Effect of Smoking on Lung Function - Research Paper Example

EFFECT OF SMOKING ON LUNG FUNCTION According to Polatli et al. (December 2000), smoking is one of the etiological risk factor of respiratory diseases. It causes premature ageing, ill health and premature death. To determine the relationship between the respiratory function and the respiratory disease, lung function was assessed to identify the lung volume. Respiratory function test is the process to measure lung volumes. This test identifies the effect of smoking on lung volume. The study performed respiratory function test to subjects composed of smokers and non-smokers. Other factors such as age, height and gender were also recorded. Respiratory function test parameters such as FEV1, FVC and PEF were obtained. Additional tests were performed to determine the effect of holding breath after hyperventilation and re-breathing of expired air compared to normal breathing of the subjects. In conclusion, the measured lung volumes were low in smokers compared to the non-smokers. Predicted normal lung volumes were calculated as reference. Primatesta (1998) stated that age, height and gender were also noted as factors that affect the lung volumes of the subjects. Lower lung volumes may indicate early deterioration of the lungs affirmed by Polatli et al. (December 2000). INTRODUCTION: Years ago, people enjoy smoking thought it was harmless and relieves tension stated by Kenny (April 2006). However,studies today revealed smoking as a harmful substance to the human body. It causes respiratory diseases, premature ageing, ill health and untimely death. Smokers are at greater risk of illness and early death compared to nonsmokers. Those who smoke more than 25 cigarettes a day are 25 times more likely to die from cancer and almost twice as likely to die from coronary heart disease (http://www.cancernet.co.uk/smoking.htm, 2006). As stated by Kenny (April 2006), smoking constricts the airways of the lungs. It increases the smoker's heart rate and blood pressure. The carbon monoxide in tobacco smoke deprives tissues of much-needed oxygen. All of these are dangerous short and long-term effects. Smoking leads to lung cancers, emphysema, and other respiratory diseases. Indeed, smoking causes ninety percent of all lung cancer cases. Twenty percent of heavy smokers get the chronic obstructive pulmonary disease called emphysema. This disease is rarely seen in nonsmokers. Smokers are also at least four times more likely to develop oral and laryngeal cancer than nonsmokers. Once young people start smoking, they immediately put themselves at risk of respiratory illnesses and at greater risk from serious diseases later on in life. The early they start smoking, more cigarettes they smoke, the greater the risk they face. However, stopping smoking reduces the risk of getting diseases (http://www.cancernet.co.uk/smoking.htm, 2006). One way to determine respiratory diseases is through respiratory tests. Gildea, McCarthy and Kuvuru (December 2003) believed that respiratory function tests are valuable tool for the evaluation of the respiratory system. It is a clinical assessment of many respiratory diseases, which measures individual parts of the respiratory process. Tests of respiratory function are appropriate as the tests greatly affect the improvement of diagnostic skills and disease management stated by Pain (2000). Gildea, McCarthy and Kuvuru (December 2003) said that the overall approach is to compare the measured values of an individual patient with normative values derived from predicted normal lung volumes. It is used to define normal and abnormal as well as to grade the severity of the abnormality. According to Pain (2000), it is an objective measure of abnormal physiology and a means of following a patient's progress. Considerable reliance is placed on respiratory function testing in the assessment of respiratory illness. Respiratory function test measures lung volume. Parameters were measured based on FEV1 (Forced Expiratory Volume in the first second), FVC (Forced Vital Capacity), and PEF (Peak Expiratory Flow). These parameters of lung function are affected by height, age, gender, and to a lesser extent, by weight. In general, mean FEV1, FVC and PEF increased with increasing height and decreased with age, after a peak in the late teens-early twenties stated by Primatesta (1998). Primatesta (1998) also added that various tests are used in the