Number Of Failed Attempts Research Articles

Different coupling mechanisms for a novel modular plate in acetabular fractures-a comparison using a laparoscopic model.

Acetabular fractures are among the most challenging injuries in traumatology. The complex anatomy usually requires extensive surgical approaches baring the risk for iatrogenic damage to surrounding neurovascular structures. As a viable alternative, minimally invasive endoscopic techniques have emerged during the recent years. This paper reports on the feasibility of different coupling mechanisms for a novel suprapectineal plate especially designed for minimally invasive acetabular surgery. A total number of 34 participants contributed to the present study, who differed in their arthroscopic and surgical experience. A laparoscopic model was used to compare four different coupling mechanisms by the number of failed attempts, the time required for plate fixation, the influence of surgical experience as well as the learning success for each individual coupling mechanism. Moreover, the feasibility of each mechanism was evaluated by a questionnaire. The results demonstrate that plates employing grooved and pressure-sliding coupling mechanisms exhibit fewer failed attempts and reduce trial times, especially in contrast to sole sliding mechanisms. Furthermore, our study revealed that proficiency in endoscopic procedures significantly influenced the outcome. Notably, the subjective evaluation of the participants show that the pressure base and pressure-slide base plate designs are the most supportive and feasible designs. In summary, the present study evaluates for the first-time different plate and coupling designs for minimal-invasive surgery, indicating a superior feasibility for plates with a grooved and pressure-sliding mechanism.

Ultrasound-Guided Out-of-Plane Versus In-Plane Radial Artery Cannulation in Adult Cardiac Surgical Patients

The primary objective was to compare the rate of first-pass radial arterial cannulation using out-of-plane ultrasound guidance with in-plane imaging. The secondary endpoints were a comparison of the number of times the cannula was redirected, the number of attempts, the number of skin punctures, the incidence of hematoma, the time to completion of the cannulation procedure, and the number of failed attempts between the 2 ultrasound imaging techniques. A prospective, randomized, observational study. A tertiary cardiac care center. Adult patients undergoing elective cardiac surgery. Radial artery cannulation with ultrasound guidance. Eighty-four adult patients scheduled for elective cardiac surgery were randomly assigned to the out-of-plane ultrasound group (group I, n = 42) or the in-plane ultrasound group (group II, n = 42) for left radial artery cannulation. A linear ultrasound probe was used to identify the radial artery. In each approach, the number of times first-pass success was achieved, the number of times the cannula was redirected, the number of skin punctures, the incidence of hematomas, and the number of failed attempts were recorded. The first-pass success rate was greater in the in-plane ultrasound group and was statistically significant (p = 0.007). In the out-of-plane ultrasound group, a larger number of patients needed redirection of the cannula (p = 0.002). The number of patients in whom the skin needed to be punctured more than once was greater in the out-of-plane ultrasound group compared with the in-plane ultrasound group (p = 0.002). The incidence of hematoma formation and time to completion of the technique were similar in both groups (p = 0.241 and p = 0.792, respectively). In-plane ultrasound guidance appeared to be superior for achieving a higher first-pass success rate more often with minimal redirections and skin punctures compared with out-of-plane ultrasound guidance.

A comparison of nasogastric tube insertion by SORT maneuver (sniffing position, NGT orientation, contralateral rotation, and twisting movement) versus neck flexion lateral pressure in critically ill patients admitted to ICU: a prospective randomized clinical trial

