A model to predict difficult airway alerts after videolaryngoscopy in adults with anticipated difficult airways - the VIDIAC score.

A model to classify the difficulty of videolaryngoscopic tracheal intubation has yet to be established. The videolaryngoscopic intubation and difficult airway classification (VIDIAC) study aimed to develop one based on variables associated with difficult videolaryngoscopic tracheal intubation. We studied 374 videolaryngoscopic tracheal intubations in 320 adults scheduled for ear, nose and throat or oral and maxillofacial surgery, for whom airway management was expected to be difficult. The primary outcome was whether an anaesthetist issued a 'difficult airway alert' after videolaryngoscopy. An alert was issued after 183 (49%) intubations. Random forest and lasso regression analysis selected six intubation-related variables associated with issuing an alert: impaired epiglottic movement; increased lifting force; direct epiglottic lifting; vocal cords clearly visible; vocal cords not visible; and enlarged arytenoids. Internal validation was performed by a 10-fold cross-validation, repeated 20 times. The mean (SD or 95%CI) area under the receiver operating characteristic curve was 0.92 (0.05) for the cross validated coefficient model and 0.92 (0.89-0.95) for a simplified unitary score (VIDIAC score with component values of -1 or 1 only). The calibration belt for the coefficient model was consistent with observed alert probabilities, from 0% to 100%, while the unitary VIDIAC score overestimated probabilities < 20% and underestimated probabilities > 70%. Discrimination of the VIDIAC score for patients more or less likely to be issued an alert was better than discrimination by the Cormack-Lehane classification, with mean (95%CI) areas under the receiver operating characteristic curve of 0.92 (0.89-0.95) vs. 0.75 (0.70-0.80), respectively, p < 0.001. Our model and score can be used to calculate the probabilities of difficult airway alerts after videolaryngoscopy.

Validation of a mobile app for reducing errors of administration of medications in an emergency.

Medication errors occur frequently and are a risk to patient safety. To reduce mistakes in the medication process in emergencies, a mobile app has been developed supporting the calculation of doses and administration of drugs. A simulation study was performed to validate the app as a tool to reduce medication errors. This was a randomised crossover study conducted in the Academic Hospital. The participants included were residents and attendings in anaesthesiology. 74 Participants performed four simulation scenarios in which they had to calculate and administer drugs for emergencies. Two scenarios were performed with the app ("app scenarios") and the other two scenarios were performed without the use of the app ("control scenarios"). The order of drugs, simulation patients and usage of aid were randomized. The accuracy of administered drug doses were measured. Medications were categorised as either "accurate" ([Formula: see text]% of target dosage) or "wrong" (less than 50% or more than 200% of target dosage). The dosage calculated and the dosage administered were documented separately to differentiate between calculation and handling errors. During app scenarios, there were no "wrong" dosages, whereas 6.8 (95% CI 2.7-10.8%) of dosages in control scenarios were evaluated as "wrong". The probability of giving an "accurate" dosage was increased from 77.7 (70.9-84.5%) in control scenarios to 93.9 (90-97.8%) in app scenarios. Calculation errors were the main cause for wrong dosing. The app is an appropriate and feasible tool to reduce calculation and handling errors and may increase patient safety.

[Psychological factors in the context of perioperative knee and joint pain: the role of treatment expectations in pain evolvement]. / Psychologische Faktoren im Kontext perioperativer Knie- und Gelenkschmerzen: die Rolle der Behandlungserwartungen für den Schmerzverlauf.

Chronic knee and joint pain, like all chronic pain, is a complex multidimensional event that involves somatic, psychological and social factors. Patients with knee and other joint pain experience limited mobility in their daily lives, in their professional and personal activities, and in their leisure physical exercise activities. Pain increasingly prevents them from achieving their goals. Psychological factors not only interact with neurobiological and immunological processes of pain, they play an important role in the development and maintenance of pain. Within that, expectations concerning the course of the disease and its treatment play a significant role. Study designs involving a placebo knee surgery show the high influence of these variables. The patients receiving the verum surgery do not report-as expected-less pain or better functioning than those receiving a placebo surgery. This significant influence of psychological factors may be clinically relevant. A positive patient-staff relationship-characterized by trust, warmth and empathy-is essential in order to achieve optimal therapeutic efficacy of a treatment. Every surgeon, pain physician, pain psychologist or pain physiotherapist is responsible for establishing a trusting interpersonal relationship between themselves and their patients.