quantitative evaluation of lung function. Respiratory tests such as spirometry, vitalograph and peak flow meter were used to evaluate lung volumes. Lung volumes were measured in the following parameters. FEV1 (Forced Expiratory Volume in the first second), the volume (in liters) that can be expelled in the first second of a forced expiration (starting from a full inspiration) FVC (Forced Vital Capacity), the full volume of gas in liters that can be expelled PEF (Peak Expiratory Flow), the fastest rate of exhalation (in liters per minute) recorded during the measurement. In accordance with Primatesta (1998), these measurements are determined largely by the size of the lungs, which in turn depends on age, sex, gender, and personal habits such as smoking. In both sexes, the variation of respiratory function is generally agreed by standing height and age characteristics that correlate best with lung volume measurements. Measurements of lung volume determine early diagnosis and prevention of probable respiratory diseases. MATERIALS and METHODS Materials: Spirometer Kymograph drum and paper Vitalograph Peak flow meter Timers Paper bags Height meter Nose clips Weighing scales Milton Solution Methods: The study was carried out in a subjects composed of 3 smokers and 2 nonsmokers. Age (years), gender, and height (meters) of the subjects were recorded. Predicted normal lung volumes were calculated as reference values. Measurements of FEV1, FVC and PEF were performed with a spirometry, vitalograph and peak flow meter in accordance to the test procedures. The results of the predicted lung volumes were compared to the actual values measured from respiratory equipments. Another test was performed to determine the homeostatic control of respiration. Holding breath after hyperventilation and re-breathing of expired air were compared to normal breathing of the smokers and nonsmokers. Lung volumes of smokers and nonsmokers were recorded to determine the effect of smoking on human lungs. RESULTS Table 1: Predicted Normal Lung Volumes The data presented are based on the three parameters (FEV1, FVC, and PEF). Primatesta (1998) stated reference values were calculated based on predicted normal lung volumes and were derived from predictor variables of age, gender and height. Female on average, have smaller lung volume compared to males of the same age and height. Primatesta (1998) added that in general, mean FVC, FEV1 and PEF increased with increasing height and decreased with age, after a peak in the late teens-early twenties. Body weight is not used to calculate reference values, but obesity could be a factor to lower the measured lung volumes (http://www.cdc.gov/niosh/docs/2004-154c/pdfs/2004-154c-ch6.pdf, 2006). Table 2 - Vitalograph Measurements of Lung Volumes Subject VC (l) FVC (l) FEV1 (l) PEF (l/sec) Aidan 5.70 5.38 4.53 7.8 Jung 3.83 4.00 3.28 7.4 Rob 7.92 7.60 5.97 10.1 Mehrnaz 4.07 3.72 3.25 6 Elyse 3.94 3.6 3.34 6.3 According to Primatesta (1998), results of lung function tests usually rely on comparison with reference values. This is required in order to determine whether or not a test result can be considered "normal". By comparing the predicted values for healthy adults with the observed values who have the same predictor characteristics (age and height), a measure of relative lung function is obtained. A reading substantially below the predicted value in principle indicates a potential impairment of the lung function. Figure 1 - Comparison of Measured Forced Vital Capacity (FVC) versus Predicted Normal Lung Volumes. Smokers composed of 3 males namely Aidan, Jung and Rob were compared to 2 female nonsmokers namely Mehrnaz and Elyse. Results showed that Jung, oldest among the smokers, have the lowest FVC. Smokers also demonstrated lower FVC values compared to the predicted normal lung volumes and nonsmokers. However, abnormal results were obtained to Rob. The FVC values of Rob were higher than its predicted normal lung volume. In my perception, Rob could be an athlete or a smoker who exercises frequently that may result to FVC above normal. Exercise is one of the factors that help improve lung volume. Figure 2 - Comparison of Measured Forced Expiratory Volume in the 1st second (FEV1) versus Predicted Normal Lung Volumes. Like FVC, the measured FEV1 of smokers showed the same lower value results compared to predicted normal lung volume. Jung who has lower values of FVC and FEV1 may have a suspected