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Biomedical subjects

S B Johnson

Publications and source records attributed to S B Johnson.

At least 37 records · Page 2Linked to original sources
PubMed1999

Use of an Objective Structured Clinical Examination (OSCE) for the assessment of physician performance in the ultrasound evaluation of trauma.

BACKGROUND: A reliable means of assessing physician competency in performing ultrasound (US) is critical for training and credentialing. Objective Structured Clinical Examinations (OSCE) have been used successfully to assess clinical competency in other areas of surgical education but have not been applied previously to trauma ultrasound training. The objectives of this study were to assess physician performance in the focused abdominal sonography in trauma (FAST) examination by using a specifically designed OSCE, and to determine whether the OSCE detects differences in two determinants of competency (knowledge acquisition and clinical interpretation skills). METHODS: Eighty-two physicians in surgery (n = 49) and emergency medicine (n = 33) at a Level I trauma center were evaluated. All participated in a FAST course consisting of didactic sessions on US physics, indications, and technique, FAST examination videos, and a hands-on session with human models. The OSCE consisted of two parts: written examination that assessed factual knowledge, and videotape of real-time US examinations that assessed interpretation skills. The OSCE was administered before and after the FAST course. RESULTS: Significant improvements in postcourse OSCE scores were observed for factual knowledge (52.5 +/- 2.0 vs. 87.5 +/- 1.1, p < 0.001) and interpretation skills (27.2 +/- 1.4 vs. 62.9 +/- 1.3, p < 0.007). Scores for US interpretation were significantly lower than those for factual knowledge at both precourse (27.2 +/- 1.4 vs. 52.5 - 2.0, p < 0.001) and postcourse (62.9 +/- 1.3 vs. 87.5 +/- 1.1, p < 0.01). No performance differences were observed between surgeons and emergency medicine physicians and no effect of training level on test scores was observed. CONCLUSION: Knowledge acquisition and US interpretation skills can be assessed reliably with a specifically designed OSCE. Although both skills improved after participation in a FAST course, US interpretation scores were consistently lower than those for factual knowledge. This study supports the use of the objective structured clinical examination in both the design of ultrasound teaching programs and the assessment of physician competency.

Clinical Competence↗
PubMed1999

Catheter tip orientation affects radiofrequency ablation lesion size in the canine left ventricle.

While some factors influencing size of RF lesions in ventricular tissue have been characterized, the effects of catheter electrode-endocardial surface orientation on lesion generation have not been investigated. Therefore, the effects of parallel versus perpendicular catheter electrode-endocardial surface orientation on dimensions of RF lesion produced with 4-, 6-, 8-, 10-, and 12-mm distal electrode lengths were studied in 20 closed-chested dogs. Orientation was established by biplane fluoroscopy and confirmed by intracardiac echocardiography for the majority of energy deliveries (71%). RF voltage was titrated to maintain constant catheter electrode temperature of 75 degrees C for 60 seconds. In the perpendicular orientation, lesion size did not change significantly with increasing electrode lengths. There was a statistically significant interaction between electrode orientation and maximum lesion length (analysis of variance [ANOVA] P = 0.04], lesion width (ANOVA P = 0.01), lesion area (ANOVA P = 0.02), and estimated lesion volume (ANOVA P < 0.005) over all electrode lengths. With parallel tip-tissue orientation, lesion size was a function of increasing electrode length. For 4-, 6-, 8-, 10-, and 12-mm electrodes, maximum lesion surface areas were 95 +/- 38, 97 +/- 38, 119 +/- 29, 147 +/- 52, and 147 +/- 67 mm2, respectively. For electrode lengths 8, 10, and 12 mm, estimated lesion volumes were significantly greater with parallel orientation (P < 0.05 for all). Thus, ventricular lesion size is dependent on catheter electrode length, but only when the catheter is oriented parallel to the endocardial surface. This information may be helpful in increasing lesion dimensions for RF ablation of ventricular tachycardias.

Animals↗
PubMed1999

Behavioral science in diabetes. Contributions and opportunities.

