Comparison of published pressure gradient symbols and equations in mechanics of breathing.
(41/270)
In the literature of pulmonary medicine we found dismaying diversity of and inconsistency in terms used to describe physiologic pressure gradients. Standardized terms, definitions, symbols, and equations published by the American Physiological Society, the American College of Chest Physicians, the American Thoracic Society, and the American Association for Respiratory Care have not been consistently used. Rather, researchers have often used their own definitions for transpulmonary pressure, transairway pressure, transthoracic pressure, transrespiratory pressure, and transdiaphragmatic pressure. We describe the variety of definitions and equations we found for those terms. We contend that it would benefit researchers, students, clinicians, and educators to define these terms precisely and use them consistently. (+info)
Zen and the art of nomenclature maintenance: a revised approach to respiratory symbols and terminology.
(42/270)
In this paper we point out that there are different entities involved in the mathematical descriptions, or models, of the respiratory system: variables and parameters. These, in turn, can be divided into different types. Variables can be primary variables, difference variables, or change variables. Difference variables express the difference between primary variables measured simultaneously at 2 locations. Change variables are primary variables measured relative to fixed reference values. Parameters that appear in input-output models that are valid over a wide range of inputs can be interpreted as properties. There are 3 levels of properties, depending on the detail included in the model. If the model specifically includes the geometry of the system and the substances of which the system is composed, then the parameters in the model are material properties. If the model includes the general structures that compose the system, the parameters are structural properties. And if the model describes the behavior of the system as a whole with no detail included pertaining to internal makeup, then the parameters can be considered system properties. Parameters that appear in mathematical descriptions of input and/or output wave shapes can be interpreted as waveform characteristics. General waveform characteristics are attributes of arbitrary inputs and/or outputs. However, in those special cases in which a system is subjected to a well-defined, specialized input and the output waveform is described mathematically (even if only at a single point), the parameter(s) in such descriptions can be considered system response characteristic(s). We suggest that the symbols and names given to these various entities should follow well-defined guidelines that distinguish among the entity types. These guidelines should include symbol and name conventions and also sign conventions and expected unit ranges on appropriate measurement scales. One such set of conventions would be as follows. Italicize all variables. Use upper-case for primary (absolute) variables. Use the delta symbol (Delta) to denote difference variables (difference between 2 locations). Use lower-case letters for change variables (change relative to a reference, or operating, point) and for abbreviations (eg, "pl" for "pleural"). Use upper-case characters to represent the initial letters of words (eg, "AO" for "airway opening"). Make bold nonitalicized groups of letters used for properties (upper-case, lower-case, multi-height). Do not bold or italicize groups of letters used for characteristics (upper-case, lower-case, multi-height). Compound symbols are those that include subscripts and/or superscripts. Subscripts following a symbol indicate location, direction, or index (time); if more than one subscript, separate them by commas. Superscripts following a symbol indicate a component, or it can indicate a power if the symbol is enclosed in parentheses. Letters on the same line as initial letter but in smaller type are part of the generic symbol. Arguments are enclosed in parentheses; parentheses are also used to isolate compound symbols from powers or additional subscripts. Adapt currently standard symbols to retain their identity but conform to the above conventions. The sign of an entity is always dictated by and its interpretation is based on the model in which the entity is used. Units used are consistent with measurement resolution and accuracy. Copious examples of the applications of this set of suggested conventions are given in the text and in 4 tables. Our hope is that the presentation of these suggestions will start a dialogue in the field and will influence journal and book publishers to adopt a consistent set of conventions for the names and symbols used for respiratory-system-related terms. (+info)
Management of tracheal intubation in the respiratory intensive care unit by pulmonary physicians.
