CHP. 8 Disorders of Fluid, Electrolyte, & Acid-Base Balance

When reviewing blood gas findings, why does the nurse review the serum anion gap?

It helps the nurse determine the cause of metabolic acidosis. The serum anion gap is used to help ensure that the causative factor for acidosis is properly identified and treated appropriately.

Trousseau sign, Chvostek sign, and tetany are clinical manifestations of which calcium balance or imbalance. Choose all that apply. 1. hypocalcemia 2. low serum calcium 3. normal serum calcium 4. hypercalcemia 5. high serum calcium

1 &2

Which of the following statements about sodium imbalance are correct? Choose all that apply. 1. Hypernatremia will cause water to shift out of the cells. 2. Both hyper- and hyponatremia can cause neurological problems. 3. Hyponatremia will cause an increase in vascular fluid volume. 4. Patients with SIADH do not have problems with fluid excess. 5. Hypertonic 3% NaCl is given slowly.

1, 2, & 5

Which of the following are clinical signs of hypervolemia? Choose all that apply. 1. Poor skin turgor 2. Dry mucous membrane 3. Difficulty breathing 4. Edema 5. Third spacing

3, 4, 5

Which of the following statements about phosphorus are accurate? 1. Renal failure is a common cause for hyperphosphatemia. 2. The normal serum phosphorus level is 2.5 to 4.5 mg/dL. 3. Phosphorus is regulated by the thyroid gland. 4. Phosphorus is an essential component of bone. 5. Renal failure and excessive vitamin D intake may cause hypophosphatemia. 6. Tetany can occur with severe hyperphosphatemia.

4

Which intravenous (IV) solution is expected for a patient with cerebral edema? Normal saline 1/2 normal saline D5 normal saline 3% saline

3% saline Hypertonic solutions such as 3% saline pull water from in the cell into the extracellular fluid. These are useful in cases of severe hyponatremia and severe edema, specifically cerebral edema.

A patient is ordered potassium replacement for a potassium level of 3.2 mEq/dL. What is the best way to administer this medication? Crushed and added to applesauce Whole pill by mouth Intravenous push Subcutaneous

Whole pill by mouth Potassium can be given whole by mouth or via intravenous infusion. It should never be pushed or crushed, and it is not available subcutaneously.

Which is a healthy pH range? 7.55-9.00 7.00-7.25 6.55-8.00 7.35-7.45

7.35-7.45

What is the normal range of normal serum chloride? 1. <75 mEq/L 2. 75-94 mEq/L 3. 96-105 mEq/L 4. 106-115 mEq/L 5. >115 mEq/L

96-105 mEq/L

A 50-year-old woman presents with symptomatic hypercalcemia. She has a recent history of breast cancer treatment. A. How do you evaluate this person with increased plasma calcium levels? B. What is the significance of the recent history of malignancy? C. What further tests may be indicated?

A. Evaluation of increased plasma calcium levels involves confirming hypercalcemia with repeated measurements, assessing serum albumin, PTH levels, serum phosphate, renal function, and possibly imaging studies. B. The recent history of malignancy, such as breast cancer treatment, is significant because certain cancers, particularly those with bone involvement like breast cancer, can lead to hypercalcemia due to bone metastases or production of substances that stimulate bone resorption. C. Further tests that may be indicated include measurement of serum PTHrP levels, imaging studies to assess for bone involvement, urine studies for calcium and creatinine levels, and assessment of other metabolic parameters to differentiate between various causes of hypercalcemia.

A 40-year-old man with advanced acquired immunodeficiency syndrome presents with an acute chest infection. Investigations confirm a diagnosis of Pneumocystis jiroveci (formerly P. carinii) pneumonia. Although he is being treated appropriately, his plasma sodium level is 118 mEq/L (118 mmol/L). Results of adrenal function tests are normal. A. What is the likely cause of his electrolyte disturbance? B. What are the five cardinal features of this condition?

A. The likely cause of the electrolyte disturbance (hyponatremia) in this patient is Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH), which results from excessive release of antidiuretic hormone (ADH) from the posterior pituitary gland. B. The five cardinal features of SIADH are hyponatremia, hypotonicity, inappropriately concentrated urine, euvolemia or hypervolemia, and normal renal and adrenal function.

A 16-year-old girl is seen by her primary care provider because of her parents' concern over her binge eating and their recent discovery that she engages in self-induced vomiting. A tentative diagnosis of bulimia nervosa is made. Initial laboratory tests reveal a plasma K+ of 3 mEq/L (normal, 3.5 to 5.0 mEq/L) and a Cl− of 93 mEq/L (normal, 98 to 106 mEq/L). A. Explain her low K+ and Cl−. B. What type of acid-base abnormality would you expect her to have?

