Chapter 17 - Fluid & Electrolytes
You are caring for a patient admitted with an exacerbation of asthma. After several treatments, the ABG results are pH 7.40, PaCO2 40 mm Hg, HCO3 24 mEq/L, PaO2 92 mm Hg, and O2 saturation of 99%. You interpret these results as A. slight metabolic acidosis. B. slight respiratory acidosis. C. slight respiratory alkalosis.
? The normal pH is 7.35 to 7.45. Normal PaCO2 levels are 35 to 45 mm Hg, and HCO3 is 22 to 26 mEq/L. Normal PaO2 is >80 mm Hg. Normal oxygen saturation is >95%. Since the patient's results all fall within these normal ranges, the nurse can conclude that the patient's blood gas results are within normal limits.
Which serum potassium result best supports the rationale for administering a stat dose of potassium chloride 20 mEq in 250 mL of normal saline over 2 hours? A. 3.1 mEq/L B. 3.9 mEq/L C. 4.6 mEq/L D. 5.3 mEq/L
A. 3.1 mEq/L The normal range for serum potassium is 3.5 to 5.0 mEq/L. This IV order provides a substantial amount of potassium. Thus the patient's potassium level must be low. The only low value shown is 3.1 mEq/L.
When assessing the patient with a multi-lumen central line, the nurse notices that the cap is off one of the lines. On assessment, the patient is in respiratory distress, and the vital signs show hypotension and tachycardia. What is the nurse's priority action? A. Administer oxygen. B. Notify the physician. C. Rapidly administer more IV fluid. D. Reposition the patient to the right side.
A. Administer oxygen. The cap off the central line could allow entry of air into the circulation. For an air emboli, oxygen is administered; the catheter is clamped; the patient is positioned on the left side with the head down. Then the physician is notified.
The dehydrated patient is receiving a hypertonic solution. What assessments must be done to avoid risk factors of these solutions (select all that apply)? A. Lung sounds B. Bowel sounds C. Blood pressure D. Serum sodium level E. Serum potassium level
A. Lung sounds C. Blood pressure D. Serum sodium level BP, lung sounds, and serum sodium levels must be monitored frequently because of the risk for excess intravascular volume with hypertonic solutions.
The patient has chronic kidney disease and ate a lot of nuts, bananas, peanut butter, and chocolate. The patient is admitted with loss of deep tendon reflexes, somnolence, and altered respiratory status. What treatment should the nurse expect for this patient? A. Renal dialysis B. IV potassium chloride C. IV furosemide (Lasix) D. IV normal saline at 250 mL per hour
A. Renal dialysis Renal dialysis will need to be administered to remove the excess magnesium that is in the blood from the increased intake of foods high in magnesium. If renal function was adequate, IV potassium chloride would oppose the effects of magnesium on the cardiac muscle. IV furosemide and increased fluid would increase urinary output which is the major route of excretion for magnesium.
You receive a physician's order to change a patient's IV from D5½ NS with 40 mEq KCl/L to D5NS with 20 mEq KCl/L. Which serum laboratory values on this same patient best support the rationale for this IV order change? A. Sodium 136 mEq/L, potassium 4.5 mEq/L B. Sodium 145 mEq/L, potassium 4.8 mEq/L C. Sodium 135 mEq/L, potassium 3.6 mEq/L D. Sodium 144 mEq/L, potassium 3.7 mEq/L
A. Sodium 136 mEq/L, potassium 4.5 mEq/L The normal range for serum sodium is 135 to 145 mEq/L, and the normal range for potassium is 3.5 to 5.0 mEq/L. The change in the IV order decreases the amount of potassium and increases the amount of sodium. Therefore for this order to be appropriate, the potassium level must be near the high end and the sodium level near the low end of their respective ranges.
You are caring for a patient admitted with diabetes mellitus, malnutrition, and massive GI bleed. In analyzing the morning lab results, the nurse understands that a potassium level of 5.5 mEq/L could be caused by which factors in this patient (select all that apply)? A. The potassium level may be increased if the patient has renal nephropathy. B. The patient may be excreting extra sodium and retaining potassium because of malnutrition. C. The potassium level may be increased as a result of dehydration that accompanies high blood glucose levels. D. There may be excess potassium being released into the blood as a result of massive transfusion of stored hemolyzed blood. E. The patient has been overeating raisins, baked beans, and salt substitute that increase the potassium level.