indication of lung deterioration. We must also take note that the nonsmokers were females thus their lung volume is smaller than the males. Comparison of lung volumes between the smokers (males) and nonsmokers (females) may not bring directly proportional results. Figure 3 - Comparison of Measured Peak Expiratory Flow versus Predicted Normal Lung Volumes. According to Blaivas (January 2004), the peak expiratory flow rate measures how fast a person can exhale air. It is one of many tests that measure the function of the airways, which are commonly affected by diseases such as asthma, or chronic obstructive pulmonary disease. These lung diseases, may decreased airflow exhalation by narrowing the airways. Peak expiratory flow monitoring is used by many patients to monitor their lung function. This allows them to anticipate when their breathing will become worse and to take appropriate medications or call physician before symptoms become severe. The graph showed the difference of measured PEFof the smokers and the nonsmokers. Jung resulted to have slower PEF compared to other smokers. He has the largest difference of PEF against the predicted normal lung volumes. The difference of the measured PEF were mostly observed to the smokers than the nonsmokers. The data may presume that smokers may have suspected narrowing of the airways or constriction of the bronchioles that may lower the values of exhaled air. Table 3 - Comparison of Methods for Measuring PEF against Predicted Values Subject PEF (l/min) Predicted PEF Vitalograph PEF Peak flow rate (mean) Aidan 610.2 468 600 Jung 587.724 444 640 Rob 674.67 606 696.66 Mehrnaz 413 360 400 Elyse 419 378 493.33 As stated by Pain (2000), the peak flow meter is extensively promoted as a simple lung function monitor. Serial measurements in conditions such as asthma provide valuable information about disease progress. Peak expiratory flow (PEF) measures how fast a person can breathe out using the greatest effort. It is used in the monitoring and treatment of asthma or COPD to determine how well your lungs are functioning. The patient's peak flow drops when the tubes that carry air to the lungs (bronchial tubes) narrow. A decrease in the peak flow can show that the bronchial tubes have narrowed even before asthma symptoms develop. PEF is very effort dependent (earliest portion of forced expiration). Figure 4 - Comparison of Methods Measuring PEF versus Predicted Normal Volume Miller et al. (1992) said that the variability of peak expiratory flow (PEF) is now commonly used in the diagnosis and management of asthma. It is essential for PEF meters to have a linear response in order to obtain an unbiased measurement of PEF variability. To check the accuracy of the PEF meters led to correct results. The results showed that each device has different readings. The Wright peak flow meter resulted to have higher PEF results compared to vitalograph and predicted normal lung volume. In view of the methods used, results showed that Vitalograph tests have higher accuracy to test PEF compared with the Wright Peak Flow Meter. Variation of results may lead to incorrect findings and bias in executing strategies of asthma management. It is proper to check results according to accuracy. Table 4 - Comparison of Methods for Measuring Vital Capacity against Predicted Values Subject Vital capacity (l) Predicted VC Vitalograph VC Spirometer VC Aidan 5.404 5.7 4 Jung 5.0956 3.83 3.875 Rob 6.34 7.92 5.25 Mehrnaz 3.56 4.07 3 Elyse 3.58 3.94 2.43 Vital capacity is the total amount of air that a person can expire after a complete inspiration (http://en.wikipedia.org/wiki/Vital_capacity, 2006). Spirometry meaning measuring of breath is the most common of the Pulmonary Function test.The FVC test were performed using different varieties of spirometers. FVC tests varies slightly depending on the equipment used (http://en.wikipedia.org/wiki/Spirometry, 2006). Figure 5 - Comparison of Methods Measuring Vital Capacity versus Predicted Normal Volume The graph illustrated the results of spirometer measuring vital capacity are more accurate compared to vitalograph. Vitalograph demonstrates abnormal results revealing higher results compared to predicted normal volume. Only Jung demonstrated comparative result in both methods. Thus, the results of Jung indicate that he may have probable respiratory disease due to smoking. Table 5 - Comparison of Breath Holding After Hyperventilation and Re-Breathing