Mr. L is a 58-year-old man recovering in the orthopedic unit from a right total knee replacement performed two days ago. He has type 1 diabetes, diagnosed at 12 years old, and manages his condition with blood glucose checks four times daily: before meals and at bedtime. He uses Humulin-R insulin on a sliding scale based on his glucose results. Mr. L weighs 315 lbs and has osteoarthritis in both knees, necessitating surgical replacement of the right knee joint.

At 8:15 AM, the nurse enters Mr. L's room for a morning assessment. She finds him awake but with an altered mental status and a fruity odor on his breath. His vital signs are: HR 100 bpm, RR 32/minute, BP 116/78 mm Hg. His last blood glucose level was 156 mg/dl the previous night, and he received 2 units of insulin but has not had a morning glucose check or insulin dose. A rapid bedside glucose check shows 468 mg/dl. The nurse contacts the physician, and Mr. L is diagnosed with diabetic ketoacidosis (DKA).

1. **Describe how diabetic ketoacidosis could develop in a patient who has undergone surgery.**

2. Mr. L has an elevated respiratory rate, identified as Kussmaul respirations. **Explain this respiratory pattern.**

3. Mr. L reports excessive thirst and sudden blurry vision. The nurse observes a large amount of clear urine in his catheter bag, which tests positive for ketone bodies.
**How does the body release ketone bodies into the urine during DKA?**
**Explain why Mr. L has increased urinary output, blurred vision, and increased thirst.**

4. The physician orders 0.9% Sodium Chloride IV at 500 mL/hour for 1 hour, then 200 mL/hour for 4 hours. Regular insulin is to be administered at 0.1 mg/kg/hour. Lab work, including a metabolic profile and arterial blood gases, is ordered. Results are:
- Na: 135 mEq/L
- K: 3.2 mEq/L
- Cl: 95 mmol/L
- Ca: 8.5 mg/dl
- Arterial Blood Gases: pH 7.31, pCO2 20 mmHg, pO2 95 mmHg, HCO3 12 mmol/L

**What is the rationale for administering IV fluids at this rate?**
**Explain why the patient’s potassium result is at this current level.**
**Based on the metabolic profile results, what is the next step the nurse should most likely take?**
**Explain why DKA likely produces these types of blood gas results.**

5. An hour after starting the insulin, the nurse checks Mr. L's blood glucose levels, noting a decrease to 208 mg/dl. He appears more comfortable, and his vital signs are: HR 92 bpm, RR 22/minute, BP 116/70 mm Hg, O2 saturation 95% on 2L of oxygen.
**What should the nurse do next?**