[Nonoperating room anesthesia]. / Dezentrale Arbeitsplätze in der Anästhesiologie.

Anesthesia services outside central surgical facilities (nonoperating room anesthesia, NORA) have become more important. Nonoperating room anesthesia is a challenging field with a wide range of patient ages and interventions. The anesthesiologist is caught between the existing expertise in sedation, respiratory and emergency management and the fact that it may be a potentially avoidable cost factor. The efforts of some specialist departments to carry out sedation themselves even with more complex interventions have therefore increased. In order to permanently establish anesthesia here, apart from the pure anesthesiological expertise, a pronounced willingness to interdisciplinary communication and cooperation is necessary. Only in this way can the participating specialist disciplines be convinced of the anesthesiological added value for the patient. Groups of patients requiring special attention include pediatric patients. The care especially for children under 2 years old also requires the particular anesthesiological expertise of the supervising anesthesiologist; however, profound knowledge, for example in cardiac anesthesia, is also required if special interventions are decentrally managed in the cardiac catheterization laboratory.

[Influence of social characteristics on the duration of treatment, severity of the disease and social support of patients in a surgical intensive care unit]. / Einfluss sozialer Charakteristika auf die Behandlungsdauer, Erkrankungsschwere und soziale Unterstützung von Patienten einer operativen Intensivstation.

BACKGROUND: In critical illnesses low socioeconomic status (SES) is associated with higher morbidity and mortality. In addition to the SES, further factors at an individual level (e.g., sex, health insurance status and place of residence) may influence the severity of illness and medical treatment. We investigated these additional parameters in a secondary analysis of the ECSSTASI data. METHODS: Within the framework of the ECSSTASI study, 996 patients were recruited from a surgical intensive care unit. We examined the influence of sex, insurance status and place of residence on health-related behavior, disease severity, duration of intensive care and ventilation (28 ventilator-free days score, 28-VFDS) and social support by the next of kin. Multivariate-adjusted logistic regression analyses were carried out and odds ratios (OR) are presented with corresponding 95% confidence intervals. RESULTS: Among patients admitted to the intensive care unit, the disease severity (SOFA score >5) was significantly lower in women than in men (OR 0.62 [0.45-0.87]). Increasing size of the patient's town of residence was associated with a significantly shorter duration of treatment on the intensive care unit (OR 0.54 [0.32-0.91]). An increasing number of persons in the household was associated with a significantly increased risk of being ventilated longer compared to 1­person households (p = 0.028). Patients with private insurance (OR 1.87 [1.28-2.70]), patients from households with ≥4 persons (OR 1.92 [1.1-3.33]) and patients without German citizenship (OR 2.56 [1.39-4.55]) were visited significantly more often by next of kin. CONCLUSION: In addition to the SES, sociodemographic characteristics of the individual patient are associated with the course of treatment in intensive care medicine. The extent of social support by the next of kin depends on intercultural and individual patient characteristics. An increasing size of the town of residence and private health insurance status positively influence intensive care outcomes. In order to evaluate these data, further epidemiological studies in intensive care medicine are necessary.

[Outpatient palliative medicine : Attitudes in the care of palliative emergencies. Prospective questionnaire-based investigation]. / Ambulante Palliativmedizin : Einstellungen in der Versorgung palliativer Notfälle. Prospektive Fragebogenuntersuchung.

BACKGROUND: The right to adequate outpatient palliative care has existed for several years in Germany. In recent years outpatient palliative care has developed very positively. Nevertheless, in emergency situations paramedics and emergency physicians were often included in the care of palliative care of patients. The aim of our study was to investigate the cooperation between outpatient palliative care teams and the emergency medical services. Another aim was to identify structural realities and based on these to discuss the possibilities in the optimization of outpatient palliative medical emergency situations. METHODS: A standardized self-designed questionnaire was distributed to specialized outpatient palliative care teams (SPCS) in Germany. For this purpose, closed and open questions (mixed methods) were used. The evaluation was carried out according to the questionnaire categories in quantitative and qualitative forms. The questionnaire was subdivided into general information and specific questions. RESULTS: The survey response rate was 79% from a total of 81 SPCS in 2011. The following standards in palliative emergency care were recommended: (1) early integration of outpatient palliative care services and basic outpatient palliative care systems, (2) end-of-life discussions, (3) defined emergency medical documents, emergency drug boxes, do not attempt resuscitation orders and (4) emergency medical training (physicians and paramedics). CONCLUSION: Outpatient palliative care in Germany has developed very positively during the last years; however, there are still deficits in terms of optimal patient care, one of which refers to the treatment of palliative care emergencies. In this context, optimization in the cooperation between outpatient palliative care services and emergency medical services should be discussed.

