207 results on '"Pedersen, O. F."'
Search Results
52. The relationship between maximal ventilation, breathing pattern and mechanical limitation of ventilation.
- Author
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Jensen, J I, Lyager, S, and Pedersen, O F
- Abstract
1. The extent to which the pattern of breathing at maximal ventilation in man is affected by the mechanical properties of the respiratory pump has been studied. 2. The maximal effort flow volume (MEFV) loop has been used to calculate the shortest possible inspiratory (TI) and expiratory (TE) durations associated with the highest ventilation for all tidal volumes (VT). These minimal TIS and TES hve been plotted on a VT‐TI‐TE diagram. 3. Such predicted minimal TIS and TES were compared with observed minimal values from five healthy subjects who tried to reach their maximal ventilations during three experimental conditions: maximal voluntary hyperventilation, rebreathing, and graded exercise. 4. We have found that exercise increases the maximal flows at all lung volumes and confirmed that rebreathing has no such effect. 5. During hyperventilation the mechanical limits were followed closely for all VTS. During exercise and rebreathing the VT‐TI and the VT‐TE relationships showed a definite maximum of VT at submaximal ventilation in half the cases. The calculated minimal TIS and TES were approached but not reached. This indicates that maximal ventilation is not entirely limited by the mechanical properties of the respiratory pump, but that mechanical factors influence the regulation of breathing pattern when ventilation approaches the maximal capacity of the respiratory pump.
- Published
- 1980
- Full Text
- View/download PDF
53. Serum antibodies and immunoglobulins in smokers and nonsmokers
- Author
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Andersen, P, Pedersen, O F, Bach, B, and Bonde, G J
- Subjects
Adult ,Male ,Adolescent ,Smoking ,Immunoglobulins ,Middle Aged ,Antibodies, Bacterial ,Antibodies ,Immunoglobulin A ,Immunoglobulin G ,Candida albicans ,Escherichia coli ,Humans ,Female ,Antibodies, Fungal ,Research Article - Abstract
Antibodies to antigens in humidifier water were detected by double immunodiffusion in 30 of 63 (47.6%) persons who were exposed to aerosols from a water humidification unit in a cigar plant, whereas no antibodies could be detected in 49 unexposed blood donors (P less than 0.001). The presence of antibodies could not be related to fever or pulmonary symptoms (cough, expectoration, dyspnoe). Antibodies were found in 14 (93.3%) of 15 nonsmokers and in only 13 (31.7%) of 41 smokers (P less than 0.001), and the titres were highest in nonsmokers. Serum IgG and IgA levels were higher in nonsmokers than in smokers, and the variances within the groups were significantly different (F less than 0.05 and F less than 0.05, respectively). The mean serum IgM values were not significantly different in the two groups. Antibodies to Candida albicans and Escherichia coli 04 and 075 were detected with equal prevalences and titres in smokers and nonsmokers. These findings suggest that tobacco smoking may suppress the humoral immune response to inhaled antigens but not to antigens which are supposed to be absorbed through membranes other than those of the bronchopulmonary system. They may partly explain the reported increased incidence of allergic alveolitis in nonsmokers.
- Published
- 1982
54. A new approach in the examination of the nose
- Author
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Hilberg, Ole, Pedersen, O. F., and Jackson, A. C.
- Published
- 1988
55. Dust exposure, eye redness, eye cytology and mucous membrane irritation in a tobacco industry
- Author
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Søren K. Kjærgaard and Pedersen, O. F.
- Subjects
conjunctiva ,tear fluid ,polymorphonuclear leukocytes ,red eyes ,epithelium - Abstract
In a study of 75 workers employed in a tobacco factory producing cheroots we measured cellular contents of tear fluid, redness of eyes, discomfort, total (0–5.7 mg/m3) and respirable dust in the breathing zone and total ambient dust by stationary sampling (0.08–1.0 mg/m3). A matched group of 50 office workers in a telephone company (total ambient dust concentration between 0.08–0.13 mg/m3) was similarly examined as referents. We found a difference between the two companies with regard to cell counts, with tobacco workers having the largest numbers except for lymphocytes. Among tobacco workers we furthermore found that the number of cuboidal and columnar epithelial cells increased during the day. The increase of cuboidal cells, however, occurred mainly in a small group of tobacco workers exposed to the highest concentrations of tobacco dust (mean =1.26 mg/m3). No difference in the sensation of eye irritation was found between companies, but increased irritation in the morning was associated with increased exposure to total dust during the work-shift among tobacco workers. A dose-dependent difference in photographically measured eye redness was found among the tobacco workers. It could not be explained by differences in tobacco smoking, sex, age, sleeping habits or use of glasses. Irritation of lips and upper airways as reported by questionnaire were more common in tobacco workers than in referents. In conclusion the tobacco workers, more often than the referents, had complaints and objective changes in the mucous membranes of the eyes. These may be related to tobacco dust exposure.
- Published
- 1989
56. Risk factors for new onset asthma among farming students and non-farming rurals
- Author
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Øyvind Omland, Charlotte Hjort, Pedersen, O. F., Miller, M. R., and Torben Sigsgaard
57. The shape of the maximum expiratory flow-volume curve reflects exposure in farming
- Author
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Omland, Ø., Torben Sigsgaard, Pedersen, O. F., and Miller, M. R.
- Subjects
Male ,Smoking ,Dust ,respiratory system ,Asthma ,respiratory tract diseases ,Agricultural Workers' Diseases ,Cohort Studies ,Forced Expiratory Volume ,Occupational Exposure ,Linear Models ,Animals ,Humans ,Bronchial Hyperreactivity ,circulatory and respiratory physiology ,Demography ,Maximal Expiratory Flow-Volume Curves - Abstract
The objective of the study was to examine the effect of farming exposure, respiratory symptoms and smoking on the shape of the MEFV-curve in 1,691 male farming students and 407 male controls and to relate the slope ratio with FEV(1) and FEV(1) /FVC. Each subject underwent a medical interview and the slope ratios from the MEFV-curve at 75 (SR75), 50 (SR50) and 25 (SR25) %FVC together with FEV1 and FVC were recorded. Histamine bronchial reactivity (Yan method) was measured and skin prick test with inhalant allergens was performed. In smokers, SR75 increased with increasing exposure to: general farming, swine and dairy cattle (p
58. Metodebetingede forskelle i vitalkapacitet
- Author
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Lone Sunde, Pedersen, O. F., Søren Lyager, and Noe Naeraa
- Subjects
Adult ,Male ,Adolescent ,Spirometry ,Vital Capacity ,Humans ,Female ,Middle Aged ,Aged
59. Respiratory health and allergy among young farmers and non-farming rural males in Denmark: the SUS study
- Author
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Torben Sigsgaard, Hjort, C., Omland, O., Miller, M. R., and Pedersen, O. F.
60. Exposure to environmental tobacco smoke in childhood is associated to lung function in smoking adults
- Author
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Øyvind Omland, Tine Halsen Malling, Pedersen, O. F., Vivi Schlünssen, Torben Sigsgaard, Skadhauge, Lars R., David Lee Sherson, Jesper Bælum, and Gert Thomsen
61. Airway dynamics in transition between peak and maximal expiratory flow
- Author
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Pedersen, O. F., primary, Lyager, S., additional, and Ingram, R. H., additional
- Published
- 1985
- Full Text
- View/download PDF
62. Density dependence of maximal expiratory flow before and during tracheal constriction in dogs
- Author
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Castile, R. G., primary, Pedersen, O. F., additional, Drazen, J. M., additional, and Ingram, R. H., additional
- Published
- 1986
- Full Text
- View/download PDF
63. Interdependent regional lung emptying during forced expiration: a transistor model
- Author
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Solway, J., primary, Fredberg, J. J., additional, Ingram, R. H., additional, Pedersen, O. F., additional, and Drazen, J. M., additional
- Published
- 1987
- Full Text
- View/download PDF
64. Low concentrations of formaldehyde in bronchial asthma: a study of exposure under controlled conditions.
- Author
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Harving, H, primary, Korsgaard, J, additional, Dahl, R, additional, Pedersen, O F, additional, and Molhave, L, additional
- Published
- 1986
- Full Text
- View/download PDF
65. Acoustic Rhinometry
- Author
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Grymer, L. F., primary, Hilberg, O., additional, Elbr??nd, O., additional, and Pedersen, O. F., additional
- Published
- 1989
- Full Text
- View/download PDF
66. Density dependence of maximum expiratory flow in the dog
- Author
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Pedersen, O. F., primary, Castile, R. G., additional, Drazen, J. M., additional, and Ingram, R. H., additional
- Published
- 1982
- Full Text
- View/download PDF
67. Airway compliance and flow limitation during forced expiration in dogs
- Author
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Pedersen, O. F., primary, Thiessen, B., additional, and Lyager, S., additional
- Published
- 1982
- Full Text
- View/download PDF
68. Respiratory Disease and Lung Function in a Tobacco Industry
- Author
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Kjaergaard, Søren K., primary, Pedersen, O. F., additional, Frydenberg, M., additional, Schønheyder, H., additional, Andersen, P., additional, and Bonde, G. J., additional
- Published
- 1989
- Full Text
- View/download PDF
69. Human response to controlled levels of toluene in six-hour exposures.
- Author
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Andersen, Ib, primary, Lundqvist, Gunnar R, additional, Molhave, L, additional, Pedersen, O F, additional, Proctor, Donald F, additional, Vaeth, M, additional, and Wyon, David P, additional
- Published
- 1983
- Full Text
- View/download PDF
70. Response of solvent-exposed printers and unexposed controls to six-hour toluene exposure.
- Author
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Baelum, J, primary, Andersen, I B, additional, Lundqvist, Gunnar R, additional, Molhave, L, additional, Pedersen, O F, additional, Vaeth, M, additional, and Wyon, David P, additional
- Published
- 1985
- Full Text
- View/download PDF
71. Human reactions to a mixture of indoor air volatile organic compounds
- Author
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Molhave, L., Kj*aergaard, S. K., and Pedersen, O. F.
- Subjects
AIR pollution ,ORGANIC compounds ,REACTIVITY (Chemistry) - Published
- 1991
72. New concepts for expressing forced expiratory volume in 1 s arising from survival analysis.
- Author
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Miller MR and Pedersen OF
- Subjects
- Adult, Age Distribution, Aged, Body Height, Female, Humans, Male, Middle Aged, Multivariate Analysis, Predictive Value of Tests, Proportional Hazards Models, Reference Values, Sex Distribution, Young Adult, Forced Expiratory Volume, Lung Diseases diagnosis, Lung Diseases mortality, Spirometry standards, Spirometry statistics & numerical data
- Abstract
Spirometric lung function is partly determined by sex, age and height (Ht). Commonly, lung function is expressed as a percentage of the predicted value (PP) in order to account for these effects. Since the PP method retains sex, age and Ht bias, forced expiratory volume in 1 s (FEV(1)) standardised by powers of Ht and by a new sex-specific lower limit (FEV(1) quotient (FEV(1)Q)) were investigated to determine which method best predicted all-cause mortality in >26,967 patients and normal subjects. On multivariate analysis, FEV(1)Q was the best predictor, with a hazard ratio for the worst decile of 6.9 compared to 4.1 for FEV(1)PP. On univariate analysis, the hazard ratios were 18.8 compared to 6.1, respectively; FEV(1) x Ht(-3) was the next-best predictor of survival. Median survival was calculated for simple cut-off values of FEV(1)Q and FEV(1) x Ht(-3). These survival curves were accurately fitted (r(2) = 1.0) by both FEV(1)Q and FEV(1) x Ht(-3) values expressed polynomially, and so an individual's test result could be used to estimate survival (with sd for median survival of 0.22 and 0.61 yrs, respectively). It is concluded that lung function impairment should be expressed in a new way, here termed the FEV(1)Q, or, alternatively, as FEV(1) x Ht(-3), since these indices best relate spirometric lung function to all-cause mortality and survival.
- Published
- 2010
- Full Text
- View/download PDF
73. Interpretative strategies for lung function tests.
- Author
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Pellegrino R, Viegi G, Brusasco V, Crapo RO, Burgos F, Casaburi R, Coates A, van der Grinten CP, Gustafsson P, Hankinson J, Jensen R, Johnson DC, MacIntyre N, McKay R, Miller MR, Navajas D, Pedersen OF, and Wanger J
- Subjects
- Europe, Humans, United States, Algorithms, Diagnosis, Computer-Assisted methods, Diagnosis, Computer-Assisted standards, Lung Diseases diagnosis, Practice Patterns, Physicians' standards, Respiratory Function Tests methods, Respiratory Function Tests standards
- Published
- 2005
- Full Text
- View/download PDF
74. Standardisation of the single-breath determination of carbon monoxide uptake in the lung.
- Author
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Macintyre N, Crapo RO, Viegi G, Johnson DC, van der Grinten CP, Brusasco V, Burgos F, Casaburi R, Coates A, Enright P, Gustafsson P, Hankinson J, Jensen R, McKay R, Miller MR, Navajas D, Pedersen OF, Pellegrino R, and Wanger J
- Subjects
- Humans, Carbon Monoxide, Gases, Pulmonary Gas Exchange physiology, Respiratory Function Tests standards
