A nurse in a critical care unit is caring for a client who suffered a knife wound to the chest. The nurse suspects the client is developing cardiac tamponade. Which of the following assessment findings should the nurse identify as supporting this suspicion?

Choice A Reason: This choice is incorrect because flatened neck veins are not a sign of cardiac tamponade. Cardiac tamponade is a condition in which fluid accumulates in the pericardial sac that surrounds the heart, causing compression and impaired filling of the heart chambers. This leads to reduced cardiac output and hypotension. One of the manifestations of cardiac tamponade is distended neck veins due to increased venous pressure and impaired venous return.

Choice B Reason: This choice is incorrect because bradycardia is not a sign of cardiac tamponade. Bradycardia is a condition in which the heart rate is slower than normal (less than 60 beats per minute). It may be caused by various factors such as vagal stimulation, medication side effects, hypothyroidism, or sinus node dysfunction. It may cause symptoms such as fatigue, dizziness, or syncope, but it does not indicate cardiac tamponade.

Choice C Reason: This choice is incorrect because sudden lethargy is not a specific sign of cardiac tamponade. Lethargy is a condition in which the person feels tired, sluggish, or drowsy. It may be caused by various factors such as sleep deprivation, depression, infection, anemia, or hypoglycemia. It may affect the person's mental and physical performance, but it does not indicate cardiac tamponade.

Choice D Reason: This choice is correct because muffled heart sounds are a sign of cardiac tamponade. Muffled heart sounds are heart sounds that are fainter or softer than normal due to reduced transmission of sound waves through fluid-filled pericardial sac. They may indicate that the heart function is compromised by cardiac tamponade and require immediate intervention such as pericardiocentesis (removal of fluid from pericardial sac).

Choice A Reason: This choice is incorrect because slowing the rate to 50 mL/hr may not be enough to prevent cerebral edema, which is a common complication of head injury. Cerebral edema is a swelling of the brain tissue due to increased fluid accumulation. It can cause increased intracranial pressure (ICP), which can lead to brain damage or death. Therefore, the nurse should limit the fluid intake of the client with head injury to avoid worsening the condition.

Choice B Reason: This choice is incorrect because increasing the rate to 250 mL/hr may cause fluid overload, which can also increase the ICP and worsen the cerebral edema. Fluid overload is a condition in which the body has too much fluid, which can impair the function of the heart, lungs, and kidneys. Therefore, the nurse should avoid giving too much fluid to the client with head injury.

Choice C Reason: This choice is correct because slowing the rate to 20 mL/hr may help to maintain adequate hydration and electrolyte balance, while preventing fluid overload and cerebral edema. This is a conservative approach that can be used until the client's neurological status and ICP are assessed and monitored.

Choice D Reason: This choice is incorrect because continuing the rate at 125 mL/hr may not be appropriate for the client with head injury, depending on their individual needs and condition. The nurse should adjust the fluid rate according to the client's vital signs, urine output, serum osmolality, and ICP. Therefore, the nurse should not assume that this rate is optimal for the client without further evaluation.