[Use of near-infrared spectroscopy for control of limb perfusion during venoarterial ECMO treatment : Application and limitations]. / Verwendung der Nahinfrarotspektroskopie zur Kontrolle der Extremitätenperfusion unter venoarterieller ECMO-Therapie : Einsatz und Limitationen.

Patients undergoing peripheral venoarterial extracorporeal membrane oxygenation have a high risk of lower limb ischemia. In general, regular controls are carried out based on clinical and laboratory parameters in order to quickly detect and treat complications. These controls are challenging due to states of shock, nonpulsatile flow and vasopressor therapy. As additional monitoring the use of near-infrared spectroscopy (NIRS) is described in the literature as being very successful in detecting ischemia. The present article describes the use and possible limitations of NIRS for the diagnostics of peripheral ischemia.

Performance of a new-generation continuous autotransfusion device including fat removal and consequences for quality controls.

BACKGROUND AND OBJECTIVES: Cell salvage plays a key role in blood conservation. To maintain high performance, quality management is recommended. Accordingly, a new-generation autotransfusion device was tested for its performance and compared with its predecessor. Two different calculations of quality parameters were applied. MATERIALS AND METHODS: In an experimental study, the continuous autotransfusion devices CATSmart and Continuous Autotransfusion System (C.A.T.S) plus were tested using banked blood adjusted to a haematocrit of 20% and anticoagulated with heparin 5 U/L. Test blood was processed using an emergency programme, a high-quality programme/smart wash programme and a low-volume wash programme. Samples were taken after the production of 200 mL of red blood cells (RBC) and after the final emptying of the separation chamber. In an additional set of tests, blood containing 1·25% fat was processed with both devices to examine fat removal. RESULTS: Both devices demonstrated an equally high performance with regards to product hematocrit (Hct); RBC recovery; and elimination rates of protein, heparin and fat. The high fat elimination rate (>99·8%) reported for C.A.T.S plus was confirmed for CATSmart, regardless of the used programme. Samples taken during the ongoing process show a higher haematocrit and RBC recovery rate than samples taken after the final emptying of the separation chamber. Interface sensors were not affected by fat in the blood. CONCLUSIONS: The new-generation autotransfusion device CATSmart is not inferior to its predecessor and shows high performance with regards to RBC recovery, plasma and fat elimination in all programme modes. Samples for quality controls should be taken during blood processing.

Robot-assisted microwave thermoablation of liver tumors: a single-center experience.

PURPOSE: To evaluate and compare the needle placement accuracy, patient dose, procedural time, complication rate and ablation success of microwave thermoablation using a novel robotic guidance approach and a manual approach. METHODS: We performed a retrospective single-center evaluation of 64 microwave thermoablations of liver tumors in 46 patients (10 female, 36 male, mean age 66 years) between June 2014 and February 2015. Thirty ablations were carried out with manual guidance, while 34 ablations were performed using robotic guidance. A 6-week follow-up (ultrasound, computed tomography and MRI) was performed on all patients. RESULTS: The total procedure time and dose-length product were significantly reduced under robotic guidance (18.3 vs. 21.7 min, [Formula: see text]; 2216 vs. 2881 mGy[Formula: see text]cm, [Formula: see text]). The position of the percutaneous needle was more accurate using robotic guidance (needle deviation 1.6 vs. 3.3 mm, [Formula: see text]). There was no significant difference between both groups regarding the complication rate and the ablation success. CONCLUSION: Robotic assistance for liver tumor ablation reduces patient dose and allows for fast positioning of the microwave applicator with high accuracy. The complication rate and ablation success of percutaneous microwave thermoablation of malignant liver tumors using either CT fluoroscopy or robotic guidance for needle positioning showed no significant differences in the 6-week follow-up.

[The challenge of acute kidney injury : Cross-sectional study on prevalence and costs in a university intensive care unit]. / Die Herausforderung akute Nierenschädigung : Querschnittsstudie zu Prävalenz und Kosten auf einer universitären Intensivstation.

