Ultrasound-guided approach to nerves (direct vs. tangential) and the incidence of intraneural injection: a cadaveric study.

This study evaluated the incidence of nerve puncture and intraneural injection based on the needle approach to the nerve (direct vs. tangential). Two expert operators in regional anaesthesia performed in-plane ultrasound-guided nerve blocks (n = 158) at different levels of the brachial plexus in cadavers, aiming either directly for the nerve (n = 77) or tangentially inferior to the nerve (n = 81). After reaching the outer limit of the nerve, the needle was intentionally advanced approximately 1 mm in both approaches, and 0.2-0.5 ml of saline was injected. Each operator classified (in real time) the needle tip and injectate as intraneural or not. Video clips showing the final position of the needle and the injection were evaluated in the same manner by seven independent expert observers who were blinded to the aims of this study. In addition, 20 injections were performed with ink for histological evaluation. Intraneural injections of saline were observed by the operator in 58% (45/77) of cases using the direct approach and 12% (10/81) of cases using the tangential approach (p < 0.001). The independent observers agreed with the operator in a substantial number of cases (Cohen's kappa index 0.65). Histological studies showed intraneural spread in 83% (5/6) of cases using the direct approach and in 14% (2/14) of cases using the tangential approach (p = 0.007). No intrafascicular injections were observed. There was good agreement between the operators' assessment and subsequent histological evaluation (Cohen's kappa = 0.89). Simulation of an unintentional/accidental advancement of the needle 'beyond the edge' of the nerve suggests significantly increased risk of epineural perforation and intraneural injection when a direct approach to the nerve is used, compared with a tangential approach.

Saved by focused echo evaluation in resuscitation.

A 74-year-old woman received thrombolysis for pericarditis. She subsequently developed shock and cardiac arrest. The case report describes the events of how a simple immediate bedside focused echo proved to be a life saving assessment. Current availability and training issues in focused transthoracic echo are discussed.

Ultrasound in regional anaesthesia.

Ultrasound guidance is rapidly becoming the gold standard for regional anaesthesia. There is an ever growing weight of evidence, matched with improving technology, to show that the use of ultrasound has significant benefits over conventional techniques, such as nerve stimulation and loss of resistance. The improved safety and efficacy that ultrasound brings to regional anaesthesia will help promote its use and realise the benefits that regional anaesthesia has over general anaesthesia, such as decreased morbidity and mortality, superior postoperative analgesia, cost-effectiveness, decreased postoperative complications and an improved postoperative course. In this review we consider the evidence behind the improved safety and efficacy of ultrasound-guided regional anaesthesia, before discussing its use in pain medicine, paediatrics and in the facilitation of neuraxial blockade. The Achilles' heel of ultrasound-guided regional anaesthesia is that anaesthetists are far more familiar with providing general anaesthesia, which in most cases requires skills that are achieved faster and more reliably. To this ends we go on to provide practical advice on ultrasound-guided techniques and the introduction of ultrasound into a department.

Astronomy. ASASSN-15lh: A highly super-luminous supernova.

We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu ,AB = -23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 10(45) ergs s(-1), which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ -25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 10(52) ergs, challenging the magnetar model for its engine.

Clinical pharmacokinetics of ropinirole.

Ropinirole is a selective non-ergoline dopamine D2 receptor agonist indicated for use in treating Parkinson's disease. When taken as oral tablets, ropinirole is rapidly and almost completely absorbed, and it is extensively distributed from the vascular compartment. The bioavailability is approximately 50%. Ropinirole shows low plasma protein binding. The drug is inactivated by metabolism in the liver, and none of the major circulating metabolites have pharmacological activity. The principal metabolic enzyme is the cytochrome P450 (CYP) isoenzyme CYP1A2. Ropinirole shows approximately linear pharmacokinetics when given as single or repeated doses, and is eliminated with a half-life of approximately 6 hours. Population pharmacokinetics have demonstrated that gender, mild or moderate renal impairment, Parkinson's disease stage and concomitant illnesses or the use of several common concomitant medications have no effect on the pharmacokinetics of ropinirole. Clearance is slower for patients older than 65 years compared with those who are younger, and in women taking hormone replacement therapy compared with those who are not. The CYP1A2 inhibitor ciprofloxacin produced increases in the plasma concentrations of ropinirole when these 2 drugs were coadministered, but no interaction was seen with theophylline which, like ropinirole, is also a substrate for CYP1A2. There is no obvious plasma concentration-effect relationship for ropinirole.

The playground maze: a new method for measuring directed exploration in the rat.

A new test, called the 'playground maze', is described. Rat exploratory responses to a single novel object are measured in the context of responses to 7 familiar objects in a familiar environment. Responses are measured as time spent in areas around the objects on a circular open field. These times are expressed as percentages of the total time spent exploring all the objects and a value which is significantly greater than the expected chance level (12.5%) indicates a novelty response. The paths traversed by the animals on the maze are also recorded and the lengths of these give a measure of locomotion. Preliminary experiments on the effects of chlordiazepoxide (CDP) (1-5 mg/kg) and amphetamine (1.5-4 mg/kg) are reported. CDP significantly increased the novelty response but had no effect on locomotion. Amphetamine treatment at 4 mg/kg abolished the response to novel objects while lower doses (1.5 and 2 mg/kg) did not affect it. All 3 doses of amphetamine significantly increased locomotion. This test provides a new way of measuring the exploratory response to novelty under low stress conditions and allows the separation of drug effects on directed exploration and locomotion.

