# Stage 3 — Prioritize hypotheses. A 42-year-old client with type 1 diabetes has had nausea, vomiting, and abdominal pain for 2 days and has taken no basal or bolus insulin for 36 hours. She drinks wine socially, none in 2 weeks. BP is 100/64, HR 112, RR 26 with deep, regular breathing, temperature 37.2°C (99°F), and SpO2 98% on room air. She is alert and oriented, and her oral mucosa is dry. Results: glucose 478 mg/dL, beta-hydroxybutyrate 6.8 mmol/L, venous pH 7.18, bicarbonate 9 mmol/L, and serum potassium 5.8 mmol/L. Additional results: sodium 134 mmol/L, anion gap 24 mmol/L, effective osmolality 295 mOsm/kg, lactate 1.6 mmol/L, and blood alcohol undetectable. Complete the diagram by selecting the condition the client is most likely experiencing, 2 actions the nurse should take to address that condition, and 2 parameters the nurse should monitor to assess the client's progress.

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> subject: Expected Actions/Outcomes  
> category: PPT

## Question

Stage 3 — Prioritize hypotheses. A 42-year-old client with type 1 diabetes has had nausea, vomiting, and abdominal pain for 2 days and has taken no basal or bolus insulin for 36 hours. She drinks wine socially, none in 2 weeks. BP is 100/64, HR 112, RR 26 with deep, regular breathing, temperature 37.2°C (99°F), and SpO2 98% on room air. She is alert and oriented, and her oral mucosa is dry. Results: glucose 478 mg/dL, beta-hydroxybutyrate 6.8 mmol/L, venous pH 7.18, bicarbonate 9 mmol/L, and serum potassium 5.8 mmol/L. Additional results: sodium 134 mmol/L, anion gap 24 mmol/L, effective osmolality 295 mOsm/kg, lactate 1.6 mmol/L, and blood alcohol undetectable. Complete the diagram by selecting the condition the client is most likely experiencing, 2 actions the nurse should take to address that condition, and 2 parameters the nurse should monitor to assess the client's progress.

Condition

Select 1
Diabetic ketoacidosis
Hyperosmolar hyperglycemic state
Alcoholic ketoacidosis
Lactic acidosis from sepsis

Actions to take

Select 2
Add 20 mEq potassium chloride to the first liter of saline
Give sodium bicarbonate for the pH of 7.18
Begin 0.9% sodium chloride at 1 L/h as prescribed
Restrict IV fluids to lower cerebral edema risk
Start the prescribed IV regular insulin infusion

Parameters to monitor

Select 2
Effective serum osmolality every 4 hours
Serum potassium every 2 hours
Blood alcohol level
Anion gap and serum bicarbonate
Serum lactate level

## Explanation

Glucose 478 mg/dL, beta-hydroxybutyrate 6.8 mmol/L, venous pH 7.18, and bicarbonate 9 mmol/L with an anion gap of 24 after 36 hours without insulin confirm DKA. Isotonic saline at 1 L/h as prescribed restores volume, and because potassium is 5.8 mmol/L (above 3.5), the prescribed IV insulin infusion can start. Serum potassium every 2 hours and closure of the anion gap with rising bicarbonate track safe, effective treatment.

## In-depth explanation

Quick answer
Diabetic ketoacidosis; begin 0.9% sodium chloride at 1 L/h and start the prescribed IV regular insulin infusion; monitor serum potassium every 2 hours and the anion gap with serum bicarbonate.

Why this is correct
The client meets all three DKA criteria: hyperglycemia (478 mg/dL), ketonemia (beta-hydroxybutyrate 6.8 mmol/L), and a high anion gap metabolic acidosis (venous pH 7.18, bicarbonate 9 mmol/L), precipitated by 36 hours without insulin. Isotonic fluid corrects the volume deficit shown by HR 112, BP 100/64, and dry mucosa. Insulin is safe to start because potassium is above 3.5 mmol/L; it stops ketone production and closes the anion gap. Insulin drives potassium into cells, so potassium is rechecked frequently and replaced once it falls into the normal range.

Easy analogy or mental picture
Picture a car running on the wrong fuel (fat) because the key (insulin) is missing: refill the radiator (fluids), put the key back (insulin), and watch the battery gauge (potassium), because turning the key drains it fast.

Memory hook
"Fluid in, key in, watch K; the gap tells you when it's over."

NCLEX decision rule
In DKA, give isotonic fluid and start IV insulin only when potassium is at least 3.5 mmol/L; resolution is judged by acid-base values and the anion gap, while potassium is trended to prevent hypokalemia.

Why the other choices are wrong
Adding potassium to the first liter is right later, but not while potassium is 5.8 mmol/L. Bicarbonate is reserved for pH below 7.0. Restricting fluids ignores the volume deficit that drives the tachycardia and low-normal blood pressure. HHS is excluded by an effective osmolality of 295 mOsm/kg with severe acidosis; alcoholic ketoacidosis by no alcohol for 2 weeks, an undetectable blood alcohol, and marked hyperglycemia; and sepsis-related lactic acidosis by a temperature of 37.2°C and a lactate of 1.6 mmol/L. Osmolality, blood alcohol, and lactate track those differentials rather than DKA resolution.

References
1ADA Consensus Report — Hyperglycemic Crises in Adults With Diabetes (2024)DKA is defined by hyperglycemia, ketonemia, and metabolic acidosis; treatment begins with isotonic fluid and IV insulin once potassium is at least 3.5 mmol/L, with bicarbonate reserved for pH below 7.0.

## Clinical scenario

Case update
Glucose 478 mg/dL, beta-hydroxybutyrate 6.8 mmol/L, venous pH 7.18, and bicarbonate 9 mmol/L after 36 hours without insulin, with potassium 5.8 mmol/L before treatment.

## Key concepts

- **Anion gap** — Sodium minus (chloride + bicarbonate); an elevated gap reflects unmeasured acids such as ketones, and its closure marks DKA resolution.
- **Ketonemia** — Elevated blood ketones from fat breakdown when insulin is absent.
- **Effective osmolality** — 2 x sodium + glucose/18; a value above 320 mOsm/kg points toward hyperosmolar hyperglycemic state.

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