Ch 25 Fluid,Electrolyte and Acid Balance

A nursing instructor is teaching students about water and electrolyte balance. Which statement made by a student indicates a need for additional teaching?

"Infants lose less water due to a smaller body surface area." Rationale: Infants have a large body surface area compared to body weight. So, they lose more water through their skin than adults. Since water is present in every cell, it acts as a medium for the transportation of cellular substances. Water constitutes more than half of a person's body weight. It serves as a medium for the digestion of food as it is an excellent solvent.

The nurse is caring for a patient diagnosed with chronic heart failure. The nurse understands that the patient is at risk of developing extracellular fluid volume excess. Which clinical findings would the nurse observe in this patient?

-ankle edema -Overnight weight gain -Neck veins full when upright Rationale: Chronic heart failure can cause extracellular fluid volume excess due to decreased renal output caused by elevated aldosterone. It can result in fluid retention manifested as ankle edema and weight gain. The neck veins may feel full on palpation when the patient is in the upright position. Postural hypotension occurs when there is extracellular fluid volume deficit and not with excess of extracellular fluid volume. Weight loss is observed when there is extracellular fluid volume deficit and not with excess extracellular fluid volume.

Which fluid output measurement is the most concerning for a nurse?

100 mL of urine in a 5-hour period Rationale: Urine output should be at least 30 mL/hr; 5 hours × 30 mL/hr = 150 mL in 5 hours. Urine output is 720 mL in a 24-hour period, which is calculated as 30 mL/hr. Urine output is 600 mL in a 10-hour period, which is more than 30 mL/hr. Urine output is 60 mL in a 2-hour period, which is calculated as 30 mL/hr.

A patient has been diagnosed with cerebral edema. The primary health care provider has prescribed intravenous therapy for the patient. What intravenous solution does the nurse administer to the patient?

40% dextrose Rationale: A 40% dextrose solution is often used to lower cerebral edema. This is because it draws fluid from the intracellular to the extracellular compartment, thereby relieving cellular edema. Albumin is used to diminish ascites (intraperitoneal fluid) and maintain blood pressure. A solution of 0.45% sodium chloride is used to replace hypotonic fluid losses and to maintain the fluid balance. Ringer's solution is generally used for patients with fluid loss and for those waiting for blood products.

Which electrolyte is essential for the formation of hydrochloric acid in the stomach?

Chloride Rationale: Chloride is essential for the formation of hydrochloric acid, which is secreted in the stomach to aid digestion. Calcium is essential for the formation of bones and teeth and for blood coagulation. Potassium is essential for nerve transmission and muscle contraction. Phosphate is essential for the formation of adenosine triphosphate.

What are the symptoms of hypomagnesemia?

Chvostek sign Trousseau sign

Hyponatremia may be caused by what?

Congestive heart failure (CHF) Rationale: CHF results in excessive water retention without concurrent sodium retention. This results in a hypervolemia combined with hyponatremia. Decreased secretion of aldosterone can result in sodium loss. Stroke does not cause hyponatremia. Dehydration may cause hypernatremia.

A nurse is teaching a group of students about dehydration. Which statement by a student indicates a need for additional teaching?

Dehydration can be assessed in the elderly by pinching the skin." Rationale: Checking for tenting is not an accurate way to assess dehydration in the elderly because their skin loses elasticity with aging and will tent with normal hydration. It is better to check for dry mucous membranes, concentrated urine, and other signs and symptoms in these patients. Elderly patients are more prone to dehydration than younger patients. The mucous membranes become dry due to loss of water. Increased fluid volume causes increased urination, and decreased fluid volume causes decreased urination.

A nurse is caring for a patient with dehydration. After a meal, the nurse makes a note of the food before the food tray is removed. What is the rationale behind this?

For accuracy of recording Rationale: The nurse makes a note of the patient's fluid intake before removing a food tray from the room. A more accurate count is obtained in this way than if the nurse were to rely on memory. Record keeping can be done later by asking what the patient ate, but doing it after a meal ensures accuracy. The patient is given foods to aid recovery and cause minimum discomfort. Allergic reactions are taken into account before any meals are planned.

