Efficient application of volatile anaesthetics: total rebreathing or specific reflection?

The circle system has been in use for more than a 100 years, whereas the first clinical application of an anaesthetic reflector was reported just 15 years ago. Its functional basis relies on molecular sieves such as zeolite crystals or activated carbon. In a circle system, the breathing gas is rebreathed after carbon dioxide absorption; a reflector on the other hand specifically retains the anaesthetic during expiration and resupplies it during the next inspiration. Reflection systems can be used in conjunction with intensive care ventilators and do not need the permanent presence of trained qualified staff. Because of easy handling and better ventilatory capabilities of intensive care ventilators, reflection systems facilitate the routine use of volatile anaesthetics in intensive care units. Until now, there are three reflection systems commercially available: the established AnaConDa? (Sedana Medical, Uppsala, Sweden), the new smaller AnaConDa-S?, and the Mirus? (Pall Medical, Dreieich, Germany). The AnaConDa consists only of a reflector which is connected to a syringe pump for infusion of liquid sevoflurane or isoflurane. The Mirus represents a technical advancement; its control unit includes a gas and ventilation monitor as well as a gas dispensing unit. The functionality, specific features, advantages and disadvantages of both systems are discussed in the text.     

Repair of Left Ventricular Assist Device Driveline Damage Directly at the Transcutaneous Exit Site

With increasing support duration of cardiac assist devices, transcutaneous drivelines remain a weak point of the therapy. First, they can be an entry point for infections, and second, cable lesions and even electrical failures due to material fatigue and eventual carelessness can occur. We report a case of a damaged outer sheath of a ventricular assist device driveline cable directly at the exit site, where the standard repair procedure with self‐fusing tape may lead to biocompatibility problems and irritation of the entrance through the skin. Therefore, a new procedure was developed using a special sleeve expander tool and a highly expandable latex tubing to stabilize the defect in a flexible and biocompatible manner. A patient experienced a fracture of the outer sheath of a HeartWare HVAD driveline directly at the skin entrance (approximately 15 mm long, 5 mm distal from the skin). The metal strands and the electrical functionality were yet not affected, therefore, a pump exchange was not indicated. After considering several conventional solutions for repair as not applicable, a new approach was developed: a sleeve expander tool was applied, which allowed radial stretching of the latex tubing. After preparations of the tool and the cable site, the pump was briefly disconnected, the tubing was moved over the connector and was released at the site of fracture. The problem could be solved by keeping the cable's flexibility and without additional risks to the skin. Within a still ongoing (5‐month) follow‐up, the skin entrance returned to perfect condition and no further intervention was necessary. In conclusion, this method allows a quick stabilization and repair of damaged driveline isolations even near the exit site, resulting in a biocompatible surface and consistent flexibility of the cable.     

Pelargonium sidoides preparation EPs 7630 in COPD: health-related quality-of-life and other patient-reported outcomes in adults receiving add-on therapy

Objective: Patient-reported outcomes (PRO) such as health-related quality-of-life (HRQoL) belong to the most important criteria for the evaluation of medical therapies in clinical trials or practice-based benefit assessments. This study, therefore, revisited results of an earlier published clinical trial investigating the effects of the herbal drug preparation from the roots of Pelargonium sidoides EPs 7630, administered as add-on therapy in patients suffering from chronic obstructive pulmonary disease (COPD), with respect to HRQoL and other PRO.

Methods: A total of 199 adults diagnosed with COPD stages II/III and receiving standard treatment according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) were randomly assigned to add-on therapy with EPs 7630 or placebo for 24 weeks. HRQoL (disease-specific St. George’s Respiratory Questionnaire, SGRQ; current HRQoL state according to the EuroQuol visual analog scale, EQ VAS) and PRO (Integrative Medicine Outcomes Scale, IMOS; Integrative Medicine Patient Satisfaction Scale, IMPSS; symptom severity score of cough, sputum production and sternal pain while coughing; duration of inability to work) were assessed at each study visit or documented daily by the patient in a patient diary, respectively.

Results: At week 24, all HRQoL and PRO measures showed a more pronounced improvement under EPs 7630 than under placebo (EQ VAS, p?p?p?=?.021; duration of inability to work, p?=?.004; two-sided t-test each; IMOS, p?p?Conclusions: Add-on therapy with EPs 7630 led to an improvement in HRQoL and other PRO in adult patients with COPD compared to placebo while showing a good long-term tolerability.     

Platelet-derived growth factor triggers PKA-mediated signalling by a redox-dependent mechanism in rat renal mesangial cells

Inflammatory glomerular kidney diseases are often accompanied with a massive production of reactive oxygen species (ROS) that affect the function of the glomerular filtration barrier and contribute to mesangiolysis via the induction of cell death in mesangial cells. Intriguingly, ROS also trigger fine-tuned signalling processes that affect gene expression and cell proliferation or migration. To define such redox-driven signalling devices, a proteomics approach was performed to identify the formation of protein complexes induced by ROS. To this end, protein lysates of human podocytes were treated with or without hydrogen peroxide (250 μM). Thereafter cell lysates were subjected to diagonal 2D gel electrophoresis and putative redox-affected proteins were analysed by MS/MS analysis. Among others, the regulatory subunit of protein kinase A (PKA) could be identified that forms homodimers under oxidative conditions. To evaluate whether ROS dependent dimerization of PKA also occurs in a more physiological setting, rat mesangial cells were treated with platelet-derived growth factor-BB (PDGF-BB) to induce ROS formation. This regimen resulted in a redox dependent dimerization of the R-subunits of PKA. To demonstrate whether PDGF-BB induced ROS formation affects PKA dependent pathways, the effects of PDGF-BB on phosphorylation of serine 157 of vasodilator stimulated protein (VASP) a classical target of PKA were analysed. Interestingly PDGF-BB induced VASP phosphorylation in a ROS dependent manner but independent of changes in cAMP levels. Taken together, we demonstrate a redox-mediated activation of PKA by PDGF-BB thus highlighting a physiological role of ROS as regulator of PKA activity in rat mesangial cells.     

Neurophysiology and the Problem of Human Free Will: A Case of “Nihil Sub Sole Novum”?

Over the last decade in Germany, a number of neuroscientists—and among them most prominently Wolf Singer—have claimed to be able to offer scientific evidence derived from neurophysiologic findings to conclusively negate the existence of human free will. In this paper, Singer’s position is examined according to its principal characteristics in order to answer the question whether it is a novel position as opposed to a position pertaining to one of the traditions of western philosophy and anthropology. Furthermore, we try to judge whether the neurobiological findings Singer and others use to justify their position are apt to satisfy the criteria for the presence of scientific evidence, i.e., if they are good reasons to believe that human will is unfree.