A nurse is caring for a client who has a traumatic brain injury (TBI). Which of the following groups should the nurse understand has a higher risk of sustaining a TBI?

A. The aortic and mitral valves are the most commonly replaced valves: This statement is accurate. The aortic and mitral valves are indeed the most commonly replaced valves in cardiac valve replacement surgeries. Aortic valve replacement is commonly performed for conditions such as aortic stenosis or regurgitation, while mitral valve replacement is often indicated for mitral regurgitation or stenosis.

B. Mitral valve insufficiency occurs during the diastolic phase of the cardiac cycle: This statement is incorrect. Mitral valve insufficiency, also known as mitral regurgitation, occurs during the systolic phase of the cardiac cycle. It involves the backflow of blood from the left ventricle into the left atrium during ventricular systole, leading to volume overload of the left atrium and potentially causing symptoms such as dyspnea and fatigue.

C. Inadequate closure of the tricuspid valve causes overload in the left ventricle: This statement is incorrect. Inadequate closure of the tricuspid valve leads to regurgitation of blood from the right ventricle back into the right atrium during ventricular systole. This condition, known as tricuspid regurgitation, causes volume overload in the right atrium and ventricle, rather than overload in the left ventricle.

D. Aortic stenosis increases right ventricular systolic pressure and decreases afterload: This statement is partially correct. Aortic stenosis indeed increases left ventricular systolic pressure and decreases afterload, not right ventricular pressure. The increased afterload on the left ventricle can lead to left ventricular hypertrophy and eventually heart failure. However, aortic stenosis does not directly affect right ventricular systolic pressure.

A. White blood cell level of 5,900 mm3: While abnormal white blood cell levels can indicate infection or inflammation, they are not typically associated with directly contributing to an episode of delirium. However, underlying conditions that cause abnormal white blood cell levels, such as infection or inflammation, may contribute to delirium.

B. Potassium level of 4.1 mEq/L: Potassium imbalances can lead to various neurological symptoms, including weakness, paralysis, and cardiac arrhythmias. However, a potassium level of 4.1 mEq/L is within the normal range and is unlikely to directly contribute to an episode of delirium.

C. Hemoglobin level of 14.2 g/dL: Hemoglobin levels reflect the oxygen-carrying capacity of the blood and are not directly associated with delirium. While severe anemia or hypoxia can cause neurological symptoms, a hemoglobin level of 14.2 g/dL is within the normal range and is unlikely to directly contribute to delirium.

D. Blood glucose level of 254 mg/dL: Elevated blood glucose levels, as indicated by a blood glucose level of 254 mg/dL, can contribute to an episode of delirium. Hyperglycemia can lead to alterations in cerebral metabolism, neuronal dysfunction, and impaired cognitive function, predisposing individuals to delirium. Additionally, hyperglycemia can exacerbate preexisting neurological conditions and increase the risk of developing delirium in critically ill patients. Therefore, monitoring and managing blood glucose levels are essential in preventing and managing delirium in hospitalized patients.