bluuebunny/crossref_metadata_2025 huggingface dataset:
On The Role of the Eshelby Energy-Momentum Tensor in Materials with Multiple Natural Configurations
Authors: Rajagopal K. R. , Srinivasa A. R.
Published: June 2007

We discuss the connection between two important parallel developments in continuum mechanics that has gone unnoticed despite intense activity in both these seemingly disparate areas: the first stems from the pioneering work of Eckart on the role of the evolution of “natural configurations” in the inelastic response of solids; the second stems from the seminal work of Eshelby concerning the energy-momentum tensor associated with the driving forces that arise as a consequence of inhomogeneities and defects during the deformations of solids. We show that a variety of driving forces manifest themselves as a consequence of the evolution of natural configurations, depending on the particular process under consideration. Our study makes it clear that no new balance laws need be invoked in order to accommodate such driving forces, the usual balances laws of mechanics being sufficient.
Dead Regions in the Cochlea: Diagnosis, Perceptual Consequences, and Implications for the Fitting of Hearing Aids
Authors: Moore Brian C. J.
Published: June 2007

Hearing impairment is often associated with damage to the hair cells in the cochlea. Sometimes there may be complete loss of function of inner hair cells (IHCs) over a certain region of the cochlea; this is called a “dead region”. The region can be defined in terms of the range of characteristic frequencies (CFs) of the IHCs and/or neurons immediately adjacent to the dead region. This paper reviews the following topics: the effect of dead regions on the audiogram; methods for the detection and delineation of dead regions based on psychophysical tuning curves (PTCs) and on the measurement of thresholds for pure tones in “threshold equalizing noise” (TEN); effects of dead regions on speech perception; effects of dead regions on the perception of tones; implications of dead regions for fitting hearing aids. The main conclusions are: (1) Dead regions may be relatively common in people with moderate-to-severe sensorineural hearing loss; (2) Dead regions cannot be reliably diagnosed from the audiogram; (3) PTCs provide a useful way of detecting dead regions and defining their boundaries. However, the determination of PTCs is probably too time-consuming to be used for routine diagnosis of dead regions in clinical practice; (4) The measurement of detection thresholds for pure tones in TEN provides a simple method for clinical diagnosis of dead regions; (5) Pure tones with frequencies falling in a dead region do not evoke clear pitch sensations (pitch matching is highly variable) and the perceived pitch is sometimes, but not always, different from “normal”. However, ratings of pitch clarity cannot be used as a reliable indicator of a dead region; (6) Amplification of frequencies well inside a high-frequency dead region usually does not improve speech intelligibility, and may sometimes impair it. However, there may be some benefit in amplifying frequencies up to 50 to 100% above the estimated low-frequency edge of a high-frequency dead region; (7) The optimal form of amplification for people with low-frequency dead regions remains somewhat unclear. There may be some benefit from avoiding the amplification of frequencies well inside a dead region; (8) Patients with extensive dead regions are likely to get less benefit from hearing aids than patients without dead regions; (9) For patients with diagnosed dead regions at high frequencies, consideration should be given to use of a hearing aid incorporating frequency transposition and/or compression.
Digital Noise Reduction: An Overview
Authors: Bentler Ruth , Chiou Li-Kuei
Published: June 2007

Digital noise reduction schemes are being used in most hearing aids currently marketed. Unlike the earlier analog schemes, these manufacturer-specific algorithms are developed to acoustically analyze the incoming signal and alter the gain/output characteristics according to their predetermined rules. Although most are modulation-based schemes (ie, differentiating speech from noise based on temporal characteristics), spectral subtraction techniques are being applied as well. The purpose of this article is to overview these schemes in terms of their differences and similarities.
Effect of Probe Tube Insertion Depth on Spectral Measures of Speech
Authors: Caldwell Marc , Souza Pamela E. , Tremblay Kelly L.
Published: June 2007

This study investigated how depth variations in the tip of the probe tube affected spectral measures of speech recorded in the external ear canal. Consonant-vowel nonsense syllables were recorded with a probe tube microphone system in 10 adult participants with normal middle ear function. Recordings were made with the probe tube tip placed 1 mm, 5 mm, and 10 mm beyond the medial tip of a custom earmold. The effect of probe depth was evaluated on spectral levels (one-third octave and one-twelfth octave band). Extending the probe tube 10 mm past the medial tip of the earmold gave the most accurate results, with relatively lower sound levels for either the 1-mm or 5-mm insertion depth. In general, the effect of insertion depth was minimal at frequencies below 3 to 4 kHz, although this varied with the specific phoneme and the width of the analysis bands. The authors found no significant difference between 1- and 5-mm insertion depths, suggesting that as long as the tip of the probe tube is sufficiently close to the tympanic membrane to capture the highest frequency of interest, it makes little difference if it is less than 5 mm beyond the earmold tip.
Digital Hearing Aids From the Perspective of One Consumer/Audiologist
Authors: Ross Mark
Published: June 2007

