's recommendations and statements were agreed upon. RESULTS: This guideline contains seven evidence-based recommendations and 30 good clinical practice (GCP) recommendations. Evidence-based recommendations are given in favor of hydrogel, hyperbaric oxygenation, and integrated care, and against the use of medicinal honey and growth factors. Terms are defined precisely in order to ease communication and to specify what is meant by "wound debridement" (a procedure performed by a physician) as opposed to cleansing a wound. Under the premise of preventing pain, exudation, and maceration, local therapeutic agents can be chosen on the basis of the scientific evidence, the patient's preference, the physician's experience, and the wound situation. Costs should also be considered. CONCLUSION: Scant evidence is available to answer many of the relevant questions about chronic wounds. There are valid data in support of hyperbaric oxygen and integrated care. More research is needed.