Case two: bowtie
a five-cell bowtie canvas with one center action cell, two condition cells on the left, two parameter cells on the right, and the three option banks printed beneath their wings.
THE CASE
Mr. D, 19 years old, has had type 1 diabetes for six years. His roommate brings him to the emergency department. He has vomited for three days following a viral illness and stopped taking his insulin because he was not eating. He is alert but drowsy and answers slowly. Respirations are deep and rapid at 32 per minute. His breath has a fruity odor. Mucous membranes are dry, skin tents when pinched, capillary refill is 4 seconds. Heart rate 124. Blood pressure 96/58. He reports losing 8 lb in three days.
Point-of-care glucose reads HIGH. Venous laboratory panel: glucose 512 mg/dL, pH 7.18, bicarbonate 12 mEq/L, anion gap 24, potassium 5.6 mEq/L, sodium 129 mEq/L, creatinine 1.4 mg/dL, serum ketones positive.
THE BOWTIE
Complete all five cells. Use each bank only for its own wing.
LEFT — POTENTIAL CONDITIONS (choose two) → CENTER — ACTION TO TAKE (choose one) → RIGHT — PARAMETERS TO MONITOR (choose two)
Action bank (choose one for the center cell)
- Begin an intravenous infusion of 0.9% sodium chloride.
- Administer an intravenous insulin bolus.
- Administer intravenous sodium bicarbonate.
- Administer intravenous potassium chloride.
- Give an oral rehydration solution by mouth.
- Administer an intravenous antiemetic.
Conditions bank (choose two for the left cells)
- Diabetic ketoacidosis
- Hypovolemia from osmotic diuresis
- Hyperosmolar hyperglycemic state
- Lactic acidosis from sepsis
- Syndrome of inappropriate antidiuretic hormone
Parameters bank (choose two for the right cells)
- Serum potassium
- Serum bicarbonate with the anion gap
- Serum glucose alone
- Urine ketones every 4 hours
- Serum creatinine alone
Why this order? Before you turn the page, write one sentence saying why the action you chose has to come before the one you rejected. One sentence. Do not look at page 65 first.
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Margin note: "fluid first, always."
> Watch out: insulin drives potassium into cells. A potassium of 5.6 mEq/L in this client is a number on its way down. > → BOOK 10 · P6 and → BOOK 07 · P8
Takeaway. In ketoacidosis the client is dying of dehydration and acidosis before he is dying of glucose, so volume comes first, and the anion gap rather than the glucose tells you when it is over.