Recent developments in hearing aids are reviewed in the context of the author's personal experience as an audiologist and as a hearing aid wearer. The need for evidence of benefit specific to digital signal processing in hearing aids is stressed, as well as addressing cost-benefit ratios in view of the high cost of digital hearing aids.
The Future of Hearing Aid Technology
Authors: Edwards Brent
Published: June 2007

Hearing aids have advanced significantly over the past decade, primarily due to the maturing of digital technology. The next decade should see an even greater number of innovations to hearing aid technology, and this article attempts to predict in which areas the new developments will occur. Both incremental and radical innovations in digital hearing aids will be driven by research advances in the following fields: (1) wireless technology, (2) digital chip technology, (3) hearing science, and (4) cognitive science. The opportunities and limitations for each of these areas will be discussed. Additionally, emerging trends such as connectivity and individualization will also drive new technology, and these are discussed within the context of the areas given here.
Adult Aural Rehabilitation: What Is It and Does It Work?
Authors: Boothroyd Arthur
Published: June 2007

Adult aural rehabilitation is here defined holistically as the reduction of hearing-loss-induced deficits of function, activity, participation, and quality of life through a combination of sensory management, instruction, perceptual training, and counseling. There is a tendency for audiologists to focus on sensory management, aural rehabilitation being seen as something done by someone else after the provision of hearing aids or cochlear implants. Effective sensory management may, by itself, lead to improved activity, participation, and quality of life, but there is no guarantee that these outcomes will be automatic or optimal. In fact, there is often a disconnect between clinical measures of assisted auditory function and self-assessed benefit. Costs associated with a holistic approach can be minimized by bundling as many as possible into the cost of hearing devices, by taking advantage of computer-based perceptual training, and by capitalizing on the benefits of group counseling.
Technologic Advances in Aural Rehabilitation: Applications and Innovative Methods of Service Delivery
Authors: Sweetow Robert W. , Sabes Jennifer Henderson
Published: June 2007

The level of interest in aural rehabilitation has increased recently, both in clinical use and in research presentations and publications. Advances in aural rehabilitation have seen previous techniques such as speech tracking and analytic auditory training reappear in computerized forms. These new delivery methods allow for a consistent, cost-effective, and convenient training program. Several computerized aural rehabilitation programs for hearing aid wearers and cochlear implant recipients have recently been developed and were reported on at the 2006 State of the Science Conference of the Rehabilitation Engineering Research Center on Hearing Enhancement at Gallaudet University. This article reviews these programs and outlines the similarities and differences in their design. Another promising area of aural rehabilitation research is the use of pharmaceuticals in the rehabilitation process. The results from a study of the effect of d-amphetamine in conjunction with intensive aural rehabilitation with cochlear implant patients are also described.
An Internet Survey of Individuals With Hearing Loss Regarding Assistive Listening Devices
Authors: Harkins Judith , Tucker Paula
Published: June 2007

An Internet survey of individuals with hearing loss was conducted to determine their use of assistive listening devices for face-to-face conversation and, while part of an audience, their satisfaction with assistive listening devices, their interest in the concept of a universal assistive listening device receiver, and their interest in receiving audiologic information and services through the Internet. The 423 respondents who used assistive listening devices found them to be of significant benefit across a range of listening situations. Most respondents were open to the idea of purchasing a personal device that could work both with hearing aids and a range of transmission media. Probably because of the sampling bias inherent in an Internet survey, respondents were inclined to choose Internet-based and peer-based sources of information, and made many suggestions for both improving assistive listening devices and for improving information available about them by using the Internet.
From awareness to acknowledgment: The development of concern among Latina mothers of children with disruptive behaviors
Authors: Arcia Emily , Fernández María C.
Published: June 2007

The purpose of this study was to describe the process by which Latina mothers become concerned about their children’s disruptive behaviors and deem professional help to be a necessary measure. A sample fo 62 Latina first-time help seekers were asked to narrate their stories of their children’s behavior, the process by which they became concerned, and their decision to seek professional services. Both qualitative and quantitative measures and procedures were used.

Key findings include the following. Most mothers described onset after age 3.75. Earlier recognition of disruptive behaviors and earlier concern over these were associated with greater perceptions of functional impairment and with a greater degree of maternal distress at the time of the interview. Increases in awareness and in concern were associated with life events such as moving, migration, and changes in family composition. Mothers often assumed these life events to be causally linked to children’s difficulties. Earlier concern did not speed the awareness process. A “saturation point” was a better descriptor of the culmination of maternal concern than “problem recognition” or “problem labeling” School report of negative behavior was the strongest catalyst to problem acknowledgement. Mothers who recognized onset after their children entered school progressed through the concern process significantly faster than mothers who became concerned at younger child ages.
A chart review study of the Inattentive and Combined Types of ADHD
Authors: Weiss M. , Worling D. , Wasdell M.
Published: June 2007

Studies of the clinical correlates of the subtypes of Attention-Deficit/Hyperactivity Disorder (ADHD) have identified differences in the representation of age, gender, prevalence, comorbidity, and treatment. We report retrospective chart review data detailing the clinical characteristics of the Inattentive (IA) and Combined (C) subtypes of ADHD in 143 cases of ADHD-IA and 133 cases of ADHD-C.

