Fourth Attempt Research Articles

Hypotrophic Clavicle Pseudoarthrosis Treatment: a Case Report

Background. The treatment of post-traumatic of the clavicle false joint remains a subject of discussion regarding the technology of the surgical intervention. Recently, the use of vascularized fibular flap reconstruction technique has been popularized, but the potential of the external osteosynthesis remains relevant. Clinical case description. A 70-year-old patient got a fracture of the middle third of the left clavicle diaphysis as a result of a fall. He underwent four surgical treatment options: plate osteosynthesis; plate osteosynthesis + bone autoplasty; plate osteosynthesis + vascularized fibular flap reconstruction; external osteosynthesis. A month after the fourth attempt of surgical treatment, fusion, improvement of the function of the right upper limb and the quality of life of the patient were achieved. Technological inaccuracy, namely, the lack of the fragments fixation stability due to the incorrectly chosen length of the plate, as well as an incomplete assessment of the anamnesis and the identified cognitive behavioral features of the patient, are considered as possible reasons for the treatment failure. Conclusion. Attempts of surgical treatment using plates in combination with bone autoplasty, including vascularized skin-bone flaps, do not always ensure the achievement of clavicle fractures fusion. In such situations, it is advisable to use the potential of external osteosynthesis with the reasonable planning.

The "Painting by Numbers Method" for education of students in crown preparation.

No commercially available solution to improve the teaching of a crown preparation directly on typodont teeth exists at the moment. To fill this gap and support the supervisors of dental courses, a printable and inexpensive tooth was created for structured self-assessment. The aim of this study was to test this printable tooth under realistic pre-clinical situations. A two-coloured, double-layer practice tooth was developed. This tooth was consisting of a layer for a correct preparation and the crown. All printed teeth were produced with a stereolithographic printer. 35 voluntary second-year dental students in the second pre-clinical course in prosthodontics were randomly divided into two groups. All students had experience with typodont teeth and models. The first group was trained on four standard model teeth. The second group used model teeth for the first and fourth attempt and printed teeth for second and third attempt. The preparations of the students were scanned by an in-lab scanner and the surface deviations in contrast to a perfect preparation were measured. The differences between the first and fourth attempt were calculated. Benefits of the printed tooth were also evaluated by a questionnaire using German school grades completed by the students (1=Excellent, 2=Good, 3=Satisfactory, 4=Adequate, 5=Poor, 6=Unsatisfactory). The workflow was feasible and cost-effective regarding the production of the printed teeth. The overall rating of the printed tooth in the questionnaire was good (Ø 2.1±0.22). Students reported different advantages of this method in the free text. The comparison of the preparation between the first and fourth attempt showed that there was a significant better preparation with the printed teeth. The complete preparation had median values of 0.05mm (Group1: standard model tooth) and -0.03mm (Group2: printed tooth) (P=.005). Divided into single surfaces, the vestibular and occlusal regions were significantly better. The vestibular surface was 0.11mm (Group1) and -0.04mm (Group2) (P=.018). The occlusal surface was 0.13mm (Group1) and -0.05mm (Group2) (P=.009). The aim of this study was fulfilled. The printed tooth was tested successfully in a pre-clinical course. The feasibility of this teaching concept was confirmed by the questionnaire and the analysis of the preparation form. A significant difference to a standard model tooth was measurable. The students had the possibility to learn a correct crown preparation on a standardised two-layered tooth with included preparation. This printed tooth enabled the students to control the crown preparation directly on their own.

