A patient's ventilator settings are adjusted to treat hypoxemia.The fraction of inspired oxygen is increased from .60 to .70,and the positive end-expiratory pressure is increased from 10 to 15 cm H?O.Shortly after these adjustments,the nurse notes that the patient's blood pressure drops from 120/76 mm Hg to 90/60 mm Hg.What is the most likely cause of this decrease in blood pressure?

Question

Quizplus · Accepted Answer

Positive end-expiratory pressure increases intrathoracic pressure and may result in decreased venous return.Cardiac output decreases as a result,and is reflected in the lower blood pressure.It is essential to assess the patient to identify optimal positive end-expiratory pressure-the highest amount that can be applied without compromising cardiac output.Although hypovolemia can result in a decrease in blood pressure,there is no indication that this patient has hypovolemia.As noted,higher levels of positive end-expiratory pressure may cause a decrease,not an increase,in venous return.Oxygen toxicity can occur in this case secondary to the high levels of oxygen needed to maintain gas exchange; however,oxygen toxicity is manifested in damage to the alveoli.

A Patient's Ventilator Settings Are Adjusted to Treat Hypoxemia