- Published
- 2005
- Full Text
- View/download PDF
75. Standardisation of spirometry.
- Author
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Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, Crapo R, Enright P, van der Grinten CP, Gustafsson P, Jensen R, Johnson DC, MacIntyre N, McKay R, Navajas D, Pedersen OF, Pellegrino R, Viegi G, and Wanger J
- Subjects
- Humans, Maximal Voluntary Ventilation, Peak Expiratory Flow Rate, Spirometry instrumentation, Spirometry methods, Vital Capacity, Spirometry standards
- Published
- 2005
- Full Text
- View/download PDF
76. General considerations for lung function testing.
- Author
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Miller MR, Crapo R, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, Enright P, van der Grinten CP, Gustafsson P, Jensen R, Johnson DC, MacIntyre N, McKay R, Navajas D, Pedersen OF, Pellegrino R, Viegi G, and Wanger J
- Subjects
- Adult, Age Factors, Airway Resistance, Female, Humans, Male, Middle Aged, Quality Control, Risk Factors, Sensitivity and Specificity, Severity of Illness Index, Spirometry standards, Airway Obstruction diagnosis, Lung Diseases diagnosis, Respiratory Function Tests standards
- Published
- 2005
- Full Text
- View/download PDF
77. Time domain and flow indices of bronchial hyperresponsiveness: association with asthma symptoms, atopy and smoking.
- Author
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Miller MR, Sigsgaard T, Omland O, and Pedersen OF
- Subjects
- Adult, Asthma complications, Bronchial Hyperreactivity complications, Forced Expiratory Volume physiology, Humans, Male, Reproducibility of Results, Respiratory Hypersensitivity complications, Sensitivity and Specificity, Time Factors, Vital Capacity physiology, Asthma diagnosis, Asthma physiopathology, Bronchial Hyperreactivity diagnosis, Bronchial Hyperreactivity physiopathology, Bronchial Provocation Tests, Forced Expiratory Flow Rates physiology, Respiratory Hypersensitivity diagnosis, Respiratory Hypersensitivity physiopathology, Smoking physiopathology
- Abstract
Conventional measures of bronchial hyperresponsiveness (BHR) are only weakly associated with respiratory symptoms in epidemiological studies. Partial and maximal forced expiratory manoeuvres were recorded during histamine challenge testing in 1,959 young male farmers. Analysis was performed to test whether novel measures of BHR, using alternative flow and time domain indices, are more closely associated with asthma symptoms, smoking status and atopy than forced expiratory volume in one second (FEV1) and conventional measures of BHR. The first moments to 75% and 90% of the forced vital capacity (FVC) were calculated from full (F) and partial (P) forced expiratory manoeuvres (i.e. alpha1 75%F, alpha1 75%P), together with the instantaneous flows when 40% and 30% of the FVC remained to be expired (MEF40 and MEF30). BHR was measured by the provocative dose causing a 20% change (PD20) in the FEV1 and alpha1 75%, and also by the method of log dose slopes (LDS). Asthma was diagnosed from symptoms associated with asthma in 158 (8.1%) of the subjects. PD20 FEV1 could only be recorded in 190 subjects (9.7%), of whom only 48 had asthma, whereas LDSFEV1 was recorded in 1,725 (88%) subjects. From the prechallenge data, alpha1 75%, expressed as standardised residuals, showed the largest difference between smokers with and without asthma symptoms, and no indices showed significant differences between nonsmokers with and without asthma symptoms. From BHR data in both smokers and nonsmokers, LDSFEV1 showed one of the largest differences between those with and without asthma symptoms. With smoking status and atopy accounted for, the greatest partial correlation with asthma diagnosis was found for LDSMEF40P, and then for LDSFEV1, but LDSMEF40P was measurable in only just over one-half of the subjects. The authors conclude that time-domain indices are promising measures for longitudinal epidemiological studies concerning the relationship between bronchial hyperresonsiveness and environmental exposures. However, indices from the partial flow-volume loop suffer from censored data.
- Published
- 2002
- Full Text
- View/download PDF
78. The short-term repeatability of histamine bronchial testing in young males. The SUS study.
- Author
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Omland Ø, Miller MR, Sigsgaard T, and Pedersen OF
- Subjects
- Adult, Forced Expiratory Volume drug effects, Humans, Male, Maximal Expiratory Flow-Volume Curves, Maximal Midexpiratory Flow Rate drug effects, Reproducibility of Results, Statistics, Nonparametric, Vital Capacity drug effects, Bronchial Provocation Tests standards, Histamine
- Abstract
We have measured bronchial responsiveness (BR) to histamine on two occasions between 5 and 24 h apart, to determine if conventional and new indices of BR are repeatable. A random sample of 29 healthy male subjects with a mean age of 19 (SD 3.44) years from a larger study repeated a Yan method test of BR, recording both partial and maximal expiratory flow volume (PEFV and MEFV) curves. From the MEFV curves log-dose slopes (LDS) for forced expiratory volume in 1 sec (FEV1), forced expiratory flow between 25% and 75% of forced vital capacity (FVC) (FEF(25-75%)), mean expiratory flow at 30% and 40% of FVC (MEF30, MEF40), and the first moment of the spirogram (alpha1) truncated at 75% and 90% of FVC were calculated, as well as the provocative dose that induces a 20% fall in FEV1 (PD20FEV1). From the PEFV curves LDS for alpha(1)75% and alpha(1)90%, and MEF30 and MEF40 were derived. Apart from MEF30 and alpha(1)90% the second test was significantly lower (P<0.05) than the first when measuring the repeatability of spirometric indices, whereas the LDS of the indices showed no significant change. The repeatability expressed as intra-class correlation coefficient (ICC) was highest for LDS FEV1 (0.87), second highest for LDS MEF40 (0.67) and LDS MEF30 (0.65). The LDS for moment indices were much less repeatable and the lowest ICC was found in all LDS indices derived from PEFV curves. Within-subject variance was not influenced by atopic status, smoking habits or recordable PD20FEV1. As tests for bronchial hyper-responsiveness (BHR) the LDS of FEV1, MEF40 and MEF30 seem to be acceptable for use in population studies.