[Analysis of the personnel development in anesthesiology over the last two decades with special attention to gender aspects]. / Eine Analyse der Personalentwicklung in der Anästhesiologie unter besonderer Berücksichtigung von Gender-Aspekten.

Skills shortage of nursing staff and physicians is a "hot topic" in health politics. For the future recruitment of medical staff in anesthesiology, an analysis of the staff development during the last decades considering gender aspects seems to be important. Therefore, the authors conducted a comparative analysis of data from the "Statistisches Bundesamt" (Fachserie 12 Reihe 7.3.1 and Fachserie 12 Reihe 6.1.1.) from 1994 until 2015. The analysis compared the development of anesthesiological staff (physicians) with the overall development of medical staff (physicians) in respect of the number of residents, consultants and department chairs. There are two major differences between the development of medical staff in anesthesiology and the overall development of medical staff: (1) in anesthesiology there is a high percentage of consultants without management tasks, (2) though the percentage of female colleagues is increasing both in anesthesiology and overall, the percentage of female colleagues in management or chair positions is lower in anesthesiology compared to the other disciplines, altogether. Anesthesiology is a discipline in which both the number of tasks and personnel have risen over the last two decades. The comparatively huge increase in the number of residents and consultants without management tasks suggests that the number of tasks in daily routine has substantially increased for anesthesiologists. The comparatively low percentage of female colleagues in chair positions should give an impulse to improve the compatibility of family and working live both for clinical and scientific careers.

[Patient endangerment due to device diversity? : Discussion of a risk factor based on the results of two surveys of German hospitals]. / Patientengefährdung durch Gerätediversität? : Diskussion eines Risikofaktors anhand der Ergebnisse zweier Befragungen an deutschen Kliniken.

BACKGROUND: The Federal Institute for Drugs and Medical Devices (BfArM) was notified of an event in which it was not possible to sufficiently ventilate a patient suffering a severe asthma attack. It turned out that the ventilation pressures used by the device for pressure-controlled ventilation were below the values set by the user, which the user was not aware of. The ventilation pressures chosen by the user exceeded the preset alarm limits of the ventilator. This pressure and alarm management significantly differed from that of other ventilators used in the hospital. This and similar incident reports suggest that safely operating medical devices for anesthesia and intensive care may be impaired when different models of a device are used within a hospital. If different models are used, more device information needs to be stored in memory. Existing knowledge on human memory suggests that the more individual memory items (e. g. different operating rules) are stored, the greater the risk of memory interference and hence of impaired retrieval, particularly if the different items are associated with overlapping retrieval cues. This is the case when different devices are used for a single functional purpose under identical or similar circumstances. OBJECTIVE: Based on individual incident reports and theoretical knowledge on an association between device diversity and use problems, this study aimed to determine the organizational conditions regarding device diversity that prevail in German hospitals. Additionally, the anesthetists' perspectives and experiences in defined clinical settings were investigated. METHODS: For selected groups of medical devices, the biomedical engineers of German hospitals were surveyed about the different makes used in their hospital. Additionally, questionnaires were sent to a department of anesthesiology of a large University Hospital to investigate the personal experiences of working with different makes and models of a device. RESULTS: Using devices by different manufacturers was particularly frequent for ventilators, but there were also a considerable number of hospitals with syringe pumps and patient monitoring systems from different manufacturers. Almost all participants stated that they work or have worked with different models of a device. The majority of respondents had encountered problems or errors, which they ascribed to the requirement to learn a different method of operation for each device; however, they also listed various benefits, for instance the possibility to optimally address the requirements of specific situations or patient groups. Both biomedical engineers and anesthetists suggested a homogeneous device pool within the hospital and regular and repeated training sessions for each device model used. DISCUSSION: Using different device models for anesthesia and intensive care seems to be common in many German hospitals, particularly for ventilators. An association between device diversity and problems operating a device is plausible, given the functioning of human memory. This topic should be investigated by future studies in order to identify factors that may contribute to such problems and possible solutions for clinical settings. Likewise, the potential benefits of having different device models at one's disposal should be evaluated. To pinpoint the measures that will be most effective given the specific settings of the individual hospital, all underlying clinical and economic considerations must be carefully balanced against the associated potential risks.

