Fluid & Electrolyte Balance Application Exam

"My feet swell if I eat salt," says Mr. Cor, who has chronic compensated heart failure, "so I stopped eating it like my nurse practitioner said, but I do not understand how salt causes swelling." Choose the best response. A. Salt holds water in your blood and makes more pressure against your blood vessels, so fluid leaks out into your tissues and makes them swell. B. Gravity makes more pressure down by your feet than up at the top of your body, so more fluid leaks into your tissues at your feet and they swell. C. Salt makes your blood vessels relax and the blood does not flow as fast, so some of it leaks into your tissues and makes swelling. D. Salt binds to the proteins in your blood and changes the osmotic pressure so more fluid can leak out and stay in the tissues, causing swelling.

A. Salt holds water in your blood and makes more pressure against your blood vessels, so fluid leaks out into your tissues and makes them swell. (Salt holds water in the ECV, thus increasing capillary hydrostatic pressure.)

Which individual is at highest risk for developing hypernatremia? A. Mr. W, who self-administers a daily tap-water enema to manage a partial bowel obstruction B. Mr. X, who receives tube feedings because he is comatose after a stroke C. Mr. Y, who has ectopic production of ADH from small cell carcinoma of the lung D. Mr. Z, who is receiving IV 0.9% NaCl at a fast rate

B. Mr. X, who receives tube feedings because he is comatose after a stroke (Tube feedings are associated with hypernatremia due to intake of highly concentrated solution that causes the kidneys to excrete extra water to remove the solute load)

Mrs. Gunro, who is 8 months pregnant, has developed eclampsia and is receiving intravenous magnesium sulfate to prevent seizures. What assessment should you perform regularly to determine if her infusion rate is too high? A. Patellar reflex; if it becomes more and more hyperactive, her infusion rate probably is too high and she is at risk for respiratory depression or cardiac arrest. B. Patellar reflex; if it becomes weak or absent, her infusion rate probably is too high and she is at risk for respiratory depression or cardiac arrest. C. Patellar reflex; if it stays the same, her infusion rate probably is too high and she is at risk for respiratory depression or cardiac arrest. D. Watch for seizure activity. If no seizures occur, her infusion rate is correct.

B. Patellar reflex; if it becomes weak or absent, her infusion rate probably is too high and she is at risk for respiratory depression or cardiac arrest. (Hypermagnesemia causes decreased neuromuscular excitability and testing the patellar reflex can detect that.)

Ms. Cancer is hospitalized with a malignant tumor that secretes parathyroid hormone-related peptide. How should you monitor for the resulting electrolyte imbalance? A. Serum calcium, Chvostek and Trousseau signs B. Serum calcium, bowel function, level of consciousness C. Serum potassium, Chvostek and Trousseau signs D. Serum potassium, bowel function, level of consciousness

B. Serum calcium, bowel function, level of consciousness (Parathyroid hormone increases the plasma calcium concentration, and constipation and lethargy are manifestations of hypercalcemia.)

Mrs. Frisioni has drainage from an intestinal fistula that is being managed at home while it heals. You are the home health nurse who changes the dressing. Today she is already lying down when you arrive, saying that she feels "weak and dizzy" when she stands. Her supine blood pressure is 92/70, heart rate 78. When she sits up, she slumps sideways and is temporarily unresponsive while you are deflating the blood pressure cuff. You could read only the systolic pressure, which was 77, before she fell sideways and you could tell that her heart rate was very fast while you were deflating the cuff. She has regained consciousness now that she is lying down. What should you do before you telephone her physician or nurse practitioner? Why? A. Sit her up again, with proper support, so you can have an accurate upright blood pressure and heart rate to report. B. Give her a drink of water or juice, talk with her to calm her down, and ask if she slept well last night. C. Give her water or juice and some salty crackers and ask if she has had any diarrhea and vomiting. D. Assess small vein filling time, look for ankle edema, and ask if she had any fluid to drink yet today.

C. Give her water or juice and some salty crackers and ask if she has had any diarrhea and vomiting. (Her substantial systolic postural blood pressure decrease with tachycardia and syncope when upright are indicators of ECV deficit, and she needs salt and water. Your questions will provide information for her physician or nurse practitioner regarding the origin of the ECV deficit.)

