Latent Hazards Research Articles

Safety challenges of medical equipment in nurse anaesthetist training in Haiti

Safety challenges related to the use of medical equipment were investigated during the training of nurse anaesthetists in Haiti, using a systems approach to Human Factors and Ergonomics (HFE). The Observable Performance Obstacles tool, based on the Systems Engineering Initiative for Patient Safety (SEIPS) model, was used in combination with exploratory observations during 13 surgical procedures, to identify performance obstacles created by the systemic interrelationships of medical equipment. The identification of performance obstacles is an effective way to study the accumulation of latent factors and risk hazards, and understand its implications in practice and behaviour of healthcare practitioners. In total, 123 performance obstacles were identified, of which the majority was related to environmental and organizational aspects. These findings show how the performance of nurse anaesthetists and their relation to medical equipment is continuously affected by more than user-related aspects. The contribution of systemic performance obstacles and coping strategies to enrich system design interventions and improve healthcare system is highlighted. In addition, methodological challenges of HFE research in low-resource settings related to professional culture and habits, and the potential of community ergonomics as a problem-managing approach are described.

In situ simulated cardiac arrest exercises to detect system vulnerabilities.

Sudden cardiac arrest is the leading cause of death in the United States. Despite new therapies, progress in this area has been slow, and outcomes remain poor even in the hospital setting, where providers, drugs, and devices are readily available. This is partly attributed to the quality of resuscitation, which is an important determinant of survival for patients who experience cardiac arrest. Systems problems, such as deficiencies in the physical space or equipment design, hospital-level policies, work culture, and poor leadership and teamwork, are now known to contribute significantly to the quality of resuscitation provided. We describe an in situ simulation-based quality improvement program that was designed to continuously monitor the cardiac arrest response process for hazards and defects and to detect opportunities for system optimization. A total of 72 simulated unannounced cardiac arrest exercises were conducted between October 2010 and September 2013 at various locations throughout our medical center and at different times of the day. We detected several environmental, human-machine interface, culture, and policy hazards and defects. We used the Systems Engineering Initiative for Patient Safety (SEIPS) model to understand the structure, processes, and outcomes related to the hospital's emergency response system. Multidisciplinary solutions were crafted for each of the hazards detected, and the simulation program was used to iteratively test the redesigned processes before implementation in real clinical settings. We describe an ongoing program that uses in situ simulation to identify and mitigate latent hazards and defects in the hospital emergency response system. The SEIPS model provides a framework for describing and analyzing the structure, processes, and outcomes related to these events.

Use of FLIM histology-based HER2-HER3 heterodimer quantification and a Bayesian latent class proportional hazards model to predict cetuximab response in the COIN and new EPOC trials.

e14535 Background: Up-regulation of the EGFR-HER3 dimer may limit the efficacy of anti-EGFR treatment in breast cancerand may constitute a pathway of resistance to Cetuximab in colorectal cancer. T...

Agent-based mapping of credit risk for sustainable microfinance.

By drawing analogies with independent research areas, we propose an unorthodox framework for mapping microfinance credit risk---a major obstacle to the sustainability of lenders outreaching to the poor. Specifically, using the elements of network theory, we constructed an agent-based model that obeys the stylized rules of microfinance industry. We found that in a deteriorating economic environment confounded with adverse selection, a form of latent moral hazard may cause a regime shift from a high to a low loan payment probability. An after-the-fact recovery, when possible, required the economic environment to improve beyond that which led to the shift in the first place. These findings suggest a small set of measurable quantities for mapping microfinance credit risk and, consequently, for balancing the requirements to reasonably price loans and to operate on a fully self-financed basis. We illustrate how the proposed mapping works using a 10-year monthly data set from one of the best-known microfinance representatives, Grameen Bank in Bangladesh. Finally, we discuss an entirely new perspective for managing microfinance credit risk based on enticing spontaneous cooperation by building social capital.

Survival extrapolation in the presence of cause specific hazards.