Electromagnetic organ tracking allows for real-time compensation of tissue shift in image-guided laparoscopic rectal surgery: results of a phantom study.

BACKGROUND: Laparoscopic resection is a minimally invasive treatment option for rectal cancer but requires highly experienced surgeons. Computer-aided technologies could help to improve safety and efficiency by visualizing risk structures during the procedure. The prerequisite for such an image guidance system is reliable intraoperative information on iatrogenic tissue shift. This could be achieved by intraoperative imaging, which is rarely available. Thus, the aim of the present study was to develop and validate a method for real-time deformation compensation using preoperative imaging and intraoperative electromagnetic tracking (EMT) of the rectum. METHODS: Three models were compared and evaluated for the compensation of tissue deformation. For model A, no compensation was performed. Model B moved the corresponding points rigidly to the motion of the EMT sensor. Model C used five nested linear regressions with increasing level of complexity to compute the deformation (C1-C5). For evaluation, 14 targets and an EMT organ sensor were fit into a silicone-molded rectum of the OpenHELP phantom. Following a computed tomography, the image guidance was initiated and the rectum was deformed in the same way as during surgery in a total of 14 experimental runs. The target registration error (TRE) was measured for all targets in different positions of the rectum. RESULTS: The mean TRE without correction (model A) was 32.8 ± 20.8 mm, with only 19.6% of the measurements below 10 mm (80.4% above 10 mm). With correction, the mean TRE could be reduced using the rigid correction (model B) to 6.8 ± 4.8 mm with 78.7% of the measurements being <10 mm. Using the most complex linear regression correction (model C5), the error could be reduced to 2.9 ± 1.4 mm with 99.8% being below 10 mm. CONCLUSION: In laparoscopic rectal surgery, the combination of electromagnetic organ tracking and preoperative imaging is a promising approach to compensating for intraoperative tissue shift in real-time.

[Simulation-based training in anesthesia and emergency medicine: preparation for the unexpected: on the way to new standards of education in Germany]. / Simulationsbasiertes Training - Für den Notfall vorbereitet sein in Anästhesie und Notfallmedizin : Auf dem Weg zu neuen Standards der Ausbildung in Deutschland.

Medical expertise consists of knowledge, professional skills and individual attitudes. Training and education of this expertise starts in medical school and develops throughout the qualification process of anesthesists and emergency physicians. Medical decisions are not only rational but also intuitive. The combination of these characteristics cannot and should not be trained on patients. The implementation of modern simulation techniques offers the opportunity to train for emergency situations similar to training systems in the energy industry and aviation. Repetitive training of rare emergency situations brings routine to seldomly used procedures. In simulation training mistakes can be detected and systematically corrected. The team interactions and soft skills can also be focussed on. Video analysis gives the participant the opportunity for self-reflection and can lead to correction of individual behavior patterns. This dimension of education cannot be done in real patient care. This training goes far beyond the level of skills training. Through simulation training involves the whole team, the communication and the interaction between the team members in medically challenging situations. Crisis resource management leads to measurable improvements in patient safety and safety culture as well as personnel satisfaction.

[Uvular edema. Rare complication in anesthesia]. / Uvula-Ödem. Seltene anästhesiologische Komplikation.

A uvular edema can be associated with angioedema, urticaria and anaphylaxis. Furthermore, it can be caused by medications, such as angiotensin-converting enzyme (ACE) inhibitors, non-steroidal anti-inflammatory drugs and angiotensin II receptor antagonists. Other reasons can be cannabis or cocaine use or a traumatic irritation of the uvula. This article presents the case of a patient who underwent kidney transplantation and developed extensive edema of the uvula that occurred postoperatively after general anaesthesia. The case report describes the diagnosis and therapy of this rare disease.

