Standardisierte Kontrastmittelsonographie (CEUS) in der klinischen Akut- und Notfallmedizin sowie Intensivmedizin (CEUS-Akut)

Die Anaesthesiologie -     

Effect of cholinergic crisis on the potency of different emergency anaesthesia protocols in soman-poisoned rats

Background: In a military or terrorist scenario, combination of organophosphorus compounds (OP) poisoning with physical trauma requiring surgical treatment and thus general anaesthesia are possible. Previous in vitro studies showed an altered potency of relevant anaesthetics during cholinergic crisis. Hence, it is not clear, which anaesthetics are suitable to achieve the necessary stage of surgical anaesthesia in OP poisoning.

Methods: In the present study, different anaesthetic regimens (ketamine-midazolam, propofol-fentanyl, thiopental-fentanyl), relevant in military emergency medicine, were examined in soman-poisoned rats. Clinical signs and cardiovascular variables were recorded continuously. Blood samples for acetylcholinesterase (AChE) activity were drawn. After euthanasia or death of the animals, brain and diaphragm were collected for cholinesterase assays.

Results: Propofol-fentanyl and thiopental-fentanyl resulted in surgical anaesthesia throughout the experiments. With ketamine-midazolam, surgical anaesthesia without respiratory impairment could not be achieved in pilot experiments (no soman challenge) and was therefore not included in the study. Soman-poisoned and control animals required a comparable amount of propofol-fentanyl or thiopental-fentanyl. In combination with atropine, significantly less propofol was needed. Survival rate was higher with thiopental compared to propofol. Atropine improved survival in both groups. Blood and tissue AChE activities were strongly inhibited after soman administration with and without atropine treatment.

Discussion: The current in vivo study did not confirm concerns of altered potency of existing anaesthetic protocols for the application of propofol or thiopental with fentanyl due to soman poisoning. Despite severe cholinergic crisis, sufficient anaesthetic depth could be achieved in all animals.

Conclusion: Further experiments in in vivo models closer to human pharmaco- and toxicokinetics (e.g., swine) are required for confirmation of the initial findings and for improving extrapolation to humans.     

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.     

Is bone-cement augmentation of screw-anchor fixation systems superior in unstable femoral neck fractures? A biomechanical cadaveric study

Objectives

Improved fixation techniques with optional use of bone cements for implant augmentation have been developed to enhance stability and reduce complication rates after osteosynthesis of femoral neck fractures. This biomechanical study aimed to evaluate the effect of cement augmentation on implant anchorage and overall performance of screw-anchor fixation systems in unstable femoral neck fractures.

Die „neue“ Borderline-Persönlichkeitsstörung: Dimensionale Klassifikation im DSM-5 und ICD-11

Psychotherapie Forum - Die jahrzehntelange und zunehmende Unzufriedenheit mit der bisherigen kategorialen Klassifikation der Persönlichkeitsstörungen (PS) im amerikanischen DSM-IV und in...