OBJECTIVE: To summarize the current status of behavioral research and practice in diabetes and to identify promising future directions. RESEARCH DESIGN AND METHODS: We review behavioral science contributions to diabetes in self-management and patient empowerment, interventions with children and adolescents, and special problems including blood glucose awareness training and complications such as depression. We also identify emerging areas in which behavioral science stands to make significant contributions, including quality of life, worksite and community programs, interventions using new information technologies, and translation research evaluating practical programs in representative settings. We then discuss the gap between the generally encouraging research on behavioral contributions to diabetes and the infrequent incorporation of such contributions in practice. Suggestions are made for how to close this gap, including ways to increase understanding of behavioral issues, opportunities for funding of key research and implementation questions, and how behavioral science principles can become more integrated into diabetes organizations and care. CONCLUSIONS: Changes are required on the part of behavioral scientists in how they organize and present their research and on the part of potential users of this knowledge, including other health professions, organizations, and funding agencies. Integrating behavioral science advances with other promising genetic, medical, nutritional, technology, health care, and policy opportunities promises not only to broaden our understanding of diabetes but also to improve patient care, quality of life, and public health for persons with diabetes.

Behavioral Sciences↗
PubMed1999

Clinical and scientific importance of source control in abdominal infections: summary of a symposium.

In May 1997, a panel of surgeon-investigators met to discuss the clinical importance and research implications of controlling the source of abdominal infections. It was concluded that source control is critical to therapeutic success and that antimicrobial therapy and other adjunctive interventions will fail if the source of infection is not controlled by resection, exteriorization or other means. The panelists presented different definitions of source control, depending on the scientific purpose of the definition. All participants agreed that failure to consider the adequacy of source control of infection has limited the value of most clinical trials of therapeutic anti-infective agents. Besides recognizing source control as an essential goal of patient care, the panelists emphasized the need for further investigative work to define, record and stratify the adequacy of source control in clinical trials of therapeutic agents for abdominal infections.

Abdomen↗
PubMed1999

Use of the Extensible Stylesheet Language (XSL) for medical data transformation.

Recently, the Extensible Markup Language (XML) has received growing attention as a simple but flexible mechanism to represent medical data. As XML-based markups become more common there will be an increasing need to transform data stored in one XML markup into another markup. The Extensible Stylesheet Language (XSL) is a stylesheet language for XML. Development of a new mammography reporting system created a need to convert XML output from the MEDLee natural language processing system into a format suitable for cross-patient reporting. This paper examines the capability of XSL as a rule specification language that supports the medical XML data transformation. A set of nine relevant transformations was identified: Filtering, Substitution, Specification, Aggregation, Merging, Splitting, Transposition, Push-down and Pull-up. XSL-based methods for implementing these transformations are presented. The strengths and limitations of XSL are discussed in the context of XML medical data transformation.

Database Management Systems↗
PubMed1999

Security architecture for multi-site patient records research.

A security system was developed as part of a patient records research database project intended for both local and multi-site studies. A comprehensive review of ethical foundations and legal environment was undertaken, and a security system comprising both administrative policies and computer tools was developed. For multi-site studies, Institutional Review Board (IRB) approval is required for each study, at each participating site. A sponsoring Principal Investigator (PI) is required at each site, and each PI needs automated enforcement tools. Systems fitting this model were implemented at two academic medical centers. Security features of commercial database systems were found to be adequate for basic enforcement of approved research protocols.

Clinical Protocols↗
PubMed1999

A technique for semantic classification of unknown words using UMLS resources.

Natural Language Processing (NLP) is a tool for transforming natural text into codable form. Success of NLP systems is contingent on a well constructed semantic lexicon. However, creation and maintenance of these lexicons is difficult, costly and time consuming. The UMLS contains semantic and syntactic information of medical terms, which may be used to automate some of this task. Using UMLS resources we have observed that it is possible to define one semantic type by its syntactic combinations with other types in a corpus of discharge summaries. These patterns of combination can then be used to classify words which are not in the lexicon. The technique was applied to a corpus for a single semantic type and generated a list of 875 words which matched the classification criteria for that type. The words were ranked by number of patterns matched and the top 95 words were correctly typed with 80% accuracy.

Humans↗
PubMed1999

Extended SQL for manipulating clinical warehouse data.

Health care institutions are beginning to collect large amounts of clinical data through patient care applications. Clinical data warehouses make these data available for complex analysis across patient records, benefiting administrative reporting, patient care and clinical research. Data gathered for patient care purposes are difficult to manipulate for analytic tasks; the schema presents conceptual difficulties for the analyst, and many queries perform poorly. An extension to SQL is presented that enables the analyst to designate groups of rows. These groups can then be manipulated and aggregated in various ways to solve a number of useful analytic problems. The extended SQL is concise and runs in linear time, while standard SQL requires multiple statements with polynomial performance. The extensions are extremely powerful for performing aggregations on large amounts of data, which is useful in clinical data mining applications.