The children with ADHD-IA were older, more likely to be female, and had more comorbid internalizing disorders and learning disabilities. Individuals in the ADHD-IA group were two to five times as likely to have a referral for speech and language problems. The children with ADHD-IA were rated as having less overall functional impairment, but did have difficulty with academic achievement. Children with ADHD-IA were less likely to be treated with stimulants. One eighth of the children with ADHD-IA still had significant symptoms of hyperactivity/impulsivity, but did not meet the DSM-IV threshold for diagnosis of ADHD-Combined Type.

The ADHD-IA subtype includes children with no hyperactivity and children who still manifest clinically significant hyperactive symptomatology but do not meet DSM-IV criteria for Combined Type. ADHD-IA children are often seen as having speech and language problems, and are less likely to receive medication treatment, but respond to medical treatment with improvement both in attention and residual hyperactive/impulsive symptoms.
EEG biofeedback vs. placebo treatment for Attention-Deficit/Hyperactivity Disorder: A pilot study
Authors: Heywood C. , Beale I.
Published: June 2007

Method: Seven children diagnosed with attention-deficit hyperactivity disorder (ADHD) were trained using a standard EEG biofeedback treatment protocol designed to alter SMR/theta ratios and reduce behavioral symptomatology diagnostic of ADHD. During alternate periods they were also trained using a placebo protocol that was identical to the treatment protocol, save that the association between EEG patterns and feedback to the participants was random. Single-case design elements were used to control for the effects of internal validity threats such as maturation, history, and treatment order. Two participants failed to complete all training sessions, and the effects of training on behavior were analyzed both including and excluding these non-completers.

Results: When all participants were included in analyses that controlled for overall trend, EEG biofeedback was found to be no more effective than the placebo control condition involving non-contingent feedback, and neither procedure resulted in improvements relative to baseline levels. When overall behavioral trends unrelated to training were not controlled for and noncompleters were excluded from the analysis, it could be mistakenly concluded that EEG biofeedback is significantly more effective than placebo and that the effect sizes involved are moderate to large. These results indicate that many previous reports of the efficacy of EEG biofeedback for ADHD, particularly those presenting series of single cases, might well have been based on spurious findings.
The effects of yoga on the attention and behavior of boys with Attention-Deficit/hyperactivity Disorder (ADHD)
Authors: Jensen Pauline. S. , Kenny Dianna T.
Published: June 2007

Boys diagnosed with ADHD by specialist pediatricians and stabilized on medication were randomly assigned to a 20-session yoga group ( n = 11) or a control group (cooperative activities; n = 8). Boys were assessed pre- and post-intervention on the Conners’ Parent and Teacher Rating Scales-Revised: Long (CPRS-R:L & CTRS-R:L; Conners, 1997), the Test of Variables of Attention (TOVA; Greenberg, Cormna, & Kindschi, 1997), and the Motion Logger Actigraph.

Data were analyzed using one-way repeated measures analysis of variance (ANOVA). Significant improvements from pre-test to post-test were found for the yoga, but not for the control group on five subscales of the Conners’ Parents Rating Scales (CPRS): Oppositional, Global Index Emotional Lability, Global Index Total, Global Index Restless/Impulsive and ADHD Index. Significant improvements from pre-test to post-test were found for the control group, but not the yoga group on three CPRS subscales: Hyperactivity, Anxious/Shy, and Social Problems. Both groups improved significantly on CPRS Perfectionism, DSM-IV Hyperactive/Impulsive, and DSM-IV Total .For the yoga group, positive change from pre- to post-test on the Conners’ Teacher Rating Scales (CTRS) was associated with the number of sessions attended on the DSM-IV Hyperactive-Impulsive subscale and with a trend on DSM-IV Inattentive subscale. Those in the yoga group who engaged in more home practice showed a significant improvement on TOVA Response Time Variability with a trend on the ADHD score, and greater improvements on the CTRS Global Emotional Lability subscale. Results from the Motion Logger Actigraph were inconclusive.

Although these data do not provide strong support for the use of yoga for ADHD, partly because the study was under-powered, they do suggest that yoga may have merit as a complementary treatment for boys with ADHD already stabilized on medication, particularly for its evening effect when medication effects are absent. Yoga remains an investigational treatment, but this study supports further research into its possible uses for this population. These findings need to be replicated on larger groups with a more intensive supervised practice program.
The acute effect of methylphenidate in Brazilian male children and adolescents with ADHD: A randomized clinical trial
Authors: Szobot C. M. , Ketzer C. , Parente M. A. , Biederman J. , Rohde L. A.
Published: June 2007

Objective: To evaluate the acute efficacy of methylphenidate (MPH) in Brazilian male children and adolescents with ADHD.

Method: In a 4-day, double-blind, placebo-controlled, randomized, fix dose escalating, parallel-group trial, 36 ADHD children and adolescents were allocated to two groups: MPH ( n = 19) and placebo ( n = 17). Participants were evaluated pre- and posttreatment using the 10-item Conners Abbreviated Rating Scale (ABRS), the Children’s Global Assessment Scale (CGAS), and a simplified version of the Continuous Performance Test (CPT).