BACKGROUND AND OBJECTIVES: The prognosis of intensive care patients with acute kidney injury (AKI), which is associated with increased mortality is still poor. Current data on the prevalence and the resulting costs of AKI and an overview of the most common diagnoses associated with AKI in German intensive care units (ICU) are lacking. PATIENTS AND METHODS: In this retrospective study all adult admissions (> 18 Jahre) in the five ICUs at the University Clinic Regensburg (in total 78 beds) from1 January 2011 to 31 December 2013 were evaluated. The ICU diagnoses commonly associated with AKI were identified using the international classification of diseases 10 (ICD 10). The length of ICU and hospital stays and AKI-associated hospital costs in the diagnosis-related groups (DRG) based reimbursement system were compared. RESULTS: A total of 891 ICU patients with AKI were classified according to the ICD 10 code. Acute respiratory distress syndrome (ARDS), myocardial infarction (MI) and sepsis were the three most common ICU conditions associated with AKI. A total of 1103 patients were admitted with 1 of these 3 main diagnoses and 249 (22.6 %) of these patients developed AKI. Patients with AKI had significantly longer mean ICU and hospital stays compared to patients without AKI (18.6 vs 5.1 days and 23.8 vs. 10.4 days, respectively, p < 0.001). The presence of AKI in critically ill patients with ARDS, MI and sepsis resulted in additional costs of 2,019,120.42 € at the University Hospital of Regensburg in 2013. CONCLUSION: Acute kidney injury in critically ill patients represents a significant medical and socioeconomic burden. Early recognition of patients at risk, coordinated research into novel interventions and establishment of the National Acute Kidney Injury Network for implementation of evidence-based therapies may be the next steps to decrease the incidence and severity of AKI and save costs for the national healthcare system.

[Anesthesia management in implantation of baroreceptor stimulators]. / Anästhesiologisches Management bei Implantation von Barorezeptorstimulatoren.

Baroreceptor stimulators are novel implantable devices that activate the carotid baroreceptor reflex. This results in a decrease in activity of the sympathetic nervous system and inhibition of the renin-angiotensin-aldosterone system. In patients with drug-resistant hypertension, permanent electrical activation of the baroreceptor reflex results in blood pressure reduction and cardiac remodeling. For correct intraoperative electrode placement at the carotid bifurcation, the baroreceptor reflex needs to be activated several times. Many common anesthetic agents, such as inhalation anesthetics and propofol dampen or inhibit the baroreceptor reflex and complicate or even prevent successful placement. Therefore, a specific anesthesia and pharmacological management is necessary to ensure successful implantation of baroreceptor reflex stimulators.

Effects of ropivacaine, bupivacaine and sufentanil in colon and pancreatic cancer cells in vitro.

The perioperative period is supposed to be a vulnerable period for cancer progression. Results of clinical studies indicate that the use of regional anesthesia can influence and improve oncological outcome of cancer patients. Uncontrolled cell proliferation and resistance to apoptotic cell death are important characteristics of solid tumors. The aim of this study was to investigate the effects of the clinically used local anesthetics ropivacaine or bupivacaine and the opioid analgesic sufentanil on cell proliferation, cell cycle distribution and apoptosis of colon (HT 29 and SW 480) and pancreatic (PaTu 8988t and PANC 1) cancer cell lines in vitro. Cell proliferation was measured by Cell Proliferation ELISA BrdU Assay. Apoptosis was analyzed by annexin V staining and cell cycle distribution was detected by flow cytometry. Ropivacaine, bupivacaine and sufentanil did not change apoptosis rate and cell cycle distribution in clinically concentration. Only high concentrations of ropivacaine or bupivacaine revealed antiproliferative potency. Protective effects of epidural anesthesia observed in clinical studies seem not to be based on direct effects of these drugs on cancer cells.

[Patients with implanted ventricular assist devices : Challenge for emergency medicine]. / Patienten mit implantierten Herzunterstützungssystemen : Herausforderung in der Notfallmedizin.

Due to a huge increase in the implantation of ventricular assist devices (VAD) over the last few years and the enormous technical advances in functional safety, a growing number of patients with VAD are discharged from hospital, who are still considered to be severely ill. This results in an increased probability of these patients interacting with emergency services where personnel are unaware of the presence of a VAD, creating anxiety and uncertainty regarding how to treat these patients. This article presents an overview of the most common problems and pitfalls regarding VADs. It also presents an algorithm for dealing with emergencies involving these patients including the diagnostics, treatment and primary transport.

