Biomedical subjects

S B Johnson

Publications and source records attributed to S B Johnson.

At least 19 recordsLinked to original sources

PubMed1995

Unlocking clinical data from narrative reports: a study of natural language processing.

OBJECTIVE: To evaluate the automated detection of clinical conditions described in narrative reports. DESIGN: Automated methods and human experts detected the presence or absence of six clinical conditions in 200 admission chest radiograph reports. STUDY SUBJECTS: A computerized, general-purpose natural language processor; 6 internists; 6 radiologists; 6 lay persons; and 3 other computer methods. MAIN OUTCOME MEASURES: Intersubject disagreement was quantified by "distance" (the average number of clinical conditions per report on which two subjects disagreed) and by sensitivity and specificity with respect to the physicians. RESULTS: Using a majority vote, physicians detected 101 conditions in the 200 reports (0.51 per report); the most common condition was acute bacterial pneumonia (prevalence, 0.14), and the least common was chronic obstructive pulmonary disease (prevalence, 0.03). Pairs of physicians disagreed on the presence of at least 1 condition for an average of 20% of reports. The average intersubject distance among physicians was 0.24 (95% Cl, 0.19 to 0.29) out of a maximum possible distance of 6. No physician had a significantly greater distance than the average. The average distance of the natural language processor from the physicians was 0.26 (Cl, 0.21 to 0.32; not significantly greater than the average among physicians). Lay persons and alternative computer methods had significantly greater distance from the physicians (all > 0.5). The natural language processor had a sensitivity of 81% (Cl, 73% to 87%) and a specificity of 98% (Cl, 97% to 99%); physicians had an average sensitivity of 85% and an average specificity of 98%. CONCLUSIONS: Physicians disagreed on the interpretation of narrative reports, but this was not caused by outlier physicians or a consistent difference in the way internists and radiologists read reports. The natural language processor was not distinguishable from the physicians and was superior to all other comparison subjects. Although the domain of this study was restricted (six clinical conditions in chest radiographs), natural language processing seems to have the potential to extract clinical information from narrative reports in a manner that will support automated decision-support and clinical research.

Humans↗

PubMed1995

Transesophageal echocardiography in the diagnosis of traumatic rupture of the aorta.

BACKGROUND: Rupture of the aorta is a major cause of death after motor vehicle accidents. Survival depends on early diagnosis, and emergency aortography is the standard imaging method. Although transesophageal echocardiography is noninvasive and can provide high-resolution images of the aorta, information about its value in patients with trauma is limited. We conducted this study to assess prospectively the value of transesophageal echocardiography in the emergency evaluation of patients at risk for aortic injury. METHODS: Transesophageal echocardiography of the aorta was attempted in 101 patients admitted to the emergency room with a diagnosis of possible traumatic rupture of the aorta. Echocardiography and aortography personnel were notified simultaneously of the arrival of the patient, and the two tests were performed sequentially by operators who were blinded to the results of the other test. The sensitivity and specificity of transesophageal echocardiography were calculated on the basis of the results of aortography of the arch, surgery, or autopsy. RESULTS: Transesophageal echocardiography was attempted in 101 patients. The study was successfully performed in 93 patients but could not be completed in 8 because of lack of cooperation on the part of the patient (7 patients) or maxillofacial trauma (1 patient). Despite a high injury-severity score (mean, 29.6), transesophageal echocardiography was performed without complications, and within a mean (+/- SD) of 29 +/- 12 minutes. Eleven of the 93 studies (12 percent) demonstrated rupture of the aorta near the isthmus. The findings were confirmed in 10 of the 11 patients by aortography (9 patients), surgery (9 patients), or autopsy (1 patient), yielding a sensitivity of 100 percent and specificity of 98 percent for the detection of injury to the aorta. There was one false positive echocardiogram. CONCLUSIONS: Transesophageal echocardiography is a highly sensitive and specific method of detecting injury to the thoracic aorta. This technique can be used safely and quickly in critically injured patients with suspected traumatic rupture of the aorta and compares favorably with arch aortography.