A nurse is caring for a patient with excess fluid volume. The patient has been put on fluid restriction but reports thirst and demands water. What response should the nurse make?

Give the patient chewing gum Rationale: If not prohibited, hard candies and chewing gum can help relieve thirst. Water, when administered intravenously, can raise the patient's fluid volume and cause complications. Advising the patient to control the thirst will not be effective as thirst cannot be voluntarily controlled. Measurement of the patient's input and output is done during monitoring, and will not quench the patient's thirst.

A nurse assesses a patient who presents with a potassium serum value of 3.25 mEq/L and pain in the abdomen. What is an appropriate nursing action in this context?

Give the patient foods high in potassium Rationale: A potassium serum value of 3.25 mEq/L indicates hypokalemia. This is often accompanied by abdominal pain. The nurse will thus give the patient foods high in potassium. Increased fluid intake is encouraged in hypernatremia. The nurse restricts the fluid intake of the patient during hyponatremia. Pain-relieving medication may treat the pain but will not address the underlying problem.

A patient reports decreased urination, lethargy, and weakness. The physical assessment reveals flushed skin and a loss of skin turgor. Which condition does the nurse suspect?

Hypernatremia Rationale: Hypernatremia occurs when the sodium concentration increases or when there is excessive water loss from the body. A patient with hypernatremia will exhibit oliguria, lethargy, weakness, dry mucous membranes, a loss of skin turgor, and flushed skin. Hyperkalemia is suspected when a patient exhibits muscle weakness, hypotension, paresthesia, and changes on an electrocardiogram. Hypercalcemia is suspected in a patient who exhibits anorexia, polyuria, and cardiac arrest. Hypermagnesemia is suspected in a patient who exhibits hypotension, sweating, flushing, muscle weakness, and respiratory depression.

A patient exhibits paresthesia, hand spasms, difficulty swallowing, and dyspnea, as well as positive Chvostek and Trousseau signs. Which condition does the nurse suspect?

Hypocalcemia Rationale: Hypocalcemia occurs when a patient has a deficiency of calcium or vitamin D. A patient with hypocalcemia will present with paresthesia, hand spasms, difficulty swallowing, dyspnea, and positive Chvostek and Trousseau signs. A patient with hypokalemia presents with muscle weakness, urinary retention, lethargy, and cardiac arrhythmia. Confusion, anorexia, decreased sensation, vomiting, and muscle cramps are clinical manifestations of hyponatremia. Numbness, weakness, confusion, and osteomalacia are clinical manifestations of hypophosphatemia.

A patient who had a bowel resection reports insomnia and often experiences leg cramps. The patient has had one seizure in the past week. What is an appropriate interpretation of the patient's symptoms?

Hypomagnesemia Rationale: Hypomagnesemia can manifest with insomnia, hyperactive reflexes, leg and foot cramps, twitching, tremors, and seizures. Patients with a bowel resection with an ileostomy or colostomy are at high risk. Hypercalcemia manifests with anorexia, abdominal pain, constipation, polyuria, and confusion. Hypermagnesemia is characterized by hypotension, sweating and flushing, nausea and vomiting, and muscle weakness. Hypophosphatemia is often associated with confusion, seizures, numbness, weakness, and possible coma.

A nurse is caring for a 70-year-old patient with diarrhea. The patient was extremely thirsty and had drunk a lot of plain water. What complication does the nurse monitor for in this patient?

Hyponatremia Rationale: Hyponatremia is the most common electrolyte imbalance experienced by patients. Sodium loss may occur from excessive vomiting or diarrhea when the fluid loss is replaced with plain water. Chronic renal failure can often lead to hyponatremia, which does not cause chronic renal failure. Hypernatremia is the excess of sodium in the body and is often caused by water loss that is not compensated by fluid intake. Edema is the accumulation of excess fluid.

