ch 19- fluid electrolyte and acid-base imbalances

Which of the following serum potassium results best supports the rationale for administering a stat dose of potassium chloride 20 mmol in 250 mL of NSS over two hours? a. 3.1 mmol/L b. 3.9 mmol/L c. 4.6 mmol/L d. 5.3 mmol/L

a. 3.1 mmol/L The normal range for serum potassium is 3.5 to 5.0 mmol/L. This IV order provides a substantial amount of potassium. Thus, the patient's potassium level must be low. The lowest value shown is 3.1 mmol/L.

The nurse receives a physician's order to change a patient's IV from D5½NS with 40 mmol KCl/L to D5NS with 20 mmol KCl/L. Which of the following serum laboratory values, documented on this same patient, best supports the rationale for this IV order change? a. Sodium 136 mmol/L, potassium 4.5 mmol/L b. Sodium 145 mmol/L, potassium 4.8 mmol/L c. Sodium 135 mmol/L, potassium 3.6 mmol/L d. Sodium 144 mmol/L, potassium 3.7 mmol/L

a. Sodium 136 mmol/L, potassium 4.5 mmol/L The normal range for serum sodium is 135 to 145 mmol/L, whereas the normal range for potassium is 3.5 to 5.0 mmol/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.

The nurse is 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 of the following factors in this patient? (Select all that apply.) a. The patient may be excreting extra sodium and retaining potassium because of malnutrition. b. The potassium level may be increased as a result of dehydration that accompanies high blood glucose levels.

a. The patient may be excreting extra sodium and retaining potassium because of malnutrition. Hyperkalemia may result from hyperglycemia, renal insufficiency, 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 nurse is caring for a patient with metastatic bone cancer. Which of the following 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.

The nurse is 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 mnol/L, PaO2 92 mm Hg, O2 saturation 99%. The nurse interprets these results as which of the following? a. Within normal limits b. Slight metabolic acidosis c. Slight respiratory acidosis d. Slight respiratory alkalosis

a. Within normal limits Normal pH is 7.35 to 7.45. Normal PaCO2 levels are 38 to 48 mm Hg and HCO3 is 22 to 26 mmol/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.

The nurse is caring for a patient admitted with heart failure. The morning laboratory results reveal a serum potassium level of 2.9 mmol/L. Which of the following classifications of medications should the nurse 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.

The nurse is admitting a patient with complaints of abdominal pain, nausea, and vomiting. A bowel obstruction is suspected. The nurse assesses this patient for which of the following anticipated primary acid-base imbalances 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.

Which of the following nursing interventions is most appropriate when caring for a patient with dehydration? a. Auscultate lung sounds q2h. 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 that 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 patient admitted with a diagnosis of COPD who has the following arterial blood gas results: pH 7.33, PaO2 47 mm Hg, PaCO2 60 mm Hg, HCO3 32 mmol/L, and O2 saturation of 92%. Which of the following 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 38-48 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 of the following 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 on a prn basis.

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

The nurse must prepare the correct IV solution before administration. The order reads for the patient to receive D5½ NS with 40 mmol KCl/L at 125 mL/hr. The nurse must add KCl to the IV because no premixed solutions are available. The unit medication supply has a stock of KCl 3 mmol/mL in multidose vials. Which of the following amounts of KCl should the nurse add to a litre of D5½ NS to obtain the correct solution? a. 10 mL b. 7.5 mL c. 13.3 mL d. 15 mL

c. 13.3 mL 40 mEq/L (dose desired) ÷ 3 mmol/mL (dose available) = 13.3 mL

The nurse is caring for a patient receiving D5W at a rate of 125 mL/hr. During the 1600-hour assessment of the patient, the nurse determines that 500 mL is left in the present IV bag. At which of the following times should the nurse anticipate hanging the next bag of D5W? a. 1800 hours b. 1900 hours c. 2000 hours d. 2200 hours

c. 2000 hours Divide the 500 mL left in the IV bag by the hourly rate of 125 mL to calculate that the present solution will remain infusing for another four hours. If the nurse made this notation at 1600 hours, the bag is due to be changed at 2000 hours.

When planning care for adult patients, the nurse concludes that which of the following oral intakes 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.

When planning the care of a patient with dehydration, the nurse would instruct the nursing assistive personnel (NAP) to report which of the following? 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 two consecutive hours, the nurse should be notified so that additional fluid volume replacement therapy can be instituted.

When planning care for a patient with dehydration related to nausea and vomiting, the nurse would anticipate which of the following fluid shifts 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 spaces into the blood vessels

d. Fluid movement from the interstitial spaces 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 of the following findings 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.

the nurse is caring for an older adult patient who is receiving IV fluids postoperatively. During the 0800 assessment of this patient, the nurse notes that the IV solution, which was ordered to infuse at 125 mL/hr, has infused 950 mL since it was hung at 0400. Which of the following is the priority nursing intervention? a. Notify the physician and complete an incident report. b. Slow the rate to keep the vein open until the 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 four hours of infusion time, 500 mL of IV solution should have infused, not 950 mL. This patient is at risk for fluid volume excess. The nurse should assess the patient's respiratory status and lung sounds as the priority action and then notify the physician for further orders.

The nurse is caring for a patient receiving calcium carbonate for the treatment of osteopenia. Which of the following serum laboratory results would the nurse identify as an adverse effect related to this therapy? a. Sodium falling to 138 mmol/L b. Potassium rising to 4.1 mmol/L c. Magnesium rising to 29 mg/L d. Phosphorus falling to 21 mg/L

d. Phosphorus falling to 21 mg/L 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 21 mg/L (normal 24-44 mg/L), may be a result of the phosphate-binding effect of calcium carbonate.