Health economic evaluations require estimates of expected survival from patients receiving different interventions, often over a lifetime. However, data on the patients of interest are typically only available for a much shorter follow‐up time, from randomised trials or cohorts. Previous work showed how to use general population mortality to improve extrapolations of the short‐term data, assuming a constant additive or multiplicative effect on the hazards for all‐cause mortality for study patients relative to the general population. A more plausible assumption may be a constant effect on the hazard for the specific cause of death targeted by the treatments. To address this problem, we use independent parametric survival models for cause‐specific mortality among the general population. Because causes of death are unobserved for the patients of interest, a polyhazard model is used to express their all‐cause mortality as a sum of latent cause‐specific hazards. Assuming proportional cause‐specific hazards between the general and study populations then allows us to extrapolate mortality of the patients of interest to the long term. A Bayesian framework is used to jointly model all sources of data. By simulation, we show that ignoring cause‐specific hazards leads to biased estimates of mean survival when the proportion of deaths due to the cause of interest changes through time. The methods are applied to an evaluation of implantable cardioverter defibrillators for the prevention of sudden cardiac death among patients with cardiac arrhythmia. After accounting for cause‐specific mortality, substantial differences are seen in estimates of life years gained from implantable cardioverter defibrillators. © 2014 The Authors Statistics in Medicine Published by John Wiley & Sons Ltd.

Evaluation of a Risk Awareness Perception Training Program on Novice Teen Driver Behavior at Left-Turn Intersections

Collisions at left turn intersections are among the most prevalent types of teen driver serious crashes, with inadequate surveillance as a key factor. Risk awareness perception training (RAPT) has shown effectiveness in improving hazard anticipation for latent hazards. The goal of this study was to determine if RAPT version 3 (RAPT-3) improved intersection turning behaviors among novice teen drivers when the hazards were not latent and frequent glancing to multiple locations at the intersection was needed. Teens aged 16-18 with ≤180 days of licensure were randomly assigned to: 1) an intervention group (n=18) that received RAPT-3 (Trained); or 2) a control group (n=19) that received no training (Untrained). Both groups completed RAPT-3 Baseline Assessment and the Trained group completed RAPT-3 Training and RAPT-3 Post Assessment. Training effects were evaluated on a driving simulator. Simulator (gap selection errors and collisions) and eye tracker (traffic check errors) metrics from six left-turn stop sign controlled intersections in the Simulated Driving Assessment (SDA) were analyzed. The Trained group scored significantly higher in RAPT-3 Post Assessment than RAPT-3 Baseline Assessment (p< 0.0001). There were no significant differences in either traffic check and gap selection errors or collisions among Trained and Untrained teens in the SDA. Though Trained teens learned about hazard anticipation related to latent hazards, learning did not translate to performance differences in left-turn stop sign controlled intersections where the hazards were not latent. Our findings point to further research to better understand the challenges teens have with left turn intersections.

Simulator Evaluation of an Integrated Road Safety Training Program

Younger drivers aged 16 to 18 show disproportionately higher crash rates than middle-aged drivers, partly due to a decrement in their abilities to anticipate latent hazards, mitigate hazards and maintain attention on the forward roadway. Training programs have been developed to train novice drivers on each of the specific skills, hazard anticipation (RAPT), hazard mitigation (ACT), and attention maintenance (FOCAL). The current study both measures the effectiveness of a novel integrated training program (SAFE-T) that takes only a third as long to complete as do the three individual training programs and determines if integrating the training of all three higher cognitive skills will yield results comparable to the existing programs. The results indicated that drivers in the SAFE-T-trained group were significantly more likely to anticipate hazards, quicker and more effective at responding to hazards, and more likely to keep glance durations under a critical threshold of 2 seconds as compared to drivers in the placebo-trained group. Moreover, the results suggest that the SAFE-T training program can effectively reduce the time of the overall training and maintain effect sizes comparable to those of the previous programs.