Results: The MPH group had a significantly greater decrease in ABRS scores and a significantly higher increase in CGAS scores than the placebo group ( p < 0.01). The MPH group showed also a significantly higher proportion of patients with a robust improvement (decrement of at least 50% in the ABRS score after the intervention) than the placebo group ( p < 0.01). The MPH effect size for the ABRS was 1.05 (95% CI = 0.73-1.37).

Conclusion: Our results extend the efficacy of MPH on the ADHD core symptoms extensively demonstrated in clinical trials with samples from some developed countries to a sample from a developing country where a diverse culture may modulate the clinical presentation of the disorder.
Efficacy and safety of atomoxetine in childhood Attention-Deficit/Hyperactivity Disorder with comorbid Oppositional Defiant Disorder
Authors: Kaplan S. , Heiligenstein J. , West S. , Busner J. , Harder D. , Dittmann R. , Casat C. , Wernicke J. F.
Published: June 2007

Objective: To compare the safety and efficacy of atomoxetine, a selective inhibitor of the norepinephrine transporter, versus placebo in Attention-Deficit/Hyperactivity Disorder (ADHD) patients with comorbid Oppositional Defiant Disorder (ODD).

Methods: A subset analysis of 98 children from two identical, multi-site, double-blind, randomized, placebo-controlled trials involving 9 weeks of treatment with atomoxetine or placebo was conducted. Patients met DSM-IV ADHD criteria. ODD was diagnosed with the Diagnostic Interview for Children and Adolescents-IV (DICA-IV; Reich, Welner, & Herjanic, 1997). ADHD severity was assessed with the ADHD Rating Scale-IV-Parent Version: Investigator Administered and Scored (ADHD-RS-IV-Parent:Inv; DuPaul, Power, Anastopoulos, & Reid, 1998); the short version of the Conners’ Parent Rating Scales-Revised (CPRS-R:S; Conners, 2000); and the Clinical Global Impressions of ADHD Severity (CGI-ADHD-S; Guy, 1976). Clinical response was defined as a ≥ 25% reduction in ADHD-RS-IV-Parent:Inv total score.

Results: ADHD-RS-IV-Parent:Inv, CGI-ADHD-S, and three CPRS-R:S subscale scores improved markedly with atomoxetine treatment. However, a decrease in the CPRS-R:S Oppositional subscore for atomoxetine-treated patients was not significantly greater than scores for placebo-treated patients. Clinical response rates were 65.4% in the atomoxetine group, and 36.4% in the placebo group ( p = .007).

Conclusion: Atomoxetine was effective for the treatment of ADHD in patients with comorbid ODD. It did not significantly reduce the severity of ODD symptoms, and was well tolerated by the patients.
Neuropsychological Testing: Methodology, Interpretation and Outcomes
Authors: Stump David A.
Published: June 2007

The outcome most dreaded by patient and surgeon alike is a brain dysfunction. Numerous surveys indicate most patients would prefer death to significant neurological impairment. Cardiac surgery currently enjoys a remarkable safety record in regard to a low death rate and major cerebral infarctions. However, neurobehavioral dysfunction, i.e. memory, coordination, and attention deficits, continues to be an area that is identified in the literature as a major negative outcome associated with cardiac surgery.

If the cardiac surgical community is going to eliminate brain injury associated with interoperative methods and apparatus, then a sensitive, reproducible and quick assessment of brain function that can be reliably correlated with surgical interventions is a basic requirement. This paper discusses the experimental design, environmental and statistical concerns relative to selecting a battery of neurobehavioral assessment tools appropriate for cardiac surgery patients so, as a team, we can make a safe operation safer.
Fat Embolism: A Central Nervous System Problem
Authors: Byrick Robert J.
Published: June 2007

Microvascular fat in the systemic circulation is a common postmortem finding in patients dying after trauma or cardiopulmonary bypass. The causative relationship between the microvascular fat and tissue inflammation, ischemia, and injury is unclear. Characteristic clinical lesions on magnetic resonance imaging and evidence in animal models suggest that focal cerebral edema may be associated with fat microemboli. This fat occludes cerebral vessels 5-15 microns in diameter, after passing through either the lung or filters in cardiopulmonary bypass circuits. Microvascular fat may directly cause the injury or may be a ‘second hit’ phenomenon, thus aggravating a pre-existing inflammatory reaction to injury, indirectly causing cerebral injury and adverse neurocognitive outcomes after cardiac surgery and trauma.
Anesthesia for Pediatric Chest Trauma
Authors: Agarwal Rita
Published: June 2007

Thoracic trauma in children is the second most frequent cause of death in the pediatric population. The majority of these children will have multisystem injuries. Management of these patients starts with the primary survey, resuscitation, and secondary survey as described in Advanced Trauma Life Support training. Most children with thoracic injuries can be observed or treated nonoperatively. The majority of children who do need surgery will need exploratory laparotomy and may have significant blood loss. The anesthesiologist needs to be prepared to manage a patient with severe underlying respiratory derangements, ongoing blood loss, and /or cardiac dysfunction. Moreover, one-lung ventilation may be necessary for optimal surgical exposure, which will present considerable challenges.
Rapid Transfusion Devices for Hemorrhagic Cardiothoracic Trauma
Authors: Elia Elia , Kang Yoogoo
Published: June 2007

