Peripheral nerve blocks on the upper extremity: Technique of landmark-based and ultrasound-guided approaches.

The German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und Intensivmedizin, DGAI) established an expert panel to develop preliminary recommendations for the application of peripheral nerve blocks on the upper extremity. The present recommendations state in different variations how ultrasound and/or electrical nerve stimulation guided nerve blocks should be performed. The description of each procedure is rather a recommendation than a guideline. The anaesthesiologist should select the variation of block which provides the highest grade of safety according to his individual opportunities. The first section comprises recommendations regarding dosages of local anaesthetics, general indications and contraindications for peripheral nerve blocks and informations about complications. In the following sections most common blocks techniques on the upper extremity are described.

Obesity in regional anesthesia--a risk factor for peripheral catheter-related infections.

BACKGROUND: Obesity is believed to increase the risk of surgical site infections and possibly increase the risk of catheter-related infections in regional anesthesia. We, therefore, analyzed the influence of obesity on catheter-related infections defined within a national registry for regional anesthesia. METHODS: The German Network for Regional Anesthesia database with 25 participating clinical centers was analyzed between 2007 and 2012. Exactly, 28,249 cases (13,239 peripheral nerve and 15,010 neuraxial blocks) of patients ≥ 14 years were grouped in I: underweight (BMI 13.2-18.49 kg/m(2) , n = 597), II: normal weight (BMI 18.5-24.9 kg/m(2) , n = 9272), III: overweight (BMI 25.0-29.9 kg/m(2) , n = 10,632), and IV: obese (BMI 30.0-70.3 kg/m(2) , n = 7,744). The analysis focused on peripheral and neuraxial catheter-related infections. Differences between the groups were tested with non-parametric ANOVA and chi-square (P < 0.05). Binary logistic regression was used to compare obese, overweight, or underweight patients with normal weight patients. Odds ratios (OR and 95% confidence interval) were calculated and adjusted for potential confounders. RESULTS: Confounders with significant influence on the risk for catheter-related infections were gender, age, ASA score, diabetes, preoperative infection, multiple skin puncture, and prolonged catheter use. The incidence (normal weight: 2.1%, obese: 3.6%; P < 0.001) and the risk of peripheral catheter-related infection was increased in obese compared to normal weight patients [adjusted OR: 1.69 (1.25-2.28); P < 0.001]. In neuraxial sites, the incidence of catheter-related infections differed significantly between normal weight and obese patients (normal weight: 3.2%, obese: 2.3%; P = 0.01), whereas the risk was comparable [adjusted OR: 0.95 (0.71-1.28); P = 0.92]. CONCLUSION: This retrospective cohort study suggests that obesity is an independent risk factor for peripheral, but not neuraxial, catheter-related infections.

[Infection control measures and surveillance of patients with ventricular assist devices]. / Infektionsprävention und -Surveillance bei Kunstherzpatienten.

Ventricular assist devices (VAD) are a new routine therapy option for end-stage heart failure. However, the incidence of VAD-related infections varies between 20 and 188% and makes a major contribution to VAD-related morbidity. Therefore, optimised infection control policies should be applied to prevent VAD-related infections. As to date only a few studies exist investigating particular prevention measures for VAD recipients, we have tried to adapt evidence-based guidelines. In detail the following preventive measures are discussed: antibiotic prophylaxis, endocarditis prophylaxis, dressing technique for the driveline-exit site and education of patients and medical staff. A new patient-based surveillance system is proposed which reflects the different times since implantation of VADs and therefore allows a fair method for interhospital comparison.

Outcome following single vs bilateral lung transplantation in recipients 60 years of age and older.

AIMS: The significant shortage of donor organs in lung transplantation necessitates a careful selection of lung transplant recipients. The outcome of lung transplant recipients aged 60 years and older has not been analyzed systematically. METHODS: We retrospectively reviewed our experience with older recipients. Between January 1999 and July 2003, 248 patients underwent lung transplantation at our institution, of which 18 were aged 60 years and older (7.3%, range 60-66, mean 62 +/- 1.1). RESULTS: Eleven (61%) of the recipients 60 years and older received a single (SLTx) and seven (39%), a bilateral lung transplant. Donor age in the single transplant cohort was 30 +/- 4 years. It was 33 +/- 3 years in bilateral patients. Posttransplant ventilation time was significantly different among groups, with 282 +/- 32 hours after bilateral and 56 +/- 13 hours after transplant (P < .05). Also significantly longer was the length of the ICU stay in the bilateral group. First PaO2 in the ICU was not different among the two groups. The 1-year survival in the single transplant group was significantly better compared to the bilateral group with 73% versus 43%, respectively. CONCLUSIONS: The 1-year survival following lung transplantation in patients older than 60 years is markedly reduced compared to recipients under 60 years of age. If a lung transplant is considered in a recipient above the age of 60 years, a single transplant should be favoured. If that is not indicated, patients over 60 should be very carefully selected for bilateral transplant.