- Published
- 2001
- Full Text
- View/download PDF
79. Comparative oral and topical decongestant effects of phenylpropanolamine and d-pseudoephedrine.
- Author
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Erickson CH, McLeod RL, Mingo GG, Egan RW, Pedersen OF, and Hey JA
- Subjects
- Administration, Oral, Administration, Topical, Animals, Blood Pressure drug effects, Cats, Disease Models, Animal, Histamine Release drug effects, Nasal Cavity drug effects, Nasal Obstruction physiopathology, Adrenergic alpha-Agonists administration & dosage, Ephedrine administration & dosage, Nasal Decongestants administration & dosage, Nasal Obstruction drug therapy, Phenylpropanolamine administration & dosage
- Abstract
Nonselective adrenergic alpha-agonists such as phenylpropanolamine and d-pseudoephedrine are widely used as decongestants to treat nasal congestion associated with a variety of nasal diseases. Although the activity of these drugs is well established in clinical studies, a direct comparison of their nasal decongestant effect as determined by changes in nasal cavity dimensions and nasal architecture has not been studied. Using acoustic rhinometry, we evaluated the effects of these drugs on nasal cavity volume, minimum cross-sectional area (Amin), and the distance from the nosepiece to the Amin (Dmin) in a feline, pharmacological model of nasal congestion. Administration of topical compound 48/80 (1%), a mast cell histamine liberator, into the left nasal passageway decreased nasal volume by 66%, reduced Amin by 51%, and increased Dmin by 116%. The congestive responses to compound 48/80 (1%) were reproducible through six weeks. In a subset of cats, the nasal cavity volume effect of repetitive exposure to compound 48/80, given once every two weeks for six weeks, was not different from the nasal responses after the initial exposure to compound 48/80. Pretreatment with oral phenylpropanolamine (10 mg/kg) or oral d-pseudoephedrine (10 mg/kg) attenuated the nasal effects of compound 48/80, but were associated with a pronounced increase in systolic blood pressure of +51 and +82 mmHg, respectively. A similar decongestant profile was observed with phenylpropanolamine (1%) and d-pseudoephedrine (1%) when given topically. Topical phenylpropanolamine (1%) and d-pseudoephedrine (1%) 45 minutes after dosing increased blood pressure +44 and +17 mmHg, respectively, over control animals. We conclude that oral and topical phenylpropanolamine and d-pseudoephedrine display equieffective nasal decongestant activity and produce similar cardiovascular profiles characterized by significant increases in blood pressure.
- Published
- 2001
- Full Text
- View/download PDF
80. Acoustic rhinometry in infants and children.
- Author
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Djupesland P and Pedersen OF
- Subjects
- Acoustics, Child, Child, Preschool, Forecasting, Humans, Infant, Nasal Cavity growth & development, Anthropometry methods, Nasal Cavity anatomy & histology
- Abstract
Acoustic rhinometry (AR), introduced a decade ago for assessment of the nasal airways of adults, has several attractive features relevant to application in a paediatric population. Its non-invasive nature, simplicity and rapidity are prime assets when examining infants and small children. Valid AR measurements can be obtained in a few seconds and require minimal co-operation. The striking consistency of AR studies of healthy subjects and the agreement with CT-derived and directly measured choanal dimensions are a strong indication of its reliability. Acoustic rhinometry optimised for infants and small children opens new perspectives and possibilities in the assessment of nasal airway dimensions and their relationship to pathological conditions in both the upper and the lower airways. The objective of this paper is to describe the advantages of AR in infants and children, but also point out its limitations and potential sources of error. Practical guidelines as to the measurement procedure and analysis and interpretation of AR-data are outlined.
- Published
- 2000
81. Acoustic rhinometry: recommendations for technical specifications and standard operating procedures.
- Author
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Hilberg O and Pedersen OF
- Subjects
- Acoustics, Animals, Forecasting, Humans, Reference Values, Reproducibility of Results, Research, Anthropometry methods, Nasal Cavity anatomy & histology
- Abstract
This document is the result of the work and discussion of the Standardization Committee on Acoustic Rhinometry and presents guidelines for quality control and optimal application of acoustic rhinometry at its present stage. It is suggested that: 1. A well-defined standard nose is used for testing and optimising the equipment (data for a standard nose is given in the paper). 2. Procedures for evaluation of accuracy and repeatability of the measurements in the standard nose are presented, and error limits are defined for the area-distance curve as a whole, for the minimum cross-sectional area and for the volume from 0-5 cm into the nose. 3. Publication of results should include the volume 0-5 cm into the nose (volume from 2-5 cm for mucosal changes) the minimum cross-sectional area or preferably the two first minima and the distances to those areas. 4. The operator should be trained, follow a standard operating procedure and the environmental conditions (temperature and noise) be controlled. 5. Attention should be given to the nosepiece and the coupling between the equipment and the nose to obtain correct position, and sufficient seal without disturbing the anatomy. 6. The manufacturer should give information about the performance of the equipment, calibration procedures and maintenance, hygiene, environmental and safety standards.
- Published
- 2000
82. Central airways behave more stiffly during forced expiration in patients with asthma.
- Author
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Brackel HJ, Pedersen OF, Mulder PG, Overbeek SE, Kerrebijn KF, and Bogaard JM
- Subjects
- Adult, Bronchi physiopathology, Elasticity, Female, Humans, Lung Volume Measurements, Male, Systemic Inflammatory Response Syndrome physiopathology, Trachea physiopathology, Airway Resistance physiology, Asthma physiopathology, Lung Compliance physiology
- Abstract
Chronic inflammation and extracellular remodeling of the airway wall characterize asthma. The purpose of this study was to examine whether these features cause a change in airway mechanical properties. We examined 14 healthy and 10 young adults with long-lasting asthma, the latter treated with inhaled bronchodilators and corticosteroids. To obtain area-versus-transmural pressure (A-Ptm) curves during forced expiration (Pedersen, O. F., et al. J. Appl. Physiol. 1982;52:357-369), we used an esophageal balloon and a Pitot static probe positioned at five locations between the right lower lobe and midtrachea. Cross-sectional area (A), airway compliance (Caw = dA/dPtm), and specific airway compliance (sCaw = Caw/A) were obtained from the A-Ptm curves. Results showed that: (1) A was larger in males than in females; (2) Caw and sCaw decreased with a more downstream position; and (3) Caw and sCaw were significantly lower in the patients with asthma, with the differences between the asthmatic patients and the healthy subjects becoming smaller toward the trachea. The lower Caw and sCaw in the patients with long-lasting asthma support the concept that chronic inflammation and remodeling of the airway wall may result in stiffer dynamic elastic properties of the asthmatic airway.
- Published
- 2000
- Full Text
- View/download PDF
83. Particle deposition in the nose related to nasal cavity geometry.
- Author
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Rasmussen TR, Andersen A, and Pedersen OF
- Subjects
- Adult, Aerosols, Female, Humans, Individuality, Male, Middle Aged, Models, Theoretical, Dust, Nasal Cavity anatomy & histology
- Abstract
A number of studies have been made to characterise the deposition-pattern of inhaled airborne particles in the nose. Common to all results has been considerable differences in deposition fractions between normal human subjects. It was the aim of the current study to improve our understanding of individual differences in nasal deposition of inhaled particles. Depositions were measured in ten adult normal subjects and were related to dimensional measurements by acoustic rhinometry. Five litres of a polydisperse aerosol (MMAD = 0.7 micron, sigma g = 1.7) were inhaled through one nostril only during 5 inspirations with flows of 10, 20, and 30 L/min with decongested mucosa. Increasing flow was found to increase the fraction deposited in the nose, while there was an inverse correlation between nasal deposition fraction and minimum cross-sectional area of the nasal cavity (Amin). Information based on acoustic rhinometry measurements significantly reduced the amount of unexplained variation between subjects in nasal deposition fraction. We conclude that an estimate of maximum linear air velocity, calculated as airflow divided by Amin, was the best single predictor of nasal deposition fraction, which was found to increase with increasing air velocity raised to a power of approximately 4/3.