Clinical Laboratory Techniques↗
PubMed1999

Therapeutic paralysis of critically ill trauma patients: perceptions of patients and their family members.

BACKGROUND: Neuromuscular blocking agents are used in critically ill patients to induce therapeutic paralysis. These drugs leave patients fully immobile but conscious. Analgesics and sedatives are concomitantly administered with the paralytic agents. Little is known about what patients remember when they receive these combinations of drugs. Even less is known about the experiences and needs of the patients' family members during the patients' paralysis. OBJECTIVES: To obtain recollections of therapeutic paralysis in critically ill adult trauma patients and to determine the psychological, emotional, and educational needs of the patients' family members during the time the patients were paralyzed. METHODS: A qualitative phenomenological approach was used to investigate the "lived" experience of therapeutic paralysis of 11 pairs of subjects. Each pair consisted of one critically ill adult trauma patient and one member of the patient's family. RESULTS: The patients recalled their experience of therapeutic paralysis with vagueness, as if they had been dreaming. Few recalled pain or painful procedures. Patients remembered having nurses and family members provide emotional support and encouragement. Family members understood the rationale for use of the drugs. They remembered being encouraged to touch and talk with patients. The subjects suggested providing additional education about events that occur when paralysis is being reversed. CONCLUSIONS: Two confounding variables may have affected these findings: a liberalized visiting policy and use of effective pain and sedation protocols. Healthcare professionals and patients' family members should monitor bedside conversations and use touch and words of encouragement to support patients during therapeutic paralysis.

Adaptation, Psychological↗
PubMed1998

Developing online support for clinical information system developers: the FAQ approach.

OBJECTIVE: We investigate a knowledge-based help system for developers of an integrated clinical information system (CIS). The first objective in the study was to determine the system's ability to answer users' questions effectively. User performance and behavior were studied. The second objective was to evaluate the effect of using questions and answers to augment or replace traditional program documentation. DESIGN: A comparative study of user and system effectiveness using a collection of 47 veritable questions regarding the CIS, solicited from various CIS developers, is conducted. Most questions were concerning the clinical data model and acquiring the data. MEASUREMENTS: Answers using current documentation known by users were compared to answers found using the help system. Answers existing within traditional documentation were compared to answers existing within question-answer exchanges (Q-A's). RESULTS: The support system augmented 39% of users' answers to test questions. Though the Q-A's were less than 5% of the total documentation collected, these files contained answers to nearly 50% of the questions in the test group. The rest of the documentation contained about 75% of the answers. CONCLUSIONS: A knowledge-based help system built by collecting questions and answers can be a viable alternative to large documentation files, providing the questions and answers can be collected effectively.

Artificial Intelligence↗
PubMed1998

Management of major tracheobronchial injuries: a 28-year experience.

BACKGROUND: Tracheobronchial injuries are rare but potentially life threatening. Their successful diagnosis and treatment often require a high level of suspicion and surgical repairs unique to the given injury. METHODS: We reviewed our experience with 32 patients with tracheobronchial injuries treated over the past 28 years. RESULTS: Forty-one percent (13/32) of the injuries were due to blunt trauma and 59% (19/32), to penetrating trauma. Most penetrating injuries were located in the cervical trachea (74%), whereas blunt injuries were more commonly located close to the carina (62%). Fifty-nine percent of the patients required urgent measures to secure the airway. Penetrating injuries were usually diagnosed by clinical findings or at surgical exploration. The diagnosis of blunt injuries was more difficult and required a high index of suspicion and the liberal use of bronchoscopy. The majority of the injuries were repaired primarily using techniques specific to the injury, and most patients returned to their normal activity soon after discharge. CONCLUSIONS: A high level of suspicion and the liberal use of bronchoscopy are important in the diagnosis of tracheobronchial injury. A tailored surgical approach is often necessary for definitive repair.

Adolescent↗
PubMed1998

The surgeon's use of transesophageal echocardiography.

Transesophageal echocardiography has become an instrumental diagnostic modality for the accurate evaluation of cardiac and aortic anatomy and function. Multiplanar technology has facilitated improved visualization of structures and enhanced TEE over TTE in many situations. Care of the trauma patient and critically ill patient is improved with the appropriate and timely performance of TEE. Education, certification, credentialing, and determination of competency are areas that need to be addressed continually in the future.

Aortic Dissection↗