Cardiothoracic trauma patients are frequently hypovolemic and hypothermic and may require massive transfusion, which can itself causesuch complications as acidosis, electrolyte imbalance (hypocalcemia and hyperkalemia), hypothermia, di lutional coagulopathy, and adultrespiratory distress syn drome. At the present time, there are a number of rapid infu sion devices such as Level I® (capable of delivering 37°C at a flow rate of up to 600 ml/min), Fluid Management System® (FMS®) (which can deliver 37.5°C of fluid at a flow rate of up to 500 ml/min), Rapid Infusion System® (RIS®) (which can pro vide up to 1,500 ml of 37°C fluid in one and one half minutes), and Rapid Solution Administration Set® (RSASO) (which can not only deliver a maximum of 2,200 m/min, but can warm the fluid to normothermia at a flow rate of 500 ml/min). However, pressurized devices such as Level IO can cause air embolism, interstitial infiltration and the compartment syndrome, and the flow rate is not operator-controlled. Devices such as FMS®, RIS®, and RSAS® incorporate a cardiotomy reservoir which has the potential for clot formation when any calcium-con taining solution is added. In this article, rapid infusion devices are compared, and complications associated with massive transfusion are described.
Mechanical Support After Cardiac Surgery
Authors: Naughton Paul , Bashour C. Allen
Published: June 2007

Mechanical circulatory support for low cardiac output after cariac surgery was first attempted in 1962. Since then, many ventricular assist devices have been developed and employed. The following is a discussion of the history, demographics, inications, and devices used for mechanical circulatory suport in this setting. lntra-aortic balloon pulsation, pulsatile verus non-pulsatile flow, volume bypass, roller and centrifugal pumps, extracorporeal membrane oxygenation, and imlantable devices are reviewed. Early postoperative care, reovery and weaning from mechanical circulatory support, and the special issues that relate to biventricular failure and control of right-sided ventricular function, as well as anticoagulation, and sepsis are addressed.
Current Issues Affecting Critical Care Practice
Authors: Higgins Thomas L.
Published: June 2007

Internal and external forces continue to impact the practice of critical care medicine. Contracting for purchase of hospital services will soon be guided by the presence or absence of specific hospital attributes, including computerized physician order entry, evidence-based hospital referral, and the staffing model for intensive care unit care. The Leapfrog group, a consortium of health care purchasers, prefers to contract with hospitals that have implemented full-time intensive care unit physician staffing. This requirement is likely to increase the demand for critical care specialists. Personnel shortages are already apparent in critical care nursing and are expected to occur with physician specialists as well. Other current issues include the demand for increasingly detailed information on intensive care unit outcomes, a focus on patient safety, and cost control.
Cardiac Considerations for the Obstetric Patient
Authors: Osibamiro-Sedun Adebambo , Johnson Calvin
Published: June 2007

Pregnancy and heart disease present a unique challenge to the anesthesiologist. Pregnancy results in physiological changes to the parturient's cardiovascular system that can unmask or worsen underlying heart disease. To avoid untoward complications resulting in significant maternal and/or fetal morbidity or mortality, the anesthesiologist must be knowledgeable about the progression of heart disease during pregnancy. Discussed are the pathophysiology, clinical presentation, and anesthetic management of valvular, congenital, vascular, and ischemic heart disease, and cardiomyopathy in pregnancy.
Endovascular Abdominal Aortic Aneurysm Repair
Authors: Kuchta Kenneth F.
Published: June 2007

Although endovascular surgery for aortic aneurysms can be traced to the 19th century, open surgery has dominated during the past 50 years. Indeed, open repair of aneurysms has been one of the most successful developments in vascular surgery. Despite improvements in mortality rates, open repair remains a major operation often undertaken in patients with significant comorbidities. Starting from basic research dating back several decades, the 1990s were noted for very active clinical development of endovascular abdominal aortic repair in an attempt to provide an alternative to open repair, especially for high-risk patients. Early successes with decreased intensive care unit and hospital stays were tempered by technical issues and the “endoleak,” the term given to an incomplete exclusion of the aneurysm from the circulation. This potential for rupture, despite treatment, was cause for concern. The need for long-term surveillance and secondary procedures, if not conversion to open repair, further compounded these issues. Despite these concerns, progress continued, and by the end of 2002, the Food and Drug Administration had approved three devices for marketing. Although surgeons are faced with increasingly complex issues related to endovascular repair, anesthesiologists have found their management of this procedure to be simpler in many ways. The smaller incisions and improved hemodynamic stability have led to a variety of anesthetics being tried, including monitored anesthesia care. Anesthesiologists continue to explore a number of opportunities to improve patient outcome in these procedures. These include selection of the most optimal anesthetic, the most appropriate perioperative renal protection, and the best preparation for and management of a conversion to an open procedure. Whatever the final role for endovascular surgery in the management of abdominal aortic aneurysms, it is an intellectually stimulating and scientifically promising technique for surgeons, anesthesiologists, and the patients they serve.
Effects of General Anesthetics on Regulation of the Peripheral Vasculature
Authors: Stekiel Thomas A. , Bosnjak Zeljko J. , Stekiel William J.
Published: June 2007