[Simulation as possible training for palliative emergencies: prospective initial data analysis of participants from two simulation training sessions]. / Simulation als Möglichkeit zum Training palliativer Notfälle : Prospektive erste Datenanalyse von Teilnehmern zweier Simulationstrainings.

BACKGROUND: Palliative emergencies describe an acute situation in patients with a life-limiting illness. At present defined curricula for prehospital emergency physician training for palliative emergencies are limited. Simulation-based training (SBT) for such palliative emergency situations is an exception both nationally and internationally. AIM: This article presents the preparation of recommendations in the training and development of palliative care emergency situations. MATERIAL AND METHODS: A selected literature search was performed using PubMed, EMBASE, Medline and the Cochrane database (1990-2013). Reference lists of included articles were checked by two reviewers. Data of the included articles were extracted, evaluated und summarized. In the second phase the participants of two simulated scenarios of palliative emergencies were asked to complete an anonymous 15-item questionnaire. The results of the literature search and the questionnaire-based investigation were compared and recommendations were formulated based on the results. RESULTS: Altogether 30 eligible national and international articles were included. Overall, training curricula in palliative emergencies are currently being developed nationally and internationally but are not yet widely integrated into emergency medical training and education. In the second part of the investigation, 25 participants (9 male, 16 female, 20 physicians and 5 nurses) were included in 4 multiprofessional emergency medical simulation training sessions. The most important interests of the participants were the problems for training and further education concerning palliative emergencies described in the national and international literature. CONCLUSION: The literature review and the expectations of the participants underlined that the development and characteristics of palliative emergencies will become increasingly more important in outpatient emergency medicine. All participants considered palliative care to be very important concerning the competency for end-of-life decisions in palliative patients. For this reason, special curricula and simulation for dealing with palliative care patients and special treatment decisions in emergency situations seem to be necessary.

Factors of tidal volume variation during augmented spontaneous ventilation in patients on extracorporeal carbon dioxide removal. A multivariate analysis.

BACKGROUND: Extracorporeal carbon dioxide removal (ECCO2-R) allows lung protective ventilation using lower tidal volumes (VT) in patients with acute respiratory failure. The dynamics of spontaneous ventilation under ECCO2-R has not been described previously. This retrospective multivariable analysis examines VT patterns and investigates the factors that influence VT, in particular sweep gas flow and blood flow through the artificial membrane. METHODS: We assessed VT, respiratory rate (RR), minute ventilation (MV), and levels of pressure support (0-24 cm H2O), sweep gas flow (0-14 L/min) and blood flow through the membrane (0.8-1.8 L/min) in 40 patients from the moment they were allowed to breathe spontaneously. Modest hypercapnia was accepted. RESULTS: Patients tolerated moderate hypercapnia well. In a generalized linear model the increase in sweep gas flow (P<0.001), a low PaCO2 (P=0.029), and an increased breathing frequency (P<0.001) were associated with lower VT. Neither blood flow through the membrane (P=0.351) nor the level of pressure support (P=0.595) influenced VT size. CONCLUSION: Higher sweep gas flow is associated with low VT in patients on extracorporeal lung assist and augmented spontaneous ventilation. Such a technique can be used for prolonged lung protective ventilation even in the patient's recovery period.

[Assessment of the transplantation scandal by the media : scientific discourse analysis of selected German newspapers]. / Wertungen des "Transplantationsskandals" durch die Medien : Diskursanalytische Studie an ausgesuchten deutschen Zeitungen.

