Fluid and Electrolytes: Balance and Disturbance

1. Mrs. Dean is 75-year-old woman admitted to the hospital for a small bowel obstruction. Her medical history includes hypertension. Mrs. Dean is NPO. She has a nasogastric (NG) tube to low continuous suction. She has an IV of 0.9% NS at 83 mL/hr. Current medications include furosemide 20 mg daily and hydromorphone 0.2 mg every 4 hours, as needed for pain. The morning electrolytes reveal serum potassium of 3.2 mEq/L. (Learning Objective 4)

a. What are possible causes of a low potassium level?
a. The possible causes of the low potassium may be related to the fact that she is NPO, the suction may be another cause, in addition to the furosemide.

b. What action should the nurse take in relation to the serum potassium level? a. The nurse should administer potassium to the patient to balance her levels.

c. What clinical manifestations might the nurse assess in Mrs. Dean? a. The clinical manifestations that the nurse might asses are fatigue, anorexia, nausea and vomiting, muscle weakness, polyuria, decreased bowel motility, ventricular asystole or fibrillation, parasthesias, leg cramps, low blood pressure, ileus, abdominal distension, hypoactive reflexes. In an ECG flattened T waves, prominent U waves, ST depression, and prolonged PR interval.

2. Conrad Jackson is a 28-year-old man who presents to the emergency department with severe fatigue and dehydration secondary to a 4-day history of vomiting. During the interview, he describes attending a family reunion and states that perhaps he “ate something bad.” Upon admission his vital signs are a temperature of 102.7°F, heart rate of 116 bpm, respiratory rate of 18 breaths/min, and blood pressure of 86/54 mm Hg. The nurse also notes the patient has dry mucous membranes and tenting of skin. The physician orders an IV to be started with 0.45% normal saline, and orders a serum electrolytes and an arterial blood gas. (Learning Objective 7)

The following results are returned from the laboratory:

Sodium (Na+)150
Potassium (K+) 5.5
Chloride (Cl¯)110
BUN 42
Creatinine 0.8
Glucose 86
pH7.32
PaCO2 35
HCO3¯ 20
PaO2 90
O2 Sat 98%

a. What is your interpretation of this arterial blood gas sample? a. The pH is low at 7.32 (normal is 7.4), HCO3 is also too low

b. Explain the high potassium in this patient.
a. His dry mucous membranes and skin tenting tell that the patient is dehydrated which would lead to the high potassium level.

c. Calculate the patient’s anion gap:
a. 150 – (110+20) = 20
b. Na-(cl+hco3) is the formula used

d. What is the interpretation of this anion gap?
a. A high anion gap (over 16) indicates metabolic acidosis.