Advanced Pathophysiology: The Top Things You Need to Know

Question 1 

The key characteristics that individuals suffering from emphysema exhibit include decreased mental alertness, shortness of breath, challenges in executing activities of daily living, and dyspnea (Mayo Clinic, 2017). Moreover, the patients exhibit limitation of the expiratory flow with the relative preservation of the inspiration flow. The general examination findings that indicate emphysema include the use of accessory respiratory muscles, tachypnea, cyanosis, evidence of the Hoover sign, which refers to the paradoxical in-drawing of the lower spaces, peripheral edema, and an elevated jugular venous pulse. On the other hand, a pulmonary examination can indicate emphysema or barrel chest, crackles, hyper-resonance, wheezing, and rhonchi (McCance & Huether, 2014). A physical examination may also reveal pink puffers, whereby patients bend forwards with arms resting on something that helps them breathe or extended. In the later stages of the disease, patients also exhibit appearances of a bluish to purplish discoloration of the skin or signs of hypoxia-induced cyanosis as a result of higher amounts of hemoglobin in the blood. 

Question 2 

Pulmonary function tests (PFTs) refer such non-invasive tests as plethysmography and spirometry that illustrate how effectively the lungs are functioning. The tests measure residual volume, functional residual capacity (FRC), vital capacity, minute volume, tidal volume, forced vital capacity (FVC), total lung capacity, forced expiratory flow, peak expiratory flow rate, and the forced expiratory volume (FEVI) (Johns Hopkins Medicine, 2018). The PFT results play a vital role in assisting healthcare providers to diagnose, form treatment plans, and in the management of respiratory conditions and diseases (Johns Hopkins Medicine, 2018). 

Question 3 

Emphysema is diagnosed using several approaches, including the CT scan, radiography, pulmonary function tests (PFTs), and the arterial blood gas (McCance & Huether, 2014). In emphysema, PFTs specify lower FEVI due to the obstruction of gas flow during expiration, increased FRC, total lung capacity, and residual volume, as well as decline in FVC from the airway collapse, and trapping of air in the distant parts of the lung (McCance & Huether, 2014).The diffusing capacity also decreases as a result of the damage of alveoli capillary membranes. Moreover the lung fields appear over distended while the diaphragm demonstrates a flattened appearance on radiographs (McCance & Huether, 2014). In cases where the PFTs are not ideal for detecting emphysema, CT scanning is indicated. On the other hand, McCance and Huether (2014) indicate that arterial blood gases are commonly used in detecting hypercapnia and hypoxemia. 

Question 4 

The respiratory center comprises of different groups of neurons that are responsible for respiration in the pons and the medulla oblongata (McCance & Huether, 2014). The groups include the pneumotaxic center, the ventral respiratory group, the apneustic center, and dorsal respiratory group (McCance & Huether, 2014). The role of the dorsal respiratory group is to transmit nerve impulses into the inspiratory intercostals muscles and the diaphragm making them to relax and contract. The group is also responsible for receiving afferent impulses from the peripheral chemoreceptors found in the aortic and carotid bodies so as to detect the partial pressure of carbondioxide and oxygen in the arterial blood (McCance & Huether, 2014). On the other hand, the ventral group, which comprises of expiratory and inspiratory neurons, mainly remain inactive unless in cases where ventilator effort is necessary. Moreover, the apneustic and pneumotaxic centers, which are found in the pons, are responsible for modifying the inspiratory rate and depth (McCance & Huether, 2014). 

Question 5 

Oxyhemoglobin forms when hemoglobin binds with oxygen (McCance & Huether, 2014). The oxyhemoglobin dissociation curve refers to the desaturation and saturation of hemoglobin that is plotted on a graph, producing a sigmoid (S-shaped) curve. A shift of the curve to the right indicates that oxygen saturation has decreased, and the hemoglobin is binding to oxygen loosely, therefore delivering oxygen into the tissue more freely (McCance & Huether, 2014). Some of the common factors that cause the right shift include increased biphosphoglyceric acid, hypercapnia, , acidosis, and fever. Conversely, shifts to the left emanate from decreased biphosphoglyceric acid, hypocapnia, hypothermia, and alkalosis. The shift leads to lower partial pressure of oxygen as a result of oxygen binding more tightly to hemoglobin, therefore minimizing the dissociation of oxygenation in the tissues as well as higher oxygen saturation. 

Question 6 

Bronchitis causes ventilation-perfusion mismatch with air trapping, hypoxemia, hypoventilation, decreased tidal volume, and hypercapnia (Mayo Clinic, 2017). A productive cough is the key sign of bronchitis; however, it may be accompanied by wheezing, decreased exercise tolerance, prolonged expiration, shortness of breath, polycythemia, chronic hypoventilation, cor pulmonale, pulmonary hypertension, cyanosis, increased functional residual capacity and residual volume, and decreased forced vital capacity and forced expiratory volume. Bronchitis is described as chronic if it persists for three months in a year for two successive years (McCance & Huether, 2014). 

References  

Johns Hopkins Medicine. (2018). Pulmonary function tests. Retrieved from https://www.hopkinsmedicine.org/healthlibrary/test_procedures/pulmonary/pulmonary_function_tests_92,P07759 

Mayo Clinic. (2017). Bronchitis. Retrieved from https://www.mayoclinic.org/diseases-conditions/bronchitis/symptoms-causes/syc-20355566 

Mayo Clinic. (2017). Emphysema . Retrieved from https://www.mayoclinic.org/diseases-conditions/emphysema/symptoms-causes/syc-20355555 

McCance, K. L., & Huether, S. E. (2014). Pathophysiology: The biologic basis for disease in adults and children . (7 th ed.). St. Louis, MO: Elsevier.