BACKGROUND: The press is an important medium and plays a significant role as an information source for people. Moreover, the daily press transmits opinion-forming contents. During the German "transplantation scandal" various articles were published in the German press focusing on organ donation, transplantation, allocation of organs and brain death determination. Selected important newspaper articles were analyzed using a scientific text analysis as it was assumed that the publications might have had an important influence on attitudes or mistrust of transplantation medicine. MATERIAL AND METHODS: A total of 216 articles from Süddeutsche Zeitung, Die Welt, Frankfurter Allgemeine Zeitung and Die Zeit published between summer 2012 and early 2013, which focused on the transplantation scandal were analyzed using a modern form of scientific text analysis. From these articles 12 categories of contents were identified which were analyzed quantitatively and qualitatively. RESULTS: Most articles were published between June and August 2012 when the accusations of organ allocation manipulation were made public. A second wave was found in the early months of 2013, when the court proceedings against the predominantly blamed physician began. Most of the categories (63.8 %) transmitted a negative evaluative opinion (i.e. loss of confidence, enrichment of the persons involved, fraud, misconduct, rejection of brain death and disturbing the peace of the dead) leading to mistrust of transplantation per se, while the minority (36.2 %) were categorized as endeavoring to convey objective information, focus on ethical responsibility for organ donation or the problems of organ shortage. Furthermore, a striking increase of articles doubting the concept of brain death was observed. CONCLUSION: German newspapers as important opinion-leading and opinion-forming media have a substantial impact in accomplishing the demands for objective and factual information of transplantation medicine. Physicians, ethicists, journalists and politicians are invoked to have a closer collaboration in the future.

[Malignant hyperthermia]. / Maligne Hyperthermie.

Malignant hyperthermia (MH) is a rare hereditary, mostly subclinical myopathy. Trigger substances, such as volatile anesthetic agents and the depolarizing muscle relaxant succinylcholine can induce a potentially fatal metabolic increase in predisposed patients caused by a dysregulation of the myoplasmic calcium (Ca) concentration. Mutations in the dihydropyridine ryanodine receptor complex in combination with the trigger substances are responsible for an uncontrolled release of Ca from the sarcoplasmic reticulum. This leads to activation of the contractile apparatus and a massive increase in cellular energy production. Exhaustion of the cellular energy reserves ultimately results in local muscle cell destruction and subsequent cardiovascular failure. The clinical picture of MH episodes is very variable. Early symptoms are hypoxia, hypercapnia and cardiac arrhythmia whereas the body temperature rise, after which MH is named, often occurs later. Decisive for the course of MH episodes is a timely targeted therapy. Following introduction of the hydantoin derivative dantrolene, the previously high mortality of fulminant MH episodes could be reduced to well under 10 %. An MH predisposition can be detected using the invasive in vitro contracture test (IVCT) or mutation analysis. Few elaborate diagnostic procedures are in the developmental stage.

[Interaction of anesthetics and analgesics with tumor cells]. / Interaktion von Anästhetika und Analgetika mit Tumorzellen.

The results of preclinical and clinical studies indicate that the perioperative period is a vulnerable period for cancer progression and metastasis. The risk of cancer cell dissemination is enhanced by the combination of surgical manipulation and perioperative immunosuppression. Whether the oncological outcome of cancer patients can be influenced by the choice of anesthetic techniques is still a matter of debate. This review summarizes the molecular characteristics of cancer and interaction of anesthetic and analgesic drugs with cancer cells.

Lipid emulsion pretreatment has different effects on mepivacaine and bupivacaine cardiac toxicity in an isolated rat heart model.

BACKGROUND: The use of lipid emulsions to reduce cardiac toxicity of local anaesthetics (LAs) has shown success in experimental studies and some clinical cases, and thus has been implemented in clinical practice. However, lipid treatment is usually given after the occurrence of neurological or cardiovascular symptoms of systemic intoxication. The aim of this study was to determine if pretreatment with lipid emulsion reduces cardiac toxicity produced by bupivacaine or mepivacaine. METHODS: Isolated rat hearts were perfused with or without lipid emulsion (0.25 ml kg(-1) min(-1)) before administration of equipotent doses of bupivacaine (250 µM) or mepivacaine (1000 µM). Haemodynamic parameters and times from start of perfusion LA to a 1 min period of asystole and recovery were determined. RESULTS: Pretreatment with lipid emulsion extended the time until occurrence of asystole and decreased times to recovery in bupivacaine-induced cardiac toxicity but not in mepivacaine-induced cardiac toxicity compared with control. Lipid pretreatment impaired rate-pressure product recovery in mepivacaine-intoxicated hearts. CONCLUSIONS: This study confirms that pretreatment with a lipid emulsion reduces cardiac toxicity of LAs. The efficacy of pretreatment with lipid emulsion was LA-dependent, so pharmacokinetic properties, such as lipophilicity, might influence the effects of lipid emulsion pretreatment.

