A 65-year-old woman on chronic hemodialysis presents with difficulty breathing and inability to sleep. The patient has had shortness of breath, diaphoresis, and nausea, but has not vomited.
She denies having abdominal pain, diarrhea, or chest pain. She has tachycardia and tachypnea, and exhibits peaked T waves with occasional PVCs on the ECG. Serum chemistry values are:
* Sodium: 137 mEq/L
* BUN: 125 mg/dL
* Potassium: 7.2 mEq/L
* Creatinine: 12.8 mg/dL
* Chloride: 97 mEq/L
* Glucose: 95 mg/dL
* HCO3- : 11 mEq/L
* Calcium: 8.5 mg/dL
* Albumin: 3.1 g/dL
* Phosphorus: 1.7 mg/dL
Which of the following should the pharmacotherapy specialist recommend for immediate therapy?

The risk of methemoglobinemia is highest with the use of: