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 but 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%. She is alert and oriented, her oral mucosa is dry, and she has voided twice in 24 hours. 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. 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.

Quick answer
Diabetic ketoacidosis. Begin the prescribed isotonic IV fluid and start the IV regular insulin infusion. Monitor serum potassium and serum bicarbonate.

Why this is correct
Without insulin, fat breakdown produces ketoacids, causing ketonemia, a low pH and bicarbonate, Kussmaul respirations, and osmotic diuresis with volume loss. Fluids restore perfusion first, and IV insulin stops ketone production; insulin is safe to start because potassium is 5.8 mmol/L. The initial high potassium reflects a shift out of cells, while total body potassium is depleted, so potassium falls quickly once insulin and fluids are running.

Easy analogy or mental picture
In DKA the cells are starving in a sea of sugar because the door (insulin) is locked. Fluids refill the tank, insulin opens the door, and potassium rushes back into the cells with the sugar, so the blood level drops fast.

Memory hook
"Fluids first, then insulin if K is above 3.5; watch K and the bicarbonate close."

NCLEX decision rule
In DKA, check potassium before starting insulin, and judge recovery by acid-base values and potassium rather than glucose alone.

Why the other choices are wrong
HHS needs a high osmolality with minimal ketones and a near-normal pH; this pH of 7.18 with high ketones is DKA, so osmolality is not the key response measure. Alcoholic ketoacidosis needs recent heavy drinking with usually low or normal glucose, and starvation ketosis does not cause glucose 478 or a pH of 7.18. Bicarbonate is not indicated at pH 7.18, and adding potassium is right later but not while potassium is 5.8 mmol/L. Glargine alone is too slow to treat DKA. Urine dipsticks measure acetoacetate and lag behind blood ketones, and lipase would matter only if pancreatitis were suspected.