Clinical management and recommendations for children with more than four episodes of recurrent intussusception following successful reduction of each: an institutional review

To describe patterns and risk factors of multiple recurrences to optimise management for pediatric patients with more than four episodes of intussusception. Following IRB approval, all sonographic evaluations for intussusception in patients <18 years over a 6-year period were reviewed. Data extracted included age at onset of first intussusception, gender, presenting symptoms, symptoms upon recurrence, presence of pathological lead points, and surgical findings. During a 6-year period, five cases had four or more instances of recurrence after enema reduction attempts. All patients were male with an average age of 16 months. Two of the five cases resolved after the fourth enema reduction and no lead points were identified. Two other cases involved surgical reduction with intraoperative findings of Meckel's diverticulum and juvenile polyp. The final case had five recurrence episodes and six separate enema reductions. Ultimately, lymphoid hyperplasia was discovered on colonoscopy and the patient never recurred after being treated with steroids. Given the favorable reduction rate in re-recurrent cases and complete lack of perforation observed, up to four attempts at enema reduction is recommended before considering an alternative strategy. If recurrence continues past the fourth reduction attempt, computed tomography (CT) is recommended to identify a lead point. If CT remains inconclusive, then consider exploratory laparotomy.

Western Michigan University Homer Stryker M.D. School of Medicine.

Western Michigan University Homer Stryker M.D. School of Medicine.

First-time handling of different inhalers by chronic obstructive lung disease patients

Background: There is a lack of guidance on inhaler device selection and how to individualize inhaler choice when prescribed for the first-time.Aim of the work: To compare different inhalers regarding ease of use and number of counseling attempts needed for correct handling in subjects with a first experience to such inhalers; also, to investigate if there is a correlation between total correct steps achievements and patient demographics/clinical variables.Method: An open-label, non-drug interventional, cross-over study was conducted including 180 Egyptian patients with chronic obstructive pulmonary disease (COPD). The study evaluated handling of the most common inhalers in subjects with a first experience with them before hospital discharge. Subjects were randomized to handle 10 placebo inhalers including: [metered dose inhaler (pMDI), Aerolizer, Handihaler, Turbohaler, Diskus, Breezhaler, Ellipta, Easyhaler, Diskhaler, and Respimat] without receiving verbal or demonstrative instruction with allowable access to the patient information leaflets in native language supported by figures with enough time to read (baseline assessment). Subjects were then crossed-over to other inhalers with a first experience randomly. Inhalers with a reported past-experience were excluded. Inhaler-technique was assessed by using previously defined checklists, including essential steps and critical errors. The whole handling of the inhaler was demonstrated and the number of counseling attempts needed to correct handling was recorded. Patient demographics and clinical variables were recorded and correlated with correct handling steps.Results: The baseline percentages of total correct steps achievements as mean ± SD were 50 ± 19, 52 ± 16, 58 ± 14, 60 ± 17, 64 ± 10, 67 ± 16, 72 ± 17, 73 ± 11, 77 ± 14 and 86 ± 11% for Respimat, pMDI, Diskhaler, Diskus, Aerolizer, Handihaler, Easyhaler, Turbohaler, Breezhaler, and Ellipta respectively with p < 0.001. Baseline percentages of participants with at least 1 critical error significantly differed between inhalers (p < 0.05) with Ellipta showing the lowest percentage (37%). pMDI, Diskhaler, and Respimat showed the highest percentages (100%, 97% and 94% respectively). The number of counseling attempts needed to reach correct handling showed a significant difference among inhalers (p < 0.05). Ellipta showed the highest percentage of participants with correct handling with no counseling (20%) and the highest percentage of participants achieved with one counseling attempt (78%). Diskhaler, pMDI, and Respimat were the only inhalers included in a fourth counseling attempt (15%, 9%, and 6% respectively). Weak and very weak correlations were found between patient demographics/clinical variables and percentages of total correct steps achievements.Conclusion: Inhalers techniques greatly vary in their ease of use (self-explaining) ranging from easy inhalers (Ellipta) to intermediate inhalers (breezhaler, Easyhaler, Turbohaler, Aerolizer, Handihaler, and Diskus) followed by the most difficult inhalers (pMDI, Diskhaler, and Respimat). That must be considered when prescribing inhalers for the first time; choice of the inhaler should, in part, be based on ease of use and to be accompanied by repeated counseling.