A. The potassium level may be increased if the patient has renal nephropathy. C. The potassium level may be increased as a result of dehydration that accompanies high blood glucose levels. D. There may be excess potassium being released into the blood as a result of massive transfusion of stored hemolyzed blood. Hyperkalemia may result from hyperglycemia, renal insufficiency, and/or cell death. Diabetes mellitus, along with the stress of hospitalization and illness, can lead to hyperglycemia. Renal insufficiency is a complication of diabetes. Malnutrition does not cause sodium excretion accompanied by potassium retention. Thus it is not a contributing factor to this patient's potassium level. Stored hemolyzed blood can cause hyperkalemia when large amounts are transfused rapidly. The patient with a massive GI bleed would have an NG tube and not be eating.
While caring for a patient with metastatic bone cancer, which clinical manifestations would alert the nurse to the possibility of hypercalcemia in this patient? A. Weakness B. Paresthesia C. Facial spasms D. Muscle tremors
A. Weakness Signs of hypercalcemia are lethargy, headache, weakness, muscle flaccidity, heart block, anorexia, nausea, and vomiting. Paresthesia, facial spasms, and muscle tremors are symptoms of hypocalcemia.
You are admitting a patient with complaints of abdominal pain, nausea, and vomiting. A bowel obstruction is suspected. You assess this patient for which anticipated primary acid-base imbalance if the obstruction is high in the intestine? A. Metabolic acidosis B. Metabolic alkalosis C. Respiratory acidosis D. Respiratory alkalosis
B. Metabolic alkalosis Because gastric secretions are rich in hydrochloric acid, the patient who is vomiting will lose a significant amount of gastric acid and be at an increased risk for metabolic alkalosis.
A 22-year-old male is admitted to the emergency department with a stab wound to the abdomen. The patient's vital signs are blood pressure 82/56 mm Hg, pulse 132 beats/minute, respirations 28 breaths/minute, and temperature 97.9° F (36.6° C). Which fluid, if ordered by the health care provider, should the nurse question? A. 0.9% saline B. 0.45% saline C. Packed red blood cells D. Lactated Ringer's solution
B. 0.45% saline IV administration of 0.45% saline is hypotonic and is used for maintenance fluid replacement and dilutes the extracellular fluid. Intravenous solutions used for volume expansion for hypovolemic shock include lactated Ringer's solution and 0.9% saline. If hypovolemia is due to blood loss, blood may be administered.
The patient was admitted for a paracentesis to remove ascites fluid. Five liters of fluid was removed. What IV solution may be used to pull fluid into the intravascular space after the paracentesis? A. 0.9% sodium chloride B. 25% albumin solution C. Lactated Ringer's solution D. 5% dextrose in 0.45% saline
B. 25% albumin solution After a paracentesis of 5 L or greater of ascites fluid, 25% albumin solution may be used as a volume expander. Normal saline, lactated Ringer's, and 5% dextrose in 0.45% saline will not be effective for this action.
The patient is admitted with metabolic acidosis. Which system is not functioning normally? A. Buffer system B. Kidney system C. Hormone system D. Respiratory system
B. Kidney system When the patient has metabolic acidosis, the kidneys are not combining H+ with ammonia to form ammonium or eliminating acid with secretion of free hydrogen into the renal tubule. The buffer system neutralizes hydrochloric acid by forming a weak acid. The hormone system is not directly related to acid-base balance. The respiratory system releases CO2 that combines with water to form hydrogen ions and bicarbonate. The hydrogen is then buffered by the hemoglobin.
You are caring for a patient admitted with heart failure. The morning laboratory results reveal a serum potassium level of 2.9 mEq/L. Which classification of medications should you withhold until consulting with the physician? A. Antibiotics B. Loop diuretics C. Bronchodilators D. Antihypertensives
B. Loop diuretics Loop diuretics are contraindicated during episodes of hypokalemia because these medications cause the kidneys to excrete sodium and potassium. Thus administration of this type of medication at this time would worsen the hypokalemia, putting the patient at risk for dysrhythmias. The prescribing physician should be consulted for potassium replacement therapy, and the drug should be withheld until the potassium has returned to normal range.