Acute Disease↗

PubMed1995

The relationship between faculty ward evaluations, OSCE, and ABSITE as measures of surgical intern performance.

BACKGROUND: This study determined the degree to which ward evaluations, the American Board of Surgery In-Training Examination (ABSITE), and an Objective Structured Clinical Examination (OSCE) provide equivalent information about intern performance. METHODS: Twenty-two general surgery interns completed both the ABSITE and a 17-problem, 35-station OSCE. Faculty members completed several 12-item ward evaluations for each intern. Pearson product-moment correlations were employed to determine the degree of association among the various evaluation measures. RESULTS: The total OSCE score correlated with both the total ABSITE score and the overall ward evaluations, but the latter two measures did not correlate with each other. The ward evaluations identified the performance of 1 of the 22 interns (5%) as deficient, the ABSITE identified 9 (41%) as deficient in knowledge, and the OSCE 8 (36%). CONCLUSIONS: In the future, performance-based testing methods such as the OSCE should become more important as an evaluative parameter in assessing the clinical performance of postgraduate surgical trainees.

Attitude of Health Personnel↗

PubMed1995

Echocardiography in the evaluation of thoracic trauma.

Echocardiography has become a useful diagnostic modality in the evaluation of cardiovascular injury after thoracic trauma. Valuable information about cardiac wall motion, valvular function, pericardial effusions, and ventricular volume status can be obtained without significant risk. More recent application for the diagnosis of traumatic aortic disruption provides a safer, easier, less expensive, and more accurate method for detecting these injuries. Cardiac evaluation with TTE is unsuccessful in approximately 20% of examinations and is unable to provide the image resolution of the more invasive transesophageal approach.

Aorta, Thoracic↗

PubMed1995

Patients with anorexia nervosa demonstrate deficiencies of selected essential fatty acids, compensatory changes in nonessential fatty acids and decreased fluidity of plasma lipids.

The objective of this study was to assess the essential fatty acid status of patients with anorexia nervosa. Blood was collected from eight fasting female anorexia nervosa patients with a mean of 81% ideal body weight. Fatty acid composition of phospholipids, nonesterified fatty acids, triglycerides and cholesteryl esters of plasma were determined by capillary gas chromatography to indicate polyunsaturated fatty acids status compared with 19 healthy female adults < 25 y old. Subjects with anorexia nervosa showed polyunsaturated fatty acid deficiencies in plasma phospholipids different from simple nutritional essential fatty acid deficiency or chronic malnutrition. The phospholipid profile showed significantly lower (n-6) and (n-3) elongation and desaturation products, and elevated short-chain saturated, short-chain monounsaturated, branched-chain and odd-chain fatty acids. These elevations indicate enhancement of biosynthesis of alternative fatty acids that only partially compensated for the loss of polyunsaturated fatty acids in providing membrane "fluidity." Calculated mean melting point of the fatty acids of phospholipids in patients with anorexia nervosa was elevated 7.7 degrees C above normal values. These results demonstrate that patients with anorexia nervosa have deficiencies of selected essential fatty acids, compensatory changes in nonessential fatty acids and decreased fluidity of plasma lipids.

Adolescent↗

PubMed1995

Penetrating intrapericardial wounds: clinical experience with a surgical protocol.

BACKGROUND: From 1972 to 1977, a treatment protocol was developed at our institution for patients with suspected penetrating intrapericardial wounds. It consists of immediate transport to the operating room, pericardial decompression by subxiphoid pericardial window under local or light general anesthesia in patients in stable condition, and median sternotomy and operative repair with limited use of cardiopulmonary bypass. METHODS: The records of 79 consecutive patients with acute penetrating intrapericardial injury who underwent operation from March 1978 to July 1991 were reviewed. There were 59 patients (75%) with stab wounds and 20 (25%) with gunshot wounds. Wound location was as follows: right ventricle, 33 (42%); left ventricle, 28 (35%); multiple sites, 8 (10%); atrium, 5 (6%); and great vessels, 5 (6%). RESULTS: Subxiphoid pericardial window was performed under local or light general anesthesia in 53 patients (67%). Cardiopulmonary bypass was required in only 4 patients. Overall mortality was 6%. CONCLUSION: Approach to a trauma victim must be systematic. We believe one treatment protocol for patients with suspected penetrating intrapericardial wounds is effective.

