Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
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Analysis of the percent predicted values of FEV1 using different reference value in asthmatics ADVISER Tiago António Queirós Jacinto CLASS 2 Barbosa M., Barbosa T., Brito T., Campos J., Carvalho L., Carvalho R., Costa A., Dias J., Dória M., Maciel C., Mosca A., Pires C., Silva F., Viana D. - [email protected] Introduction to Medicine I 2009/2010
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Analysis of the percent predicted values of FEV1 using different reference value in asthmatics . Barbosa M., Barbosa T., Brito T., Campos J., Carvalho L., Carvalho R., Costa A., Dias J., Dória M., Maciel C., Mosca A., Pires C., Silva F., Viana D. - [email protected]. - PowerPoint PPT Presentation
Transcript of Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
ADVISER Tiago António Queirós Jacinto CLASS 2
Barbosa M., Barbosa T., Brito T., Campos J., Carvalho L., Carvalho R., Costa A., Dias J., Dória M., Maciel C., Mosca A., Pires C., Silva F., Viana D. - [email protected]
Introduction to Medicine I 2009/2010
SUMMARY
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Many respiratory diseases such as asthma and COPD can be now diagnosed and also monitored using spirometry
Introduction
Research questions and aims
Methods
Expected results
It analyses how well you can breathe
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
INTRODUCTION Respiratory diseases can be monitored using spirometry
FEV1 is the amount of air breath out during the first second
Reference formulas convert the values of FEV1 to a percentage whose optimal range is between 80 and 120
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
There are several reference formulas
The evolution, changes in society, as well as interpersonal differences (ethnicity, etc.) are not taken into account
Most formulas are now obsolete
INTRODUCTION
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
RESEARCH
QUESTIONS AND AIMS
Explore the use of different reference values
Analyze the reference values of FEV1 in asthmatics
Interpret the cause of some misdiagnosis
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
METHODS
Target population: Asthmatic patients from the Allergology Department of Hospital de S. João, Porto
Sampling methods: 100 asthmatic people consecutively chosen from an acute database of the Allergology Department of Hospital de S. João
Inclusion criteria: The inclusion criteria are: (1) being adult, (2) being asthmatic and (3) have performed spirometry
Units of analysis: Asthmatic participants
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
METHODS
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DATA COLECTION METHODS
Consecutively collected
Same technique and instrument
STUDY DESIGN
Observational Transversal
Analytical
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
METHODSVARIABLES DESCRIPTION
Age (in years) Height (in cm) Weight (in kg) Gender
FVC Forced vital capacity
FEV1 Forced expiratory volume in one second PEF Expiratory peak flow
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
METHODS
STATISTICAL ANALYSIS
Reference equations published by Crapo et al, Knudson et al and Morris et al to calculate the FEV1 predicted value
The percent predicted values of FEV1 are the result of the quotient:
(FEV1 collected through spirometry)/(FEV1 predicted value)
These procedures will be accomplished using the Statistical Analysis Software SPSS
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
Individual FVC (L)
PEF (L)
FEV1 (L)
*FEV1 FVC
K = Knudson
FEV1 predicted
(L)
K – FEV1(L)
Knudson FEV1
percentage(%)
C =Crapo FEV1
predicted(L)
C – FEV1(L)
Crapo FEV1 percentage
(%)
M =Morris FEV1
predicted(L)
M – FEV1(L)
Morris FEV1 percentage
(%)
1
2
.
.
100
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
*Tiffeneau Index
METHODS
METHODS
EXPECTED RESULTS
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Significant differences among the results obtained by these equations in patients with asthma
This fact can be in the origin of misdiagnosis and errors in therapy due to different conclusions drawn when these values are compared to the optimal range of 80/120
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
REFERENCES
American Thoracic Society, Lung Function Testing: Selection of references values and Interpretative Strategies; 1991.144: 1202-1218
Arabalibeik H, Khomami MH, Agin K, Setayeshi S; Classification of restrictive and obstructive pulmonary diseases using spirometry data. Tehran University of Medical Sciences, Tehran, Stud Health Technol Inform 2009. 142: 25
Collen, J. et. al., Discordance in Spirometric Interpretations using three commonly used reference equations vs National Health and Nutrition Examination Study III; 2008.134 1009-1014.
Crapo, RO; Morris, AH; Gardner, RM (1981) Reference spirometric values using techniques and equipment that meet ATS recommendations. Am Rev Respir Dis 123:659–664
Enright,Pl.; Testing your lungs: spirometry [Internet]; [Cited 15 October 2009], Available from: http://www.european-lung foundation.org/uploads/Document/WEB_CHEMIN_13424_1222861696.pdf
Kerstjens HA, Rijcken B, Schouten JP, Postma DS; Decline of FEV1, by age and smoking status: facts, figures, and fallacies, Department of Pulmonology, University of Groningen, The Netherlands, Thorax. 1997 Sep;52(9):820-7
Knudson, RJ; Lebowitz MD; Holberg CJ et al(1983) Changes in the normal maximal expiratory flow-volume curve with growth and aging. Am Rev Respir Dis 127:725–734
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
Marek W, Marek E, Mückenhoff K, Smith HJ, Kotschy-Lang N, Kohlhäufl M; Lung function in the elderly: do we need new reference values? Institut für Arbeitsphysiologie an der Augusta-Kranken-Anstalt, Bochum, Pneumologie. 2009 Apr;63(4):235-43. Epub 2009 Apr 2.
Memon MA, Sandila MP, Ahmed ST, editors. Spirometric reference values in healthy, non-smoking, urban Pakistani population, J Pak Med Assoc, 2007.57:193-195
Miller M et. al. Debating the definition of airflow obstruction: time to move on?. Dept of Medicine, University Hospital Birmingham NHS Trust, Birmingham, UK, Eur Respir J 2009. 34: 527–528
Miller M et. al. Standardization of Spirometry, Eur Respir J 2005 26: 319–338
Morris, JF; Koski, A; Johnson, LC (1971) Spirometric standards for healthy nonsmoking adults. Am Rev Respir Dis 103:57–67
Quadrelli S, Roncoroni A, Montiel G; Assessment of respiratory function: influence of spirometry reference values and normality criteria selection. Sección Neumonología, Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires, Argentina, Respir Med. 1999 Aug;93(8):523-35
Sood A, Dawson BK, Henkle JQ, Hopkins-Price P, Quails C; Effect of change of reference standard to NHANES III on interpretation of spirometric 'abnormality'. Southern Illinois University School of Medicine, Springfield, IL 62794-9636, USA, Int J Chron Obstruct Pulmon Dis. 2007;2(3):361-7
REFERENCES
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
Analysis of the percent predicted values of FEV1 using different reference value in asthmatics
ADVISER Tiago António Queirós Jacinto CLASS 2
Barbosa M., Barbosa T., Brito T., Campos J., Carvalho L., Carvalho R., Costa A., Dias J., Dória M., Maciel C., Mosca A., Pires C., Silva F., Viana D. - [email protected]
Introduction to Medicine I 2009/2010