Which person needs teaching regarding increasing dietary intake of potassium to help prevent or manage an electrolyte imbalance for which she has high risk? A. Mrs. A, who has advanced breast cancer and takes very large doses of vitamin D in hopes of a cancer cure B. Mrs. B, who has fatty stools from taking an OTC weight-loss product that decreases absorption of fat C. Mrs. C, who has chronic heart failure that is treated with diuretics D. Mrs. D, who has anorexia and chronic oliguric renal failure

C. Mrs. C, who has chronic heart failure that is treated with diuretics (Chronic heart failure causes increased secretion of aldosterone, which often causes hypokalemia by increasing renal excretion of potassium; most diuretics used to treat heart failure also increase renal excretion of potassium.)

2. "My 2-month-old baby is throwing up and has frequent diarrhea," says Mr. Worry over the telephone. "I keep giving him Pedialyte [oral electrolyte replacement solution] like you said, but I am worried that he will get dehydrated and I shall not know it." Choose the best response. A. Clinical dehydration is the combination of extracellular fluid volume deficit and hypernatremia, so those are the diagnostic criteria. B. If he does not wet his diaper all afternoon and his neck veins look flat when he is lying down, then he is probably dehydrated. C. If he sleeps more than usual and acts tired when he is awake, then he is probably dehydrated. D. If the soft spot on the top of his head feels sunken in and his mouth is dry between his cheek and his gums, then he is probably dehydrated.

D. If the soft spot on the top of his head feels sunken in and his mouth is dry between his cheek and his gums, then he is probably dehydrated. (These are useful assessments of ECV deficit in an infant, which is an important part of clinical dehydration. Although the diaper information provides a useful assessment, neck veins are not a reliable assessment in an infant.)

Mr. Thanatos has a positive Chvostek sign. How should you interpret this finding? A. Either hypocalcemia or hypomagnesemia, or both B. Either hypercalcemia or hypermagnesemia, or both C. Either hypokalemia or hyperkalemia D. Increased neuromuscular excitability

D. Increased neuromuscular excitability (Positive Chvostek sign indicates increased neuromuscular excitability, which can be caused by hypocalcemia, hypomagnesemia, or other factors)

8. Your assessment in the middle of your shift reveals the following changes this morning for four of your patients. Which one should you report most urgently to a physician? A. Mrs. A, whose serum potassium concentration is decreasing and has developed abdominal distention but says her breathing is fine. B. Mrs. B, whose serum calcium concentration is decreasing and has developed constipation but is alert and says she feels fine. C. Mrs. C, whose serum calcium concentration is increasing and has developed constipation but is alert and says she feels fine. D. Mrs. D, whose serum potassium concentration is increasing and has developed cardiac dysrhythmias but says her breathing is fine.

D. Mrs. D, whose serum potassium concentration is increasing and has developed cardiac dysrhythmias but says her breathing is fine. (Cardiac dysrhythmias from hyperkalemia need rapid attention to prevent potentially life-threatening consequences and are therefore the highest priority for reporting)

You are volunteering in a remote area after an earthquake. A man was pulled from the wreckage after being trapped in a basement for 3 days. He has no injuries but is dazed and confused. The triage team sends him to you for oral rehydration. As they bring him to you on a stretcher, you see that his neck veins are collapsing every time he inhales. Quick assessment shows that his mouth is very dry and his pulse is weak. You have two fluids available: bottled water and salty soup. Which one should you give him? Why? A. Bottled water because he is so weak that he might choke on the fluid when he swallows and water would be less damaging to the lungs than salty soup. B. Bottled water because it will rehydrate his cells. C. Salty soup because he needs nutrition as well as fluid. D. Salty soup because it will provide some sodium to help hold the fluid in his blood vessels and interstitial fluid.

D. Salty soup because it will provide some sodium to help hold the fluid in his blood vessels and interstitial fluid. (This man has indicators of clinical dehydration and he needs salt to hold the water in his extracellular compartment.)