Adolescent↗

PubMed1995

Homograft patch repair for hemorrhagic mediastinitis.

Hemorrhage from the heart and great vessels is a potentially lethal complication of post-sternotomy mediastinitis. We report 2 cases in which a cryopreserved descending thoracic aortic homograft was used successfully to repair defects of the ascending aorta and right ventricle in the setting of active mediastinal infection. An overview of mediastinitis and management strategies for life-threatening mediastinal bleeding is included.

Aorta, Thoracic↗

PubMed1995

Medical decision support: experience with implementing the Arden Syntax at the Columbia-Presbyterian Medical Center.

We began implementation of a medical decision support system (MDSS) at the Columbia-Presbyterian Medical Center (CPMC) using the Arden Syntax in 1992. The Clinical Event Monitor which executes the Medical Logic Modules (MLMs) runs on a mainframe computer. Data are stored in a relational database and accessed via PL/I programs known as Data Access Modules (DAMs). Currently we have 18 clinical, 12 research and 10 administrative MLMs. On average, the clinical MLMs generate 50357 simple interpretations of laboratory data and 1080 alerts each month. The number of alerts actually read varies by subject of the MLM from 32.4% to 73.5%. Most simple interpretations are not read at all. A significant problem of MLMs is maintenance, and changes in laboratory testing and message output can impair MLM execution significantly. We are now using relational database technology and coded MLM output to study the process outcome of our MDSS.

Academic Medical Centers↗

PubMed1995

Architectural requirements for a multipurpose natural language processor in the clinical environment.

A considerable amount of research has been concerned with the development of natural language systems to automate the encoding of clinical information that occurs in textual form. The task is very complex, and not many language processors are used routinely within clinical information systems. Those systems that are operational, have been implemented in narrow domains for particular applications. For a system to be truly useful, it should be designed so that it could be widely used within the clinical environment. This paper examines architectural requirements we have identified as being necessary for portability and describes the architecture of the system we developed. Our system was designed so that it could be used in different domains to serve a variety of applications. It has been integrated with the clinical information system at Columbia-Presbyterian Medical Center where it routinely encodes clinical information from radiological reports of patients.

Computer Systems↗

PubMed1995

A data model that captures clinical reasoning about patient problems.

We describe a data model that has been implemented for the CPMC Ambulatory Care System, and exemplify its function for patient problems. The model captures some nuances of clinical thinking about patients that are not accommodated in most other models, such as an evolution of clinical understanding about patient problems. A record of this understanding has clinical utility, and serves research interests as well as medical audit concerns. The model is described with an example, and advantages and limitations in the current implementation are discussed.

Ambulatory Care Information Systems↗

PubMed1995

Applying a controlled medical terminology to a distributed, production clinical information system.

To maximize the value of computerized medical records systems, an organizing structure is needed. That structure can be provided by a controlled medical terminology (CMT). At Columbia-Presbyterian Medical Center, we have been employing a controlled medical terminology, our Medical Entities Dictionary (MED), to mediate the storage and retrieval of patient data and enable decision support applications. This paper describes how the MED is actually used for data management in our distributed clinical information systems environment. Our system tools which access the MED for production purposes facilitate the mapping of terms from many sources to a uniform representation of concepts and also return information about the relationships between concepts. Applications which access a CMT for production purposes should be optimized for performance in high volume settings, fault tolerant, synchronizable, extensible, portable, and maintainable. We briefly describe our system architecture and then demonstrate how we utilize the MED for translation and semantic information as data is moved into and out of our patient database. We discuss our current tools and present a preview of the next generation of applications which will manage access to the MED for our production systems.

Computer Communication Networks↗

PubMed1995

Managing vocabulary for a centralized clinical system.

