Impact and Predictors of Noncircular Left Ventricular Outflow Tract Shapes on Estimating Aortic Stenosis Severity by Means of Continuity Equations

Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm²) was underestimated by the standard method (1.05 ± 0.47 cm²; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index.     

Carboxylesterase catalyzed 18O-labeling of carboxylic acid and its potential application in LC-MS/MS based quantification of drug metabolites

LC-MS quantification of drug metabolites is sometimes impeded by the availability of internal standards that often requires customized synthesis and/or extensive purification. Although isotopically labeled internal standards are considered ideal for LC-MS/MS based quantification, de novo synthesis using costly isotope-enriched starting materials makes it impractical for early stage of drug discovery. Therefore, quick access to these isotope-enriched compounds without chemical derivatization and purification will greatly facilitate LC-MS/MS based quantification. Herein, we report a novel ¹⁸O-labeling technique using metabolizing enzyme carboxylesterase (CES) and its potential application in metabolites quantification study. Substrates of CES typically undergo a two-step oxygen exchange with H₂¹⁸O in the presence of the enzyme, generating singly- and doubly-¹⁸O-labeled carboxylic acids; however, unexpected hydrolytic behavior was observed for three of the test compounds – indomethacin, piperacillin and clopidogrel. These unusual observations led to the discovery of several novel hydrolytic mechanisms. Finally, when used as internal standard for LC-MS/MS based quantification, these in situ labeled compounds generated accurate quantitation comparable to the conventional standard curve method. The preliminary results suggest that this method has potential to eliminate laborious chemical synthesis of isotope-labeled internal standards for carboxylic acid-containing compounds, and can be developed to facilitate quantitative analysis in early-stage drug discovery.     

Relationship between physical growth and motor development in the WHO Child Growth Standards

Aim: To examine relationships among physical growth indicators and ages of achievement of six gross motor milestones in the WHO Child Growth Standards population. Methods: Gross motor development assessments were performed longitudinally on the 816 children included in the WHO Child Growth Standards. Six milestones (sitting without support, hands-and-knees crawling, standing with assistance, walking with assistance, standing alone, walking alone) were assessed monthly from 4 until 12 mo of age and bimonthly thereafter until children could walk alone or reached 24 mo. Failure time models were used 1) to examine associations between specified ages of motor milestone achievement and attained growth z scores and 2) to quantify these relationships as delays or accelerations in ages of milestone achievement. Results: Statistically significant associations were noted between ages of achievement of sitting without support and attained weight-for-age, weight-for-length and BMI-for-age z scores. An increase of one unit z score in these indicators was associated with 3 to 6 d acceleration in the respective achievement age. Statistically significant associations also were noted between various milestone achievement ages and growth when 3- or 6-mo and birth length-for-age z scores were entered jointly in the failure time models. In these analyses, one unit z-score increase in length-for-age was associated with 1 to 3 d delay in the respective achievement age.
Conclusion: Sporadic, significant associations were observed between gross motor development and some physical growth indicators, but these were quantitatively of limited practical significance. These results suggest that, in healthy populations, the attainment of these six gross motor milestones is largely independent of variations in physical growth.     

Quantifying how location and dose of botulinum toxin injections affect muscle paralysis

Despite the widespread use of botulinum toxin to treat muscle dystonias, no method exists to quantify muscle paralysis in either human or nonhuman models. In this study we examined how the location, dose, and volume of botulinum injection affects paralysis in the rat tibialis anterior muscle. Paralysis was quantified by electrically stimulating the nerve to the tibialis anterior and then staining sections of the muscle for glycogen. The areas of glycogen-containing fibers represented regions of botulinum action. The results showed that the most important injection technique is to inject botulinum directly into the motor endplate region of a muscle. Injections only 0.5 cm from the motor endplate resulted in a 50% decrease in paralysis. Increases in dose increased paralysis, however, some of that increase was simply due to the increased volume of injection. Thus, delivering toxin in small volumes near the MEP band of a muscle should produce the most effectiveparalysis. © 1993 John Wiley & Sons, Inc.     

Microformats: Three Proposed Standards for Solving the Need for Standard Data Presentation

The continuous glucose monitor market is just starting to develop. Current trends in the availability of diabetes information tools highlight the need for standard data presentation for continuous glucose monitors. These trends and their implications are discussed. This article proposes a set of standards for blood glucose data presentation. If device manufacturers adopt these standards, they will ensure that their continuous glucose monitors meet both the short-term and the long-term needs of users. This should increase the demand for these monitors and enable future device developments that appeal to a wider range of users.     