The heart is a passively filling pump in a circulatory system that is connected in series with distensible blood vessels. Therefore, systemic blood pressure and tissue perfusion depend upon adequate peripheral vascular tone as well as myocardial function. Likewise, pharmacologic agents that alter circulatory stability can affect one or both of these components. The generalized depressor effects of general anesthetics have been well known clinically for over 50 years. Moreover, there are many similarities in basic cellular regulatory mechanisms among the different tissue types, and general anesthetics are well known to distribute freely among the perfusion-rich tissues (eg, central nervous system, cardiovascular system, and renal system). Therefore, it is likely that the hemodynamic depression resulting from the systemic administration of anesthetics results from actions on regulatory mechanisms of the peripheral vasculature as well as on the heart. The peripheral vasculature is regulated by extrinsic neural, endothelial, and humoral mechanisms, which interact with each other as well as with intrinsic membrane and intracellular systems within the vascular smooth muscle cell. Different general anesthetics have been found to act on specific mechanisms at each of these levels. However, the large number and complexity of these known mechanisms, as well as the many anesthetic agents, has made it extremely difficult to determine which are significant in terms of the meaningful mechanisms that are responsible for anesthetic action, major side effects, or both. Current knowledge about the effects of general anesthetics on both the extrinsic intrinsic regulatory mechanisms of peripheral vascular control is reviewed.
Devices for Monitoring Heparin and Protamine in the Operating Room
Authors: Santrach Paula J.
Published: June 2007

Ongoing monitoring of heparin anticoagulation is an essential component of many cardiothoracic and vascular surgical procedures in order to prevent significant thrombotic and hemorrhagic complications. The classic test to assess high-dose (>1 unitlmL) heparin anticoagulation is the activated clotting time. Although simple to perform, the activated clotting time has many variations and can be affected by a number of nonanalytical and patient-related factors. Correlation with the heparin concentration may be poor. Alternatively, other test systems assess the individual patient's responsiveness to heparin in order to customize the heparin administration and subsequent protamine neutralization. The choice of test and system depends on the clinical application and the desired outcome. Regulatory and accreditation standards govern this type of testing; modern instrumentation can facilitate compliance with these standards. Understanding of the nature of the test and its performance under a variety of conditions is critical for proper interpretation.
Quantification in Echocardiography
Authors: Korsten Hendrikus H. M. , Mischi Massimo , Grouls Rene J. E. , Jansen Annemiek , van Dantzig Jan-Melle , Peels Kathinka
Published: June 2007

Until recently, more than 2200 Swan Ganz catheters were used annually in the operating rooms (OR) and intensive care unit (ICU) of the Catharina Hospital in Eindhoven, The Netherlands. After cardiologists who were specialists in echocardiography (ECHO) trained anesthesiologists in ECHO, the need for these catheters in cardiac and noncardiac surgery was reduced. Initially intended as a local teaching project, an ECHO teaching compact disk (CD) was produced during the training and distributed later worldwide, thanks to a positive review in a major anesthesiology publication. By reducing the number of Swan Ganz catheters, the hospital could finance and acquire two echocardiography machines for the OR and ICU. The availability of these machines resulted in a further reduction of the number of Swan Ganz catheters. However, the need for quantification (eg, measurements of cardiac output) remained. During the creation of the ECHO teaching CD, the idea was born to apply indicator-dilution principles on injected echo contrast. This study was performed in cooperation with the Signal Processing Department of the Eindhoven University of Technology. Advanced signal processing and modelling were used to develop algorithms to enable quantification of intrapulmonary blood volume, ejection-fraction, and flow from the transesophageal echocardiography approach. These quantitative measurements, which can be performed on an outpatient basis, may become a real asset in cardiology, anesthesiology, and intensive care.
Advanced Systolic and Diastolic Function: Beyond the E-and A-wave
Authors: Kamp Otto
Published: June 2007

The rationale and clinical use of Doppler echocardiography for the assessment of left ventricular diastolic dysfunction is described with focus on recent developments. Noninvasive measurement of elevated left atrial pressure can be performed with transthoracic and transesophageal echocardiography in daily practice and thus, can be used for clinical management in patients with heart failure.
Hyperglycemia and Outcome After Myocardial Infarction and Cardiac Surgery: So What?
Authors: Hiesmayr Michael J.
Published: June 2007

Hyperglycemia is a frequent observation during acute illness such as myocardial infarction and after major surgery. The proportion of patients with hyperglycemia may be as high as 95% to 100% after cardiac surgery. This stress-induced hyperglycemia has a detrimental effect on outcome after myocardial infarction and cardiac surgery. Mortality may increase by a factor of 4, especially in non-diabetic patients. Control of hyperglycemia to normalize blood glucose is associated with a clear clinical benefit. This effect is most beneficial in nondiabetic patients with hyperglycemia. The exact target level of glycemia is still a matter of investigation, but normalization to values between 80 and 125 mg/dL is probably optimal.
Glucose-Insulin-Potassium Techniques in Cardiac Surgery: Historical Overview and Future Perspectives
Authors: Van Wezel Harry B.
Published: June 2007