Which nursing intervention is most appropriate when caring for a patient with dehydration? A. Auscultate lung sounds every 2 hours. B. Monitor daily weight and intake and output. C. Monitor diastolic blood pressure for increases. D. Encourage the patient to reduce sodium intake.
B. Monitor daily weight and intake and output. Measuring weight is the most reliable means of detecting changes in fluid balance. Weight loss would indicate the dehydration is worsening, whereas weight gain would indicate restoration of fluid volume. Recall that a 1-kg weight gain indicates a gain of approximately 1000 mL of body water.
The nurse is caring for a 76-year-old woman admitted to the clinical unit with hypernatremia and dehydration after prolonged fever. Which beverage would be safest for the nurse to offer the patient? A. Malted milk B. Orange juice C. Tomato juice D. Hot chocolate
B. Orange juice Orange juice has the least amount of sodium (approximately 2 mg in 8 ounces). Hot chocolate has approximately 75 mg sodium in 8 ounces. Tomato juice has approximately 650 mg sodium in 8 ounces. Malted milk has approximately 625 mg sodium in 8 ounces.
You are caring for a patient admitted with a diagnosis of chronic obstructive pulmonary disease (COPD) who has the following arterial blood gas results: pH 7.33, PaO2 47 mm Hg, PaCO2 60 mm Hg, HCO3 32 mEq/L, and O2 saturation of 92%. What is the correct interpretation of these results? A. Fully compensated respiratory alkalosis B. Partially compensated respiratory acidosis C. Normal acid-base balance with hypoxemia D. Normal acid-base balance with hypercapnia
B. Partially compensated respiratory acidosis A low pH (normal 7.35-7.45) indicates acidosis. In the patient with respiratory disease such as COPD, the patient retains carbon dioxide (normal 35-45 mm Hg), which acts as an acid in the body. For this reason, the patient has respiratory acidosis. The elevated HCO3 indicates a partial compensation for the elevated CO2.
While performing patient teaching regarding hypercalcemia, which statements are appropriate (select all that apply)? A. Have patient restrict fluid intake to less than 2000 mL/day. B. Renal calculi may occur as a complication of hypercalcemia. C. Weight-bearing exercises can help keep calcium in the bones. D. The patient should increase daily fluid intake to 3000 to 4000 mL. E. Treatment of heartburn can best be managed with Tums as needed.
B. Renal calculi may occur as a complication of hypercalcemia. C. Weight-bearing exercises can help keep calcium in the bones. D. The patient should increase daily fluid intake to 3000 to 4000 mL. A daily fluid intake of 3000 to 4000 mL is necessary to enhance calcium excretion and prevent the formation of renal calculi, a potential complication of hypercalcemia. Tums are a calcium-based antacid that should not be used in patients with hypercalcemia. Weight-bearing exercise does enhance bone mineralization.
A 50-year-old woman with hypertension has a serum potassium level that has acutely risen to 6.2 mEq/L. Which type of order, if written by the health care provider, should be questioned by the nurse? A. Limit foods high in potassium B. Spironolactone (Aldactone) daily C. Calcium gluconate IV piggyback D. Administer intravenous insulin and glucose
B. Spironolactone (Aldactone) daily Spironolactone (Aldactone) is a potassium-sparing diuretic that inhibits the exchange of sodium for potassium in the distal renal tubule and helps to prevent potassium loss. Spironolactone is contraindicated in a patient with hyperkalemia (serum potassium >5.0 mEq/L). Collaborative management for patients with hyperkalemia may include limiting foods high in potassium, IV insulin and glucose, administration of calcium gluconate, potassium-wasting diuretics (e.g., furosemide [Lasix]), hemodialysis, sodium polystyrene sulfonate (Kayexalate), and IV fluid administration.
When planning care for adult patients, which oral intake is adequate to meet daily fluid needs of a stable patient? A. 500 to 1500 mL B. 1200 to 2200 mL C. 2000 to 3000 mL D. 3000 to 4000 mL
C. 2000 to 3000 mL Daily fluid intake and output is usually 2000 to 3000 mL. This is sufficient to meet the needs of the body and replace both sensible and insensible fluid losses. These would include urine output and fluids lost through the respiratory system, skin, and GI tract.
A 46-year-old woman with a subclavian triple-lumen catheter is transferred from a critical care unit after an extended stay for respiratory failure. Which action is important for the nurse to take? A. Change the injection cap after the administration of IV medications. B. Use a 5-mL syringe to flush the catheter between medications and after use. C. During removal of the catheter, have the patient perform the Valsalva maneuver. D. If resistance is met when flushing, use the push-pause technique to dislodge the clot.