Exploring the potential high energy locations and intensities in confined work spaces of waveguide dimensions

Adequately identifying and managing hazards at the workplace can be a tedious task which extends into the realm of uncertainty, probability and prediction models in order to fully comprehend the nature of the hazard. As such, organizations cannot be blamed for knowledge gaps in the training of personnel they contract to ensure a safe and healthy work environment, especially where there are latent hazards. Electromagnetic wave propagation at frequencies in the SAR (specific absorption rate) region is a special concern to authorities involved in setting RF (radiofrequency) and microwave exposure guidelines. Despite that there is no conclusive evidence to suggest that non-ionizing electromagnetic radiation causes adverse health effects other than thermal, no effort should be lost to ensure that workers and the public at large are adequately protected from unnecessary exposure to radiation. Standards however set exposure limits for free space, plane wave propagation but fall short in compiling information on intensities of these waves after they undergo reflection and diffraction from wall surfaces. Waveguide technology has managed to constrain microwaves to remain within set boundaries, with fixed frequencies that force the waves to behave differently to if they were moving in free space. This technology has offered the ability to transport more energy for communication purposes other than transmission lines. The size of a waveguide may be to the order of a few centimetres and can guide RF of wavelengths of the order of centimetres also but what if spaces of larger dimensions are capable of being waveguides and can guide waves of larger wavelengths such as those that correspond to frequencies between 30MHz to 300MHz? Such RF waves belong to the SAR region of the spectrum where strict exposure limits are set for health and safety protection since a standing man acts as a dipole antenna for this radiation and can absorb maximum energy from propagating RF waves. This review visits the likelihood for potential energy build-up due to RF propagation in confined spaces that are of waveguide design but with larger dimensions. Such confined spaces include silos, tanks, pipes, manholes, air-condition ducts, tunnels, wells, engine rooms and operator rooms on board vessels. In these confined spaces waves reflect off of the walls and combine constructively or destructively with incident waves producing reinforcement or cancellation respectively. Where there is reinforcement, the intensity of the wave for a particular distance in accordance with the standard, may exceed the exposure limit for this distance from the source thereby exposing the worker to larger intensities than the accepted limit and presenting a potential health and safety threat.

Caracterización del Sector Cerámico Tradicional del Valle de Aburrá y los Riesgos Profesionales Latentes en su Proceso Productivo

El presente estudio busca caracterizar y diagnosticar los peligros y riesgos presentes en las empresas que pertenecen al sector cerámico tradicional del Valle de Aburrá. En primera instancia se caracteriza el sector cerámico a partir de la revisión bibliográfica existente a nivel nacional y regional, para finalmente realizar un diagnóstico de los factores de riesgos profesionales que se presentan en el sector, mediante encuestas realizadas a gerentes y/o líderes de las áreas, encargados de velar tanto por la productividad de la empresa como por la gestión de los riesgos, teniendo como principales hallazgos las debilidades que presentan las organizaciones para identificar y valorar los riesgos profesionales latentes.

POLLUTION RESPONSE IN POST DISASTER RECOVERY- BEST PRACTICES FROM HURRICANE SANDY

ABSTRACT Operational Planning is the controlled process of quickly transitioning from chaos to calm; the ability to quell the unknown and create an environment of known, manageable hazards. The most notable challenge during all-hazards operations is moving emergency response operations forward in a concerted effort in somewhat nebulous and demanding environments, yet in accordance with all-hazards frameworks, laws and standing agency policies. Hurricane Sandy post-disaster response operations provided just the right test for that capability- an austere environment, an expansive geographic area, joint agency operations and latent hazards. Nevertheless, Hurricane Sandy post-disaster response operations, particularly those supporting Emergency Support Function 10 (ESF-10), proved infinitely successful, largely due to the deliberate operational planning and data processing methodologies developed to establish the clearest possible operational picture. Developed protocols, established later as a best practice, combined federal policies and regulations on pollution response operations and disaster response into a single operating standard for ESF-10 pollution response activities in support of Coast Guard Sector New York Unified Command operations in New York and New Jersey. Environmental response operations encompassed eight geographic Divisions and included thousands of potential pollution sources. This paper highlights specific methodologies for analyzing and prioritizing threats post-response, coordinating efforts across a joint-agency landscape and mounting an expeditious and efficient environmental response campaign in a concerted, unified manner.