[Pharmacogenetics. Clinical relevance in anesthsiology]. / Pharmakogenetik. Klinische Bedeutung in der Anästhesiologie.

BACKGROUND: Pharmacogenetics deals with hereditary factors which influence the pharmacodynamics and pharmacokinetics of drugs leading to individual diverse reactions. Also in anesthesiology differences in the pharmacogenetics of patients can lead to relevant alterations in the pharmacodynamics of drugs. AIM: This article provides a summary of polymorphisms relevant to commonly used anesthetic agents and the clinical relevance in patients treated with these compounds. It describes the possibilities, the problems and limits of pharmacogenetic diagnostics and therapy and explains how this follows the target of individualized medicine. MATERIAL AND METHODS: This article describes in detail the alterations in pharmacodynamics and pharmakokinetics relevant for anesthesia and their clinical significance. Based on the results of current studies, an overview of the most important drugs in anesthesiology with significant polymorphisms is given. These include opioids, muscle relaxants, volatile anesthetic agents, non-steroidal anti-inflammatory drugs (NSAIDs), benzodiazepines, antiemetics and cardiovascular drugs as well as platelet aggregation inhibitors, anticoagulants and the so-called new oral anticoagulants. RESULTS: Genetic alterations can lead to substantial modifications in the effectiveness of drugs. Genetic alterations of opioid receptors and the enzyme cytochrome P450 (CYP) 2D6 can result in a failure of analgesia after administration of opioids. Alterations in plasma cholinesterase activity are associated with a prolonged effectiveness of muscle relaxants. Polymorphisms in ryanodine receptors can contribute to the development of the feared MH in patients after administration of volatile anesthetics or succinylcholine. CONCLUSION: The study results presented here emphasize that these days knowledge on pharmacogenetics should not be missing in modern induction of anesthesia. In the future a blood sample could enable physicians to identify pharmacologically relevant markers. And these could guide the decision on the prescription of drugs and their appropriate dose, in order to achieve the lowest risk of side effects and the highest effectiveness of the active substance.

Engineering new limits to magnetostriction through metastability in iron-gallium alloys.

Magnetostrictive materials transduce magnetic and mechanical energies and when combined with piezoelectric elements, evoke magnetoelectric transduction for high-sensitivity magnetic field sensors and energy-efficient beyond-CMOS technologies. The dearth of ductile, rare-earth-free materials with high magnetostrictive coefficients motivates the discovery of superior materials. Fe1-xGax alloys are amongst the highest performing rare-earth-free magnetostrictive materials; however, magnetostriction becomes sharply suppressed beyond x = 19% due to the formation of a parasitic ordered intermetallic phase. Here, we harness epitaxy to extend the stability of the BCC Fe1-xGax alloy to gallium compositions as high as x = 30% and in so doing dramatically boost the magnetostriction by as much as 10x relative to the bulk and 2x larger than canonical rare-earth based magnetostrictors. A Fe1-xGax - [Pb(Mg1/3Nb2/3)O3]0.7-[PbTiO3]0.3 (PMN-PT) composite magnetoelectric shows robust 90° electrical switching of magnetic anisotropy and a converse magnetoelectric coefficient of 2.0 × 10-5 s m-1. When optimally scaled, this high coefficient implies stable switching at ~80 aJ per bit.

[Do opioids induce hyperalgesia?]. / Induzieren Opioide Hyperalgesie?

Opioids are the most potent drugs for treatment of acute and chronic pain. However, accumulating evidence suggests that opioids may paradoxically also enhance pain, often referred to as opioid-induced hyperalgesia. Opioid-induced hyperalgesia is defined as an increased sensitivity to pain or a decreased pain threshold in response to opioid therapy. Several mechanisms have been proposed to support opioid-induced hyperalgesia. However, it remains unclear whether opioid-induced hyperalgesia develops during continuous chronic application of opioids or on their withdrawal. This review provides a comprehensive summary of clinical research concerning opioid-induced hyperalgesia and the molecular mechanisms of opioid withdrawal and opioid tolerance and other potential mechanisms which might induce hyperalgesia during opioid therapy will be discussed. The status quo of our knowledge will be summarized and the clinical relevance of opioid-induced hyperalgesia will be discussed.

