The Underlying Pathology of COPD - Case Study Example

RESPIRATORY FOR PARAMEDIC Department Describe the underlying pathology of COPD. What impacts do these pathological changes have on normal physiology? In particular, describe alveolar ventilation in a normal individual and discuss how this might be different in Mr Wenham. (20 marks) COPD is a complex syndrome associated with the inflammation of the airways, dysfunctional mucociliary and the consequent changes in the structure of the airways. The firs changes that often occur in people with COPD are the chronic inflammation of the airways, pulmonary blood vessels and lung tissues including alveoli. When irritants are inhaled, they result into swellings of the cells within the respiratory tract (Barnes, 2002 p.52). These cells are then activated to initiate an inflammatory process thus triggers the release of other mediators for inflammatory process like the interleukins, tumour necrosis factor alpha, matrix-metalloproteinase, fibrinogen, interferon gamma and C-reactive protein (Steurer-Stey et al, 2012 p.367). These mediators are responsible for the sustained inflammation process which results to the severe damage to the tissues as well as many other systematic systems. The inflammation sustained inflammation of the tissues of the respiratory system results into changes in the structure of the lungs which further lead to the limitation of the airflow. The inflammatory response associated with COPD is as a result into the remodelling of COPD thus result into the narrowing of the airways. According to Barnes (2002 p.84), three main factors are responsible for these structural changes namely; accumulation of scar tissue as a result of damage to the airways, peribronchial fibrosis as well as the over multiplication of the epithelial cells within the lining of the airways. These structural changes results into the loss of elasticity of the lung tissue and destruction of parenchyma. Alveoli is also affected because the structures feeding and supporting the alveoli are also destroyed leading to a condition referred to as emphysema. This is the most dangerous process of pathology of COPD since it results into the collapse of the small airways such as alveoli. This is very dangerous since it impedes the flow of air as well as trapping air within the lungs thus reducing lung capacity as compared to normal individuals. The other change that occurs as a result of COPD is the dysfunction of the mucociliary. Irritants that lead to inflammation of the airways also result into the inflammation of the mucosa glands that that line the airway walls in the lungs. The inflammation of the mucosa glands thus healthy and goblet cells are replaced by more mucus-secreting cells (Barnes, 2002 p.88). Moreover, this type of inflammation lead to the damage of the mucociliary transport which play a vital role of clearing the mucus from the airways. In this respect, there is excess accumulation of mucus within the airways leading to blockage of the airways and worsening the already challenged airflow. 2. Discuss why you would administer salbutamol and describe how it works at the cellular level. (10 marks) Salbutamol is an active ingredient found in many drugs known as short acting beta against pulmonary obstruction. Salbutamol is also available in different brand names but works in the same way. The mechanism of action by salbutamol is by acting on the lung receptors known as beta 2 receptors (Coyne, 2006 p.382). The function of salbutamol is to stimulate these receptors thus leading to the relaxation of the muscles within the walls of the airways thus leading to the opening of the airways (Bates & Cydulka, 2011 p.350). This is very important in situations where there is narrowing of the airways like COPD because it exhibits bronchitis and emphysema symptoms.. However, salbutamol makes breathing easier by opening the airways through relaxation of the muscles. 3. Discuss why they would take an arterial blood gas and explain how the results relate to the pathophysiology you described. (10 marks) Arterial blood gas (ABG) is an important test for critically ill patients. This test is critical in helping make proper diagnosis as well as indicate the degree of severity of a condition which is very important in assessing treatments options (Hanania & Sharafkhaneh, 2011 p.28). ABG test often assesses adequacy of the ventilation, oxygenation and the acid base levels. The blood pH for Mr. Wenham is indicated as 7.12 which is indicates acidosis of the presence of academia. However, since acidosis or alkalosis would occur whether even within the normal pH range (7.35 – 7.45), PaCO2 and HCO3- test would be very important (Woodrow & Moore, 2009 p.182). PaCO2 test for Mr. Wenham shows 110 Hg, PaO2 is 100mmHg while HCO3- shows 38. From the history of Mr. Wenham, these tests indicate that COPD has impaired oxygenation and chronically elevated PaCO2. The apnoea period increased his PaCO2 further which resulted to low pH and respiratory acidosis. However, due to COPD, there is increased HCO3-. Moreover, the gradient between PaO2 and inspired oxygen shows that there is impairment of oxygenation. Finally, we can conclude that there is significant acidaemia (pH 7.12) which is an indication of additional respiratory acidosis resulting most probably from respiratory arrest. 4. Discuss the issues surrounding the use of supplemental oxygen therapy in patients with severe exacerbations of COPD. What problems can it cause and why? (20 marks) Supplemental oxygen therapy plays a key role in treating exacerbations of COPD especially when in advanced phase. The primary goal of administering of supplemental oxygen is to increase PaO2 in order to prevent hypoxemia which would otherwise threaten the life of Mr. Wenham (Woodrow & Moore, 2009 p.181). Supplemental oxygen is important in helping oxygen delivery to the peripheral tissues thus helps in alleviating COPD symptoms especially dyspnoea (Goldbart et al, 2013 p.7). However, supplemental oxygen must be administered in moderately low concentrations of between 24% and 28% at the flow rate of 2-4 litres per minute (Woodrow & Moore, 2009 p.181). This strategy is sufficient enough to increase PaO2 from 10-15mg which is necessary to maintain the optimal values above 60 mmHg as well as ensure enough SaO2. This is procedure should be taken in a moderate rate discussed above also to avoid the detrimental acidosis and carbon dioxide retention. Proper monitoring of the patient is also important in administering of supplemental oxygen. This is because the low flow devices such as cannulae or nasal prongs exhibit low accuracy hence delivery varying and high inspired oxygen concentration which is likely to result into “the suppression of the respiratory drive, carbon dioxide narcosis and finally respiratory arrest” (Akinci et al, 2013 p.973). This monitoring can be accurately achieved through assessment of arterial blood gas analysis discussed in the previous question. According to Steurer-Stey et al (2012, p.370), pulse oximetry is a non invasive and alternative method that accurate in adjusting oxygen therapy settings. It is also recommendable to monitor arterial pH and blood gas tensions after each and every one hour of beginning the therapy during moderate or severe exacerbations. 