BackgroundAlthough many techniques have been introduced to facilitate nasogastric tube (NGT) insertion using anatomic landmarks and a group of devices, there is a lack of general consensus regarding a standard method. The current study purposed to investigate if SORT maneuver (sniffing position, NGT orientation, contralateral rotation, and twisting movement) increases the success rate of NGT correct placement versus neck flexion lateral pressure (NFLP) method.MethodsA randomized controlled trial study was conducted in two university affiliated intensive care units (tertiary referral center). Three hundred and ninety-six critically ill patients older than 18 years of age were randomly divided into SORT (n = 200) and NFLP (n = 196) groups. The technique was classified as “failed” after the third unsuccessful attempt. Patient characteristics, success rate for the first attempt, time required for the successful first attempt and overall successful insertion time, various complications including kinking, coiling and bleeding and ease of insertion were noted as main outcomes measured.ResultsEase of insertion was significantly better in the SORT group compared to the NFLP group (P < 0.001). The number of failed attempts was significantly higher in the NFLP group (7.5%) vs the SORT group (3.0%) (P = 0.046). The pattern of complications was not different between two study groups (P = 0.242). The odds of stage II (odds ratio (OR) = 49.9; 95% confidence interval (CI) 25.2 to 98.6), stage III (OR = 67.1; 95% CI 14.9 to 302.8)) and stage IV (OR = 11.8; 95% CI 3.4 to 41.2) ease of insertion were much higher in NFLP compared to SORT group, after adjusting for age and body mass index (BMI). The odds of failure was not significantly different in NFLP group compared to SORT group (OR = 2.3; 95% CI 0.85 to 6.3), after adjusting for age and BMI.ConclusionsSORT technique may be considered as a promising method for successful NGT insertions in critically ill patients. However, more trials are needed to confirm the results of this study. The decision must account for individual patient and clinical factors and the operator’s experience and preference.Trial registration: The study was registered at government registry of clinical trials in Iran (http://www.IRCT.ir) (number: IRCT20091012002582N18, 13 March 2018)

Pediatric Intraosseous Access Performed by Emergency Department Nurses Using Semiautomatic Devices: A Randomized Crossover Simulation Study.

No study has examined the performance of emergency department (ED) nurses in establishing intraosseous access (IO) access. This study aimed to evaluate ED nurses' success rate in establishing pediatric IO access using semiautomatic devices. A randomized crossover simulation study was conducted. The success rates of ED nurses were compared with those of paramedics with similar years of experience. The study instruments were the new spring-loaded injector (NIO) and the battery power drill (EZ-IO). Uncooked piglets' bones were used as the study model. All attempts were filmed by a video camera. Successful placement was defined as the visualization of flow from the marrow cavity. Participants recorded their ranking of the "ease of use" of each device. No differences in 1-attempt success rate was found between nurses and paramedics (27/34 [79.4%] vs 25/30 [83.3%], P = 0.68). Nurses and paramedics had similar success rates with the 2 semiautomatic IO devices (12/17 vs 12/15 with the spring-loaded injector, P = 0.69, and 15/17 vs 13/15 with the battery power drill, P = 0.9). The number of failed attempts and the causes for failure were equally distributed between nurses and paramedics. Median ease-of-use Likert-scale scores of the spring-loaded injector and the battery power drill were 4 (interquartile range [IQR] = 3-4) and 5 (IQR = 5-5) (P < 0.04) for the nurses and 5 (IQR = 4-5) and 5 (IQR = 4-5) (P = 0.44) for the paramedics, respectively. Emergency department nurses and paramedics had a similarly high insertion success rates on a pediatric bone model. This pilot study suggests that ED nurses can successfully perform this procedure.

Formal Semantics in the Neurology Clinic: Atypical Understanding of Aspectual Coercion in ALS Patients.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of the motor system with subtle adverse effects on cognition. It is still unclear whether ALS also affects language and semantics, and if so, what aspects and processes exactly. We investigated how ALS patients understand verb phrases modified by temporal preposition phrases, e.g., “To watch TV for half an hour.” Interpretation here requires operations such as aspectual coercion that add or delete elements from event structures, depending on temporal modifiers, and constraints on coercion, which make combinations with certain modifiers not viable. Using a theoretically-motivated experimental design, we observed that acceptance rates for aspectual coercion were abnormally high in ALS patients. The effect was largest for the more complex cases of coercion: not those that involve enrichment of event structures (“To switch on the TV in half an hour,” where a number of failed attempts must be included in the interpretation) but those that, if applied, would result in deletion of event structure elements (“To repair the TV for half an hour”). Our experimental results are consistent with a deficit of constraints on coercion, and not with impaired semantic processes or representations, in line with recent studies suggesting that verb semantics is largely spared in ALS.