[Perioperative fluid management]. / Perioperatives Volumenmanagement.

An appropriate perioperative infusion management is pivotal for the perioperative outcome of the patient. Optimization of the perioperative fluid treatment often results in enhanced postoperative outcome, reduced perioperative complications and shortened hospitalization. Hypovolemia as well as hypervolemia can lead to an increased rate of perioperative complications. The main goal is to maintain perioperative euvolemia by goal-directed therapy (GDT), a combination of fluid management and inotropic medication, to optimize perfusion conditions in the perioperative period; however, perioperative fluid management should also include the preoperative and postoperative periods. This encompasses the preoperative administration of carbohydrate-rich drinks up to 2 h before surgery. In the postoperative period, patients should be encouraged to start per os hydration early and excessive i.v. fluid administration should be avoided. Implementation of a comprehensive multimodal, goal-directed fluid management within an enhanced recovery after surgery (ERAS) protocol is efficient but the exact status of indovodual items remains unclear at present.

Opioids.

Opioids are the most effective and widely used drugs in the treatment of severe pain. They act through G protein-coupled receptors. Four families of endogenous ligands (opioid peptides) are known. The standard exogenous opioid analgesic is morphine. Opioid agonists can activate central and peripheral opioid receptors. Three classes of opioid receptors (mu, delta, kappa) have been identified. Multiple pathways ofopioid receptor signaling (e.g., G(i/o) coupling, cAMP inhibition, Ca++ channel inhibition) have been described. The differential regulation of effectors, preclinical pharmacology, clinical applications, and side effects will be reviewed in this chapter.

Rapid upregulation of mu opioid receptor mRNA in dorsal root ganglia in response to peripheral inflammation depends on neuronal conduction.

S.c. painful inflammation leads to an increase in axonal transport of opioid receptors from dorsal root ganglia (DRG) toward the periphery, thus causing a higher receptor density and enhanced opioid analgesia at the injured site. To examine whether this increase is related to transcription, the mRNA of Delta- (DOR) and mu-opioid receptor (MOR) in lumbar DRG was quantified by real time Light Cycler polymerase chain reaction (LC-PCR), and correlated to ligand binding in DRG and sciatic nerve. In normal DRG, DOR mRNA was seven times less abundantly expressed than MOR mRNA. After induction of unilateral paw inflammation, mRNA content for DOR remained unchanged, but a bi-phasic upregulation for MOR mRNA with an early peak at 1-2 h and a late increase at 96 h was found in ipsilateral DRG. As no changes were observed in DRG of the non-inflamed side, this effect was apparently not systemically mediated. A significant increase in binding of the MOR ligand DAMGO was detected after 24 h in DRG, and after early and late ligation in the sciatic nerve, indicating an enhanced axonal transport of MOR in response to inflammation. The early increase in MOR mRNA could be completely prevented by local anesthetic blockade of neuronal conduction in sciatic nerve. These data suggest that mRNA of the two opioid receptors DOR and MOR is differentially regulated in DRG during peripheral painful inflammation. The apparently increased axonal transport of MOR in response to this inflammation is preceded by upregulated mRNA-transcription, which is dependent on neuronal electrical activity.

Control of mu opioid receptor expression by modification of cDNA 5'- and 3'-noncoding regions.

Removal of a 712 base pair (bp) sequence following the coding region of a human micro opioid receptor (hmuOR) cDNA unexpectedly increased expression of the receptor protein. A series of 3'-noncoding region deletion mutants revealed that at least three discrete regions following the stop codon influenced receptor expression levels. Deletion of the 205-bp 5'-noncoding region immediately preceding the Kozak sequence doubled receptor expression relative to wild type, and simultaneous deletion of 5'- and 3'-noncoding regions increased expression several fold. The hmuOR noncoding regions may participate in a regulatory mechanism that controls the number of cell surface receptors.

