Question

Discussion Board 6 (DB #6) R.S. has smoked for many years and has developed chronic bronchitis, 0 a chronic obstructive pulmonary disease (COPD). He also has a history of coronary artery disease and peripheral arterial vascular disease. His arterial blood gas (ABG) values are pH = 7.32, PaCO2 = 60 mm Hg. PaO2 = 50 mm Hg, HCO3- = 30 mEq/L. His hematocrit is 52% with normal red cell indices. He is using an inhaled B2 agonist and theophylline to manage his respiratory disease. At this clinic visit, it is noted on a chest x-ray that R.S. has an area of consolidation in his right lower lobe that is thought to be consistent with pneumonia. Discussion Questions 1. What clinical findings are likely in R.S. as a consequence of his COPD? How would these differ from those of emphysematous, COPD? 2. Interpret RS's laboratory results. How would his acid-base disorder be classified? What is the most likely cause of his polycythemia? 3. What is the rationale for treating RS with theophylline and a B2 agonist 4. What effects would his respiratory disease have on his cardiovascular function? 5. Considering both his COPD and pneumonia, in what position would RS have the worst ventilation-perfusion matching?

Answer 1

AS THERE ARE MANY QUESTIONS, LET ME ANSWER THE FIRST 4 (AS PER HOMEWORKLIB RULES)

1. The clinical consequences of COPD

• Bronchitis is a consequence of his obstructive lung disease. People with chronic bronchitis are at risk for frequent respiratory tract infection, and here RS has pneumonia or the lung parenchymal infection.
• Polycythemia is a result of COPD caused hypoxia in the patient
• COPD patients usually present with increased PaCO2 levels as the increased CO2 levels trigger the respiratory center in them unlike non COPD people.
• Respiratory acidosis may also be a result of his COPD.

EMPHYSEMATOUS COPD is a chronic lung condition and small airways collapse when you exhale, impairing airflow out of your lungs.

Early symptoms of pulmonary emphysema may include:

• Cough, Rapid breathing,Shortness of breath which gets worse with activity, Sputum production and Wheezing.

The clinical presentations may be

• Pneumothorax: Collapsed lung can be life-threatening in people who have severe emphysema, because the function of their lungs is already so compromised.
• Cor pulmonale: Emphysema can increase the pressure in the arteries that connect the heart and lungs causing a condition called cor pulmonale, in which a section of the heart expands and weakens.
• Bullae formation: Some people with emphysema develop empty spaces in the lungs called bullae. They can reduce the amount of space available for the lung to expand and can increase your risk of pneumothorax.

2. pH 7.32, PaCO2 60mm Hg, PaO2 50mm Hg, HCO3 30mEq/L

His PCO2 is very high and the HCO3 has also increased to compensate the increased PCO2 levels. But the pH is still acidic indicating the acidosis has not been fully compensated.

RS has got Respiratory acidosis which is partially compensated

Secondary polycythemia may be due to hypoxia caused by the COPD. Hypoxia cause stimulation of Erythropoietin. This in turn stimulate the production of more RBC s resulting in polycythemia.

3. The Broncho dilating action of theophylline and beta 2 agonist is the reason for its use in management of COPD. A regimen containing both theophylline and an inhaled beta 2 agonist provides significantly greater bronchodilation than either drug alone.

4. Individuals with COPD have high risk for cardiovascular disease mostly due to systemic inflammation, tissue hypoxia and oxidative stress. Tobacco smoking is a shared risk factor for both COPD and cardiovascular disease.

• Bronchitis and pneumonia can affect the rate of the heart and cause tachycardia and sometimes arrhythmias.
• Studies show that the chance of heart attack is more in patients with bronchitis and pneumonia. This may be due to the inflammation of the blood vessels.
• Also the polycythemia increase the risk of clot formation which can directly lead to respiratory arrest, heart attack and stroke.