Questions:
1. Describe the parameters illustrating respiratory (or other?) pathology,
2. Explain the underlying physiological disturbance that has resulted in the respiratory pathology, and
3. Provide an appropriate clinical interpretation of the test result.
Answers:
Lung Function Tests
Lung Function Tests are extensively used in Medical Science for diagnosis of respiratory abnormalities of a patient. It measures lung volumes, capacities, flows and pressure to interpret various respiratory parameters. The air movement in and out of the lungs is measured efficiently in Lung Function Tests. The device used in a lung function test is Spirometer. Various Clinical questions can be answered by analyzing the test results. For accurate clinical diagnosis data regarding history of the patient, physical examination and chest radiograph are also necessary; although test patterns provide strong indications of the presence of certain clinical conditions. Inconsistencies regarding the normal predicted values need consideration while interpreting the results.
A lung function test can provide the several lung volumes: tidal volume, inspiratory reserve volume, expiratory reserve volume and residual volume. It also measures different lung capacities: vital capacity, total lung capacity, functional residual capacity, inspiratory capacity and expiratory capacity.
There are various types of Respiratory disorders, which can be classified into Obstructive, Restrictive and Mixed patterns of disorder. Forced Expiratory Volume in one second (FEV1) and Forced Vital Capacity (FVC) are of utmost importance in this context. In Obstructive Lung disease the patient suffers from narrowing of the pulmonary airways as a result of which air the air cannot be exhaled out of the lung. Even after maximal exhalation large amount of air remains in the lungs and the airways. Asthma, Bronchiecstasis, Chronic Obstructive Pulmonary Disorder etc. are associated diseases. On the contrary in Restrictive Lung Diseases the lung cannot expand fully and there is difficulty in inhaling sufficient amount of air inside the lungs. It may occur due to stiffening of the chest wall or due to muscle or nerve damage.Clinical conclusions can be drawn from careful interpretation of the FEV1/FVC ratio and the value of FVC itself. The Transfer factor of carbon monoxide can provide useful information about he the gas exchange efficiency of the lung and hence can determine any underlying clinical condition.
Vital Capacity is the amount of air that can be expired after forceful inspiration without forceful effort. Forced Vital Capacity is the total volume that can be forcefully exhaled from a maximum inspiratory effort. Forced Expiratory Volume in one second is the volume of air forcibly expired from a maximum inspiratory condition in the first second.
TLCO is the transfer factor of carbon mono oxide of the lungs. It is a widely used parameter to examine respiratory condition. It can assess the efficiency with which gas exchange occurs in the lung. Alveolar or vascular destruction can reduce the total surface area of the gaseous exchange and consequently reduce the TLCO. The transfer factor of the lungs can measure the ventilation of the airways, diffusion of gases in the alveolar ducts and alveoli, exchange of gases across gases and liquid interface of the alveolar and capillary membrane, chemical reactions with constituents of blood and circulation of blood.
Total Lung Capacity is the total volume of the lungs. It is the sum total of four different lung volumes viz. tidal volume, the inspiratory reserve volume, the expiratory reserve volume and the residual volume.
1. From a thorough observation of the case provided, it is seen that the spirometry and the co transfer part significantly gives a moderate result whereas the lung volume parameters show abnormality. Parameters such as FRC, TLC, RV, RV/TLC and Raw are found to be much more than the normal range and Sgaw level is lower. This shows that there is a physiological abnormality that has occurred in the lungs which in turn are resulting in the clinical condition mentioned here which is shortness of breath.
An increased FRC means that the lungs show more compliancy. The equilibrium setup between the outward as well as the inward recoiling of lungs gets hampered. So increase of FRC is indeed a matter of concern. TLC or total lung capacity automatically increases when FRC increases. TLC when increased might give an indication that the lung has lost the capability of recoiling and the contraction of the respiratory muscles shows increased strength. Increase of RV or residual volume denotes airway closure that occurs prematurely during a maximal expiration. Increased Raw results may result from constricted airways or when the elastic tissues gets destroyed keeping the small airways to be open always. Decreased of Sgaw is also associated with the symptoms of lung disorder.
