[Hygiene aspects in ultrasound-guided regional anesthesia]. / Hygieneaspekte in der ultraschallgestützten Regionalanästhesie.

BACKGROUND: Sterile and clean working conditions are one of the keystones of medical practice and this is also true for ultrasound-guided regional anesthesia. The routine clinical practice in ultrasound-guided regional anesthesia does not always comply with the principles of sterile and clean working conditions in medicine: therefore, patients are exposed to potential hazards regarding the transmission of pathogens via the ultrasound equipment. OBJECTIVE: This article deals with the question of whether sterile working conditions in ultrasound-guided regional anesthesia are a relevant topic with medical and economic implications. Is it possible to implement the general recommendations for sterile working conditions in ultrasonography for the specific application of ultrasound-guided regional anesthesia? MATERIAL AND METHODS: A search of the available literature and published guidelines in the field of sterile working conditions with ultrasound was carried out. RESULTS: The association between cross-infections and ultrasound equipment is undeniable. Many methods for cleansing and disinfection of ultrasound equipment have been published. All these methods are associated with advantages and disadvantages. The direct sterilization of ultrasound probes with high-percentage alcohol can damage ultrasound probes (especially linear). The use of self-adhesive sterile ultrasound probe covers is a practical method to achieve sterile working conditions in ultrasound-guided regional anesthesia. CONCLUSION: The use of sterile ultrasound probe covers and sterile ultrasound contact media is an important prerequisite to avoid cross-infection between patients. An appropriate scientific evaluation should serve as evidence in this field.

Validity and fidelity of the upper airway in two high-fidelity patient simulators.

BACKGROUND: Human patient simulators are frequently used for airway management training and research. However, little is known about their fidelity and validity. The use of these simulators as a benchmark model remains highly questionable. The objective of this study was to evaluate the validity and fidelity of two patient simulators (compared to actual patients) for anaesthesia residents performing three airway management techniques. METHODS: Endotracheal intubation, laryngeal mask airway insertion and mask ventilation were performed by anaesthesia residents on 80 patients undergoing elective surgery. The anaesthesia residents also used these three techniques to secure the airways of two human patient simulators in a randomised crossover study. The durations, difficulties, realism and success rates of the procedures were assessed. RESULTS: Although the performance of endotracheal intubation was comparable in patients and both manikins, no chest rise was visible in 35% (HAL) and 32.5% (SimMan) of the manikins after inserting a laryngeal mask airway. This result was not observed in patients (P<0.001). Furthermore, effective mask ventilation was not possible in 60% of the cases using HAL, compared with 0% of cases using SimMan and 2.5% of patients (P<0.001). CONCLUSION: Patient simulators are not a valid alternative to human patients for conducting scientific evaluations of supraglottic airway management techniques. HAL and SimMan do have adequate validity for endotracheal intubation, but the fidelity and validity are low when a laryngeal mask is used or if mask ventilation is performed. Therefore, previous simulation-based airway device evaluation studies must be interpreted with great caution.

Can a flowchart improve the quality of bystander cardiopulmonary resuscitation?

BACKGROUND: Since the introduction of basic life support in the 1950s, on-going efforts have been made to improve the quality of bystander cardiopulmonary resuscitation (CPR). Even though bystander-CPR can increase the chance of survival almost fourfold, the rates of bystander initiated CPR have remained low and rarely exceed 20%. Lack of confidence and fear of committing mistakes are reasons why helpers refrain from initiating CPR. The authors tested the hypothesis that quality and confidence of bystander-CPR can be increased by supplying lay helpers with a basic life support flowchart when commencing CPR, in a simulated resuscitation model. MATERIALS AND METHODS: After giving written informed consent, 83 medically untrained laypersons were randomised to perform basic life support for 300s with or without a supportive flowchart. The primary outcome parameter was hands-off time (HOT). Furthermore, the participants' confidence in their actions on a 10-point Likert-like scale and time-to-chest compressions were assessed. RESULTS: Overall HOT was 147±30 s (flowchart) vs. 169±55 s (non-flowchart), p=0.024. Time to chest compressions was significantly longer in the flowchart group (60±24 s vs. 23±18 s, p<0.0001). Participants in the flowchart group were significantly more confident when performing BLS than the non-flowchart counterparts (7±2 vs. 5±2, p=0.0009). CONCLUSIONS: A chart provided at the beginning of resuscitation attempts improves quality of CPR significantly by decreasing HOT and increasing the participants' confidence when performing CPR. As reducing HOT is associated with improved outcome and positively impacting the helpers' confidence is one of the main obstacles to initiate CPR for lay helpers, charts could be utilised as simple measure to improve outcome in cardiopulmonary arrest.