A patient has frequent bowel problems and has been taking several antacids to manage the condition. What complication related to electrolyte levels does the nurse monitor for in this patient?

Hypophosphatemia Rationale: Prolonged use of aluminum-containing antacids has been reported to lead to hypophosphatemia. The nurse will assess the patient for any overuse of aluminum-containing antacids and the risk of hypophosphatemia. Renal insufficiency is a risk factor for hyperphosphatemia. An excess fluid volume is characterized by edema and increased urination. Diarrhea is usually marked by dehydration.

A patient is diagnosed as having a serum pH level of 5.8 and a bicarbonate level of 24 mEq/L. Based on this data, what is the appropriate interpretation by the nurse?

Patient is at risk for death Rationale: The normal serum pH is 7.35 to 7.45. Death may occur at a serum pH below 6.8 or above 7.8. A bicarbonate level between 22 to 26 mEq/L is normal. Due to the production of acids by the body's metabolic systems, the body tends to become acidic if homeostasis is upset. In hypomagnesemia, the magnesium serum level falls below 1.3 mEq/L. In hypercalcemia, the serum calcium level goes above 10.6 mg/dL. Alkalosis is characterized by an increase in the pH, not a decrease in the pH.

The nurse works in an acute care facility. Which patients should the nurse monitor for development of hypokalemia

Patients with diarrhea Patients with vomiting Patients using potassium-wasting diuretics Rationale: Hypokalemia is common when potassium output is increased. Diarrhea and vomiting can increase potassium loss through the gastrointestinal tract. Potassium-wasting diuretics may increase potassium loss in urine. Adrenal insufficiency leads to hyperkalemia by decreasing excretion of potassium. Oliguria in end-stage renal disease may cause decreased excretion of potassium in the urine leading to hyperkalemia.

A patient has end-stage chronic obstructive pulmonary disease (COPD). Which acid-base imbalance would be predictable in a patient with COPD?

Respiratory acidosis Rationale: Chronic respiratory acidosis is prevalent among people with COPD. Renal failure may cause metabolic acidosis. Vomiting may cause metabolic alkalosis. Head injuries may lead to respiratory alkalosis.

A patient reports frequent vomiting and diarrhea. The nurse notes that the patient is dehydrated. The primary health care provider has prescribed intravenous therapy for the patient. What intravenous solution does the nurse administer to the patient?

Ringer's solution Rationale: Ringer's solution is usually used for fluid loss that results from vomiting and diarrhea, for those waiting for blood products, and for fluid loss during surgery. This is because it raises intravascular volume without causing cellular fluid shifts or changing the electrolyte concentrations in the plasma. Albumin is used to diminish ascites (intraperitoneal fluid) and maintain blood pressure. Twenty percent or 40% dextrose solution is often used to lower cerebral edema.

A patient has had chronic diarrhea for 3 months. The patient also suffers from repeated bouts of vomiting. The nurse is reviewing the patient's laboratory report. What are the possible findings in the laboratory study report?

Serum K+ levels are less than 3.5 mEq/L Rationale: Chronic diarrhea and vomiting can cause electrolyte imbalances in the body. Diarrhea and vomiting can result in the loss of electrolytes from the body, resulting in decreased potassium levels. Potassium, magnesium, and calcium levels may increase in the case of increased intake and absorption of these electrolytes.

A nurse is caring for a patient with dehydration. The patient is on intravenous fluids with 40 mEq of potassium. The nurse notes that the patient's urine output is less than 30 mL/hr. What is the next step the nurse should take?

Stop potassium administration and notify the physician Rationale: If the urine output of the patient is less than 30 mL/hr, potassium should not be given. Giving potassium when urine flow is inadequate may cause kidney damage. The nurse will thus stop potassium administration and notify the physician of the urinary output. The patient is checked for insomnia if hypomagnesemia is suspected. Hypotension is assessed to check the presence of hypermagnesemia. Hyperphosphatemia manifests with anorexia, nausea, and vomiting.