Using In Situ Simulation to Evaluate Operational Readiness of a Children’s Hospital-Based Obstetrics Unit

Relocating obstetric (OB) services to a children's hospital imposes demands on facility operations, which must be met to ensure quality care and a satisfactory patient experience. We used in situ simulations to prospectively and iteratively evaluate operational readiness of a children's hospital-based OB unit before it opened for patient care. This project took place at a 314-bed, university-affiliated children's hospital. We developed 3 full-scale simulation scenarios depicting a concurrent maternal and neonatal emergency. One scenario began with a standardized patient experiencing admission; the mannequin portrayed a mother during delivery. We ran all 3 scenarios on 2 dates scheduled several weeks apart. We ran 2 of the scenarios on a third day to verify the reliability of key processes. During the simulations, content experts completed equipment checklists, and participants identified latent safety hazards. Each simulation involved a unique combination of scheduled participants who were supplemented by providers from responding ancillary services. The simulations involved 133 scheduled participants representing OB, neonatology, and anesthesiology. We exposed and addressed operational deficiencies involving equipment availability, staffing, interprofessional communication, and systems issues such as transfusion protocol failures and electronic order entry challenges. Process changes between simulation days 1 to 3 decreased the elapsed time between transfusion protocol activation and blood arrival to the operating room and labor/delivery/recovery/postpartum setting. In situ simulations identified multiple operational deficiencies on the OB unit, allowing us to take corrective action before its opening. This project may guide other children's hospitals regarding care processes likely to require significant focus and possible modification to accommodate an OB service.

Disaster-Related Environmental Health Hazards: Former Lead Smelting Plants in the United States

Natural disasters exacerbate risks of hazardous environmental exposures and adverse health consequences. The present study determined the proportion of previously identified lead industrial sites in urban locations that are at high risk for dispersal of toxic chemicals by natural disasters. Geographic analysis from publicly available data identified former lead smelting plants that coincide with populated urban areas and with high-risk locations for natural disasters. From a total of 229 urban smelting sites, 66 (29%) were in relatively high-risk areas for natural disasters: flood (39), earthquake (29), tornado (3), and hurricane (2). States with urban sites at relatively high risk for natural disaster included California (15); Pennsylvania (14); New York (7); Missouri (6); Illinois (5); New Jersey (4); Kentucky (3); Florida, Oregon, and Ohio (2 each); and Indiana, Massachusetts, Rhode Island, Texas, Utah, and Washington (1 each). Incomplete historical records showed at least 10 smelting site locations were affected by natural disaster. Forgotten environmental hazards may remain hazardous in any community. Uncertainty about risks in disasters causes disruptive public anxiety that increases difficulties in community responses and recovery. Our professional and public responsibility is to seek a better understanding of the risks of latent environmental hazards.

A comparative study of two desktop hazard perception tasks suitable for mass testing in which scores are not based on response latencies

In PC-based hazard perception tests scores are traditionally based on how quickly participants respond to developing hazards in video clips. A disadvantage of this method is that latent hazards which do not develop into acute threats cannot be included in the test. The present study compared two tasks using the same stimuli but with different response methods. The stimuli consisted of thirteen animated video clips in which latent hazards did not materialize. Latent hazards could either be a visible other road user who due to the circumstances could start to act dangerously, or a hidden other road users who could be on collision course. The first-mentioned were the overt latent hazards and the latter were the covert latent hazards. In Task 1, participants had to indicate what the high priority latent hazard was after they had watched a clip. In Task 2, participants could indicate latent hazards while they were watching a clip and decide afterwards which of the indicated latent hazards had the highest priority. In both tasks the scores were based on how many high priority latent hazards were detected and were not based not on response times. Professional drivers (driver trainers and driving examiners) and learner drivers were randomly assigned to a group that performed Task 1 and a group that performed Task 2. Professionals scored significantly better on both tasks than learner drivers. Although in both tasks professionals scored significantly higher, Task 1 seems to be a more promising alternative for the traditional hazard perception test than Task 2 because professional drivers scored significantly higher on overt latent hazards than learner drivers in Task 1 but not in Task 2 and experience with computer games influenced the scores in Task 2 but not in Task 1. A weakness of Task 1 was its rather low internal consistency (α=.69).

