Which statement by the nurse when explaining the purpose of positive end-expiratory pressure (PEEP) to the patient's caregiver is accurate?

C. Mean arterial pressure (MAP) reflects the average pressure in the arteries during one cardiac cycle and is an important indicator of tissue perfusion. A MAP of 56 mm Hg is below the normal range (typically >60 mm Hg) and may indicate inadequate tissue perfusion. While norepinephrine is commonly used to increase blood pressure and improve tissue perfusion in hypotensive patients, a MAP of 56 mm Hg suggests that the current infusion rate may not be sufficient to maintain adequate perfusion, and adjusting the infusion rate may be warranted.

A. Norepinephrine is a vasopressor medication primarily used to increase blood pressure in patients with hypotension or shock. A low pulmonary artery wedge pressure (PAWP) suggests decreased preload, which may indicate hypovolemia or inadequate fluid resuscitation. In this case, adjusting the norepinephrine infusion rate may not be necessary, but rather addressing the underlying cause of hypovolemia or inadequate preload.

B. Systemic vascular resistance (SVR) represents the resistance the heart must overcome to pump blood into the systemic circulation. An elevated SVR may suggest vasoconstriction, which could be a desired effect of norepinephrine infusion to increase blood pressure. Therefore, an elevated SVR may not necessarily indicate a need to adjust the norepinephrine infusion rate, as it may reflect the medication's intended action.

D. Norepinephrine primarily acts on alpha-adrenergic receptors to increase blood pressure by inducing vasoconstriction. While it may cause reflex bradycardia due to increased systemic vascular resistance, a heart rate of 58 beats/min may be within an acceptable range depending on the patient's clinical condition and baseline heart rate. Therefore, a slow heart rate alone may not necessarily indicate a need to adjust the norepinephrine infusion rate unless it is associated with signs of inadequate tissue perfusion or other concerning symptoms.

B Somnolence, or excessive sleepiness, can indicate respiratory depression, hypercapnia (elevated PaCO2), or impending respiratory failure. Somnolence in this context is concerning as it may suggest worsening respiratory status and impending respiratory compromise. Therefore, it should be immediately reported to the healthcare provider for further evaluation and intervention.

A blood pressure of 164/98 mmHg is elevated but may not necessarily require immediate intervention, especially if the patient is not exhibiting signs of acute hypertensive crisis or end-organ damage.

However, it should be closely monitored and managed as appropriate. While hypertension may contribute to respiratory distress, it may not be the most critical finding to report immediately in a patient with possible respiratory failure and a high PaCO2.

C An oxygen saturation of 90% indicates hypoxemia, which can exacerbate respiratory failure and contribute to respiratory distress. While hypoxemia requires prompt intervention to improve oxygenation, it may not be the most critical finding to report immediately if the patient is not showing signs of severe respiratory distress or impending respiratory failure. However, it should be closely monitored and managed to prevent further deterioration.

D Weakness is a nonspecific symptom and may be related to various underlying causes, including respiratory failure, electrolyte imbalances, or systemic illness. While weakness warrants further assessment and management, it may not be the most urgent finding to report immediately in a patient with possible respiratory failure and a high PaCO2 unless it is accompanied by other concerning symptoms or signs of impending respiratory compromise.