Verbalne strategije majki djece različita spola pri pomaganju u rješavanju kognitivnih problemskih zadataka

The aim of the study was to investigate maternal verbal strategies in the process of scaffolding their children to complete cognitive tasks in the zone of proximal development, and to examine whether mothers used different verbal strategies with children of different sex. The study was conducted with mothers (N = 80) and their children (41 boys and 39 girls) aged 5 to 7. The dyads were video recorded during interaction on problem-solving tasks and the recordings were analyzed. The analysis of maternal verbal reactions was conducted after child's correct and after child's incorrect answer when children provided first incorrect and, later, correct answers. In this study there were no significant differences between maternal verbal strategies used either in the process of scaffolding children of different sex on problem-solving tasks or after the children solved the problem correctly. When children offered an incorrect answer, the most frequent maternal strategy was to encourage girls to re-think and to use the technique of scaffolding for boys. When the correct answer was given after one or a number of failed attempts, the most frequent maternal verbal strategy for boys and girls was to confirm its correctness.

Efficacy of a side-mounted vertically oriented bristle pass for improving upstream passage of European eel (Anguilla anguilla) and river lamprey (Lampetra fluviatilis) at an experimental Crump weir

Globally, populations of diadromous anguilliform morphotype fish, such as eel and lamprey, have experienced substantial declines, partly as a result of habitat fragmentation caused by river infrastructure. In the UK, a new configuration of hydraulically unobtrusive bristle pass (side-mounted and vertically oriented) has been developed to help upstream moving European eel (Anguilla anguilla) negotiate gauging weirs. The efficacy of vertically oriented bristle passes remains untested, despite their potential as a low-cost low-maintenance solution to improve habitat connectivity at low-head structural barriers worldwide. This study assessed the ability of small (82–320mm) and large (322–660mm) European eel and adult (291–401mm) river lamprey (Lampetra fluviatilis) to pass upstream over an experimental Crump weir installed in a large open-channel flume with (treatment) and without (control) side-mounted vertically oriented bristle passes under three different hydraulic regimes. Both species were highly motivated to explore their surroundings and move upstream during the trials. Under flooded control conditions, passage efficiency (the total number of times fish passed the structure as a percentage of total attempts) and passage success (the number of fish that passed the structure as a percentage of those that attempted) were high, delay was short, and number of failed attempts before passage was low for both species. When difference in head was at its greatest (230mm) and velocity and its variation downstream were high (maximum u and σ: 2.43ms−1 and 0.66ms−1, respectively), the upstream movement of small eel and lamprey was blocked, and passage efficiency and success for large eel low (4.6% and 17.2%, respectively). For large eel that successfully passed, delay was long, and number of failed attempts before upstream passage was high. When bristle passes were installed, passage efficiency for small (91.5%) and large eel (56.7%), and passage success for large eel (76.5%) and lamprey (36.7%) was higher, while delay and the number of attempts before passage was lower for both species. Bristle passes helped European eel and river lamprey pass a small experimental Crump weir, although interspecific variation in efficacy was evident.

Ease of intravenous catheterisation in dogs and cats: a comparative study of two peripheral catheters.

To evaluate animal comfort and ease of placement of a veterinary-specific intravenous catheter compared with a catheter manufactured for human use. Fifty-nine veterinary undergraduates were recruited to perform intravenous catheterisations with two brands of over-the-needle catheter [Smiths Medical Jelco® (human use) and Abbott Animal Health catheter® (veterinary use)] in 69 healthy cats (n = 28) and dogs (n = 41) requiring general anaesthesia. After a standardised pre-anaesthetic medication, each animal was randomly allocated to have one of the two brands of catheter placed. Each student was allowed a maximum of three attempts to achieve cephalic vein catheterisation. The student and a single experienced observer evaluated each attempt. Observations related to ease of placement and to the animal's reaction were recorded. Human use catheters were placed in 34 and veterinary use in 35 animals. There was no difference in weight, sex or sedation score between the two groups. The number of failed attempts was similar between the two groups. There was no difference between groups for the number of animals reacting to catheter insertion. The two types of catheters evaluated are equally suitable for intravenous catheterisation of sedated animals by veterinary undergraduate students.