The clinical computing environment at Columbia-Presbyterian Medical Center is organized around a centralized database of coded patient information collected from various ancillary sources. The Medical Entities Dictionary (MED) is the central repository for the controlled vocabulary used to encode the patient data. The MED is composed of terms used in the ancillary departments and, as such, changes in the source vocabularies must be maintained in the MED. The MED also contains some basic knowledge about the terms, and sophisticated maintenance tools have been developed that take advantage of this knowledge. This paper describes the success of the knowledge-based approach by describing the techniques used in two tasks: addition of a new vocabulary and maintenance of an existing one.

Clinical Laboratory Information Systems↗

PubMed1994

Assessing surgical residents' and medical students' interpersonal skills.

Effective physician-patient interaction is an important part of surgical practice. This study had three goals: (1) to measure the interpersonal skills (IS) of surgical students and residents in structured clinical settings and to determine the reliability of such measurements; (2) to determine the relationship of IS to clinical performance; and (3) to determine the impact of level of training on IS. Twenty third-year medical students and 30 junior-level interns (23 PGY-1s, 7 PGY-2s) interacted with nine actual or simulated patients as part of an objective structured clinical examination. Using a global rating scale, faculty graded both the IS and the organizational skills of the candidates. A two-way analysis of variance indicated significant differences among the three groups of trainees (P = 0.0002) and among the IS scores for each of the nine patient problems (P < 0.0001). Both the PGY-2s and the medical students exhibited significantly better interpersonal skills than did the PGY-1s. The IS scores correlated significantly with the data gathering scores, the data interpretation scores, and the organizational scores. We conclude that faculty measurement of IS is moderately reliable even when a simple global rating scale is used. Overall IS scores were rather poor, particularly in the PGY-1 group. IS were highly correlated with overall objective clinical performance.

Clinical Competence↗

PubMed1994

Assessing medical students' and surgery residents' clinical competence in problem solving in surgical oncology.

BACKGROUND: We sought to determine the competence of medical students and surgery residents in evaluating clinical problems (using both real and simulated patients) in surgical oncology. METHODS: Forty-five third-year medical students, 23 first postgraduate year (PGY-1) residents, and seven second postgraduate year (PGY-2) residents were presented with the same four clinical problems (breast evaluation, prostate nodule, colon cancer, and mole evaluation). The two resident groups were presented with two additional patients (breast cancer options and thyroid mass). RESULTS: Mean performance scores for the problems were generally poor (32-72%); most students and residents failed almost all of the problems. Level of training was of some importance; the overall mean scores of the PGY-2 residents were superior to those of the medical students and the PGY-1 residents (p = 0.049). However, in many areas of information gathering, diagnosis, and management, training level appeared to have no impact. Numerous important performance deficits were identified in all groups. CONCLUSION: Medical students and surgery residents are not receiving adequate training in diagnosing and treating important problems in surgical oncology.

Analysis of Variance↗

PubMed1994

Percutaneous dilational tracheostomy: report of 141 cases.

Tracheostomy is indicated frequently in the treatment of critically ill patients who require prolonged mechanical ventilation. The purpose of this prospective study was to evaluate our initial experience with 141 cases of percutaneous dilational tracheostomy (PDT) performed over a 2-year period. One hundred twenty PDTs (85%) were placed at the bedside, and 21 (15%) were performed in the operating room in conjunction with other procedures. The procedural complication rate was 11% (16 of 141). Most complications were easily recognized and did not preclude the completion of PDT. One death occurred secondary to severe bronchospasm. The postoperative complication rate was 8% (11 of 141). The most frequent complication was peristomal oozing. The average duration of follow-up after decannulation for patients discharged alive and decannulated was 36 +/- 27 weeks. There were 3 recognized cases of clinically symptomatic tracheal stenosis. We conclude that PDT is comparable with the open method and can be performed rapidly and safely at the patient's bedside.

Adolescent↗

PubMed1994

IAIMS and sharing.

The Integrated Academic Information Management System (IAIMS) concept is about sharing resources and information, and about improving the decision-making ability of health care professionals by integrating information. At Columbia-Presbyterian Medical Center, the IAIMS project has established an information architecture based on common, shared computing and networking resources. The institutional computing culture has been changed with increased sharing of information and, consequently, improved quality of information. Several classes of information in the areas of clinical, scholarly, administrative, basic research, and core resources have been identified for better understanding of information responsibility. Technical problems such as heterogeneity on workstation platforms and lack of universal syntactic and semantic standards for health care information exchange still impede inter-institutional sharing of information.