C. During removal of the catheter, have the patient perform the Valsalva maneuver. The nurse should withdraw the catheter while the patient performs the Valsalva maneuver to prevent an air embolism. Injection caps should be changed at regular intervals but not routinely after medications. Flushing should be performed with at least a 10-mL syringe to avoid excess pressure on the catheter. If resistance is encountered during flushing, force should not be applied. The push-pause method is preferred for flushing catheters but not used if resistance is encountered during flushing.
When planning the care of a patient with dehydration, what would the nurse instruct the unlicensed assistive personnel (UAP) to report? A. 60 mL urine output in 90 minutes B. 1200 mL urine output in 24 hours C. 300 mL urine output per 8-hour shift D. 20 mL urine output for 2 consecutive hours
D. 20 mL urine output for 2 consecutive hours The minimal urine output necessary to maintain kidney function is 30 mL/hr. If the output is less than this for 2 consecutive hours, the nurse should be notified so that additional fluid volume replacement therapy can be instituted
The nurse on a medical-surgical unit identifies that which patient has the highest risk for metabolic alkalosis? A. A patient with a traumatic brain injury B. A patient with type 1 diabetes mellitus C. A patient with acute respiratory failure D. A patient with nasogastric tube suction
D. A patient with nasogastric tube suction Excessive nasogastric suctioning may cause metabolic alkalosis. Brain injury may cause hyperventilation and respiratory alkalosis. Type 1 diabetes mellitus (diabetic ketoacidosis) is associated with metabolic acidosis. Acute respiratory failure may lead to respiratory acidosis.
When planning care for a patient with dehydration related to nausea and vomiting, the nurse would anticipate which fluid shift to occur because of the fluid volume deficit? A. Fluid movement from the blood vessels into the cells B. Fluid movement from the interstitial spaces into the cells C. Fluid movement from the blood vessels into interstitial spaces D. Fluid movement from the interstitial space into the blood vessels
D. Fluid movement from the interstitial space into the blood vessels In dehydration, fluid is lost first from the blood vessels. To compensate, fluid moves out of the interstitial spaces into the blood vessels to restore circulating volume in that compartment. As the interstitial spaces then become volume depleted, fluid moves out of the cells into the interstitial spaces.
When assessing a patient admitted with nausea and vomiting, which finding supports the nursing diagnosis of deficient fluid volume? A. Polyuria B. Decreased pulse C. Difficulty breathing D. General restlessness
D. General restlessness Restlessness is an early cerebral sign that dehydration has progressed to the point where an intracellular fluid shift is occurring. If the dehydration is left untreated, cerebral signs could progress to confusion and later coma.
You are caring for an older patient who is receiving IV fluids postoperatively. During the 8:00 AM assessment of this patient, you note that the IV solution, which was ordered to infuse at 125 mL/hr, has infused 950 mL since it was hung at 4:00 AM. What is the priority nursing intervention? A. Notify the physician and complete an incident report. B. Slow the rate to keep vein open until next bag is due at noon. C. Obtain a new bag of IV solution to maintain patency of the site. D. Listen to the patient's lung sounds and assess respiratory status.
D. Listen to the patient's lung sounds and assess respiratory status. After 4 hours of infusion time, 500 mL of IV solution should have infused, not 950 mL. This patient is at risk for fluid volume excess, and you should assess the patient's respiratory status and lung sounds as the priority action and then notify the physician for further orders
You are caring for a patient receiving calcium carbonate for the treatment of osteopenia. Which serum laboratory result would you identify as an adverse effect related to this therapy? A. Sodium falling to 138 mEq/L B. Potassium rising to 4.1 mEq/L C. Magnesium rising to 2.9 mg/dL D. Phosphorus falling to 2.1 mg/dL
D. Phosphorus falling to 2.1 mg/dL Calcium has an inverse relationship with phosphorus in the body. When phosphorus levels fall, calcium rises, and vice versa. Since hypercalcemia rarely occurs as a result of calcium intake, the patient's phosphorus falling to 2.1 mg/dL (normal 2.4-4.4 mg/dL) may be a result of the phosphate-binding effect of calcium carbonate.
