A nurse is assessing a client who has Lewy body dementia. The nurse should recognize that which of the following is responsible for changes in thinking, communication, movement, and emotional processing in Lewy body dementia?

A. Decreased circulation to the kidneys: Post-cardiac arrest syndrome (PCAS) is a constellation of systemic ischemia/reperfusion injury responses that occur after return of spontaneous circulation (ROSC) following cardiac arrest. One of the manifestations of PCAS is decreased circulation to the kidneys due to the systemic hypoperfusion that occurs during cardiac arrest and the subsequent reperfusion injury that follows ROSC. This can lead to acute kidney injury (AKI) in some cases.

B. Increased mental capacity: While it is crucial to monitor neurological status after cardiac arrest, an immediate increase in mental capacity is not typically indicative of PCAS. Rather, neurological assessment may involve evaluating for signs of brain injury or dysfunction, which can include altered mental status, confusion, or neurological deficits.

C. Improving respiratory function: Improvement in respiratory function after cardiac arrest is a positive sign but may not necessarily indicate the development of PCAS. PCAS primarily involves systemic responses to the ischemia/reperfusion injury that occurs during and after cardiac arrest, rather than isolated respiratory changes.

D. Improvement in heart rate and blood pressure: Improvement in heart rate and blood pressure after cardiac arrest is generally expected with successful resuscitation efforts. However, these improvements alone may not necessarily indicate the development of PCAS. PCAS involves a broader range of systemic responses beyond just cardiac and hemodynamic changes.

Pulseless electrical activity (PEA) refers to a situation in which an electrocardiogram (ECG) shows electrical activity in the heart, but there is no effective mechanical activity and no palpable pulse. PEA can result from various underlying conditions that impair cardiac function or compromise circulation.

A. Hypertension: Hypertension, or high blood pressure, is not typically a direct cause of PEA. While uncontrolled hypertension can contribute to cardiovascular disease and increase the risk of cardiac events such as myocardial infarction, it is not a direct cause of PEA.

B. Hypovolemia: Hypovolemia, or low blood volume, is a common cause of PEA. Reduced circulating blood volume leads to decreased preload and inadequate filling of the heart chambers, impairing cardiac output. This can result in ineffective cardiac contractions and the development of PEA.

C. Hypoxia: Hypoxia, or inadequate oxygenation of tissues, is a significant cause of PEA. Insufficient oxygen delivery to the myocardium impairs cardiac function and can lead to ineffective cardiac contractions. Without adequate oxygenation, the heart is unable to generate sufficient mechanical force to maintain circulation, resulting in PEA.

D. Hyperkalemia: Hyperkalemia, or elevated levels of potassium in the blood, can cause PEA by disrupting cardiac electrical activity. Excessive potassium ions in the extracellular fluid alter the normal myocardial action potential, leading to cardiac conduction abnormalities and potential arrhythmias, including PEA.

E. Hypernatremia: Hypernatremia, or elevated levels of sodium in the blood, is not typically a direct cause of PEA. While severe hypernatremia can lead to neurological symptoms and dehydration, it does not directly impair cardiac electrical activity or mechanical function to the extent that it causes PEA.

F. Hyperthermia: Hyperthermia, or elevated body temperature, is not typically a direct cause of PEA. While extreme hyperthermia can lead to cardiovascular complications such as heat stroke, it is not a common cause of PEA unless it is associated with severe systemic metabolic derangements.