Thromboelastometric detection of clotting Factor XIII deficiency in cardiac surgery patients.

AIM(S): In this article, we aimed to investigate plasma Factor XIII levels after extracorporeal circulation in cardiac surgery by thromboelastometric detection, as extracorporeal circulation causes various coagulation disorders due to the exposure of blood to artificial surfaces, inflammatory induction and mechanical destruction of platelets and coagulation factors, which may particularly affect factors with long half-lives, such as Factor XIII. BACKGROUND: Since transfusion algorithms are often empirical and laboratory analysis of Factor XIII plasma levels may not be available 24 h a day, bed-side testing using rotational thromboelastometry (ROTEM) could offer a splendid option to define the cause of excessive peri-operative bleeding disorders in general and Factor XIII levels in particular in a timely manner and thus facilitating exact substitution therapy. METHODS: In this trial, we investigated 25 cardiac surgery patients with extracorporeal bypass times over 100 min. Standard laboratory and ROTEM analyses were performed post-operatively at the time of intensive care unit admission and 6 h later. We implemented EXTEM with additional Factor XIII (teenTEM) as additional test by adding 0·625 IU Factor XIII to standard EXTEM reagents. RESULTS: In this observational study, we could not demonstrate a correlation between Factor XIII and MCFEXTEM , CFTEXTEM or MLEXTEM . Neither Factor XIII plasma levels nor MCFEXTEM could predict blood loss. In accordance with previous findings, we were able to demonstrate increased maximum clot firmness (MCF), decreased clot formation time and decreased maximum lysis by adding Factor XIII in vitro (teenTEM vs EXTEM) indicating an improvement in the coagulation process. As shown before, we also found a strong correlation between MCF and platelet and fibrinogen plasma levels. CONCLUSION: In summary, 'teenTEM' test does not seem to detect Factor XIII deficient patients in cardiac surgery. Furthermore, post-operative blood loss could not be predicted neither by ROTEM nor by laboratory analysis of Factor XIII. In vitro administration of Factor XIII appears to improve laboratory measures of haemostasis.

[Perioperative care of palliative patients by the anesthetist : medical, psychosocial and ethical challenges]. / Perioperative Betreuung von Palliativpatienten durch den Anästhesisten : Medizinische, psychosoziale und ethische Herausforderungen.

Anesthetists will encounter palliative patients in the daily routine as palliative patients undergo operations and interventions as well, depending on the state of the disease. The first challenge for anesthetists will be to recognize the patient as being palliative. In the course of further treatment it will be necessary to address the specific problems of this patient group. Medical problems are optimized symptom control and the patient's pre-existing medication. In the psychosocial domain, good communication skills are expected of anesthetists, especially during the preoperative interview. Ethical conflicts exist with the decision-making process for surgery and the handling of perioperative do-not-resuscitate orders. This article addresses these areas of conflict and the aim is to enable anesthetists to provide the best possible perioperative care to this vulnerable patient group with the goal to maintain quality of life and keep postoperative recovery as short as possible.

[Peripheral regional anesthesia in patients under general anesthesia: risk assessment with respect to parasthesia, injection pain and nerve damage]. / Periphere Regionalanästhesie beim Patienten in Allgemeinanästhesie : Risikobewertung bezüglich Parästhesie, Injektionsschmerz und Nervenschäden.

Nerve injury after peripheral regional anesthesia is rare and is not usually permanent. Some authors believe that inducing peripheral nerve blocks in patients during general anesthesia or analgosedation adds an additional risk factor for neuronal damage. This is based on published case reports showing that there is a positive correlation between paresthesia experienced during regional anesthesia and subsequent nerve injury. Therefore, many sources recommend that regional nerve blocks should only be performed in awake or lightly sedated patients, at least in adults. However, there is no scientific basis for this recommendation. Furthermore, there is no proof that regional anesthesia performed in patients under general anesthesia or deep sedation bears a greater risk than in awake or lightly sedated patients. Currently anesthesiologists are free to follow personal preferences in this matter as there is no good evidence favoring one approach over the other. The risk of systemic toxicity of local anesthetic agents is not higher in patients who receive regional anesthesia under general anesthesia or deep sedation. Finally, in children and uncooperative adults the administration of peripheral nerve blocks under general anesthesia or deep sedation is widely accepted.