A nurse is reviewing laboratory results for a client who has atrial fibrillation. Which of the following blood test results should the nurse understand can be a possible cause of atrial fibrillation?

A. Respiratory rate of 12/min: A respiratory rate of 12/min is within the normal adult range (12-20 breaths per minute). In the context of increased intracranial pressure (ICP), respiratory rate changes might be noted as part of the Cushing's reflex (which is characterized by bradycardia, hypertension, and abnormal respiratory patterns like Cheyne-Stokes or ataxic breathing), but a rate of 12/min on its own is not indicative of a worsening condition. However, if the patient begins to show signs of irregular or abnormal breathing patterns, this would raise concern.

B. Blood pressure of 108/74 mm Hg: This blood pressure is also within the normal range and does not suggest a worsening of intracranial pressure. In fact, ICP can lead to a rise in blood pressure (due to the body's compensatory mechanisms, known as Cushing's triad), along with bradycardia and abnormal respirations. Thus, a stable blood pressure like 108/74 mm Hg is not concerning in this context.

C. Changes to pupil size and shape: Changes in pupil size, shape, or reactivity are significant indicators of worsening intracranial pressure. Unequal pupils (anisocoria), sluggish or absent response to light, and fixed dilated pupils are signs of brainstem compression or damage, which often occur as ICP increases. This could indicate herniation or severe brain injury, which are worsening conditions.

D. Swelling of the optic nerve: Swelling of the optic nerve, or papilledema, is another important sign of increased intracranial pressure. It occurs due to increased pressure within the skull, which causes congestion and swelling of the optic disc. This finding can be seen on fundoscopy and indicates a worsening condition, as it suggests elevated pressure affecting the brain.

E. Decreasing Glasgow Coma scores: A decreasing Glasgow Coma Scale (GCS) score is a critical indicator of worsening neurologic function in a patient with increased ICP. The GCS is used to assess a patient's level of consciousness, and a decreasing score suggests that the brain's function is deteriorating. This can be caused by worsening edema, brain herniation, or other severe neurological impairments associated with elevated ICP.

A. Lisinopril: Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor commonly used to treat hypertension and heart failure. It is not typically contraindicated for cataract extraction surgery, and it does not significantly increase the risk of bleeding.

B. Synthroid: Synthroid is a synthetic form of thyroid hormone used to treat hypothyroidism. It does not have any direct contraindications with cataract extraction surgery and does not significantly increase the risk of bleeding.

C. Clopidogrel: Clopidogrel is an antiplatelet medication commonly used to prevent blood clots in individuals with cardiovascular diseases such as coronary artery disease or recent myocardial infarction. However, it can increase the risk of bleeding, which may be problematic during cataract extraction surgery. Therefore, it is important to question administering clopidogrel prior to the procedure and potentially coordinate with the healthcare provider regarding its management.

D. Omeprazole: Omeprazole is a proton pump inhibitor used to reduce stomach acid production and treat conditions such as gastroesophageal reflux disease (GERD) and peptic ulcer disease. It does not have any direct contraindications with cataract extraction surgery and does not significantly increase the risk of bleeding.