Recurrent Occurrence of Idiopathic Ventricular Tachycardia after Extubation Undergoing Bile Duct Resection, Roux-en-Y Hepaticojejunostomy in Young Patient

Arrhythmias occurring during surgery are mostly benign and improve without special treatment, but sometimes life threatening and poor vital signs may require immediate antiarrhythmic or electrotherapy. In some cases, permanent arrhythmias may require continued treatment after surgery. A cardiac event occurred to a 28-year-old man who underwent Bile duct resection/Roux-en-Y hepaticojejunostomy due to cholelithiasis with cholecystitis and choledocholithiasis. He diagnosed mental retardation level 2. Pre-operation laboratory test is normal except liver function test (AST 64, ALT 141). Electrocardiography shows 57 bpm heart rate, sinus rhythm, first degree AV block and long corrected QT interval that was checked 462ms and echocardiography shows LVEF 67%, normal echocardiogram. When we prepared extubation after finishing operation, Sugammadex 200mg was injected. Suddenly, patient’s oxygen saturation was low at 85%. We started manual ventilation for oxygenation and saturation was increased at 100%. When we extubated endotracheal tube, his ECG changed normal sinus rhythm to idiopathic ventricular tachycardia (VT). Firstly we considered that is paroxysmal supraventricular tachycardia and infused adenosine 6mg twice and 12mg once. But arrhythmia was continuous and vital sign changed unstable. We performed reintubation and defibrillated at 200J. After defibrillation, arrhythmia converted sinus rhythm. We transferred the patient to the ICU and evaluated further to see if the patient had heart problems. During admission in ICU, attending surgeon tried to extubate endotracheal tube 2 more times. But, Idiopathic VT occurred whenever try to extubate. Finally, in the fourth attempt, extubation without occurrence of VT succeeded with continuous intravenous infusion of esmolol and dexmedetomidine. Keywords: Arrhythmia, Extubation, Idiopathic ventricular tachycardia

Ghana’s 2016 elections: An Overview of Selected Relevant Background Themes

Seven successive elections have been held in Ghana since 1992, most recently in 2016 when the country made a fourth attempt to embrace constitutional rule. A burgeoning literature provides explanations for the outcome of the 2016 election, which saw the defeat of the erstwhile incumbent National Democratic Congress and a landslide victory for the New Patriotic Party. Yet, little attention has been given to the various undercurrents, events, and significant background dynamics prior to the elections on 7 December. This research therefore provides a partially analytical but largely descriptive presentation of selected relevant issues that contributed to the build-up to the 2016 elections. The study situates the discourse within the broader context of Ghana’s democratisation, revealing how underlying phenomena possibly pose a threat to, and challenge the prospects of democratic consolidation. However, the conclusion indicates that the outcome of elections, which were deemed free and fair, should not be the only area of interest as the processes that lead to the elections are of great concern for a democracy. The work identifies several areas of concern, in particular Ghana’s electoral management, intra-party conflicts, unconventional aggression, vituperative outbursts and personal attacks, internal party elections, campaigns, how some chiefs violated a constitutional provision and outwardly portrayed partisanship, and brief issues concerning vote buying.

A274 EARLY SINGLE-OPERATOR CHOLANGIOSCOPY ASSISTED ELECTROHYDRAULIC LITHOTRIPSY (SOC-EHL) IN THE MANAGEMENT OF DIFFICULT BILIARY STONES IS COST-EFFECTIVE WHEN COMPARED TO A DELAYED STEP-UP APPROACH TO LATER SOC-EHL