Ultrasound imaging facilitates subarachnoid blockade in patients with difficult surface anatomic landmarks

Background Ultrasound imaging of the spine has recently been proposed to facilitate identification of the anatomic landmarks for subarachnoid blockade. This study assessed the accuracy and precision of the ultrasound-guided subarachnoid blockade over the conventional surface landmark-guided technique in patients with difficult surface anatomic landmarks undergoing elective orthopedic lower limb surgery. Patients and methods This prospective, randomized controlled study was conducted on 60 patients with difficult surface anatomic landmarks for subarachnoid block, scheduled for elective orthopedic lower limb surgery. These patients were randomly allocated into two equal groups: group LM in which subarachnoid block was performed using the conventional surface landmark-guided technique and group US in which subarachnoid block was performed using the ultrasound. The primary outcome was the rate of successful dural puncture on the first needle insertion attempt. The secondary outcomes included number of needle redirection, number of repeated needle insertion, number of failed attempts, time taken to establish landmarks, and time taken to perform the spinal anesthesia. Results Successful dural puncture on the first needle insertion attempt was achieved in 21 (70%) patients in group US and in eight (26.7%) patients in group LM ( P P P Conclusion Ultrasound-guided approach is a reliable and effective method in patients in whom technical difficulty is expected.

Design of a single-DOF kinematic chain using hybrid GA-pattern search and sequential GA

With the aim of obtaining an optimal design for a single-DoF kinematic chain with the function of morphing aerofoils, two search methods are developed. The assessment criteria arethe length of the linkage and the accuracy of mapping. While the former is taken as the objective of optimization, the latter is treated as a constraint. The accuracy in mapping is measured by the aerodynamic performance deviation, a parameter defined by combining the geometric deviation and a weighting function based on the distribution of pressure coefficient. The first search method is based on a genetic algorithm (GA) with an embedded pattern search algorithm. The aim of the pattern search is to reduce the number of failed attempts in generating feasible solutions for the initial population of the GA as well as repairing infeasible individuals produced by reproduction operators. In the second search method, the set of design variables is determined in two consecutive steps by employing a sequential GA. Results of five runs of each search method reveal that while the best solution was produced by the sequential GA search method, hybrid GA-pattern search yielded more consistent results with shorter lengths and better mapping precision in average.

Modeling Customer Reactions to Sales Attempts: If Cross-Selling Backfires

Cross-selling attempts, based on estimated purchase probabilities, are not guaranteed to succeed and such failed attempts may annoy customers. There is a general belief that cross-selling may backfire if not implemented cautiously, however, there is not a good understanding of the nature and impact of this negative reaction or appropriate policies to counter-balance it. This article focuses on this issue and develops a modeling framework that makes use of a Markov decision model to account for negative customer reactions to failed sales attempts and the effect of past contacts in managing cross-selling initiatives. Three models are analyzed, where purchase probabilities are affected from customer maturity, the number of failed attempts since the last purchase, or both. The analysis shows that customer reactions to cross-sell attempts make the purchase probabilities endogenous to the firm’s cross-selling decisions; hence, the optimal cross-selling policy becomes a function of customer state. The results highlight the role that the cost of excessive cross-selling (direct as well as in the form of customer reactions) plays in optimal policies. Cross-sell data from a retail bank illustrate in what context the modeling framework can be applied and underline the importance of customizing cross-sell policies to individual customers.

Internal imagery training in active high jumpers

The main purpose of this study was to examine whether the use of internal imagery would affect high jumping performance for active high jumping athletes. Over a period of six weeks, a group of active high jumpers were trained with an internal imagery program for a total of 72 minutes. This group was compared to a control group consisting of active high jumpers that only maintained their regular work-outs during the same time period. Four variables were measured; jumping height, number of failed attempts, take-off angle, and bar clearance. There was a significant improvement on bar clearance for the group that trained imagery (p < 0.05) but not for the control group. No other differences were found. The results suggest that internal imagery training may be used to improve a component of a complex motor skill. Possible explanations and future recommendations are discussed.

Veress needle insertion in the left hypochondrium in creation of the pneumoperitoneum

To test the efficacy of the puncture in the left hypochondrium as an alternative method. Sixty-two patients randomly distributed into two groups were studied: Group LH, puncture in the left hypochondrium (n=30), and Group ML, puncture in the abdominal midline (n=32). The following were assessed: needle positioning tests, number of failed attempts at needle insertion, and time needed for creation of pneumoperitoneum. Gas flow, volume and intraperitoneal pressure were recorded at every 20 seconds, until a 12 mmHg pressure was reached inside the peritoneal cavity. A similar number of positive results for the needle positioning tests were observed in both groups. Two failed attempts to reach the peritoneal cavity were observed in Group ML and one in Group LH. The time necessary for the creation of pneumoperitoneum was on average 3 minutes and 46 seconds for Group LH, and 4 minutes and 2 seconds for Group ML. Average gas flow, volume and pressure were equivalent for both groups. Puncture in the left hypochondrium was as effective as puncture in the abdominal midline for the creation of pneumoperitoneum.

Étude clinique du masque laryngé en pédiatrie. Comparaison du LMA–classic et du LMA–ProSeal taille 2 et 2,5

Objectives To compare the Classic™ laryngeal mask airway (MLC) and the ProSeal™ LMA (MLP), size 2 and 2.5 in terms of ease of insertion, leak pressure and side effects during insertion and extraction in the recovery room. Study type Randomised prospective. Material and method All children between 10 and 30 kg scheduled for general anaesthesia with laryngeal mask (ML) were included. There was no imposed protocol for the anaesthesia. The ML size was determined according to the child's weight. The MLC was inserted using the standard technique. The MLP was inserted following the recommendations, with or without the handle according to the operator's choice. The data analysed were: insertion type, ease of insertion of the mask, of the nasogastric tube (SG), number of attempts of mask insertion, complications, gastric leaks. Results One hundred (and) twenty children were included. There was no statistical difference in terms of difficulty of insertion, number of failed attempts, leak pressure or side effects. The use of the handle did not make insertion easier. Insertion of a nasogastric tube was possible in 92% cases. Conclusion MLP is as easy to use in children as the MLC. MLP has the advantage of allowing rapid access to the stomach. It seems that the MLP is safer since its correct position is confirmed by easy gastric tube insertion.

Spatial dynamics of invasion: the geometry of introduced species

Many exotic species combine low probability of establishment at each introduction with rapid population growth once introduction does succeed. To analyse this phenomenon, we note that invaders often cluster spatially when rare, and consequently an introduced exotic's population dynamics should depend on locally structured interactions. Ecological theory for spatially structured invasion relies on deterministic approximations, and determinism does not address the observed uncertainty of the exotic-introduction process. We take a new approach to the population dynamics of invasion and, by extension, to the general question of invasibility in any spatial ecology. We apply the physical theory for nucleation of spatial systems to a lattice-based model of competition between plant species, a resident and an invader, and the analysis reaches conclusions that differ qualitatively from the standard ecological theories. Nucleation theory distinguishes between dynamics of single- and multi-cluster invasion. Low introduction rates and small system size produce single-cluster dynamics, where success or failure of introduction is inherently stochastic. Single-cluster invasion occurs only if the cluster reaches a critical size, typically preceded by a number of failed attempts. For this case, we identify the functional form of the probability distribution of time elapsing until invasion succeeds. Although multi-cluster invasion for sufficiently large systems exhibits spatial averaging and almost-deterministic dynamics of the global densities, an analytical approximation from nucleation theory, known as Avrami's law, describes our simulation results far better than standard ecological approximations.

Human progesterone receptor polymorphisms and implantation failure during in vitro fertilization

Objective Polymorphic variants of the human progesterone receptor gene have been described, but their potential influence on in vitro fertilization outcome have not been studied. Study design DNA was available from 317 women (cases) who had ≥2 embryo transfers without a clinical pregnancy and from 288 women (control subjects) who became pregnant after 1 in vitro fertilization attempt. With protocols that were specific for H770H (C/T genotype) and +331G/A polymorphism, amplification of polymorphism fragments, digestion with restriction enzymes, and gel visualization were performed. Results Allele frequencies for the 2 variants were 15.5% for H770H T and 4.1% for +331A in cases and 17.9% and 3.6% in control subjects, respectively. Both polymorphisms were rare among non-white subjects. Possession of a H770H T allele was associated with a decreased risk for implantation failure, which was nonsignificant overall but significant in women aged <35 years (adjusted relative risk, 0.52 [95% CI, 0.28, 0.97]). Possession of a +331A allele was associated with an increased risk of implantation failure, which was nonsignificant overall but significant in women who weighed <135 pounds (adjusted relative risk, 3.85 [95% CI, 1.20, 12.30]). The +331G/A polymorphism tended to increase the risk for implantation failure in women with an H770H C/C genotype, but not in women with a C/T or TT genotype ( P = .09). Among white women who were H770H C/C, there was a significant trend ( P = .03) in the proportion of +331G/A carriers as the number of implantation failures increased, from 8.6% of women with 0 failed attempts to 40% among women with ≥5 failed attempts. Conclusion Although human progesterone receptor polymorphisms do not clearly affect the risk for implantation failure in most women who undergo in vitro fertilization, the likelihood that a woman carries the +331G/A human progesterone receptor polymorphism increases with the number of failed attempts at implantation.

