Review Question - QID 109442

A 65-year-old man presents to the emergency department with shortness of breath and a sensation of anxiety. This started suddenly this afternoon and has persisted for the past several hours. The patient has a past medical history of obesity, diabetes, hypertension, and osteoarthritis. His current medications include atorvastatin, lisinopril, insulin, metformin, and ibuprofen. Laboratory values are ordered as seen below:

Serum:
Na+: 139 mEq/L
Cl-: 100 mEq/L
K+: 4.2 mEq/L
HCO3-: 24 mEq/L
BUN: 20 mg/dL
Glucose: 124 mg/dL
Creatinine: 1.1 mg/dL
Ca2+: 10.1 mg/dL
AST: 11 U/L
ALT: 11 U/L

An ECG is ordered as seen in Figure A. His temperature is 99.5°F (37.5°C), blood pressure is 147/92 mmHg, pulse is 177/min, respirations are 15/min, and oxygen saturation is 96% on room air. On physical exam, the patient appears notably uncomfortable and anxious. Pulmonary exam is notable for minor bibasilar crackles. Cardiac exam is notable for tachycardia. Which of the following is the most appropriate initial therapy?