Abstract Background Single-operator cholangioscopy assisted electrohydraulic lithotripsy is the standard of care for difficult common bile duct (CBD) stones with failed clearance using standard ERCP. This technology is expensive and optimal timing of its use in terms of cost-effectiveness in the management algorithm of patients with difficult CBD stones remains unclear Aims To determine the cost-effective timing of SOC-EHL utilization in the management of difficult CBD stones Methods A decision model was developed assessing 4 strategies and progressively delayed introduction of SOC-EHL in relation to ERCP over 6-months. Difficult stones were defined as having failed CBD clearance via standard ERCP. Probability estimates for each health state were obtained from a literature systematic review. For each strategy, outpatients undergoing ERCP underwent different timings of SOC-EHL introduction from the first to the fourth ERCP and were followed for subsequent need for re-intervention, adverse events, need for surgery, and/or successful endoscopic CBD clearance. The unit of effectiveness was complete CBD clearance without need for surgery. Deterministic sensitivity analyses were performed varying all 50 model variables across ranges spanning 30% of their respective values. Costs are in 2018US$ based on US data. Results Performing SOC-EHL immediately during the first ERCP is the least expensive approach when compared to delaying SOC-EHL. This strategy costs $15,528 on average per patient with CBD clearance avoiding surgery and can save between $260 to $720 compared to the 3 other strategies, which introduce SOC-EHL during the second to the fourth ERCP. Effectiveness is clinically comparable between the four strategies ranging from 97–99%. Deterministic sensitivity analysis shows changes in the results when the ERCP complication rate (baseline probability of 6%) decreases to 4.5%, when the SOC-EHL (baseline costs of $2,450) costs more than $2,670, or when the ERCP facility fees (baseline costs of $4,292) are less than $3,425. In all 3 scenarios, delaying the first SOC-EHL use to the fourth procedural attempt becomes the dominant strategy. Variations of the other 47 variables did not alter results. Conclusions Although SOC-EHL is expensive, this analysis demonstrates that among patients who have failed a prior attempt at stone extraction, utilization of SOC-EHL at the next (first subsequent) ERCP is less costly when compared to its delayed introduction. However, postponing the use of SOC-EHL to the fourth ERCP could be identified as the most cost-effective strategy when facility fees or ERCP complications rates are below certain thresholds, or when the costs of SOC-EHL extend beyond a defined threshold. Funding Agencies None

Revision Arthrodesis of the Subtalar Joint

Category:HindfootIntroduction/Purpose:Subtalar arthrodesis is an invaluable tool in managing arthritis, deformity, and muscular imbalance of the hindfoot. However, failed arthrodesis is complicated by bone necrosis, sclerosis with loss of bone, less than ideal biologic settings, and the literature reports a high rate of non-union. The aim of this study was to review all subtalar arthrodeses performed within a single institution, and specifically describe the management of non-union.Methods:492 consecutive subtalar arthrodesis cases were retrospectively analyzed between October 2001 and July 2013. From the primary arthrodesis group 91 (18%) were treated for subtalar coalition (100% arthrodesis), and were excluded to better depict the arthrodesis rate; the remaining 401 patients were treated primarily for post-traumatic arthritis. Pertinent demographics, comorbidities, and clinical notes were all retrieved through the electronic medical record and radiographs were reviewed through a PACS system.Results:49 patients with a mean age of 49 years (range 23 - 80) presented with subtalar non-union (overall rate 10%, adjusted rate 18%). 41 (84%) underwent revision at a mean of 16.2 months (range 2.8 - 57.1) from the index arthrodesis. The rate of revision arthrodesis was 78%, 21/30 (70%) in situ arthrodeses, 7/7 bone block arthrodesis (p=.028), and 4/4 triple arthrodesis (p=.028). Arthrodesis was present at a mean of 3.4 months (range 1.6 - 7.6). 4/9 (44%) of the recurrent nonunions elected to abstain from surgery. Of the 5 remaining patients, 2/5 had a successful third attempt at arthrodesis, 1/5 had an additional nonunion followed by a successful fourth attempt at arthrodesis, 1/5 had a successful tibiotalocalcaneal arthrodesis, and 1/5 required a below-knee amputation.Conclusion:Risk factors identified for non-union were post-traumatic arthritis, ipsilateral ankle arthrodesis, and individual patient factors (smoking, diabetes, and infection). Different methods of screw fixation were not found to be significantly different between the fused and nonunion groups. Despite directed management to obtain rigid fixation and adequate compression, the rates of subtalar arthrodesis from primary (82%), revision (78%) and secondary revision (60%) cases were very poor with the exception of the group which underwent a bone block arthrodesis (100%, p=.028).

Prospective Cohort Study of Haptic Virtual Reality Laparoscopic Appendicectomy Learning Curve Trajectory.

Background: Simulation training is strongly advocated by 24/7 risk-rich professions because swift learning curve inflection point attainment delivers earlier competence; the left-shift effect. The aim of this study was to determine the value of haptic laparoscopic virtual reality simulation, by iterative benchmark exercise (n = 8), before simulated laparoscopic appendicectomy (SLA); the hypothesis was that favorable benchmark learning curve trajectories would be associated with improved SLA competence when compared with consultant expert performance. Methods: A 28-trainee cohort completed 1349 Laparoscopic Haptic Virtual Reality Skills (LHVRS) tasks, during which 19 ergonomic variables were assessed by virtual interface, including force feedback (Surgicalscience.com), before 153 SLAs. Primary outcome measure was SLA composite competence score related to six consultant trainer experts. Results: Of the eight LHVRS tasks, the three with the steepest learning curve trajectories correlated with better median overall SLA competence scores, namely tissue grasping/lifting (rho = 0.362, P = .049), fine dissection (rho = 0.388, P = .028), and camera navigation (rho = 0.518, P = .007); fine dissection was the only haptic laparoscopic virtual reality simulation task that predicted a SLA score within a Youden index defined, 70% of the consultant expert level (area under curve [AUC] = 0.803, P = .028). A significant SLA learning curve emerged, with a learning curve trajectory inflection point at the fourth SLA attempt (first SLA 30.5% versus fourth SLA score 76.0%, gradient 76°, P = .010). Conclusion: Learning curve trajectory can be measured, influenced, and accelerated significantly; a pronounced left-shift effect, with translational potential for enhanced shorter training time and improved patient safety.

Development of a Novel 3D Printed Phantom for Teaching Neurosurgical Trainees the Freehand Technique of C2 Laminar Screw Placement

3D printed models have grown in popularity for resident training. Currently there is a paucity of simulators specifically designed for advanced cervical instrumentation. Our institution created a unique simulator for the instruction of freehand placement of C2 laminar screws using a specific 3-dimensional printing technique to replicate the corticocancellous interface. This study was designed to determine the efficacy of the simulator for teaching neurosurgical residents the freehand technique of C2 laminar screw placement. Ten participants with different experience levels participated in the study. The participants were separated into 2 groups based on experience level. Primary outcome assessments were breach rates, screw-screw interaction, and the ability to successfully place 2 screws in 1 model. Participants were graded based on a performance scoring system, and the outcomes of the 2 groups were compared. All participants in the novice group showed improved technical ability on repeated use of the simulator and were able to successfully place bilateral screws by the fourth attempt. Statistical analysis indicated an association between operative experience level and successful bilateral screw placement, implying that the simulator accurately represented an invivo intraoperative scenario. By utilizing our novel 3D printing production method, we have created a unique simulator for the freehand placement of C2 laminar screws. To our knowledge, this is the first report of a study investigating the use of a 3-dimensional printed simulator specifically designed to teach the freehand placement of C2 laminar screws to neurosurgical trainees.

Outcome of gans repositioning maneuver in patients with posterior canal benign paroxysmal positional vertigo with cervical spondylosis

Background and Objectives: Cervical spondylosis and BPPV often co-exist in older population. As GRM doesn't involve hyperextension of neck, which is better avoided among patients with cervical spine pathology, we decided to assess the outcome of GRM in patients with cervical spondylosis in terms of safety & efficacy. Methodology: Twenty patients with clinically proven posterior semicircular canal BPPV and radiologically evident cervical spondylosis without symptomatic spondylotic myelopathy or radiculopathy or severe restriction of neck or back movement were enrolled. GRM was done on the first day and repeated until resolution of nystagmus, for a maximum of four times. Lack of response to GRM even after fourth attempt was considered as failure. The manuever was repeated in the successful group on day two and after one week & these patients were followed up for one month. Results: Overall, 75% of the patients (50.9% to 91.3% - 95% C.I.) had a successful repositioning maneuver. Favourable parameters for better chances of cure were higher age (>55 years), male gender & higher grade of cervical spondylosis. 20% of patients had experienced temporary pain for few hours on the day of maneuver. None of the patients who had less than two attempts of GRM had post-procedure pain. Clinically, none of the patients had precipitation of cervical myelopathy or radiculopathy. Conclusion: GRM is a safe & effective particle repositioning maneuver for patients with posterior semicircular canal BPPV with co-existent cervical spondylosis.

Pneumocephalus and Seizures Following Combined Spinal-epidural for Labor

(J Clin Anesth. 2018;44:123–124) In this correspondence, the authors described a patient who presented with simultaneous pneumocephalus and cavernoma after receiving combined spinal-epidural analgesia for labor. However, unlike most cases of combined spinal-epidural analgesia for labor, which use loss of resistance to air to identify the epidural space, the authors used loss of resistance to saline. To the author’s knowledge, there are no published reports of the use of loss of resistance to saline for this purpose. Identification of the epidural space was successful upon the fourth attempt with the patient in a sitting position. Upon injection of local anesthetic, the patient immediately complained of a severe headache, that was unremitting with postural changes and continued into the postpartum period. On postpartum day 2, the patient presented with a tonic-clonic seizure. Magnetic resonance imaging showed intraventricular pneumocephalus and cavernoma in the right frontal region, and electroencephalogram showed abundant epileptic activity. Oxygen was added to the patient’s therapy with clinical improvement; complete reabsorption of air on radiologic examination was seen on the sixth day and the asymptomatic patient was discharged.

Estimation of probabilistic processes in wireless networks of 802.11 standard

The article analyzes mechanisms of collision in a wireless 802.11 network with competitive access to a radio channel. The calculated relationships for determining the probabilities of collisions in the network as a whole in the presence of N active stations with a saturated load, and also for one station when implementing the binary exponential mechanism of increasing the competitive window are presented. The graphs, which illustrate the proposed equations, are given in this article too. An equation is also proposed for determining the probability of successful transmission of a data frame depending on the number of active stations and the initial value of the competitive window. The equations are obtained using the concept of a virtual competitive window.It was shown that in the case, where the number of active stations is one third of the contention window, the probability of collisions is about 0.25. This means that in the network with such number of active stations, each station will experience the collision at every fourth attempt to transmit a frame of data in average. The next attempt to transmit frame of data will be carried out by using the larger contention window. Collisions will cause the increase of transmitting time duration and its irregularity.It was analyzed the efficacy of application of binary exponential law for the change of the contention window for active stations, caught in a conflict when trying to access the channel.The equation for estimate the changes in the probability of collision and the number of competing stations in the access cycle was obtained by taken into account that it will take place when a quasi-stationary mode of operation of wireless networks is established. It was shown that the most effectively this mechanism is triggered in the early stages of repeated access to radio channel. Those stations that carry out the 5-th and 6-th attempts to access channel have a little impact on the probability of collisions on the network. Such result may be explained because every station after successful transmit the data frame will begin a new attempt from the initial meaning of contention window. So, if the initial number of active stations in the wireless network approximately equal to the value of contention window, in steady state of saturated network the effective number of active stations will be twice less due to application of binary exponential law for the change of the competitive window. If the initial number of active stations will be only 30% from the value of contention window, the effective number of active stations will be less twice too.It was gave the estimation of the overall probability of collisions in a saturated 802.11 network with competitive access to the radio channel. The threat of collisions increases quickly in comparison with the increase of number of active stations in the networkFrom the analysis of the received equations and graphs it follows that for the normal operation of the wireless network, it is necessary that the number of active stations that simultaneously compete for access to the radio channel does not exceed a third of the initial value of the contention window used in this network. In this case, the probability of successful transmission will be more than 0.85.Ref. 10, fig. 7.

Ad Hoc LTE Method for Resilient Smart Grid Communications

LTE network is a good choice for delivering smart grid demand response (DR) traffic. However, LTE connectivity is not pervasively available due to smart meter improper positioning, limited of coverage, or base station software or hardware failures. In this paper, a solution is introduced to overcome issues relating to lack of LTE base station connectivity for user equipment (UE) considered as remote terminal units, i.e. communication interfaces connected to smart meters. The solution is an ad hoc mode for the LTE-Advanced UE. The ad hoc mode is applied to reach a relay node that is the nearest UE with base station connection. DR traffic is delivered between clusters of UEs and a relay node using multi-hop communications. Analytical Markov chain models and a Riverbed Modeler network simulation model are implemented to illustrate the functionalities and the performance when DR traffic is delivered with varying transmission power levels. A detailed physical layer propagation model for device-to-device communications, a static resource allocation in time domain, hybrid automatic repeat request retransmissions, and a capability for a UE to receive uplink transmissions are modeled both analytically and in the simulator. Both the disjoint analysis and simulations show that all packets are successfully transmitted at most with the fourth transmission attempt and the average network delay is low enough to support most of the smart grid DR applications (139.2–546.6 ms).

Manual heating of the radial artery (Balbay maneuver) to facilitate radial puncture prior to transradial coronary catheterization

ObjectiveTransradial access is widely used for both diagnostic and interventional cardiac procedures. The use of transradial access offers several advantages, including decreased bleeding, fewer vascular complications, and reduced length of hospital stay and cost. However, the small size of the radial artery limits the size of the equipment that can be used via this approach. In this study we sought to investigate whether preprocedural manual heating of the radial artery facilitates radial artery puncture. MethodsPatients undergoing transradial cardiac catheterization were randomized to subcutaneous nitroglycerin plus diltiazem or manual heating. The study endpoint was puncture score (score 1: easiest – puncture at first attempt; score 2: second attempt; score 3: third attempt; score 4: fourth attempt or more; score 5: puncture failed). ResultsNinety consecutive patients were enrolled in the study, 45 allocated to the drug treatment group and 45 to the heating group. Patients underwent radial artery ultrasound before catheterization. Complications were rare: one hematoma (drug treatment group) and one radial artery occlusion (heating group). Baseline demographic and clinical characteristics were similar. Baseline radial artery diameter was similar in both groups (2.41±0.46 mm and 2.29±0.48 mm in the heating and drug treatment groups, respectively). However, the median puncture score was lower in the heating group (1; interquartile range 1-2) compared to the drug treatment group (2; interquartile range 1-3; p=0.001). ConclusionsPreprocedural manual heating of the radial artery facilitates radial artery puncture in patients undergoing transradial cardiac catheterization.

Manual heating of the radial artery (Balbay maneuver) to facilitate radial puncture prior to transradial coronary catheterization

ObjectiveTransradial access is widely used for both diagnostic and interventional cardiac procedures. The use of transradial access offers several advantages, including decreased bleeding, fewer vascular complications, and reduced length of hospital stay and cost. However, the small size of the radial artery limits the size of the equipment that can be used via this approach. In this study we sought to investigate whether preprocedural manual heating of the radial artery facilitates radial artery puncture. MethodsPatients undergoing transradial cardiac catheterization were randomized to subcutaneous nitroglycerin plus diltiazem or manual heating. The study endpoint was puncture score (score 1: easiest – puncture at first attempt; score 2: second attempt; score 3: third attempt; score 4: fourth attempt or more; score 5: puncture failed). ResultsNinety consecutive patients were enrolled in the study, 45 allocated to the drug treatment group and 45 to the heating group. Patients underwent radial artery ultrasound before catheterization. Complications were rare: one hematoma (drug treatment group) and one radial artery occlusion (heating group). Baseline demographic and clinical characteristics were similar. Baseline radial artery diameter was similar in both groups (2.41±0.46 mm and 2.29±0.48 mm in the heating and drug treatment groups, respectively). However, the median puncture score was lower in the heating group (1; interquartile range 1-2) compared to the drug treatment group (2; interquartile range 1-3; p=0.001). ConclusionsPreprocedural manual heating of the radial artery facilitates radial artery puncture in patients undergoing transradial cardiac catheterization.

A new protocol for concurrently allocating licensed spectrum to underlay cognitive users

Cognitive radio technology makes efficient use of the valuable radio frequency spectrum in a non-interfering manner to solve the problem of spectrum scarcity. This paper aims to design a scheme for the concurrent use of licensed frequencies by Underlay Cognitive Users (UCUs). We develop a new receiver-initiated Medium Access Control (MAC) protocol to facilitate the selections of alternative reliable carrier frequencies. A circuit is designed to establish reliable carrier selections based on the Received Signal Strength Indicator (RSSI) at the receiving end. Based on both packet-level simulations and various performance parameters, a comparison is carried out among conventional techniques, including the Multiple Access with Collision Avoidance (MACA) and MACA by invitation(MACA-BI) techniques, and our scheme. The simulated results demonstrate that when conventional techniques are used, the system overhead time increases from 0.5s on the first attempt to 16.5s on the sixth attempt. In the proposed scheme under the same failure condition, overhead time varies from 0.5s to 2s. This improvement is due to the complete elimination of the exponential waiting time that occurs during failed transmissions. An average efficiency of 60% is achieved with our scheme while only 43% and 34% average efficiencies are achieved with the MACA and MACA-BI techniques, respectively. The throughput performance of our scheme on the fourth attempt is 7 Mbps, whereas for the MACA and MACA-BI protocols, it is 1.9 Mbps and 2.2 Mbps respectively.

Diversity, variation and fairness: Equivalence in national level language assessments

The post-1994 South African constitution proudly affirms the language diversity of the country, as do subsequent laws, while ministerial policies, both at further and higher education level, similarly promote the use of all 11 official languages in education. However, such recognition of diversity presents several challenges to accommodate potential variation. In language education at secondary school, which is nationally assessed, the variety being promoted immediately raises issues of fairness and equivalence. The final high-stakes examination of learners’ ability in home language at the exit level of their pre-tertiary education is currently contentious in South Africa. It is known, for example, that in certain indigenous languages, the exit level assessments barely discriminate among learners with different abilities, while in other languages they do. For that reason, the Council for Quality Assurance in General and Further Education, Umalusi, has commissioned several reports to attempt to understand the nature of the problem. This article will deal with a discussion of a fourth attempt by Umalusi to solve the problem. That attempt, undertaken by a consortium of four universities, has already delivered six interim reports to this statutory body, and the article will consider some of their content and methodology. In their reconceptualisation of the problem, the applied linguists involved first sought to identify the theoretical roots of the current curriculum in order to articulate more sharply the construct being assessed. That provides the basis for a theoretical justification of the several solutions being proposed, as well as for the preliminary designs of modifications to current, and the introduction of new assessments. The impact of equivalence of measurement as a design requirement will be specifically discussed, with reference to the empirical analyses of results of a number of pilots of equivalent tests in different languages.

Validation of a Difficult Endotracheal Intubation Simulator Designed for Use in Anaesthesia Training

There is a need for a validated endotracheal intubation trainer that has variable difficulty settings for the training and assessment of medical practitioners. In this study three anatomical modifications were retrofitted to a commercial manikin and then validated. These modifications included restricted movements of the mandible as well as changes to the upper incisors. A total of 130 participants comprising specialists, trainees and medical students volunteered for this study. Validity was tested using randomised between-groups comparison of the time taken to intubate the manikin on all settings. Overall, and at each setting, there was a significant difference between the times to intubation among the three levels of experience (P <0.001). Novices were more than 12 times more likely to fail than experts (odds ratio [OR] 12.4, 95% confidence intervals [CI] 3.8, 41.8, P <0.001). The median time to intubation for all three groups changed significantly between settings 1 (easiest) and 4 (most difficult), novice 18 seconds (CI 8.9, 27.1, P <0.001), intermediate 15 seconds (CI 6.5, 23.5, P=0.001), and expert 9 seconds (CI 0.4, 17.6, P=0.04). The novice group was significantly different from the expert group at all attempts (P <0.002), and from the intermediates at all attempts apart from the third (P=0.055). The time for the novice and intermediate groups improved significantly by the fourth attempt, novice 15 seconds (CI 5.4, 24.6, P=0.002) and intermediate 10 seconds (CI 1.0, 19.0, P=0.03). Other aspects of validity were also satisfied during this study. A high degree of validity was established for these modifications, which can be retrofitted to an existing manikin and then used for teaching or assessment.