No evidence for productive PERV infection of baboon cells in in vivo infection model.

OBJECTIVES: The discovery that pig endogenous retroviruses are infectious for human cells in vitro lead to vehement discussions about the possible risk of infection after clinical xenotransplantation. Since PERV transmission to non-human primate cells in vitro has been observed, similar to human cells, infection studies in non-human primates should represent the best model to analyze a potential PERV transmission after xenotransplantation. However, it is still open to discussion, whether non-human primate cells can be infected productively-similar to human cells- and whether those species are suitable to analyze PERV infection risks in vivo. METHODS: In vitro, only few cell types can be tested for susceptibility. We developed a pig to baboon cell transplantation model with special emphasis on B-cell effective immunosuppression, removal of anti Gal-alpha 1,3-Gal-antibodies, inhibition of the complement cascade and long term survival of transplanted cellular grafts. This model allows us to investigate in vivo, whether any baboon cell types may be permissive for productive PERV infection. The xenograft recipients were investigated for up to 535 days post transplantation. Gal-alpha 1,3-Gal-antibody and complement levels were monitored. Potential PERV transmission was analyzed, not only in PBMC, but in a variety of tissue samples as well as in serum and plasma samples by PCR, RT-PCR and by detection of RT-activity. Moreover, potential PERV specific immune responses were studied by a highly sensitive Western-Blot-assay. RESULTS: Despite several days of extremely low levels of Gal-alpha 1,3-Gal-antibody and complement, and despite of long term xenochimerism, no evidence for PERV infection was obtained in any of the tested tissues or in the tested serum samples. CONCLUSION: This study supplies further evidence for a low susceptibility of baboons towards productive PERV infection after xenotransplantation.

Induction of long-term peripheral microchimerism in non-human primates in a model of xenogeneic peripheral tolerance induction.

Xenotransplantation represents a promising solution to the ever increasing shortage of donor organs in allotransplantation. However, due to different and stronger modes of rejection, successful xenotransplantation will require different organ-protective regimes from those used in allogeneic transplantation today. Since one can not simply increase the dosage of the drugs used, immunomodulation or tolerance induction of the recipient would be the most desirable approach. Transfusion of donor leukocytes has been shown to downregulate recipient responses or even induce peripheral tolerance in small animal models. Since the infusion of donor cells represents a relatively simple approach, as one can purify and compose the inoculum exactly before infusion, we studied whether this approach can be successfully employed in a preclinical swine to non-human primate model of peripheral tolerance induction/immunomodulation. In our model, baboons underwent sequential column adsorption and complement blockade. The animals received only initial immunosuppression with cyclophosphamide. No further immunosuppression was given. Subsequently all animals received 1-3 x 10(10) porcine splenocytes i.v. Development and maintenance of chimerism was analyzed by sequential flow cytometric and PCR analyses. Other parameters studied included effects of the preparatory induction protocol. We could show that a low level of chimerism is maintained in these animals for up to 1.5 years, despite the fact that they received no additional immunosuppression after the initial one. At no time of the experiment did any animal display symptoms of poor health. Thus we demonstrate that the concept of donor leukocyte transfusion is transferable into preclinical xenotransplantation. We are currently conducting organ transplantation experiments into animals thus treated to directly analyze the immunomodulatory effect of the donor cells.

[Removal of lepirudin used as an anticoagulant in mechanical autotransfusion with Cell-Saver 5]. / Auswaschverhalten von Lepirudin als Antikoagulans bei der maschinellen Autotransfusion mit dem cell-saver 5.

