Review Question - QID 109698

A 29-year-old woman is recovering on the obstetrics floor after the vaginal delivery of 8-pound twin boys born at 42 weeks gestation. The patient is fatigued but states that she is doing well. Currently, she is complaining that her vagina hurts. The next morning, the patient experiences chills and a light red voluminous discharge from her vagina. She states that she feels pain and cramps in her abdomen. The patient's medical history is notable for diabetes which was managed during her pregnancy with insulin. Her temperature is 99.5°F (37.5°C), blood pressure is 107/68 mmHg, pulse is 97/min, respirations are 16/min, and oxygen saturation is 98% on room air. Laboratory values are obtained and shown below.

Hemoglobin: 12 g/dL
Hematocrit: 36%
Leukocyte count: 9,750/mm^3 with normal differential
Platelet count: 197,000/mm^3

Serum:
Na+: 139 mEq/L
Cl-: 101 mEq/L
K+: 4.2 mEq/L
HCO3-: 23 mEq/L
BUN: 20 mg/dL
Glucose: 111 mg/dL
Creatinine: 1.1 mg/dL
Ca2+: 10.2 mg/dL
AST: 12 U/L
ALT: 10 U/L

Which of the following is the most appropriate next step in treatment for this patient?