The nurse is caring for a patient whose ventilator settings i nclude 15 cm H O of positive end-expiratory pressure (PEEP). The nurse understands that although beneficial, PEEP may result in what possible problem?

Correct Answer: D

Rationale: Rationale for Correct Answer (D - Low cardiac output secondary to increased intrathoracic pressure): 1. PEEP increases intrathoracic pressure, which can impede venous return to the heart. 2. Impaired venous return reduces preload, leading to decreased cardiac output. 3. Decreased cardiac output can result in inadequate tissue perfusion and oxygenation. 4. Therefore, PEEP may cause low cardiac output due to increased intrathoracic pressure. Summary of Incorrect Choices: A. Fluid overload is not directly related to PEEP but more to fluid administration or kidney function. B. High cardiac index is unlikely as PEEP can decrease cardiac output. C. Hypoxemia is not a direct result of PEEP but may occur due to other factors like inadequate ventilation or oxygenation settings.

Correct Answer: C

Rationale: Step-by-step rationale for why choice C is correct: 1. Intrapulmonary shunting refers to blood bypassing the normal oxygenation process in the lungs. 2. Choice C describes blood being shunted from the right side of the heart (deoxygenated blood) to the left side without oxygenation, leading to systemic circulation without oxygenation. 3. Choices A, B, and D do not accurately describe intrapulmonary shunting as they focus on other concepts like alveolar perfusion, heart failure, and unilateral lung blood supply, respectively.

Correct Answer: D

Rationale: The correct answer is D: Respiratory alkalosis. Hyperventilation in severe asthma exacerbation leads to excessive removal of CO2, causing a decrease in carbonic acid levels, resulting in respiratory alkalosis. Metabolic acidosis (A) is not typically associated with hyperventilation. Metabolic alkalosis (B) is caused by excessive loss of acid or gain of bicarbonate, not by hyperventilation. Respiratory acidosis (C) is characterized by an increase in CO2 levels due to inadequate ventilation, which is the opposite of what occurs in severe asthma exacerbation.

Correct Answer: D

Rationale: The correct answer is D: Mobility. Maintaining mobility helps prevent blood stasis, a leading factor in the development of pulmonary embolism. Movement promotes circulation, reducing the risk of blood clots. A: Antiseptic oral care is important for oral hygiene but not directly related to preventing pulmonary embolism. B: Bed rest with head of bed elevated can actually increase the risk of clots due to immobility. C: Coughing and deep breathing are beneficial for preventing respiratory complications but do not address the underlying cause of pulmonary embolism.

Correct Answer: B

Rationale: The correct answer is B. Increased peak inspiratory pressure on the ventilator would cue the nurse to the potential of ARDS in a patient with respiratory distress. ARDS is characterized by severe respiratory failure with bilateral pulmonary infiltrates. An increase in peak inspiratory pressure on the ventilator indicates that the lungs are becoming stiffer, which is a common finding in ARDS due to increased inflammation and fluid accumulation in the alveoli. This finding alerts the nurse to the possibility of ARDS and the need for further assessment and intervention. Summary of other choices: A: Increased oxygen saturation via pulse oximetry is a nonspecific finding and may not specifically indicate ARDS. C: Normal chest radiograph with enlarged cardiac structures is more indicative of heart failure rather than ARDS. D: PaO2/FiO2 ratio > 300 is a criterion used to diagnose ARDS, but a value higher than 300 actually indicates mild ARDS, so it would not necessarily cue the nurse