A nurse is caring for an 80-year-old patient with dehydration. The patient asks the nurse, "I seem to lose water much faster due to old age." What is an appropriate response by the nurse?

The antidiuretic hormone loses effectiveness at this age. Rationale: There is a decrease in the effectiveness of the antidiuretic hormone (ADH) in the elderly, which contributes to faster dehydration as compared to younger patients. Infants and elderly people are more quickly and seriously affected by minor changes in fluid balance. Elderly people experience a decrease in the urine-concentrating ability of the kidney. The infant, not the elderly person, loses more fluid through the skin because of its large body surface area compared with body weight.

A nurse is caring for a patient with obesity. The patient tells the nurse, "I drink so much water. I guess water also adds to my obesity!" What is an appropriate response by the nurse?

The more fat your body has, the less water there will be Rationale:

A nurse is caring for a patient with major depressive disorder. The patient is extremely stressed and seems withdrawn. What changes related to fluid volume does the nurse expect in this patient?

The patient urine output will decrease Rationale: The patient's urine output will decrease. More antidiuretic hormone (ADH) is released when the blood becomes more concentrated or when the circulating blood volume decreases. More ADH is also released when a person experiences pain, nausea, or stress. With increased ADH, the renal tubules reabsorb more water, and urine output decreases. Hence, the patient will urinate less frequently than usual. Circulating blood volume may fall due to decreased urination. Decreased urination is a change related to fluid volume because urine output reflects water intake.

A nurse is caring for a patient with hypovolemia. The patient reports concentrated urine and decreased urination. What does the nurse appropriately interpret about the patient's pathology?

The release of antidiuretic hormone has been stimulated Rationale: In hypovolemia, the release of antidiuretic hormone is stimulated. This causes the patient to urinate less than usual. Aldosterone hormone release is inhibited during hypervolemia because fluid volume changes affect the release of hormones. Similarly, the release of antidiuretic hormone is suppressed when there is excess fluid volume. The fluid volume balance falls during hypovolemia and is not close to normal.

A nurse is caring for a patient with edema. The nurse frequently and gently repositions the patient and restricts the patient's sodium intake. What is the rationale behind this?

To prevent pressure ulcers and excess fluid volume Rationale: A break in edematous skin can quickly form a pressure ulcer; so, the nurse gently repositions and turns the patient to avoid friction on the skin. The patient with excess fluid volume may be placed on sodium restriction because sodium is usually retained along with water. Diarrhea is unlikely to occur in the patient as the patient has overhydration. Such short-term prohibition of sodium intake does not reduce risk of hypertension. Frequent turning may prevent the patient from sleeping if done at night.

A nurse is teaching a group of students about fluid volume and electrolytes. Which statement made by a student indicates effective learning?

Women have a lesser percentage of water in their bodies than men Rationale: The adult male body contains about 60% water; the adult female body, because of more fat tissue, contains about 50% water. Adult males and females differ in their water content owing to fat differences. In general, males have less water in the body than females due to less fat content. Infants and the elderly are very sensitive to minor fluid changes and dehydrate faster than middle adults.

The nurse is assessing the risk factors for fluid and electrolyte imbalance in a patient. Which factors causing extracellular volume deficit should the nurse evaluate?

diarrhea,vomiting and nasogastric suctioning Rationale: Diarrhea and vomiting can cause extracellular volume deficit, clinical dehydration, or metabolic acidosis through loss of fluids. Nasogastric suctioning can cause extracellular volume deficit, hypokalemia, and metabolic acidosis in case of intestinal or pancreatic drainage. Heart failure causes extracellular volume excess and other imbalances depending on the treatment. A sodium rich diet can cause extracellular volume excess and resulting electrolyte imbalance.

The nurse knows that the thirst mechanism is located where?

hypothalamus Rationale: The thirst mechanism located in the hypothalamus helps control fluid balance in the body. The thirst mechanism is not located in the adrenal gland, cerebral cortex, or pituitary gland.