[Abdominal aortic aneurysms-open vs. endovascular treatment : Decision-making from the perspective of the vascular surgeon]

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.

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.

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.