MED SURG EXAM 3.

MED SURG EXAM 3.Chapter 25 Assessment Respiratory System 1. The key anatomic landmark that separates the upper respiratory tract from the lower respiratory tract is the a. carina. b. larynx. c. trachea. d. epiglottis. Rationale: The carina is the anatomic landmark that separates the upper respiratory tract from the lower respiratory tract. The larynx, epiglottis, and trachea are all above the carina (part of the upper respiratory tract). 2. A patient asks, “How does air get into my lungs?” The nurse bases her answer on knowledge that air moves into the lungs because of a. positive intrathoracic pressure. b. contraction of the accessory abdominal muscles. c. stimulation of the respiratory muscles by the chemoreceptors. d. a decrease in intrathoracic pressure from an increase in thoracic cavity size. Rationale: During inspiration, the diaphragm contracts, moves downward, and increases intrathoracic volume. At the same time, the external intercostal muscles and scalene muscles contract, increasing the lateral and anteroposterior dimension of the chest. This causes the size of the thoracic cavity to increase and intrathoracic pressure to decrease. As a result, air is pulled into the lungs. 3. The nurse can best determine adequate arterial oxygenation of the blood by assessing a. heart rate. b. hemoglobin level. c. arterial oxygen partial pressure. d. arterial carbon dioxide partial pressure. Rationale: The ability of the lungs to oxygenate arterial blood adequately is determined by examination of the partial pressure of oxygen in arterial blood (PaO2) and arterial oxygen saturation (SaO2). The heartrate, hemoglobin level, and mean arterial pressure do not help evaluate oxygenation. PaCO2 evaluates the ventilation portion. 4. Defense mechanisms that help protect the lung from inhaled particles and microorganisms include the (select all that apply) a. cough reflex. b. mucociliary escalator. c. alveolar macrophages. d. reflex bronchoconstriction. e. alveolar capillary membrane. Rationale: Respiratory defense mechanisms are efficient in protecting the lungs from inhaled particles, microorganisms, and toxic gases. These include the cough reflex, mucociliary 5. A student nurse asks the RN what can be measured by arterial blood gas (ABG). The RN tells the student that the ABG can measure (select all that apply) a. acid-base balance. b. oxygenation status. c. acidity of the blood. d. bicarbonate (HCO3–). e. compliance and resistance. Rationale: Arterial blood gases (ABGs) are measured to determine oxygenation status, ventilation status, and acid-base balance. ABG analysis includes measurement of the partial pressure of oxygen in arterial blood (PaO2), partial pressure of carbon dioxide in arterial blood (PaCO2), acidity (pH), bicarbonate (HCO3–), and arterial oxygen saturation (SaO2) in arterial blood. Compliance and resistance cannot be determined with ABGs.