- Published
- 2000
84. S and Z alpha1-antitrypsin alleles are risk factors for bronchial hyperresponsiveness in young farmers: an example of gene/environment interaction.
- Author
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Sigsgaard T, Brandslund I, Omland O, Hjort C, Lund ED, Pedersen OF, and Miller MR
- Subjects
- Adult, Agricultural Workers' Diseases diagnosis, Asthma diagnosis, Asthma etiology, Bronchial Hyperreactivity diagnosis, Bronchial Provocation Tests, Confidence Intervals, Cross-Sectional Studies, Female, Humans, Hypersensitivity, Immediate diagnosis, Male, Odds Ratio, Phenotype, Regression Analysis, Risk Factors, Skin Tests, Spirometry, Agricultural Workers' Diseases genetics, Alleles, Bronchial Hyperreactivity genetics, alpha 1-Antitrypsin genetics
- Abstract
Several studies have found an association between the rare Pi-alleles and asthma or bronchial hyperresponsiveness (BHR). This study deals with the effect of Pi-type on BHR among 2,308 young Danish people living in rural areas with a mean +/- SD age of 19.7+/-2.4 yrs. Interviews, pulmonary function testing, bronchial histamine provocation and skin-prick tests were performed. Serum alpha1-antitrypsin levels were determined and phenotyping was performed by means of isoelectric focusing and the subjects categorized into four groups: 1) MM and MX; 2) MS; 3) MZ; and 4) rare, i.e. SZ, SS and ZZ. Among the farmers, a significant positive trend for sensitization towards house dust mites was found, ranging from 12% in the MM group to 22% in the rare Pi-group. A positive test for trend was found within the Pi-groups in a one-sided test for doctor-diagnosed asthma with a peak prevalence of 40% for these symptoms among smokers in the rare Pi-group. On multiple logistic regression analysis, an increased odds ratio (OR) for BHR was found among farming school attendants with the rare Pi-alleles. The OR (95% confidence interval) was 1.71 (0.84-3.49) for MS, 1.93 (1.10-3.39) for MZ and 4.34 (1.19-15.8) for the rare Pi-group. Such a relationship was not found among the conscripts. These results show that a gene/environment interaction may exist between the farming occupation and the rare Pi-alleles, leading to a higher proportion of bronchial hyperresponsiveness related to the rare Pi-alleles in farming school attendants, in contrast to what is found among other young people living in rural areas.
- Published
- 2000
- Full Text
- View/download PDF
85. Cytokine release from the nasal mucosa and whole blood after experimental exposures to organic dusts.
- Author
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Sigsgaard T, Bonefeld-Jørgensen EC, Kjaergaard SK, Mamas S, and Pedersen OF
- Subjects
- Aspergillus, Asthma immunology, Asthma physiopathology, Cross-Over Studies, Cytokines blood, Double-Blind Method, Female, Glucans immunology, Humans, Interleukins blood, Interleukins metabolism, Leukotrienes metabolism, Lipopolysaccharides immunology, Male, Nasal Lavage Fluid, Occupational Diseases immunology, Occupational Diseases physiopathology, Occupational Exposure, Tumor Necrosis Factor-alpha analysis, Tumor Necrosis Factor-alpha metabolism, Allergens, Cytokines metabolism, Dust, Nasal Mucosa metabolism, Refuse Disposal, beta-Glucans
- Abstract
The aim of this study was to assess the cytokine response after nasal exposure to organic dusts. In a double blinded, crossover study five garbage workers with occupational airway symptoms and five healthy garbage workers were intranasally exposed to endotoxin (lipopolysaccharide LPS), beta-1,3-D-glucan (GLU), Aspergillus sp., compost or the saline dilute for 15 min. Nasal cavity volume and nasal lavage (NAL) were performed at baseline and 3, 6, 11 h postexposure. NAL was analysed with differential cell counts, cysteinyl-leukotrienes, tumour necrosis factor alpha, interleukin (IL)-1beta, IL-6 and IL-8. A whole blood assay on cytokine-release was performed with LPS and GLU. NAL cytokines neutrophils, lymphocytes and albumin increased significantly at 6 h after LPS exposure. GLU induced an increase in albumin and a slight increase in IL-1beta 6-11 h post exposure. In the WBA a significant increase in all cytokines after exposure to LPS as well as GLU was found. Significantly more cells were seen in NAL of the control group 6 h post LPS exposure. In conclusion lipopolysaccharide is the most potent inducer of inflammation in the nasal mucosa whereas compost and beta-1,3-D-glucan only induce minor changes. This reaction to lipopolysaccharide is attenuated in workers with occupational airway symptoms. In whole blood assay, however, beta-1,3-D-glucan also induces cytokine release, indicating a different protective effect of the nasal mucosa towards lipopolysaccharide and beta-1,3-D-glucan.
- Published
- 2000
- Full Text
- View/download PDF
86. Peak flowmeter resistance decreases peak expiratory flow in subjects with COPD.
- Author
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Miller MR and Pedersen OF
- Subjects
- Aged, Calibration, Female, Humans, Male, Middle Aged, Models, Biological, Pulmonary Alveoli physiology, Respiratory Muscles physiology, Airway Resistance physiology, Lung Diseases, Obstructive physiopathology, Peak Expiratory Flow Rate physiology
- Abstract
Previous studies have shown that the added resistance of a mini-Wright peak expiratory flow (PEF) meter reduced PEF by approximately 8% in normal subjects because of gas compression reducing thoracic gas volume at PEF and thus driving elastic recoil pressure. We undertook a body plethysmographic study in 15 patients with chronic obstructive pulmonary disease (COPD), age 65.9 +/- 6.3 yr (mean +/- SD, range 53-75 yr), to examine whether their recorded PEF was also limited by the added resistance of a PEF meter. The PEF meter increased alveolar pressure at PEF (Ppeak) from 3.7 +/- 1.4 to 4.7 +/- 1.5 kPa (P = 0.01), and PEF was reduced from 3.6 +/- 1.3 l/s to 3.2 +/- 0.9 l/s (P = 0.01). The influence of flow limitation on PEF and Ppeak was evaluated by a simple four-parameter model based on the wave-speed concept. We conclude that added external resistance in patients with COPD reduced PEF by the same mechanisms as in healthy subjects. Furthermore, the much lower Ppeak in COPD patients is a consequence of more severe flow limitation than in healthy subjects and not of deficient muscle strength.
- Published
- 2000
- Full Text
- View/download PDF
87. Peak expiratory flow profiles delivered by pump systems. Limitations due to wave action.
- Author
-
Miller MR, Jones B, Xu Y, Pedersen OF, and Quanjer PH
- Subjects
- Calibration, Equipment Failure Analysis, Humans, Lung Diseases, Obstructive diagnosis, Lung Diseases, Obstructive physiopathology, Models, Theoretical, Predictive Value of Tests, Lung Volume Measurements instrumentation, Peak Expiratory Flow Rate physiology
- Abstract
Pump systems are currently used to test the performance of both spirometers and peak expiratory flow (PEF) meters, but for certain flow profiles the input signal (i.e., requested profile) and the output profile can differ. We developed a mathematical model of wave action within a pump and compared the recorded flow profiles with both the input profiles and the output predicted by the model. Three American Thoracic Society (ATS) flow profiles and four artificial flow-versus-time profiles were delivered by a pump, first to a pneumotachograph (PT) on its own, then to the PT with a 32-cm upstream extension tube (which would favor wave action), and lastly with the PT in series with and immediately downstream to a mini-Wright peak flow meter. With the PT on its own, recorded flow for the seven profiles was 2.4 +/- 1.9% (mean +/- SD) higher than the pump's input flow, and similarly was 2.3 +/- 2.3% higher than the pump's output flow as predicted by the model. With the extension tube in place, the recorded flow was 6.6 +/- 6.4% higher than the input flow (range: 0.1 to 18.4%), but was only 1.2 +/- 2.5% higher than the output flow predicted by the model (range: -0.8 to 5.2%). With the mini-Wright meter in series, the flow recorded by the PT was on average 6.1 +/- 9.1% below the input flow (range: -23.8 to 2. 5%), but was only 0.6 +/- 3.3% above the pump's output flow predicted by the model (range: -5.5 to 3.9%). The mini-Wright meter's reading (corrected for its nonlinearity) was on average 1.3 +/- 3.6% below the model's predicted output flow (range: -9.0 to 1. 5%). The mini-Wright meter would be deemed outside ATS limits for accuracy for three of the seven profiles when compared with the pump's input PEF, but this would be true for only one profile when compared with the pump's output PEF as predicted by the model. Our study shows that the output flow from pump systems can differ from the input waveform depending on the operating configuration. This effect can be predicted with reasonable accuracy using a model based on nonsteady flow analysis that takes account of pressure wave reflections within pump systems.
- Published
- 2000
- Full Text
- View/download PDF
88. The shape of the maximum expiratory flow-volume curve reflects exposure in farming.
- Author
-
Omland O, Sigsgaard T, Pedersen OF, and Miller MR
- Subjects
- Animals, Asthma etiology, Bronchial Hyperreactivity etiology, Cohort Studies, Demography, Dust, Humans, Linear Models, Male, Maximal Expiratory Flow-Volume Curves, Smoking, Agricultural Workers' Diseases etiology, Forced Expiratory Volume, Occupational Exposure
- Abstract
The objective of the study was to examine the effect of farming exposure, respiratory symptoms and smoking on the shape of the MEFV-curve in 1,691 male farming students and 407 male controls and to relate the slope ratio with FEV(1) and FEV(1) /FVC. Each subject underwent a medical interview and the slope ratios from the MEFV-curve at 75 (SR75), 50 (SR50) and 25 (SR25) %FVC together with FEV1 and FVC were recorded. Histamine bronchial reactivity (Yan method) was measured and skin prick test with inhalant allergens was performed. In smokers, SR75 increased with increasing exposure to: general farming, swine and dairy cattle (p< or =0.020). SR50 increased with increasing exposure to farming (p=0.015). In non-smokers, SR25 increased with increasing exposure to swine and dairy cattle (p=0. 021) and increased SR25 was associated with sensitisation to house dust mite (p=0.017). Data revealed an interaction between smoking and exposure to farming. FEV(1) and FEV(1)/FVC was not associated with farming exposure or production animals. FEV1 and FEV(1)/FVC (p< or =0.003) were lower among subjects wi bronchial hyperresponsiveness and asthma (FEV(1) and asthma only in smokers). SR75 (p=0.037) and SR50 (p=0.024) were increased in subjects with asthma and SR75 was increased in subjects with bronchial hyperresponsiveness, but only in smokers (p=0.002). In conclusion, exposure to farming seems to influence the shape of the MEFV-curve and there are indications of interaction between exposure to organic dust and smoking. These changes are seen only in the slope ratios and not in FEV(1) and FEV(1)/FVC. However, FEV(1) and FEV(1)/FVC are superior to slope ratios in differentiating healthy subjects from those with respiratory symptoms.
- Published
- 2000
89. Accuracy of measurement of acoustic rhinometry applied to small experimental animals.
- Author
-
Kaise T, Ukai K, Pedersen OF, and Sakakura Y
- Subjects
- Acoustics, Animals, Disease Models, Animal, Guinea Pigs, Male, Nasal Cavity physiopathology, Reproducibility of Results, Sensitivity and Specificity, Manometry methods, Nasal Cavity pathology, Nasal Obstruction diagnosis, Otolaryngology methods
- Abstract
Nasal obstruction is one of the major symptoms of allergic rhinitis. In the study of the mechanism of nasal obstruction, experiments on animal are useful. In adult humans, acoustic rhinometry has been used to evaluate nasal obstruction by determining nasal cavity dimensions in terms of cross-sectional areas as a function of the distance from the nostril. We modified the equipment used on humans to assess dimensions of nasal airway geometry of small experimental animals. The purpose of this study was to investigate the accuracy of measurement of the modified acoustic rhinometry applied to small experimental animals using nasal cavity models and guinea pigs. Measurement of the nasal cavity models (made of cylindrical silicone tubes) showed that the acoustic rhinometry estimated 85.5% of actual area and 79.0% of actual volume. In guinea pigs, nasal cavity volume determined by the acoustic rhinometry was 73.7 +/- 20.0% of actual volume. The actual volume was estimated by impression material instilled into the nasal cavity of the animals (IM volume), and volume determined by acoustic rhinometry significantly correlated with IM volume. Furthermore, there was a significant negative correlation between the volume and nasal airway resistance in guinea pigs. Measurement of the nasal airway resistance is the method frequently used in the evaluation of the nasal obstruction in guinea pigs. These results suggest that acoustic rhinometry is useful in evaluating nasal obstruction in small experimental animals.
