Review Question - QID 210770

A 27-year-old man presents to the emergency department. He was brought in by staff from the homeless shelter when they found him unresponsive. The patient is a known IV drug user but otherwise has an unknown past medical history. He currently attends a methadone clinic. His temperature is 99.5°F (37.5°C), blood pressure is 97/48 mmHg, pulse is 140/min, respirations are 29/min, and oxygen saturation is 98% on room air. Initial laboratory values are shown below.

Serum:
Na+: 139 mEq/L
Cl-: 100 mEq/L
K+: 6.3 mEq/L
HCO3-: 17 mEq/L
Glucose: 589 mg/dL

The patient is given treatment. After treatment, his temperature is 99.5°F (37.5°C), blood pressure is 117/78 mmHg, pulse is 100/min, respirations are 23/min, and oxygen saturation is 98% on room air. His laboratory values are seen below:

Serum:
Na+: 139 mEq/L
Cl-: 100 mEq/L
K+: 4.3 mEq/L
HCO3-: 19 mEq/L
Glucose: 90 mg/dL

Which of the following is the most appropriate next step in management?