Selection of the Best Normal Population: A New Exact Solution, Asymptotically Optimal When k=2

SYNOPTIC ABSTRACTThe problem we deal with in this paper was first stated in 1954 in Bechhofer's pioneering paper in ranking and selection. Namely, there are k (2 or more) normal populations with all parameters unknown, and the goal is to select one population which has the largest mean. Despite much interest (and a number of failed attempts to solve this problem in the literature), the first solution came in a 1975 paper by Dudewicz and Dalal. A slightly different solution followed in a 1978 paper by Rinott. While there has been other work on the problem, to date these are the only exact solutions (all other “solutions” are either heuristic or asymptotic only). It has been recognized for some time that the available exact solutions do not (asymptotically) allocate sample size in a way which corresponds to what is known to be optimal when the variances are known. In this paper we give a new, third, exact solution to the problem. The new solution is asymptotically optimal in the case when there are two populations. In an example on a real data set, we illustrate the procedure and see that it would save 7% of the sample size in that example (and asymptotically saves 6% in that example).

Preliminary Validity of the Cognitive Function Checklist: Prediction of Tower of London Performance

The objective of this project was to establish the preliminary validation of selected scales of the Cognitive Function Checklist (CFC), a 178-item parent-report screening measure designed to identify executive function (EF) disorders in children and adolescents. Selected CFC scales were assessed using multiple regression to predict Tower of London (TOL) task performance. In a sample of 34 children (aged 6 to 15 years) referred due to suspected learning problems, CFC Impulsivity, Problem Solving, and Initiation scales, along with age, served as the main predictors of the TOL overall raw score (i.e., a composite of planning efficiency, impulsivity, and speed of performance). The CFC Impulsivity scale predicted TOL variables of impulsivity (number of failed attempts), and speed of performance (solution time). Contrary to our predictions, CFC Planning failed to predict TOL performance. These findings, although preliminary, highlight the potential advantage of the CFC as a screening measure of EF, specifically with respect to impulsivity and problem-solving ability.

The tower of London test: Validation and standardization for pediatric populatons

Abstract The Tower of London Test is a measure of planning and problem solving. Variations in administration and scoring and lack of normative data has led to difficulties in interpreting performances on the task. This study standardizes administration and scoring procedures and provides normative data on children's performances. A sample of 376 children, aged 7.0 to 13.11 years were administered the test. Analyses identified age trends, with older children exhibiting shorter solution times and more items correct. Number of failed attempts was not clearly related to age. Significant correlations were detected between Tower of London and other measures of executive function. Results indicate ongoing development of executive function, with greatest increments between the ages of 7 and 9 and again between 11 and 12 years, consistent with theoretical perspectives from developmental psychology and neurophysiological evidence showing maturation within the anterior regions of the cerebral cortex around these ages.

Technical Note—Optimal Pole-Vaulting Strategy

Under present international track and field rules, a participant in a pole-vaulting competition is entitled to select the heights of his vaulting attempts at all stages of the contest. The restrictions imposed are that sequential vaulting attempts should not be at decreasing bar heights, and that three unsuccessful attempts in succession—at any height—terminates participation in the contest. The last successful vault is the height scored by that participant in the competition. A dynamic programming model has been constructed to provide the optimal set of heights which the competitor should attempt to vault. These will depend on the last height cleared successfully, the total number of previous attempts, and the number of failed attempts since the last success. The strategy is directed at achieving the maximum expected height scored in the competition using readily available experimental data. A numerical example is provided, demonstrating the advantages gained in using the optimal strategy versus traditional patterns.