- Published
- 1999
- Full Text
- View/download PDF
90. Characterization of heparin aerosols generated in jet and ultrasonic nebulizers.
- Author
-
Bendstrup KE, Newhouse MT, Pedersen OF, and Jensen JI
- Subjects
- Adult, Aerosols, Heparin, Low-Molecular-Weight administration & dosage, Humans, Particle Size, Anticoagulants administration & dosage, Heparin administration & dosage, Nebulizers and Vaporizers
- Abstract
Inhaled heparin has been used for asthma treatment, but results have been inconsistent, probably due to highly varying lung doses. We determined the output per unit time and the particle size distributions of sodium heparin, calcium heparin, and low molecular weight (LMW) heparin formulations in five concentrations from Sidestream jet nebulizers (Medic-Aid, Bognor Regis, England) and an Ultraneb 2000 ultrasonic nebulizer (DeVilbiss, Langen, Germany). We also determined the inhaled mass and the estimated respirable mass for some combinations. For the jet nebulizer, output per minute increased with increasing concentration and flow rate, and particle size decreased from 3.64 to 2.01 microns (mass median diameter [MMD]). The percentage of particles less than 3 microns ranged from 41% to 74%. For the ultrasonic nebulizer, maximum output per minute was achieved at a concentration of 7000 i.u./mL; this maximum depended upon the viscosity and temperature of the solution. MMD was independent of formulation, temperature, or concentration and ranged from 5.61 to 7.03 microns. Sodium heparin/calcium heparin in a concentration of 20,000 i.u./mL in the jet nebulizer driven at 10 L/min produced the highest dose of heparin capable of reaching the lower respiratory tract. Mass balance was determined for these combinations with the jet nebulizer run until visible aerosol generation ceased. Of a loading dose of 80,000 i.u. of heparin, 45,000 i.u. remained in the dead space of the nebulizer, 20,000 i.u. was deposited on the exhalation filter, and 15,000 i.u. was captured on the inhalation filter (inhaled mass). This corresponds to a respirable mass of 10,000 i.u. of heparin with a high probability of reaching the lower respiratory tract in normal healthy adults.
- Published
- 1999
- Full Text
- View/download PDF
91. Lung status in young Danish rurals: the effect of farming exposure on asthma-like symptoms and lung function.
- Author
-
Omland O, Sigsgaard T, Hjort C, Pedersen OF, and Miller MR
- Subjects
- Adolescent, Adult, Age Factors, Denmark, Female, Humans, Male, Prevalence, Respiratory Function Tests, Rural Population, Surveys and Questionnaires, Agricultural Workers' Diseases epidemiology, Agricultural Workers' Diseases physiopathology, Asthma epidemiology, Asthma physiopathology, Environmental Exposure, Lung physiopathology
- Abstract
The aim of this study was to assess the prevalence of asthma (self-reported) and relate this to lung function and factors associated with asthma in young farmers. Two hundred and ten female and 1,691 male farming students together with 407 males controls were studied. Each subject underwent a medical interview; forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were recorded using a dry wedge spirometer. Histamine bronchial reactivity was measured using the Yan method. Skin prick testing was performed using inhalant allergens. Nonsmokers had lower prevalence of asthma (5.4-10.8%) than smokers (11.3-21.0%) (p<0.05). Females reported symptoms of asthma nearly twice as often as males. Sex, smoking and a family history of asthma/allergy were significantly associated with asthma. Controls had higher standardized FEV1 and FVC residuals than male students, both nonsmokers (0.21 and 0.24) versus (-0.06 and -0.05) and smokers (0.29 and 0.33) versus (-0.11 and 0.13) (p<0.032). Bronchial hyperresponsiveness, asthma, siblings with allergy and working with cattle (controls only) were significantly associated with reduced lung function. In conclusion, the prevalence of asthma was significantly related to smoking, female sex, family history of asthma and allergy. Whilst bronchial hyperresponsiveness was associated with reduced lung function and lung function was slightly reduced in the male farming students, there was no association found between occupational farming exposure and either lung symptoms or lung function.
- Published
- 1999
- Full Text
- View/download PDF
92. Performance testing new peak flow meters.
- Author
-
Pedersen OF, Miller MR, and van der Mark TW
- Subjects
- Calibration, Equipment Design, Humans, Spirometry standards, Peak Expiratory Flow Rate, Spirometry instrumentation
- Published
- 1998
- Full Text
- View/download PDF
93. The rise and dwell time for peak expiratory flow in patients with and without airflow limitation.
- Author
-
Miller MR, Pedersen OF, and Quanjer PH
- Subjects
- Adult, Aged, Confidence Intervals, Female, Forced Expiratory Volume, Humans, Male, Middle Aged, Retrospective Studies, Spirometry, Vital Capacity, Peak Expiratory Flow Rate
- Abstract
The response of peak expiratory flow (PEF) meters may be affected by the magnitude of PEF, the time taken to get to PEF, and the duration that the peak is sustained. We undertook a retrospective study to define the 10 to 90% rise time (RT) and dwell time for flow above 90% (DT90) and 95% (DT95) of PEF. Blows were analyzed that had been recorded using a pneumotachograph from 912 patients older than 17 yr of age (556 men) who routinely attended a lung function laboratory. For each subject, that blow with the largest PEF was used to derive the PEF, FEV1, FVC, RT, DT90, and DT95. The values for RT, DT90, and DT95 were negatively skewed with the median values for men of 58, 29, and 19 ms, respectively, being significantly shorter than those for the women of 67, 49, and 31 ms. From the 912 subjects, there were 277 (153 men) who had all their spirometric indices within the normal range, and 305 (220 men) had both PEF and FEV1 more than 1. 645 SD below predicted, indicating airflow limitation. For subjects with airflow limitation the median RT was significantly smaller than in the normal subjects (men: 46 versus 72 ms, women: 50 versus 72 ms), and the same was found for DT90 (men: 22 versus 40 ms, women: 27 versus 56 ms) and DT95 (men: 15 versus 26 ms, women: 18 versus 34 ms). We conclude that the dwell times for PEF are shorter in men, and the rise and dwell times are shorter in patients with airflow limitation. Profiles used to test PEF meters should encompass the range of rise and dwell times found in subjects most likely to be using PEF meters, that is, those with airflow limitation.