Expired Air against Normal Breathing After normal breathing After hyperventilating After re-breathing expired air Aidan 1'25" 2'40" 0' 56" Jung 1'30" 2'20" 1'12" Rob 2'03" 2'15" 1'20" Mehrnaz 35" 1'30" 1'14" Elyse 45" 1'35" 39" Hyperventilation, or over-breathing, is an increase in respiration that upsets; the natural balance of oxygen and carbon dioxide in the system. It is a form of shallow, sometimes quite rapid, upper chest breathing. This would allow breath holding for a longer time not realizing that it decreases carbon dioxide in the blood and lungs. Smoking is one of the risk factor of hyperventilation (http://www.allstar.fiu.edu/AERO/HumFac02.htm, 2004). The most common symptoms of hyperventilation are dizziness, tingling of the toes and fingers, hot and cold sensations, nausea and sleepiness. Unconsciousness may result if the breathing rate is not corrected (http://www.allstar.fiu.edu/AERO/HumFac02.htm, 2004). The data showed that after hyperventilation breath holding increases compared with normal breathing. Thus smokers who are at risk of hyperventilation theoretically have lower length of time of breath holding compared to nonsmokers. However, the results revealed otherwise since we need to take into consideration of the lung volume of the subjects. Lung volumes of men are larger compared to women therefore may result in higher breath holding compared to women. The remedy for hyperventilation is a conscious effort to slow down the rate of breathing and to hold the breath intermittently, to allow the carbon dioxide to build up to a normal level. Sometimes, the proper balance of carbon dioxide can be more quickly restored by breathing into a paper bag, that is, by re-breathing the expelled carbon dioxide (http://www.allstar.fiu.edu/AERO/HumFac02.htm, 2004). After re-breathing of expired air the breath holding slowly returns to normal breathing. The carbon dioxide expelled would be slowly restored to normal balance. The data demonstrated the decrease of time of breath holding after re-breathing expired air compared to length of time measured after hyperventilation. CONCLUSION: Smoking is deleterious to ones health. Smoking could lead to more serious diseases later on in life. Early assessment of respiratory diseases may lead to improvement of diagnosis and management of respiratory illness. Assessment of respiratory function determines the effect of smoking on the 3 lung parameters (FEV1, FVC and PEF). Parameters were compared to smokers and nonsmokers against the predicted normal lung volume. In conclusion, the measured lung volumes were low in smokers compared to the non-smokers. Predicted normal lung volumes were calculated as reference. The age, height and gender were recorded as factors that affect the lung volumes of the subjects. Lower lung volumes may indicate early deterioration of the lungs. Hyperventilation test were done. Hyperventilation allows the subjects to hold their breath for a longer time. Smokers have shorter time of breath holding compared to nonsmokers. After hyperventilation, re-breathing of expired air normalizes the balance of oxygen and carbon dioxide. Re-breathing of expired air may lead to homeostatic control of respiration. REFERENCES: Polatli, Mehmet et al. (2000), The Early Effect of Smoking on Spirometry and Transfer Factor, Turkish Respiratory Journal, Vol. 1 No. 2. Primatesta, Paola et al. (1998), The Scottish Health Survey 1998, April 04, 2006 Smoking, April 04, 2006 Kenny, Jennifer, What are the Effects of Smoking < http://www.edhelper.com/ReadingComprehension_29_26.html> April 04, 2006 Gildea, Thomas et al. (2003), Pulmonary Function Testing: Basics of Physiology and Interpretation, < http://www.clevelandclinicmeded.com/diseasemanagement/pulmonary/pft/pft.htm> April 04, 2006 Pain, Michael C. F. (2000), Basic Tests of Respiratory Function, Australian Prescriber Vol. 23 No. 1 pp 10-12. Comparing Observed to Predicted Normal Values, April 04, 2006 Blaivas, Allen (2004), Peak Expiratory Flow Rate, Division of Pulmonary, Critical Care, and Sleep Medicine, University Hospital, Newark, NJ, ADAM. Miller, MR et al. (1992), The accuracy of portable pleak flow meters, Thorax Nov;47(11) pp. 904-9. Vital Capacity (2006), Wikipedia Encyclopedia, April 04, 2006. Spirometry (2006), Wikipedia Encyclopedia, < http://en.wikipedia.org/wiki/Spirometry> April 04, 2006 Flight Performance - Level 3, Human Factors - Section 2 (2004), April 04, 2006 Read More