MSFinals-2096

MSFinals-2096

A 91-year-old woman with known vascular dementia presents to the Emergency Department after a routine blood test uncovered that the patient had a sodium level of 149 mmol/l. Her carer comments that the patient’s fluid intake has been minimal over the past week. The patient’s past medical history includes a previous lacunar stroke and peripheral vascular disease. Her regular medications are atorvastatin, ramipril, amlodipine and clopidogrel. She currently is fully dependent on the assistance provided by carers. The patient’s National Early Warning (NEWS) score is 0, and her Glasgow Coma Scale (GCS) score is 15.
A physical examination does not reveal any source of infection. A bedside capillary glucose is recorded as 5.8 mmol/mmol. A full set of blood tests are repeated, reported as follows:
Full blood count and urea and electrolytes (U&Es):
Investigations Results Normal Values
Haemoglobin (Hb) 131 g/l 115–155 g/l
Mean corpuscular volume (MCV) 91 fl 76–98 fl
White cell count (WCC) 5 × 109/l 4–11 × 109/l
Platelets (Plt) 215 × 109/l 150–400 × 109/l
Sodium (Na+) 148 mmol/l 135–145 mmol/l
Potassium (K+) 4.8 mmol/l 3.5–5.0 mmol/l
Urea 3.3 mmol/l 2.5–6.5 mmol/l
Creatinine 66 mmol/l 50–120 mmol/l
A routine chest X-ray and urinalysis are performed and show no abnormalities.
Which of the following is the most suitable to correct the patient’s hypernatraemia?