(43/270)
BACKGROUND: Expert management of tracheal intubation has become fundamental to the routine practice of pulmonary physicians who work in respiratory intensive care units (ICUs). In Italy, tracheal intubation is not included as part of the training in respiratory medicine, and pulmonary physicians are usually dissuaded from managing intubations. METHODS: We prospectively studied the intubation success rate in 46 consecutive respiratory ICU patients who required either emergency or urgent intubation, conducted by 3 intubation-trained pulmonary physicians in our respiratory ICU. Intubation success was defined as successful tracheal intubation without any of 7 pre-defined complications. RESULTS: There were 17 emergency intubations and 29 urgent intubations. Intubation was successful in 43 of the 46 intubation attempts. Complications occurred in 3 cases: 2 patients needed to be intubated by an anesthesiologist, and 1 patient received fiberoptic intubation. CONCLUSIONS: Pulmonary physicians trained in tracheal intubation can have a high success rate in performing intubation in the respiratory ICU. Collaborative efforts between anesthesiologists and pulmonary physicians are necessary to optimize the training, skill-retention, and back-up for advanced airway management in the respiratory ICU. (+info)
Methodology to build medical ontology from textual resources.
(44/270)
In the medical field, it is now established that the maintenance of unambiguous thesauri goes through ontologies. Our research task is to help pneumologists code acts and diagnoses with a software that represents medical knowledge through a domain ontology. In this paper, we describe our general methodology aimed at knowledge engineers in order to build various types of medical ontologies based on terminology extraction from texts. The hypothesis is to apply natural language processing tools to textual patient discharge summaries to develop the resources needed to build an ontology in pneumology. Results indicate that the joint use of distributional analysis and lexico-syntactic patterns performed satisfactorily for building such ontologies. (+info)
Profile of research published in the annals of the Brazilian Pulmonology and Phthisiology Conferences held over the last twenty years.
(45/270)
OBJECTIVE: To increase the knowledge base regarding pulmonology research in Brazil. METHODS: A retrospective, observational study of the abstracts published in the Annals of the Brazilian Pulmonology and Phthisiology Conferences held from 1986 to 2004, quantifying the institutions of origin by geographic distribution and type, as well as categorizing the abstracts by study design and topic. RESULTS: A total of 6467 abstracts were published. The institutions of origin were located, variously, in the Southeast (3870 abstracts), South (1309), Northeast (783), Central-West (267) and North (84). There were 94 abstracts originating from foreign institutions, especially from institutions in Portugal (56.3%) and the United States (13.8%). Most of the studies (5825) were conducted in public Brazilian institutions. There were 4234 clinical studies, 1994 case reports and 239 original research articles. A marked, progressive increase was observed in the number of clinical studies and case reports during the period evaluated. Overall, the most common themes were tuberculosis and other infections diseases (25.2%), following by oncology (11.6%), interstitial lung diseases (8.8%) and thoracic surgery (8.5%). Nevertheless, the number of abstracts on each topic varied widely from year to year. CONCLUSION: Public Brazilian institutions are the principal sources of pulmonology research in Brazil. Such research activity is concentrated in the southeastern part of the country. Case reports account for one-third of this activity. Although there was great variability in the subjects addressed, diseases that are highly prevalent in Brazil, such as tuberculosis and other infections diseases, were the most common topics. (+info)
Is there a uniform approach to the management of diffuse parenchymal lung disease (DPLD) in the UK? A national benchmarking exercise.
