Comparative Study of Mid Expiratory Flow Rate by using Spirometry in Asymptomatic Smokers and Non Smokers as a Marker of Early Airflow Obstruction

Pavithra, P (2019) Comparative Study of Mid Expiratory Flow Rate by using Spirometry in Asymptomatic Smokers and Non Smokers as a Marker of Early Airflow Obstruction. Masters thesis, Kilpauk Medical College, Chennai.


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INTRODUCTION: Smoking is known as the major cause of chronic obstructive pulmonary disease(COPD)where most of pulmonary function tests(PFT)especially those indicating the diameter of airways are reduced. Mid Expiratory Flow Rate (MEFR) is a single parameter which helps us to quantify the obstruction. In this study, Mid Expiratory Flow Rate of smokers will be compared with those of non smokers. Mid Expiratory Flow Rate of forced vital capacity is one of the important dynamic lung function test which are used to assess the pattency of respiratory airways. The values of this flow rate is known to decrease not only in COPD but also in otherwise healthy smokers. Cigarette smokers have a higher prevalence of declining in FEV1 and a greater COPD mortality rate than non smokers. These differences between smokers and non smokers are directly proportional to the quantity of smoking. Smoking leads to gradual decline in pulmonary function tests (PFTs) specially those concerning with diameter of the airways such as forced expiratory flow in one second (FEV1), FEV1/FVC, MEFR25-75%, MVV. AIMS AND OBJECTIVES: 1. To study the influence of smoking on pulmonary functions. 2. To study the differences in Mid Expiratory Flow Rate values in smokers and non-smokers and their variation. 3. To study the ventilatory impairment caused by smoking in terms of obstructive, restrictive or mixed type. 4. To establish normal standards in healthy non-smoker adults. 5. To use pulmonary function test as a tool to identify the quantum of damage to the respiratory tree. MATERIALS & METHODS: Study Design: Observational study. Study Period: Six months. Study Area: Government Kilpauk Medical College, Chennai. Study Population: Males among age group18-50 years are recruited. Study population includes both smokers and non smokers. The subjects selected for present study will be recruited from medical outpatient Department at our hospital. Sample Size: Smokers :75 ; Non smokers :75. RESULTS: The results of test conducted among 75 participants who smokers and equal number of participants without smoking history. Age group with maximum distribution was among 41-50 years of age (N = 64 ; 42.7%). All participants selected were under 50 years to exclude inert conditions like IHD, Systemic hypertension with the interpretation of results. Duration of cigarette smoking was maximum at 11-20 years of smoking which more or less applies to majority of population in society. The mean cigarettes smoked per day was around 18 among participants. Mean duration was 20 years which extrapolates to the general population at large. Pack years amounts to 18 which leads to susceptible population. Among 150 participants age distribution was maximum among 41-50 years group (N = 64 ; 42.7%). This represents the larger proportion of people in the society and hence represents the larger picture among the community. Likewise, next lesser frequency is among 31-40 years of age (N = 50 ; 33.3%). Least representation is under 20 years of age (N = 5 ; 3.3%). 2.7% (N = 2) of participants were smoking around 1-10 cigarettes per day; majority were smoking 11 to 20 cigarettes per day (N = 64 ; 85.3%) and only 9 participants were smoking around 21-30 cigarettes (12%) which is a high burden on health. Maximum number of persons were smokers for 11-20 years (N = 45 ; 60%); with 37.3 percent of participants (N = 28) were smokers for 21-30 years. Only 2.7% of participants are smokers for 1-10 years. Mid expiratory flow rate 25-75% among smokers was calculated and results were extrapolated in terms of less than or equal to 50 and people with more than 50. Huge number of smokers had their MEF 25-75% less than 50 (N = 61 ; 81%) and a mere 14 were under 50 categories. Smokers had a mean MEF 25-75% of only 42. Non-Smokers as expected had little restriction with mean ranging around 100. CONCLUSION: Mid Expiratory flow rate 25-75% is reduced in chronic smokers. The rate of reduction in MEFR 25-75% is earlier among asymptomatic smokers than non smokers. This is contrary to the popular belief that longer the duration of smoking there is an increased rate of reduction of MEFR 25-75%. The MEFR 25-75% is normal in the non-smoker group – irrespective of the age distribution. The reduction in MEFR 25-75% is directly proportional to the duration as well as quantum of smoking. Hence decreasing the quantum of smoking as well as early cessation of smoking prevents COPD.

Item Type: Thesis (Masters)
Additional Information: Reg.No.201611160
Uncontrolled Keywords: Pulmonary function test, Mid Expiratory flow Rate, smoking, chronic obstructive pulmonary disease.
Subjects: MEDICAL > General Medicine
Depositing User: Subramani R
Date Deposited: 25 Aug 2019 07:48
Last Modified: 25 Aug 2019 07:48

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