UNLABELLED: Former studies demonstrated that small amounts of heparin might remain in the prepared retransfusion blood during intraoperative autotransfusion. This could lead to serious complications in patients suffering from heparin-induced-thrombocytopenia type II (HIT II). Lepirudin is an approved anticoagulant in HIT II-patients. We studied to what extent lepirudin is washed out during the preparation of retransfusion blood, when it is used as anticoagulant for the autotransfusion device cell saver 5. METHODS: We investigated four different concentrations of lepirudin solutions, 5 mg, 10 mg, 20 mg and 30 mg per litre normal saline. In order to imitate a clinical situation, each lepirudin solution was mixed with human blood in a 1:5-ratio and put into the reservoir of the cell saver. The device was started in the automatic mode using 1000 ml saline as washing solution. Several runs were carried out (five times using the 5 mg/l solution, ten times the 10 mg/l, eleven times the 20 mg/l and eleven times the 30 mg/l solution). The lepirudin concentration in the prepared retransfusion blood was measured. RESULTS: The median percentage reduction of the lepirudin content from the reservoir blood to the retransfusion blood was 100% for the 5 mg/l, 90.4% for the 10 mg/l, 94.3% for the 20 mg/l and 86.3% for the 30 mg/l solution. The differences of percentage reduction are not significant. But the different lepirudin concentrations in the anticoagulant solution have a significant influence on the lepirudin concentration in the retransfusion blood. The lepirudin concentration (median) in the retransfusion blood was 0.00 microgram/ml for the 5 mg/l, 0.16 microgram/ml for the 10 mg/l, 0.19 microgram/ml for the 20 mg/l and 0.66 microgram/l for the 30 mg/l lepirudin solution. CONCLUSION: Lepirudin as an anticoagulant for intraoperative autotransfusion is effectively eliminated using the cell saver 5 device in the automatic mode with 1000 ml saline as washing solution. A clinically relevant disturbance of coagulation is not to be expected, even if the highest concentration of lepirudin anticoagulant solution investigated in this study is used.

[Danaparoid (Orgaran) as an antiocoagulant for mechanical autotransfusion with Cell Saver 5 (Hemonetics)]. / Danaparoid (Orgaran) zur Antikoagulation bei der maschinellen Autotransfusion mit Cell Saver 5 (Haemonetics).

We investigated Danaparoid Sodium (Orgaran) as anticoagulant using three different concentrations (9, 4,5 or 3 U/ml anticoagulant solution) for the use in the autotransfusion device Cell Saver 5 (Haemonetics). Fresh units of whole blood packs were mixed in the reservoir in a proportion of 5:1 with the anticoagulant solution. Having started the Cell Saver 5 in the automatic mode, the amount of Danaparoid in the retransfusion blood was determined (chromogenic Antifactor-Xa test). The lowest concentration of the anticoagulant was applied in 4 patients with Heparin-induced Thrombocytopenia Type II undergoing total hip arthroplasty. There was a correlation between the concentration in the reservoir and in the retransfusion blood. None of the patients showed a disturbance of his coagulation system. One of them had slight clotting in the reservoir. We recommend the use of the lower concentrations tested: 4,5 U/ml or, particularly for patients with renal insufficiency or low body weight or expected high retransfusion volumes, 3 U/ml as anticoagulant concentrations. If the autotransfusion device is used according to the manufacturer's instructions there may be virtually no risk of clotting in the Cell Saver or of inhibition of the coagulation system in the patient.

[Fiber optic intubation using a modified laryngeal mask. Report of experiences with use in 105 patients]. / Fiberoptische Intubation mit Hilfe einer modifizierten Kehlkopfmaske. Erfahrungsbericht über die Anwendung bei 105 Patienten.

PURPOSE: This study was made to investigate the suitability of a modified laryngeal mask airway as an aid for fibreoptic endotracheal intubation in patients with a difficult airway. We used a laryngeal mask airway split lengthwise on its convex site, the incision going from a point corresponding to the teeth down to the base of the cuff. The cuff remains uncut. By this modification it is possible to ventilate an anaesthetised patient and to pass down a fibreoptic bronchoscope via splitting of the laryngeal mask airway into the trachea at the same time. An endotracheal tube of any diameter already mounted over the bronchoscope is then guided into the trachea. The feasibility of this technique was tested and haemodynamic reactions and changes of the parameters of respiration were recorded. METHODS: This technique was used in 105 patients, 68 male and 37 female, mean age 34 years, when difficult intubation was expected or occurred. Blood pressure, pulse rate and peripheral oxygen saturation was recorded on arrival in the anaesthetic room, after induction of anaesthesia, during and after fibreoptic endotracheal intubation. The respiratory minute volume was measured after insertion of the laryngeal mask airway and during the course of fibreoptic intubation. The time needed was recorded. RESULTS: In all cases endotracheal intubation was successful using this technique. The time needed was between 4 and 16 minutes. There was a statistically significant increase in peripheral oxygen saturation and decrease of the pulse rate after induction of anaesthesia. There were no further significant changes of the recorded haemodynamic parameters and the oxygen saturation during and after fibreoptic intubation compared to the results after induction of anaesthesia. CONCLUSION: It could be demonstrated that a fibreoptic intubation is possible in cases of a difficult airway using the technique described here. There is no haemodynamic strain on the patient. This method can be carried out without pressure of time and without to endanger the patient by hypoxia as the patient can be ventilated during the fibreoptic intubation. In cases of impossible intubation and insufficient mask ventilation it can be tried to establish ventilation and to avoid a emergency surgical airway or transtracheal jet ventilation by using this technique.