Increased FRC, TLC and RV are signals that indicate an obstructive disorder of the lungs. Physicians usually consider a person to be suffering from chronic obstructive pulmonary disorder who has levels of FRC,TLC and RV far above the normal level. When FRC increase several time it is usually assumed that the person suffers from COPD or asthma (Weiner et al., 2013). Alterations of the recoiling and increased time constraint for expiration are the symptoms. Increased TLC is observed from loss of reflexes from chest muscles or may be due to structural alteration. All these indicate of obstructive disorder of lungs. Increased RV by four times indicates that gas becomes captured because airways gets prematurely closed that makes the expiratory airflows slower. Increased airway resistance in turn denotes asthmatic attacks or bronchiole spasm (Peinado et al., 2013). It also may denote emphysema because the tissue of the lung becomes palliable and the flow of air also makes it difficult for the airways to remain open. All thee indicate towards a chronic obstructive disorder in man.
From the case provided, we can distinctly recognize the conditions of the lung that is marked by the increase above the normal level of the parameters of the lung volume test. The parameters denote a condition of obstructive pulmonary disorder which may have risen due to any conditions like emphysema, bronchitis or asthma (Divo et al., 2012). A change in the airways which may be inflammatory is the main reason behind the bronchitis. As a result the bronchioles get dilated abnormally and leads to a condition called bronchitis. In a similar manner, COPD also results from limitation of air flow. As a result the normal passage for the flow of air inside as well as outside gets inhibited. RV which is the total volume of air left in the lungs after the completion of expiration is a marker for recognizing the conditions. If RV gets increased, one can easily ascertain of the disorders. Here the parameter TLC or the total word count also plays an important role. It leads to a condition known as hyperinflation. It gives rise to a condition where a person develops a chest with a big diameter when measured from back to front. This condition is named as barrel chest symptom. The case also shows an increase in the Raw which is known as air resistance. This resistance usually specifies the resistance faced by the respiratory tract during inspiration and expiration. Thus the cumulative results of the lung volume tests determine an abnormality of the lungs that requires urgent attention.
From the above explanation one can make an idea of the reported condition of the patient. The test was conducted on the basis of the patient’s complain of short breath symptoms which was gradually worsening. The report of the lung volume showed the parameters which depict the exact reason of the patient’s condition. This pulmonary report should be analyzed by the physician and remedies should be prescribed immediately before the condition worsens and the patient reaches a serious condition.
2. The spirometric report of the patient reveals a Functional Expiratory Volume (in the first second) value of 1.77 with 65% predicted normal and a Functional Vital Capacity of 2.01 with 60% predicted normal. The Vital Capacity is 2.10. The ratio of FEV1/FVC or Forced Expiratory Ratio (FER) is 84%. The TLCO is normal (86%) but the KCO (138%) is high. The Maximal Expiratory Pressure (58) and the Maximal Inspiratory Pressure (31) of the patient is moderately low.
The FVC and FEV1 both are below the lower limit of normal which is 80% of the predicted value in case of this patient. But the ratio of FEV1/ FVC or (FER) is greater than the lower limit of normal which is 84. Hence the patient cannot be classified as having an airflow obstruction. Reduced FVC and FEV1 with a preserved FEV1/FVC ratio are often observed in restrictive diseases. To confirm the diagnosis of restriction Total Lung Volume (TLC) is required. Although the residual volume is unknown the vital capacity is moderately low which confirms a restrictive disease. A normal TLCO indicates extrinsic restrictive disease and a high KCO indicates lack of lung expansion. A low MIP and MEP indicates muscle weakness. Assessment of all the results suggests that the patient might be suffering from Interstitial Lung Disease.
Interstitial Lung Disease (ILD)affects the interstitium of the lungs. There are several types of ILD. The most common type is Pulmonary Fibrosis. Other types include Sarcoidosis, Extrinsic Allergic Alveolitis, etc. ILD is caused due to inflammation of the lungs and accumulation of scar tissue which leads to lung stiffness and reduction in compliance. ILD can be triggered by various causes. An autoimmune disorder may lead to ILD. Exposure to various environmental agents, certain medications and pathogens may be some of the causative factors for incidence of the disease (Cottin, 2013). Some drugs that may cause ILD are chemotherapeutic drugs, anti-inflammatory drugs, antibiotics, or some recreational drugs. Autoimmune diseases such as lupus, rheumatoid arthiritis, sarcoidosis, and scleroderma are often related to IDL. The symptoms of Interstitial Lung Disease include bronchiolitis, alveolitis or vasculitis. Bronchilitis involves the inflammation of the bronchioles, alveolitis occurs due to inflammation of the air sacs and inflammation of the blood capillaries result into vasculitis. Other very common symptoms include shortness of breath, necessity of forced breathing, fatigue, weakness, loss of appetite and weight, dry cough and lung hemorrhage. Fibrosis occurs when there is permanent loss of lung tissue and formation of scar tissue. The scar tissues may destroy surrounding alveolar tissues and capillaries causing a progression of the disease. Some patients are found to develop a heart failure and a high blood pressure as a result of IDL.