- Published
- 1998
- Full Text
- View/download PDF
94. Acoustic reflections during rhinometry: spatial resolution and sound loss.
- Author
-
Hilberg O, Lyholm B, Michelsen A, Pedersen OF, and Jacobsen O
- Subjects
- Acoustic Stimulation, Computer Simulation, Helium, Humans, Lasers, Magnetic Resonance Imaging, Models, Anatomic, Nasal Cavity anatomy & histology, Nasal Mucosa physiology, Oxygen, Reference Values, Reproducibility of Results, Airway Resistance physiology, Nasal Cavity physiology, Respiratory Function Tests instrumentation
- Abstract
The accuracy of the acoustic reflections method for the evaluation of human nasal airway geometry is determined by the physical limitations of the technique and also by the in vivo deviations from the assumptions of the technique. The present study 1) examines the sound loss caused by nonrigidity of the nasal mucosa and viscous loss caused by complex geometry and its influence on the estimation of the acoustic area-distance function; 2) examines the optimal relation between sampling frequency and low-pass filtering, and 3) evaluates advantages of breathing He-O2 during the measurements on accuracy. Measurements made in eight plastic models, with cavities exactly identical to the "living" nasal cavities, revealed only minor effects of nonrigidity of the nasal mucosa. This was confirmed by an electrical analog model, based on laser vibrometry admittance measurements of the nasal mucosa, which indicated that the error in the acoustic measurements caused by wall motion is insignificant. The complex geometry of the nasal cavity per se (i.e., departure from circular) showed no significant effects on the measurements. Low-pass filtering of the signal is necessary to cut off cross modes arising in the nasal cavity. Computer simulations and measurements in models showed that the sampling frequency should be approximately four times the low-pass filtering frequency (i.e., twice the Nyquist frequency) to avoid influence on the result. No advantage was found for the the use of He-O2 vs. air in the nasal cavity.
- Published
- 1998
- Full Text
- View/download PDF
95. Prediction of nasal obstruction based on clinical examination and acoustic rhinometry.
- Author
-
Grymer LF, Hilberg O, and Pedersen OF
- Subjects
- Acoustics instrumentation, Adolescent, Adult, Aged, Female, Humans, Logistic Models, Male, Middle Aged, Nasal Obstruction etiology, Predictive Value of Tests, Sensitivity and Specificity, Surveys and Questionnaires, Nasal Cavity anatomy & histology, Nasal Obstruction diagnosis
- Abstract
The aim of this study was to find variables which characterize nasal obstruction. Scores from the clinical history, anterior rhinoscopy and objective values from acoustic rhinometry were found of importance. In a randomly-selected adult population of 230 individuals, 14% had the subjective feeling of nasal obstruction. The variables of significant value to predict nasal obstruction were: (1) symptoms of hypersensitivity/allergy and infection; (2) anterior septal deviations; and (3) small anterior dimensions of the nasal cavity. A minimum cross-sectional area (MCA) equal to 0.50 cm2, a cross-sectional area at the piriform aperture of 0.70 cm2 and a large effect of decongestion at MCA were found to be the best variables to separate obstructed from normal noses. Also, differences between each side of the nose were found of predictive value. In conclusion, a nose at risk for nasal obstruction is one with symptoms of allergy, frequent infections, small dimensions anteriorly, large difference between both sides, and a large degree of swelling of the mucosa.
- Published
- 1997
96. Spirometry with a Fleisch pneumotachograph: upstream heat exchanger replaces heating requirement.
- Author
-
Miller MR, Pedersen OF, and Sigsgaard T
- Subjects
- Adult, Calibration, Female, Humans, Humidity, Male, Middle Aged, Respiratory Function Tests methods, Respiratory Function Tests standards, Spirometry standards, Temperature, Vital Capacity, Spirometry instrumentation
- Abstract
The exact temperature of the head of an unheated Fleisch pneumotachograph (PT) during recording is not known, and variation in its temperature may lead to errors in measuring spirometric indexes. We measured PT head temperature during blows from five normal subjects, recorded by using a PT with and without an upstream heat exchanger to condition the air to the ambient temperature that was set in a climate chamber. Group mean (+/- SD) temperature of a thermocouple (TC) placed inside the PT head was 11.8 +/- 1.9 degrees C with 7 degrees C ambient, 25.4 +/- 1.3 degrees C at 23 degrees C, and was 37.2 +/- 0.3 degrees C at 37 degrees C. The between-subject range of temperature for this TC was 7.5 degrees at 7 degrees C, 5.5 degrees at 23 degrees C, and 1.1 degrees at 37 degrees C. The mean within-subject within-blow variation of temperature for this TC was 10.0 degrees and 3.3 degrees C for ambient of 7 degrees and 23 degrees C, respectively. At the usual ambient temperature in a laboratory, these differences in temperature lead to a 3.6% between-subject bias in recording, and the within-subject differences lead to 2.6% underreading of peak expiratory flow and a 0.5% overreading later in the blow, which makes ATPS-to-BTPS correction erroneous or difficult to perform. With the use of an upstream heat exchanger, the group mean temperature was 8.7 +/- 0.4 degrees, 23.2 +/- 0.2 degrees, and 37.1 +/- 0.2 degrees C at the three ambient temperatures, respectively, and the within-subject within-blow variation was reduced to < 1 degrees C. A heat exchanger placed upstream of the PT satisfactorily conditioned expired air to the ambient temperature and removed the error.
- Published
- 1997
- Full Text
- View/download PDF
97. The Peak Flow Working Group: the definition of peak expiratory flow.
- Author
-
Pedersen OF and Miller MR
- Subjects
- Humans, Respiratory Function Tests standards, Peak Expiratory Flow Rate, Respiratory Function Tests instrumentation
- Published
- 1997
98. The Peak Flow Working Group: the characteristics and calibration of devices for recording peak expiratory flow.
- Author
-
Miller MR and Pedersen OF
- Subjects
- Calibration, Humans, Reproducibility of Results, Respiratory Function Tests standards, Peak Expiratory Flow Rate, Respiratory Function Tests instrumentation
- Published
- 1997
99. Peak expiratory flow: conclusions and recommendations of a Working Party of the European Respiratory Society.
- Author
-
Quanjer PH, Lebowitz MD, Gregg I, Miller MR, and Pedersen OF
- Subjects
- Calibration, Humans, Reference Values, Respiratory Function Tests instrumentation, Respiratory Function Tests standards, Spirometry instrumentation, Spirometry standards, Asthma diagnosis, Peak Expiratory Flow Rate
- Published
- 1997
100. The Peak Flow Working Group: test of portable peak flow meters by explosive decompression.
- Author
-
Pedersen OF and Miller MR
- Subjects
- Calibration, Decompression, Humans, Respiratory Function Tests standards, Peak Expiratory Flow Rate, Respiratory Function Tests instrumentation
- Abstract
In 1991, 50 new Vitalograph peak flow meters and 27 previously used mini-Wright peak flow meters were tested at three peak flows by use of a calibrator applying explosive decompression. The mini-Wright peak flow meters were also compared with eight new meters. For both makes of meter there was an excellent within-meter and between-meter variation. The accuracy, however, was poor, with a maximal overestimation of true flows of 50 and 70 L.min-1 in the interval from 200 to 400 L.min-1 for the Vitalograph and mini-Wright meters, respectively. The deviation is explained by the physical characteristics of the variable orifice peak flow meters. They have been supplied with equidistant scales, which give non-linear readings.
- Published
- 1997
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