The effect of experimental epilepsy induced by injection of tetanus toxin into the amygdala of the rat on eating behaviour and response to novelty.

A minute dose of tetanus toxin injected into the amygdala of rats produced an apparently reversible epileptiform syndrome similar to that previously described after injection of the toxin into the hippocampus. During the active epilepsy the toxin-injected rats occasionally exhibited 'paroxysmal eating' and also sometimes ran round in circles attempting to bite their own tails. When presented with a novel but palatable food (chocolate buttons or harvest crunch) the toxin-injected rats showed less neophobia than their controls--they ate sooner and ate more. This was found both during the active epilepsy and several weeks later when they had recovered. A similar effect of amygdala injections was found in a second experiment, in which the effect was compared with that of toxin injection in the hippocampus. These rats were tested also on the playground maze on their approach response to a neutral novel object (in a familiar environment in the context of seven familiar objects). The amygdala rats did not show any increase in their novelty response; thus their reduction in neophobia was specific to an appetitive behaviour. In contrast, the hippocampally-injected rats did not exhibit a novelty response in the playground maze, but showed normal neophobia to a new food.

The effect of Ro 15-4513, an inverse agonist at the benzodiazepine receptor, on the exploratory response to novelty in the playground maze.

The effects of chlordiazepoxide and the inverse agonist, Ro 15-4513, were compared on the exploratory response of rats to a novel object introduced into a familiar environment containing seven familiar objects. While chlordiazepoxide (5 mg/kg) increased the novelty response, Ro 15-4513 reduced the response in a dose-dependent manner (0.5-5.0 mg/kg). This action was specific to novelty since the response to the familiar objects was unaffected. Both drugs produced some reduction in ambulation. The effects of both drugs were blocked by flumazenil (10 mg/kg), which at this dose did not itself have any intrinsic effect on the response. Muscimol (0.001 mg/kg) had a weak chlordiazepoxide-like effect and baclofen (3 mg/kg) had a weak effect in the opposite direction.

Cerebral cuterebrosis in a dog.

A second instar Cuterebra larva was found in the thickened meninges of a 6-week-old female Doberman Pinscher at necropsy. The dog appeared blind and had chewing fits before death. Cerebral cuterebrosis in the dog is uncommon. This report briefly discusses the pathogenesis of the condition.

Anesthesia for trauma.

Trauma is the leading cause of death for persons aged 1 to 38 years. Successful management is facilitated by prehospital endotracheal intubation, transport to regional trauma centers, rapid resuscitation by an on-site team of trained physicians, timely operative intervention, and provision of care by well-prepared anesthesiologists familiar with the potential complications typical of traumatized patients. No particular anesthetic agent or technique is ideal. Causes for intraoperative hypotension include hypovolemia, hemopneumothorax, pericardial tamponade, an intracranial mass, acidosis, and hypothermia. The anesthesiologist should play an active role in all phases of trauma management, including provision of postoperative intensive care and pain relief.

Saved by focused echo evaluation in resuscitation.

A 74-year-old woman received thrombolysis for pericarditis. She subsequently developed shock and cardiac arrest. The case report describes the events of how a simple immediate bedside focused echo proved to be a life saving assessment. Current availability and training issues in focused transthoracic echo are discussed.

Mineralised tissues as nanomaterials: analysis by atomic force microscopy.

Mineralised tissues, such as bone, consist of two material phases: collagen protein fibrils that form the structural models upon which the mineral, calcium hydroxyapatite, is subsequently deposited. Collagen and mineral are removed in a three-dimensional manner by osteoclasts during bone turnover in skeletal growth or repair, and matrix proteins are replaced by the synthetic activity of osteoblasts and then calcify. The resolution of atomic force microscopy and use of unmodified, fully calcified samples has enabled the imaging of the overall bone and dentine structure, including collagen and mineral phases. Mineral crystals, in the diameter size range of 225 nm up to 1.4 microm, were found in unmodified bone and dentine respectively. D-banded collagen is observed in dentine after acid treatment and in bone after osteoclast-mediated matrix resorption; axial periodicity values of approximately 67 and 69 nm are observed, respectively. These experimental approaches have enabled the structure of mineralised tissues to be examined in native samples and will facilitate the study of bone structure in important clinical disorders of the skeleton, such as osteoporosis.

Traumatic rupture of the thoracic aorta-a radiological pitfall.

A previously undescribed feature of a traumatic thoracic aneurysm is presented. The pateint was a young motor cyclist who sustained multiple injuries and died 10 days after admission from delayed rupture of the thoracic aorta which had dissected along oesophageal planes into the stomach. Although the radiological features of traumatic mediastinal haematoma were evident shortly after injury, these features had disappeared in later radiographs creating a false sense of security.

The diagnosis of testicular swellings using water-path ultrasound.

Water-path ultrasound was used to investigate 29 patients with swellings of the testicle. When the swelling contained fluid, such as a hydrocele or a cyst of the epididymis, it was accurately depicted in the ultrasound scan. Seminomas appeared as anechoic areas which could not be distinguished from granulomatous orchitis, but were clearly different from the homogeneous echo pattern of the normal testis. The depiction of the epididymis was less clear. Water-path ultrasonography is a promising addition to our diagnostic armamentarium.