Potential risk of variable parameter cascade chaos system

Lyapunov index is one of criteria for testing whether the system is in a chaotic state, and its value represents the developed level of system chaotic state. To study the Lyapunov index characteristic of cascade chaotic system and reveal disturbance mechanism among subsystems in cascade chaotic system, the following researches are carried out. First, the disturbance model among subsystems is constructed from the viewpoint of pseudo noise disturbance, Lyapunov index difference between without and with external noise influence is investigated. Then the conclusion that disturbances among subsystems can be considered as pseudo noise influence is drawn. Second, the conclusion is proved that cascade system Lyapunov index is not the algebraic sum of each independent subsystems, but the one of each subsystems which consist of pre disturbances. Then taking the logistic representation for example, nine cascade systems are designed to prove this conclusion. And some novel characteristics and phenomena are found from the above investigations. They are (a) the phenomenon of “more is less”, that is, Lyapunov index will decrease with the increase of cascade levels, and the phenomenon of “A miss is as good as mile”; (b) even each independent subsystems is chaotic, the cascade system needs not to be chaotic; conversely, even each independent subsystems is not chaotic, the cascade system may be chaotic; (c) whether the cascade system is chaotic is associated with the order of subsystem. Finally, it is pointed out that cascade level has the influences of pros and cons on cascade system, thus revealing the latent hazard of parametric cascade chaotic system. The research result can provide important theoretic foundation for system security and the scientific evaluation of encryption keys.

Surgical treatment based on pedicle screw instrumentation for thoracic or lumbar spinal Langerhans cell histiocytosis complicated with neurologic deficit in children

Background contextSurgical indications and procedures for spinal Langerhans cell histiocytosis (LCH) in children are still controversial. Reports containing large samples of surgically treated patients are few in the currently available literature, and the reported operative procedures were also somewhat obsolete. So, further investigation based on large-sample cases and using improved surgical techniques is beneficial and helpful to refine the treatment strategy. PurposeTo recommend a reasonable treatment strategy for thoracic or lumbar spine LCH in children complicated with neurologic deficit. Study design/settingRetrospective/academic medical center. Patient sampleTwelve children aged from 2 to 16 years old with the diagnosis of thoracic or lumbar spinal LCH accompanied by neurologic deficit received surgical treatment from January 2005 to January 2010. Outcome measuresFrankel scale for neurologic function, fusion of the mass, and recurrence of the lesion. MethodsAll 12 patients presented initially with local pain and progressive neurologic detriment. Neurologic evaluation revealed two patients with Frankel Grade B, eight with Grade C, and two with Grade D. Radiographic features were positive for typical vertebra plana, a space-occupying mass in the spinal canal compressing neural elements, and a spinal canal encroachment rate more than 50%. Posterior instrumentation with pedicle screw combined with anterior corpectomy, decompression, and support bone graft was performed in the first seven patients as a one-stage procedure. In the remaining five patients, posterior pedicle screw fixation, laminectomy for decompression (via excision of the tumor-like mass), and repair of laminae with allograft bone block were performed. The collapsed vertebral body was left untouched. No chemotherapy or radiotherapy was administrated postoperatively in any of the cases. ResultsThe mean follow-up duration was 43.3 months. The mean operation time was 330 minutes with combined procedure and 142 minutes with single posterior approach (p=.000). The average blood loss was 933 mL with combined procedure and 497 mL with single posterior approach (p=.039). Three of seven patients who received combined surgery encountered approach-related complications, that is, one with intercostal neuralgia and two with pleural effusion. No severe neurologic deteriorate, instrumentation failure, or disease recurrence was detected at follow-up. Neurologic function completely recovered in all 12 patients from 2 to 12 weeks after surgery. The anterior bone graft fused and shaped well in all seven patients, and allograft bone block for lamina repair also achieved complete fusion in the remaining five patients. The internal fixator was removed at 3 to 5 years (average 4.1 years) after initial operation in six patients. No deformity, including scoliosis and kyphosis, has been identified during follow-up period in both procedures. ConclusionsFor spinal LCH patients, neurologic deficit is a main indication for operative treatment to prevent permanent and serious consequences. Surgery provides an opportunity for rapid recovery of neurologic function. Both combined and single-stage posterior approaches based on pedicle screw instrumentation techniques are similarly effective in relieving neurologic compression. However, single-stage posterior approach is more favorable with less complications, and preserving involved vertebral body is not a latent hazard of recurrence.