The interstitium is the space between the alveolar sacs and the blood capillaries of the lungs. In normal conditions it provides a medium for the alveoli and the capillaries to carry out efficient gas exchange (Vij&Strek, 2013). It consists of minimal connective tissue matrix and inflammatory cells such as macrophages and white blood cells. In case of an injury either known or known or in case of an autoimmune disorder the lung responds to repair its’ interstitium. Prolonged exposure or injury leads to accumulation of inflammatory cells and results in damage of the interstitium. As a result of this the gas exchange capacity of the lung is severely affected and onset of Interstitial Lung Disease may occur.
The patient needs immediate clinical assistance and must consult a professional doctor who specializes in lung conditions. CT scans and X-ray tests are highly recommended to precisely determine the severity and extent of the disease. The patient is strongly recommended to stop smoking.
3. The spirometric report of the patient reveals a Functional Expiratory Volume (in the first second) value of 2.68 with 136% predicted normal and a Functional Vital Capacity of 4.41 with 149% predicted normal. The Vital Capacity is 4.46 with 151% predicted normal. The ratio of FEV1/FVC or Forced Expiratory Ratio (FER) is 60 with 84% predicted normal. The TLCO and KCO are 12.1 and 2.2 with 54% and 58% of predicted normal respectively. The VA is 5.4 with a 91% predicted normal.
The FVC and FEV1 are both abnormally higher than normal with 136% and 149% of predicted normal. The patient is suffering from severe hyperventilation. But the ratio of FEV1/ FVC or (FER) is 87% predicted normal. Hence the patient cannot be classified as having an obstructive disease. Severely high FVC and FEV1 with a preserved FEV1/FVC ratio are often observed in severe hyperinflation. The TLCO value is slightly reducedand the KCO is normal. The assessment of the results strongly suggests that the patient is not suffering from a restrictive or obstructive disorder. In spiteof that the FEV1, FVC and VC are severely high and the TLCO is low. Further examinations are required to infer any diagnosis. The results seem contradictory and no interpretations can be drawn about the patient respiratory condition. Age and genetic predisposition may be the reason behind the unnaturally high FEV1 and FVC.
Considering the age of the patient the abnormally high FEV1, FVC and VC values indicate that the patient may be suffering from a specific clinical condition. Old patients usually show a lowering of values of the different spirometric parameters. Considering an error, either on the the part of the patient or the examiner is required. Necessary instruction should be provided to the patient regarding the correct procedure to carry out an error-free test. There is a possibility of the patient being an athlete in the early ages of his life. The amount of physical activity can be a determinant of a person’s lung capacity (Degens et al., 2013). The vital capacity of the patient is nearly double the normal value predicted for his age. The TLCO and KCO values did not deviate from the normal to a great extent. The patient history needs to be addressed to confirm if the abnormal values resulted from high level of physical activities.
References
Cottin, V. (2013). Interstitial lung disease. European Respiratory Review, 22(127), 26-32.
Degens, H., Rittweger, J., Parviainen, T., Timonen, K. L., Suominen, H., Heinonen, A., & Korhonen, M. T. (2013). Diffusion capacity of the lung in young and old endurance athletes. International journal of sports medicine,34(12), 1051-1057
Divo, M., Cote, C., de Torres, J. P., Casanova, C., Marin, J. M., Pinto-Plata, V., … & Celli, B. (2012). Comorbidities and risk of mortality in patients with chronic obstructive pulmonary disease. American journal of respiratory and critical care medicine, 186(2), 155-161.
Peinado, V. I., Gómez, F. P., Barberà, J. A., Roman, A., Montero, M. A., Ramírez, J., … & Rodriguez-Roisin, R. (2013). Pulmonary vascular abnormalities in chronic obstructive pulmonary disease undergoing lung transplant. The Journal of Heart and Lung Transplantation, 32(12), 1262-1269.
Vij, R., & Strek, M. E. (2013). Diagnosis and treatment of connective tissue disease-associated interstitial lung disease. CHEST Journal, 143(3), 814-824.
Weiner, P., Novitzky, T., Weiner, D., & Beckerman, M. (2013). [Chronic obstructive pulmonary disorder (COPD) patients with the syndrome of combined pulmonary fibrosis and emphysema, compared to patients with emphysema alone]. Harefuah, 152(5), 294-8.
