An emergency department physician evaluates a 69-year-old female resident of an assisted living facility who presents with a 4-day history of profuse, watery diarrhea and progressively worsening shortness of breath. She has a medical history of chronic obstructive pulmonary disease (COPD) and heart failure with reduced ejection fraction. She reports an increase in cough and purulent sputum production that began one week ago. Three days ago, her primary care physician obtained a sputum culture that subsequently grew *Moraxella catarrhalis* sensitive to amoxicillin, azithromycin, and cefuroxime.
| Parameter | Value |
|---|---|
| Temperature | 37.1°C (98.8°F) |
| Blood pressure | 95/60 mm Hg |
| Heart rate | 112/min |
| Respiratory rate | 26/min |
| Oxygen saturation | 89% (room air) |
Physical examination reveals dry oral mucosa and flat neck veins when supine. Lung auscultation demonstrates scattered expiratory wheezes and a prolonged expiratory phase, without crackles. Cardiac examination shows a regular tachycardia with no S3 gallop.
| Test | Result |
|---|---|
| Sodium | 134 mEq/L |
| Potassium | 3.2 mEq/L |
| Chloride | 110 mEq/L |
| Bicarbonate | 14 mEq/L |
| Blood urea nitrogen | 45 mg/dL |
| Creatinine | 1.8 mg/dL |
| Parameter | Value |
|---|---|
| pH | 7.32 |
| PaCO | 29 mm Hg |
| PaO | 58 mm Hg |
Which of the following are appropriate next steps in the management of this patient? (Select all that apply)
- Initiate isotonic crystalloid infusionCevap
- Start azithromycin therapyCevap
- CCommence broad-spectrum coverage with piperacillin-tazobactam
- DAdminister a loop diuretic such as furosemide
- EInitiate mechanical ventilation to target a PaCO of mm Hg