The effect of the molecular adsorbent recirculating system on moxifloxacin and meropenem plasma levels.

BACKGROUND: Adequate plasma antibiotic concentrations are necessary for effective elimination of invading microorganism; however, extracorporeal organ support systems are well known to alter plasma concentrations of antibiotics, requiring dose adjustments to achieve effective minimal inhibitory concentrations in the patient's blood. METHODS: A mock molecular adsorbent recirculating system (MARS) circuit was set using 5000 ml of bovine heparinized whole blood to simulate an 8-h MARS treatment session. After the loading dose of 400 mg of moxifloxacin or 2 g of meropenem had been added, blood was drawn from the different parts of the MARS circuit at various time points and analyzed by high-performance liquid chromatography. The experiments were performed in triplicate. Additionally, meropenem concentrations were determined in the plasma of one patient treated with MARS suffering from acute liver failure due to an idiosyncratic reaction to immunosuppressive medication. RESULTS: In our single-compartment model, a significant decrease in the quasi-systemic concentration of moxifloxacin and meropenem could be detected as early as 15 min after the commencing of the MARS circuit. Moreover, within 60 min the moxifloxacin and meropenem concentrations were less than 50% of the initial value. The activated charcoal removed the majority of moxifloxacin and meropenem in the albumin circuit. In our patient, the meropenem concentrations in the return line after MARS were constantly lower than in the access line, indicating a likely removal of meropenem through MARS. CONCLUSION: Our data provide evidence that moxifloxacin and meropenem are effectively removed from the patient's blood by MARS, leading to low plasma levels. Dose adjustments of both antibiotic compounds may be required.

Impact of the European Paediatric Life Support course on knowledge of resuscitation guidelines among Austrian emergency care providers.

BACKGROUND: Even though anaesthetists do not resuscitate children on a daily basis, they need to perform paediatric life support regularly due to their different duties. As the knowledge of international guidelines varies widely, highly standardized European Paediatric Life Support (EPLS) courses have been introduced to improve standards of care. This national survey among Austrian anaesthetists and EPLS course participants evaluated the impact of this course at the end of the guideline period 2005-2010. METHODS: After approval by the institutional review board an online survey about paediatric resuscitation guidelines was sent to EPLS course participants of the guideline period 2005 (EPLS group) and members of the Austrian Society of Anaesthesia, Resuscitation and Intensive Care (ÖGARI) two weeks before publication of the resuscitations guidelines 2010. Respondents without an EPLS course were assigned to the non-EPLS group. RESULTS: Of 333 respondents 247 finished the survey. One hundred eighty five persons were assigned to EPLS group and 62 to the non-EPLS group. Members of the EPLS group performed significantly better than the non-EPLS group (76 ± 19% correct answers EPLS group vs. 63 ± 18% correct answers non-EPLS group, p<0.0001). Furthermore, the EPLS group performed better than anesthetists with regular resuscitation training and or resuscitation experience but without an EPLS course. CONCLUSION: The attendance of an EPLS course within the guideline period 2005 significantly increased the theoretical knowledge of paediatric resuscitation guidelines.

Exposure to anaesthetic trace gases during general anaesthesia: CobraPLA vs. LMA classic.

BACKGROUND: To prospectively investigate the performance, sealing capacity and operating room (OR) staff exposure to waste anaesthetic gases during the use of the Cobra perilaryngeal airway (CobraPLA) compared with the laryngeal mask airway classic (LMA). METHODS: Sixty patients were randomly assigned to the CobraPLA or the LMA group. Insertion time, number of insertion attempts and airway leak pressures were assessed after induction of anaesthesia. Occupational exposure to nitrous oxide (N(2)O) and Sevoflurane (SEV) was measured at the anaesthetists' breathing zone and the patients' mouth using a photoacoustic infrared spectrometer. RESULTS: N(2)O waste gas concentrations differed significantly in the anaesthetist's breathing zone (11.7+/-7.2 p.p.m. in CobraPLA vs. 4.1+/-4.3 p.p.m. in LMA, P=0.03), whereas no difference could be shown in SEV concentrations. Correct CobraPLA positioning was possible in 28 out of 30 patients (more than one attempt necessary in five patients). Correct positioning of the LMA classic was possible in all 30 patients (more than one attempt in three patients). Peak airway pressure was higher in the CobraPLA group (16+/-3 vs. 14+/-2 cmH(2)O, P=0.01). The average leak pressure of the CobraPLA was 24+/-4 cmH(2)O, compared with 20+/-4 cmH(2)O of the LMA classic (P<0.001; all values means+/-SD). CONCLUSION: Despite higher airway seal pressures, the CobraPLA caused higher intraoperative N(2)O trace concentrations in the anaesthetists' breathing zone.

Comparison of economical aspects of interscalene brachial plexus blockade and general anaesthesia for arthroscopic shoulder surgery.

BACKGROUND: This study investigated the cost-effectiveness of ultrasonographic-guided interscalene brachial plexus blockade (ISB) in comparison with general anaesthesia (GA) for arthroscopic shoulder surgery. METHODS: Forty patients undergoing arthroscopic shoulder surgery received either an ultrasonographic-guided ISB or GA. ISB was performed outside the operation room (OR) and patients were transferred in the OR at the earliest 20 min after block performance. All drugs and disposables were recorded to evaluate the costs for both techniques. The following anaesthesia-related times were defined: ready for surgical preparation (from arrival in the OR until end of anaesthesia induction), OR emergence time (from end of dressing until leaving the OR), anaesthesia control time (from patient's arrival in the OR until readiness for positioning plus time from the end of surgery to patient's discharge from the OR), and post-anaesthesia care unit (PACU) time (from patient's arrival in the PACU to the eligibility for discharge to normal ward). Personnel costs were excluded from statistical analysis. RESULTS: The total costs were [mean (sd)] 33 (9)euro for patients with ISB and 41 (7)euro for those who received GA (P<0.01). The anaesthesia-related workflow was improved in the ISB group when compared with the GA group [ready for surgical preparation 8 (3) vs 13 (5) min, P<0.001; OR emergence time 4 (3) vs 10 (5), P<0.001; anaesthesia control time 12 (4) vs 23 (6), P<0.001; and PACU time 45 (17) vs 70 (20), P<0.001]. CONCLUSIONS: Ultrasonographic-guided ISB is a cost-effective method for arthroscopic shoulder surgery.

The endothelium secretes interleukin-6 (IL-6) and induces IL-6 and aldosterone generation by adrenocortical cells.

Endothelial cells have been shown to induce adrenal steroidogenesis and to enhance aldosterone secretion via angiotensin II and endothelin 1-independent mechanisms. It has been demonstrated that endothelial cells and adrenocortical cells are capable of producing interleukin-6 (IL-6) and IL-6 is a factor known to stimulate adrenal cortisol secretion. We therefore asked whether endothelial cells have an effect on adrenal IL-6 generation and whether IL-6 mediates biosynthesis of aldosterone as is observed after exposure of adrenocortical cells to endothelial cell-conditioned medium (ECCM). Cells from the adrenocortical cancer cell line NCI-H295R were incubated with ECCM produced from human umbilical vein endothelial cells at increasing concentrations. As detected by an enzyme-linked immunosorbent assay, pure ECCM significantly increased IL-6 protein secretion by cultured adrenocortical cells in a dose-dependent fashion, to a 18.0+/-2.0 pg/mL (mean+/-SEM). This was paralleled by an enhanced IL-6 promoter activity as determined with the transfection of an IL-6-promoter-luciferase reporter gene construct. Pure ECCM also induced aldosterone secretion by adrenocortical cells more than three times that of controls with serum-free medium. ECCM PER SE contains significant amounts of IL-6 protein. However, blockade of IL-6 signal transduction did not interfere with aldosterone synthesis. These data suggest that endothelial cells secrete IL-6 and that endothelial cell-derived factors regulate adrenal IL-6 synthesis which does not alter adrenal aldosterone secretion. Our findings support the hypothesis that the endothelium and the adrenal gland may play a role in the development of some forms of hypertension and - more speculative - inflammation.