(46/270)
BACKGROUND: Benchmarking is the comparison of a process to the work or results of others. We conducted a national benchmarking exercise to determine how UK pulmonologists manage common clinical scenarios in diffuse parenchymal lung disease (DPLD), and to determine current use and availability of investigative resources. We compared management decisions to existing international guidelines. METHODS: Consultant members of the British Thoracic Society were mailed a questionnaire seeking their views on the management of three common scenarios in DPLD. They were asked to choose from various management options for each case. Information was also obtained from the respondents on time served as a consultant, type of institution in which they worked and the availability of a local radiologist and histopathologist with an interest/expertise in thoracic medicine. RESULTS: 370 out of 689 consultants replied (54% response rate). There were many differences in the approach to the management of all three cases. Given a scenario of relapsing pulmonary sarcoidosis in a lady with multiple co-morbidities, half of respondents would institute treatment with a variety of immunosuppressants while a half would simply observe. 42% would refer a 57-year old lady with new onset DPLD for a surgical lung biopsy, while a similar number would not. 80% would have referred her for transplantation, but a fifth would not. 50% of consultants from district general hospitals would have opted for a surgical biopsy compared to 24% from cardiothoracic centres: this may reflect greater availability of a radiologist with special interest in thoracic imaging in cardiothoracic centres, obviating the need for tissue diagnosis. Faced with an elderly male with high resolution CT thorax (HRCT) evidence of usual interstitial pneumonia (UIP), three quarters would observe, while a quarter would start immunosuppressants. 11% would refer for a surgical biopsy. 14% of UK pulmonologists responding to the survey revealed they had no access to a radiologist with an interest in thoracic radiology. CONCLUSION: From our survey, it appears there is a lack of consensus in the management of DPLD. This may reflect lack of evidence, lack of resources or a failure to implement current guidelines. (+info)
Respiratory polygraphy in sleep apnoea diagnosis. Report of the Swiss respiratory polygraphy registry and systematic review of the literature.
(47/270)
BACKGROUND: Sleep related breathing disorders (SBD) are common and associated with morbidity and mortality. Since polysomnography, the conventional diagnostic gold standard is costly and not generally available, ambulatory respiratory polygraphic sleep studies (RP) are used. To evaluate whether RP reimbursement by health insurance companies was justified, the Swiss Federal Office of Public Health (FOPH) requested registration of RP during 36 months and a literature review on RP. The results are reported here. METHODS: RP reimbursed from July 2002 to December 2005 by Swiss health insurance companies were analysed. A review of the literature from 2003 comparing RP with PSG was updated. The outcome of interest was the apnoea/hypopnoea index. RESULTS: Datasets on 11,485 RP were evaluated, 8179 were performed to evaluate suspected obstructive sleep apnoea syndrome (OSAS). In patients with snoring, witnessed apnoea and hypersomnia (n = 4180), 80.2% of RP confirmed OSAS, 3.5% of RP were inconclusive prompting polysomnography. Six studies published between 2003 and 2005 were pooled with a former review of 12 studies. With a mean pre-test probability of 64% for OSAS, the post-test probability after a negative result ranged from 8% (negative likelihood ratio of 0.05) to 23% (negative likelihood ratio of 0.20). The post-test probability after a positive result was within a range of 98% (positive likelihood ratio of 23.8) to 90% (positive likelihood ratio of 5.7). CONCLUSIONS: In selected patients with clinically suspected OSAS RP allows accurate and simple diagnosis of OSAS. According to the practice in Switzerland as reflected by the registry additional PSG are rarely required, suggesting relevant cost savings by RP. Granting reimbursement for RP as introduced in the meantime by the FOPH seems justified. (+info)
A proposed classification system of central airway stenosis.
(48/270)
Tracheobronchial stenosis, a serious problem in adults and children, has multiple causes and has been treated in many ways. While developing an international multicentre study to evaluate efficacy of airway stents, it was realised that no adequate description of central airway stenosis regarding type, location and degree has been published. Thus, comparing results of different treatment modalities in different centres has been difficult due to a lack of uniformity of classification. Reports are typically descriptive and precise classification schemes have not adequately addressed either for the trachea or the main bronchi. A standardised classification scheme was proposed with descriptive images and diagrams for rapid and uniform classification of central airway stenosis. The present authors' system divides stenosis into structural and dynamic types and further classifies the disease by degree of stenosis, location and transition zone. Multiple sites can be described and each is transformed into a simple numerical scoring system prompted by a diagram, which can be easily captured for subsequent uniform analysis across sites. A pilot validation of the system, with 18 pulmonologists of varying training background, showed strong precision and agreement between observers. Such a system will enhance the ability to study the effectiveness of treatment modalities for central airway stenosis. (+info)