Polyhazard models with dependent causes

Polyhazard models constitute a flexible family for fitting lifetime data. The main advantages over single hazard models include the ability to represent hazard rate functions with unusual shapes and the ease of including covariates. The primary goal of this paper was to include dependence among the latent causes of failure by modeling dependence using copula functions. The choice of the copula function as well as the latent hazard functions results in a flexible class of survival functions that is able to represent hazard rate functions with unusual shapes, such as bathtub or multimodal curves, while also modeling local effects associated with competing risks. The model is applied to two sets of simulated data as well as to data representing the unemployment duration of a sample of socially insured German workers. Model identification and estimation are also discussed.

Computational comparison of charge neutralisations of conductors and insulators with corona ionisers

Abstract We report a numerical investigation of phenomena of charge neutralisations of insulators and conductors with a balanced DC or AC ioniser using 2-D cylindrical electrohydrodynamic modelling. The early-phase phenomena of the insulator charge neutralisation are complicated and significantly different from the conductor ones, which indicates that the evaluation by the standard test may lead to potential problems in practical applications. In addition, the results of simulations demonstrated that, in the insulator charge neutralisation, ionisers themselves can cause latent hazards during neutralisation. We propose proper use of ionisers and the standard test to avoid such hazards.

Application of Integrated Human Error Identification Techniques for Chemicals Cylinder Change Task

This paper outlines the human error identification techniques currently existent to assess and analyze the risk and human error. Even if many formal error identification techniques have existed for years, none could be validated for use to every different domain. This study considers lots of possible error modes that include external error modes, internal error modes, performance shaping factors and psychological error mechanisms, and integrates a number of execution procedures of human error identification techniques, including task analysis, criticality analysis and reliability analysis, to assess the latent human error and hazard risk in a case plant. It is concluded that the integrated method is a valuable aid to develop much safer operational processes and can be used to predict human error rates of critical tasks in the plant.

Aviation Approach Charts in an iPad®World

The process used to create charted depictions of aviation instrument approach procedures in the United States is examined. The rapid growth of iPad®-like mobile technologies is discussed relative to the historical context of chart implementation. Notional new methods of electronic chart generation are introduced, demonstrating both the functional possibilities and concerns not directly addressed by existing regulation for private aircraft operators. These concerns suggest a ‘yin-yang’ of the stifling of innovation versus the creation of latent safety hazards. The article concludes by recommending regulatory oversight review of approach chart implementation. A glossary of terms is included at the end of this paper. The facts, analysis, and opinions offered in this article represent an independent effort of the author and do not reflect the opinions of any academic institution or government agency. The author also has a limited financial interest in certain iOS®applications.

Determination of Heavy Metals and Other Elements in Artisanal Gold Mining Soils

Problem statement: The possible exposure of heavy elements to life as a result of artisanal gold mining activities can be of great concern because of its associated effect on health. Approach: Soil samples from the artisanal gold mining sites of Awwal and Bagega villages in Kebbi and Zamfara states of Nigeria were collected and analyzed for heavy and other elements by X-Ray Fluorescence (XRF) technique. Ten of the element analyses are presented in this study, based on their toxicity levels. Results: Four of the ten elements (Pb, Si, Rb and Fe) showed relatively high concentrations. Two of these four elements presented, (Si and Pb) may pose latent and immediate hazards to health. Respiratory crystalline silica is the major element constituent of the ever-well-pronounced mining dusts of the two sites. Its form of occurrence portends irreversible health problem called silicosis and is well linked to cancer forming properties; both of which develop through latency periods. Pb at whatever concentration portends both immediate and long term hazards to women and children at the greatest risks of exposures. Conclusion: Based on the results presented, there exist a possibility of an immediate and long term health risks associated with the artisanal gold mining exercises in the two sites studied if the said uncoordinated and unprofessional activities of the miners are left unchecked.