5. Do you think it is a good idea to remove Mr Wenham’s oxygen? Provide an argument supporting why it is OR why it is not. (10 marks) The removal of Mr Wenham’s oxygen was a very important procedure in helping not only relieves the pain, but also allow for alternative procedures to proceed. According to Smeltzer et al (2010 p.610), when high flow oxygen is administered to COPD patients, it leads to increase in the minute ventilation and reduction in end tidal concentration of carbon dioxide. Smeltzer et al (2010 p.610) also states that patients with COPD hyperoxia exhibit a reduction in minute ventilation followed by overshoot in carbon dioxide within the tissues of victims. This is likely to cause more obstruction and reduce ventilation of the cells where gaseous exchange occurs. Since the alveoli ventilation, where gaseous exchange takes place continues to be impaired as a result of advancement of the disorder into severe phases, the patients experience difficulty in breathing. In the view of the above, it was very important to remove excess oxygen thus create proper ventilation. As stated by Smeltzer et al (2010 p.610), “variable and high inspired oxygen can result into suppression of respiratory drive, carbon dioxide narcosis and eventually respiratory arrest”. 6. What is BiPAP? How might BiPAP help to improve Mr Wenham’s clinical condition? (10 marks) Bilevel positive airway pressure (BiPAP) is considered a system for supporting pressure used to assist patients with inhaling and exhaling. BiPAP is characterized by the provision of positive airway pressure during the finishing of exhalation and high positive pressure during inhalation phase (Kaplow & Hardin, 2007 p.302). This system was useful for Mr. Wenham because it improves ventilation as well as oxygenation. The use of BiPAP is very important for Mr. Wenham because it provides for two different pressure settings in order to help the patient inhale and exhale respectively. The machine has the ability to sense the decrease in pressure when the patient starts to inhale hence increases the air pressure mainly to support respiratory effort of the patients. When the inhalation processes is complete, the machine detects reduction in the flow of air within the respiratory airways hence there is supported exhalation and the cycle continues (Kaplow & Hardin, 2007 p.302). As stated by Murray (2002 p.402) BiPAP play an important role in increasing air delivery with less effort in breathing. This is particularly very important for Mr. Wenham whose respiratory system is already experiencing obstructions. The early use of BiPAP for the management of COPD exacerbation patients during emergency is important since it improves clinical parameters and reduces recourse to application of invasive procedures as well as morbidity. According to Cooper et al (2006 p.60), patients who exhibit the best-expected benefit is important thus it is recommended for patients with arterial pH < 7.3. Since Mr. Wenham had pH 7.12, he would gain the best expected benefit. 7. What is spirometry? (5 marks) Spirometry is a respiratory system test that measures the function of lungs by taking measurements of the speed and the amount of air that can be exhaled and inhaled respectively. It helps physicians to know the amount of air that is inhaled and exhaled which is important during primary diagnosis. As Rennard (2008 p.81) states, spirometry is an important tool used by medical personnel to generate pneumotachographs hence very useful in assessing conditions such as pulmonary fibrosis, asthma, COPD and cystic fibrosis among other pulmonary conditions. 8. Discuss the significance of the results by examining the differences between Mr Wenham’s spirometry and that of a normal individual. (10 marks) The spirometry tests results for Mr. Wenham are vital indicators for the severity of the impacts, progress of the patient and may used to know the phase or stage of COPD. The average FEV1, FVC and FEV1/FVC in healthy individuals mainly varies with age and sex, however, values between the ranges are considered normal (Rennard, 2008 p.81). The ration of FEV1/FVC is another parameter that is often used to represent the percentage of lung capacity that can be exhaled in one second. These values (FVC, FEV1 and FEV1/FVC ratio) are used to gauge the level of severity of the complication through comparison with the standard results for healthy individuals (Rennard, 2008 p.81). Mr. Wenham spirometry test results for FVC, FEV1 and FEV1/FVC are 1.5 litres, 0.75 litres and 50% respectively. With the reference values at 80%, 50-70%, 30-49% and >30% representing mild, moderate, severe and very severe COPD respectively (Barnett, 2006 p.54), Mr. Wenham shows a great improvement in reduction of airflow obstruction. According to Hyatt et al (2009 p.5), spirometry is not a good predictor of quality of life and disability in COPD, however, it is important in the assessment of the degree of severity of COPD and in predicting prognosis. It is therefore important to note that low spirometry level was as a result of obstruction within the airways though the results show a reduction in obstruction as compared to the average levels for normal individuals. 9. How does the pathology of COPD explain these differences? (5 marks) The pathology of COPD which lead to the obstruction of the airways as discussed in question one is responsible for the FEV1/FVC of 50% which represent a moderate severe COPD. Spirometry test results do not indicate very severe COPD (FEV1/FVC of >30) because of the initial medications that were administered including salbutamol, supplemental oxygen therapy and BiPAP. However, there are still structural changes as well as obstruction that blocks the flow of air in and out of the airways compared to the healthy patients. 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