Since the days of the first cardiac surgical operations in the previous century, myocardial preservation has been an essential component of the successful outcome of these procedures. Although many different techniques to achieve myocardial preservation and modulation have been described in the past 50 years, this review focuses on the use of glucose, insulin, and potassium (GIK) and its effect on ischemic and postischemic myocardium.
REMATCH and Beyond: The Cost of Treating Heart Failure Using an Implantable Left Ventricular Assist Device
Authors: Dembitsky Walter P.
Published: June 2007

Congestive heart failure is an increasingly widespread debilitating fatal condition that generates a high cost to patients, society, and health care systems. Nearly 6.5 million people in Europe and 5 million people in the United States have congestive heart failure. Unlike most cardiovascular diseases in industrialized countries, congestive heart failure is becoming more common. Therapies include medical approaches, implantable assist devices, and cardiac transplantation. Mechanical assistance devices rather than medical therapy offer improvement in quality of life and survival.
Sex, the Heart, and Heart Failure
Authors: Kiowski Wolfgang , Brunner Hanspeter , Schalcher Christoph
Published: June 2007

In the modern era of pharmacologic treatment of erectile dysfunction, men with heart disease increasingly approach their physicians regarding the possibility of restoring sexual activity. At the same time, patients are also frequently aware of public figures that have reportedly died during coitus, often in the arms of their mistresses or prostitutes. Added to this is the perception of patients, and oftentimes their physicians, that coitus and orgasm are associated with a near maximal or even “supermaximal” cardiac workload and therefore may be hazardous for a diseased heart. Accordingly, knowledge of the cardiovascular effects of sexual activity, the risks of triggering a cardiovascular event, and the potential risks inherent in the use of drug therapy of male impotence is important to properly advise patients and their spouses regarding this sensitive issue.
Inhaled Milrinone: A New Alternative in Cardiac Surgery?
Authors: Denault André Y. , Lamarche Yoan , Couture Pierre , Haddad Francois , Lambert Jean , Tardif Jean-Claude , Perrault Louis P.
Published: June 2007

The administration of milrinone through inhalation has been studied in only a few animal and human studies. Compared to the intravenous administration, inhaled milrinone has been shown to reduce pulmonary artery pressure without systemic hypotension. Therefore, this approach could represent an alternative to nitric oxide. This current state of knowledge of intravenous and inhaled milrinone is presented and summarized.
Therapeutic Hypothermia
Authors: Arrica Mauro , Bissonnette Bruno
Published: June 2007

Therapeutic hypothermia, introduced more than 5 decades ago, remains an important neuroprotective factor in the surgery for the correction of congenital heart disease, in particular when intraoperative circulatory arrest is required. Hypothermia decreases cerebral metabolism and energy consumption and reduces the extent of degenerative processes such as the excitotoxic cascade, apoptotic and necrotic cell death, microglial activation, oxidative stress, and inflammation. Neurological outcome has become the focus of several studies in the recent years, and deep hypothermic circulatory arrest durations of more than 40 minutes are associated with increased mid-and long-term disability. Physiologic cerebral flowmetabolism coupling seems to be preserved with moderate and mild hypothermia, but cerebral blood flow autoregulation is probably altered after deep hypothermic circulatory arrest, suggesting disordered cerebral metabolism and oxygen use. Although evidence from animal studies suggests potential benefit from very low temperatures, postoperative development of choreoathetosis has been found to correlate with the degree of intraoperative hypothermia, recommending the use of central temperatures greater than 15°C in the clinical practice. Cooling times longer than 20 minutes are needed to obtain homogeneous brain cooling and effective neuroprotection. Finally, there is evidence that the sites of temperature monitoring used in the clinical practice may underestimate brain temperature after cardiopulmonary bypass, with the risk of postoperative hyperthermic brain damage.
Bleeding Following Deep Hypothermia and Circulatory Arrest in Children
Authors: Mossad Emad B. , Machado Sandra , Apostolakis John
Published: June 2007

Deep hypothermic circulatory arrest (DHCA) is a technique of extracorporeal circulation commonly used in children with complex congenital heart defects undergoing surgical repairs. The use of profound cooling (20°C) and complete cessation of circulation allow adequate exposure and correction of these complex lesions, with enhanced cerebral protection. However, the profound physiologic state of DHCA results in significant derangement of the coagulation system and a high incidence of postoperative bleeding. This review examines the impact of DHCA on bleeding and transfusion requirements in children and the pathophysiology of DHCA-induced platelet dysfunction. It also focuses on possible pharmacologic interventions to decrease bleeding following DHCA in children.
The Effect of Adding Items to Scales: An Illustrative Case of LMX
Authors: Keller Tiffany , Dansereau Fred
Published: June 2007