Practice guidelines: the radiology perspective

Clinical practice guidelines have emerged as a reality for medical practitioners over the past 20 years. Although virtually all groups interested in the development of practice guidelines hope for improvements in patient care, secondary expectations vary widely among those using them. Their use in daily practice by physicians has met with resistance from barriers including concerns of “cookbook” medicine, a loss of autonomy, and increased professional liability. The recent experience of the ACR in addressing these challenges illustrates that physicians are receptive to steps perceived to mitigate the risks accompanying the use of guidelines as well as to efforts to increase their understanding of implementing guidelines in clinical practice. The experiences of other medical societies and an inventory of future trends reveal additional challenges associated with the use of practice guidelines, as third parties look to guidelines as points of reference for gauging the performance of health care providers.     

论医院质量管理推行ISO9000族标准的必要性

为了迎接医疗市场的竞争和挑战 ,医院将应用于工业企业的ISO90 0 0族标准引入到医疗服务领域。它通过严格的过程控制 ,使医院实现了质量管理制度健全化、系统化、合理化 ,大大减少了服务中的差错 ,全面提高了服务质量 ;通过工作程序化及持续改进 ,改善了医务人员的工作环境 ,提高了医院运作效率和运营效益。本文从现行的质量管理的不足分析入手 ,从八个方面阐述医院质量管理推行IS0 90 0 0族标准的必要性 ,以此来说明医院的质量管理采用ISO90 0 0族标准 ,将会使医院的质量管理有一个质的飞跃。事实证明通过认证的医院已从中收益。     

Integrating human factors into the medical curriculum

Background  The study of human factors is a scientific discipline that deals with the interactions between human beings and the elements of a system. This is important because shortcomings in these areas, if unchecked, can result in adverse outcomes. Research into human factors in industries where safety is paramount has provided the basis of countermeasures against human error. Adverse outcomes in medicine resulting from human error exact a high cost in both patient suffering and financial outlay.
CRM training  One of the approaches used to minimise the effect of human error is to train people in a set of knowledge, skills and attitudes that underpin the domain-specific competencies for that profession. These are referred to as non-technical skills (NTS). In aviation, such an approach has been shown to be both translatable from the training environment to the workplace and effective in reducing adverse outcomes.
Discussion  Medicine has incorporated this style of training, usually centred around simulator-based courses, but as yet in a piecemeal, episodic fashion which relies on participants volunteering to attend courses. Unlike other industries there is no systematic approach to linking the content of this teaching with the more conventional range of topics. As a consequence it is difficult to assess the impact of human factors training in medicine. This is partly because very little work has been done to date in identifying the key non-technical skills required in medicine, and the overall experience of workplace based assessment is limited. Lessons from other high reliability organisations may help to address the main challenges of developing the content, integrating it into the curriculum, reinforcing the concepts in the workplace through staff development and establishing its role in summative assessment.     

SRTR Center-Specific Reporting Tools: Posttransplant Outcomes

Measuring and monitoring performance—be it waiting list and posttransplant outcomes by a transplant center, or organ donation success by an organ procurement organization and its partnering hospitals—is an important component of ensuring good care for people with end-stage organ failure. Many parties have an interest in examining these outcomes, from patients and their families to payers such as insurance companies or the Centers for Medicare and Medicaid Services; from primary caregivers providing patient counseling to government agencies charged with protecting patients.
The Scientific Registry of Transplant Recipients produces regular, public reports on the performance of transplant centers and organ procurement organizations. This article explains the statistical tools used to prepare these reports, with a focus on graft survival and patient survival rates of transplant centers—especially the methods used to fairly and usefully compare outcomes of centers that serve different populations. The article concludes with a practical application of these statistics—their use in screening transplant center performance to identify centers that may need remedial action by the OPTN/UNOS Membership and Professional Standards Committee.     

Practice standards for optometry and optometric practice accreditation

Background: To assist optometrists to deliver care more efficiently and effectively, in 1995 Optometrists Association Australia decided to develop standards that would assist optometrists in better managing their practices. Existing practice management standards for health professionals were thought to be either not specific enough for optometric practice or to have shortcomings in the context of optometric practice in Australia. Methods: Following a literature search, material previously developed by Optometrists Association Australia to assist practitioners with management of their practices and standards from other professions were used to assist with the development of a draft set of standards for optometric practices in Australia. Successive drafts were circulated for comment to optometrists in practice, non‐optometrists with experience in the development of practice standards for other health professions and to Australian General Practice Accreditation Limited. The comments were used to refine the standards and the accreditation guidelines to their final form. Results: Optometric Practice Standards suitable for use in a practice accreditation program were developed. The standards comprise seven sections—Practice administration, Quality assurance, Rights and needs of the patient, Practice services, Practice facilities, Communication and Patient records. These sections are divided into criteria that provide the detail of the requirements of the standard. Indicators describing how criteria can be assessed accompany the criteria.