Mutation of human mu opioid receptor extracellular "disulfide cysteine" residues alters ligand binding but does not prevent receptor targeting to the cell plasma membrane.

The mu opioid receptor, a primary site of action in the brain for opioid neuropeptides and opiate drugs of abuse, is a member of the seven transmembrane, G protein-coupled receptor (GPCR) superfamily. Two cysteine residues, one in each of the first two of three extracellular loops (ECLs), are highly conserved among GPCRs, and there is direct or circumstantial evidence that the residues form a disulfide bond in many of these receptors. Such a bond would dramatically govern the topology of the ECLs, and possibly affect the position of the membrane-spanning domains. Recent findings from several laboratories indicate the importance of the ECLs for opioid ligand selectivity. These conserved cysteine residues in the mu opioid receptor were studied using site-directed mutagenesis. Little or no specific binding of radiolabled opiate alkaloid or opioid peptide agonists or antagonists was observed for receptors mutated at either "disulfide cysteine" residue. Each mutant mu opioid receptor was expressed in both transiently- and stably-transfected cells, in some cases at levels comparable to the wild type receptor. The two point mutants possessing serine-for-cysteine substitutions were also observed to successfully reach the cell plasma membrane, as evidenced by electron microscopy. Consistent with related work with other GPCRs, the mu opioid receptor apparently also employs the extracellular disulfide bond. This information now permits accurate molecular modeling of extracellular aspects of the receptor, including plausible scenarios of mu receptor docking of opioid ligands known to require specific extracellular loop features for high affinity binding.

Interposed cartilage as a precaution against extrusions of ceramic ossicular replacement implants.

Since 1980 we have used middle ear implants of aluminum oxide ceramic in some reconstructions of the ossicular chain. We had opportunities to examine 108 ears (91 patients); the longest period of postoperative observation was 4 years. Follow-up examinations showed that the rates of extrusion and liability to extrusion can be reduced by interposing a small disk of autologous cartilage and perichondrium. Moreover, interposing cartilage trends to improve audiometric results. On the basis of our study, we strongly recommend the interposition of a disk of autologous cartilage and perichondrium between the middle ear implant and eardrum when an Al2O3 implant is used.

[Opioids in anesthesia]. / Opioide in der Anästhesie.

Opioids are the most effective and widely used drugs in the treatment of severe acute and chronic pain. They act through opioid receptors that belong to the family of G protein-coupled receptors. Three classes of opioid receptors (mu, delta, kappa), expressed in the central and peripheral nervous system, have been identified. The analgesic effect of opioids is mediated through multiple pathways of opioid receptor signaling (e.g., G(i/o) coupling, cAMP inhibition, Ca(++) channel inhibition). The standard exogenous opioid analgesics used in the operating room are fentanyl, sufentanil, morphine, alfentanil, and remifentanil. Preclinical pharmacology, clinical applications, and side effects will be reviewed in this chapter.

[Remifentanil-based intraoperative anaesthesia and postoperative pain therapy. Is there an optimal treatment strategy?]. / Intraoperative Remifentanilgabe und postoperative Schmerztherapie. Gibt es ein optimales Vorgehen?

Remifentanil is a synthetic opioid derivate with an agonist activity at mu-opioid receptors. The pharmacokinetic profile differs from other synthetic opioids. Remifentanil is rapidly metabolised by unspecific blood and tissue esterases and the metabolites have almost no intrinsic activity. According to its unique pharmacokinetic profile, remifentanil-based anaesthesia might be associated with a high level of postoperative pain, therefore, an appropriate postoperative pain management is an import aspect. In addition, remifentanil withdrawal induces a compensatory up-regulation of secondary messenger pathways, inducing hyperalgesia. This review provides a comprehensive summary of basic and clinical research concerning the intraoperative use of remifentanil and postoperative pain therapy. The relative contribution of rapid degradation and withdrawal-induced hyperalgesia to postoperative pain will be discussed. In addition, this review attempts to identify potential clinical implications and treatment strategies.