In this article, the authors examine whether different results occur when items are added to a scale. Because different measures of leader-member exchange (LMX) have included different numbers of items, the authors used the LMX scale. The results, consistent across two studies, support the hypothesis that results based on earlier versions of the LMX measure differ from those of subsequent scales where items were added. The implications of this type of finding for scale development and meta-analysis are discussed. It is suggested that validity as well as reliability be considered when adding new items to scales.
A Generalized Solution for Approximating the Power to Detect Effects of Categorical Moderator Variables Using Multiple Regression
Authors: Aguinis Herman , Boik Robert J. , Pierce Charles A.
Published: June 2007

Investigators in numerous organization studies disciplines are concerned about the low statistical power of moderated multiple regression (MMR) to detect effects of categorical moderator variables. The authors provide a theoretical approximation to the power of MMR. The theoretical result confirms, synthesizes, and extends previous Monte Carlo research on factors that affect the power of MMR tests of categorical moderator variables and the low power of MMR in typical research situations. The authors develop and describe a computer program, which is available on the Internet, that allows researchers to approximate the power of MMR to detect the effects of categorical moderator variables given user-input information (e.g., sample size, reliability of measurement). The approximation also allows investigators to determine the effects of violating certain assumptions required for MMR. Given the typically low power of MMR, researchers are encouraged to use the computer program to approximate power while planning their research design and methodology.
Single-Item Reliability: A Replication and Extension
Authors: Wanous John P. , Hudy Michael J.
Published: June 2007

The reliability of a single-item measure of student-rated college teaching effectiveness was estimated with two different methods and at two levels of analysis. The two methods are the correction for attenuation formula and factor analysis. The two levels of analysis are the group level (10, 682 classes) and the individual level (323, 262 students). Reliability estimates were higher using factor analysis (.88) than the correction for attenuation formula (.64), and they were higher using group-level data (.82) than individual-level data (.70). Based on the assumptions and limitations of each method used, the authors conclude that a minimum estimate of .80 for single-item reliability is reasonable for group-level data. The authors reaffirm a minimum reliability estimate of .70 for individual-level data, as previously concluded by Wanous, Reichers, and Hudy, who estimated single-item reliability for measures of overall job satisfaction using individual-level data.
Estimating Interrater Agreement with the Average Deviation Index: A User’s Guide
Authors: Burke Michael J. , Dunlap William P.
Published: June 2007

The authors present guidelines for establishing a useful range for interrater agreement and a cutoff for acceptable interrater agreement when using Burke, Finkelstein, and Dusig’s average deviation (AD) index as well as critical values for tests of statistical significance with the AD index. Under the assumption that judges respond randomly to an item or set of items in a measure, the authors show that a criterion for acceptable interrater agreement or practical significance when using the AD index can be approximated as c/6, where c is the number of response options for a Likert-type item. The resulting values of 0.8, 1.2, 1.5, and 1.8 are discussed as standards for acceptable interrater agreement when using the AD index with 5-, 7-, 9-, and 11-point items, respectively. Using similar logic, the AD agreement index and interpretive standard are generalized to the case of a response scale that involves percentages or proportions, rather than discrete categories, or at the other extreme, the assessment of interrater agreement with respect to the rating of a single target on a dichotomous item (e.g., yes-no, agree-disagree, true-false item formats). Finally, the usefulness of these guidelines for judging acceptable levels of interrater agreement with respect to the metric (or units) of the original response scale is discussed.
Using Hierarchical Linear Models to Examine Moderator Effects: Person-by-Organization Interactions
Authors: Davison Mark L. , Kwak Nohoon , Seo Young Seok , Choi Jiyoung
Published: June 2007

A cross-level interaction is said to occur when the effects of client or employee characteristics interact with organizational characteristics to influence an employee or client outcome variable. Hierarchical linear modeling (HLM) is briefly described, particularly as it applies to the study of cross-level interactions. HLM is then compared to moderated multiple regression (MMR). An HLM model incorporating cross-level interactions is illustrated with data from a study of test validity across organizational units. An HLM model for person-organization congruence is then described. As compared to MMR, HLM can more readily handle large numbers of organizations. By increasing the number of organizations that can be studied, HLM should increase the power of the designs that researchers can use.
The Contest Over Meaning: Hermeneutics as an Interpretive Methodology for Understanding Texts
Authors: Prasad Anshuman
Published: June 2007

This article focuses on the methodological and epistemological aspects of hermeneutics, a leading genre of interpretive research. Beginning with a brief overview of the limitations of methodological discussions of hermeneutics in current organizational research, the article first introduces readers to the historical context of hermeneutics and then discusses the major epistemological and methodological concepts and debates that inform contemporary hermeneutics. Next, methodological guidelines for employing hermeneutics in organizational research are proposed. Finally, some conclusions are offered.
Research Design, Measurement, Andeffects of Attribute Range on Job Choice:More Than Meets the Eye
Authors: Highhouse Scott , Luong Alexandra , Sarkar-Barney Shreya
Published: June 2007

A common assertion in the job choice literature is that a job attribute (e.g., starting salary) will influence choice more when it has a wide range of values than when it has a narrow range of values. The authors suggest that this conclusion tells only part of the story concerning how attribute range influences job choice, and they show how the stage of choice determines the direction of range effects.