Fluids, Electrolytes, Acid-Base Disorders, and Nutrition Support

Patient Case

Questions 6 and 7 pertain to the following case.

A 24-year-old man (weight 90 kg) is admitted to the trauma ICU postoperatively from repair of his duodenal,

jejunal, ileal, and colon injuries; hepatorrhaphy; and splenectomy after several gunshot wounds to the abdomen.

He also received 10 units of packed red blood cells. He has a serum ionized calcium concentration of 0.86

mmol/L, K 4.6 mEq/L, and magnesium 1.8 mg/dL. His SCr concentration is 0.8 mg/dL, and his urine output is

0.5 mL/kg/hour.

Which is the most likely etiology of his hypocalcemia?

Which therapeutic regimen would be best for this patient?

Hypercalcemia

Definition: Corrected serum calcium greater than 10.5 mg/dL or ionized calcium greater than 1.32

mmol/L; signs and symptoms are more evident when total serum calcium of 12 mg/dL or greater

or ionized calcium of 1.5 mmol/L or greater.

Signs and symptoms: Mental status changes, polyuria, shortened QT interval, bradycardia,

atrioventricular block

Etiologies:

Immobilization

ii.

Chronic critical illness–associated metabolic bone disease

iii.

Excessive calcium intake

iv.

Hyperparathyroidism

Granulomatous diseases (tuberculosis, sarcoidosis)

vi.

Malignancy

vii.

Drugs (thiazide diuretics, vitamin D, lithium, teriparatide)

viii.

Dehydration

ix.

Thyrotoxicosis

Adrenal insufficiency

Mobilize the patient (if possible); discontinue calcium supplementation

ii.

Intravenous fluids with 0.9% sodium chloride (if dehydrated) at 200–300 mL/hour x 48 hours

or until rehydrated with or without furosemide 40–80 mg intravenously every 12 hours