Artificial Intelligence↗

PubMed1994

Essential fatty acid deficiency profiles in idiopathic immunoglobulin A nephropathy.

The profiles of fatty acids (FAs) of plasma phospholipids (the compartment reflecting the essential FA status of tissue lipids), nonesterified FAs (the precursor pool for autacoid synthesis), urine protein excretion, and glomerular filtration rate were measured before and after supplementation with fish oil in 15 patients with immunoglobulin A nephropathy. In the FA profiles, there was deficient 18:3 omega 3 (alpha-linolenic acid), the parent compound of omega 3 polyunsaturated FA, and deficient chain elongation products of both omega 3 and omega 6 polyunsaturated FAs with replacement by saturated and monounsaturated short-chain, odd-chain, and branched-chain FAs, producing significant loss of omega 3 FA. These alterations indicate nutritional or functional (omega 3) and metabolic (omega 6) deficiencies. Additionally, the mean melting point of the FAs was significantly increased, implying an inherent decrease in cell membrane fluidity. Enhancement of 20: 5 omega 3 (eicosapentaenoic acid) and 22:6 omega 3 (docosahexaenoic acid) and suppression of 20:4 omega 6 (arachidonate) after supplementation with fish oil were accompanied by important decreases in proteinuria and improved glomerular filtration rate. Omega-3 polyunsaturated FAs may favorably influence immunoglobulin A nephropathy through a modulation of the pathologic actions of the omega 6 eicosanoids and other diverse actions on various mediators produced by an initial immune injury.

Adult↗

PubMed1994

Myocardial lipid composition in turkeys with dilated cardiomyopathy.

OBJECTIVE: The aim was to determine if reduced heart lipid peroxidation in turkeys with two forms of dilated cardiomyopathy, previously reported, was related to an alteration in the lipid composition of the ventricle. METHODS: Myocardial lipid composition was measured in turkeys with two types of dilated cardiomyopathy. Twenty six turkeys with naturally occurring dilated cardiomyopathy, six with furazolidone induced dilated cardiomyopathy, and 18 age matched control birds were used at 1 day, 9-10 days, and 38-78 days of age. Left ventricular fatty acid composition of the phospholipid, triglyceride, free fatty acid, and cholesterol ester fractions was analysed using gas chromatography. RESULTS: Significant age related changes were identified in the fatty acid composition of the heart. In the phospholipid fraction, linoleic acid (18:2 omega 6) values increased with age, while arachidonic acid values decreased. The saturated to unsaturated fatty acid ratio in control hearts was unchanged as a function of age in the phospholipid fraction. In the triglyceride fraction, however, this ratio decreased substantially between newly hatched and nine day old birds and then markedly increased in two month old controls. There was a striking alteration in the saturated to unsaturated fatty acid ratio in the triglyceride fraction of 2 month old cardiomyopathic birds; this ratio was markedly increased in the furazolidone induced cardiomyopathic turkey hearts (5.14 v 2.79 in controls) and markedly diminished (ie, 0.97 to 1.21) in the spontaneously cardiomyopathic turkeys. A significant increase in myristic (14:0) and decrease in linoleic (18:2 omega 6) acid concentration in the furazolidone group v control and a marked decrease in myristic and increase in linoleic acid concentrations in the spontaneously cardiomyopathic group v controls was present. CONCLUSIONS: (1) There is an age related alteration in the fatty acid composition of control turkey hearts. (2) Previously identified reduced lipid peroxidation in furazolidone induced and spontaneous cardiomyopathy in turkeys does not appear to be related to reduced concentration of polyunsaturated fatty acids. (3) The two forms of dilated cardiomyopathy are associated with markedly disparate alterations in the concentration of polyunsaturated fatty acids in the triglyceride fraction of 1-2 month old turkey hearts. The changes may be related, in part, to the pathogenesis in these two different forms of dilated cardiomyopathy.

Aging↗