A. The low potassium (K+) and chloride (Cl-) levels in this patient are likely due to repeated episodes of self-induced vomiting associated with bulimia nervosa, which result in the loss of gastric contents rich in these electrolytes. B. The expected acid-base abnormality in this patient is metabolic alkalosis, caused by the loss of hydrochloric acid (HCl) from the stomach through self-induced vomiting, leading to decreased acidity in the blood. As a compensatory response, there is renal retention of bicarbonate (HCO3-), further contributing to the alkalosis.

A 34-year-old woman with diabetes is admitted to the emergency department in a stuporous state. Her skin is flushed and warm, her breath has a sweet odor, her pulse is rapid and weak, and her respirations are rapid and deep. Her initial laboratory tests indicate a blood sugar of 320 mg/dL, serum HCO3− of 12 mEq/L (normal, 22 to 26 mEq/L), and a pH of 7.1 (normal, 7.35 to 7.45). A. What is the most likely cause of her lowered pH and bicarbonate levels? B. How would you account for her rapid and deep respirations? C. Using the Henderson-Hasselbalch equation and the solubility coefficient for CO2 given in this chapter, what would you expect her PCO2 to be? D. How would you explain her warm, flushed skin and stuporous mental state?

A. The most likely cause of her lowered pH and bicarbonate levels is diabetic ketoacidosis (DKA), characterized by hyperglycemia, ketosis, metabolic acidosis, and dehydration due to insulin deficiency. B. Her rapid and deep respirations, known as Kussmaul respirations, are a compensatory mechanism for metabolic acidosis, helping to eliminate carbon dioxide and buffer the excess acidosis. C. Using the Henderson-Hasselbalch equation, the expected PCO2 based on her pH and bicarbonate levels is estimated to be approximately 36 mmHg, reflecting the compensatory respiratory response to metabolic acidosis. D. Her warm, flushed skin and stuporous mental state can be explained by hyperglycemia-induced dehydration, electrolyte imbalances, and ketone-related CNS depression associated with DKA.

A 65-year-old man with chronic obstructive lung disease has been using low-flow oxygen therapy because of difficulty in maintaining adequate oxygenation of his blood. He has recently had a severe respiratory tract infection and has had difficulty breathing. He is admitted to the emergency department because he became increasingly lethargic and his wife has had trouble arousing him. His respirations are 12 breaths/minute. She relates that he had "turned his oxygen way up" because of difficulty breathing. A. What is the most likely cause of this man's problem? B. How would you explain the lethargy and difficulty in arousal? C. Arterial blood gases, drawn on admission to the emergency department, indicated a PO2 of 85 mm Hg (normal, 90 to 95 mm Hg) and a PCO2 of 90 mm Hg (normal, 40 mm Hg). His serum HCO3− was 34 mEq/L (normal, 22 to 26 mEq/L). What is his pH?

A. The most likely cause of this man's problem is hypercapnic respiratory failure, exacerbated by his recent severe respiratory tract infection and inappropriate adjustment of his oxygen therapy due to difficulty breathing. B. The lethargy and difficulty in arousal can be explained by the effects of hypercapnia on the central nervous system, leading to respiratory acidosis and cerebral vasodilation, impairing cerebral perfusion and neuronal function. C. Arterial blood gases indicate severe respiratory acidosis with a pH of approximately 7.06, resulting from elevated partial pressure of carbon dioxide (PCO2) and compensatory metabolic alkalosis indicated by increased serum bicarbonate (HCO3-). These values suggest impaired gas exchange and ventilation-perfusion mismatch, typical of hypercapnic respiratory failure in COPD exacerbation.

A 70-year-old woman who is taking furosemide (a loop diuretic) for congestive heart failure complains of weakness, fatigue, and cramping of the muscles in her legs. Her plasma potassium is 2 mEq (2 mmol/L), and her plasma sodium is 140 mEq/L (140 mmol/L). She also complains that she notices a "strange heartbeat" at times. A. What is the likely cause of this woman's symptoms? B. An ECG shows depressed ST segment and low T-wave changes. Explain the physiologic mechanism underlying these changes.

A. The woman's symptoms, including weakness, fatigue, muscle cramping, and palpitations, along with low plasma potassium levels, are likely caused by loop diuretic-induced hypokalemia. Loop diuretics like furosemide can lead to excessive urinary loss of potassium, resulting in potassium depletion and its associated symptoms. B. The ECG findings of depressed ST segments and low T-wave changes are characteristic manifestations of hypokalemia. Hypokalemia alters cardiac repolarization, leading to delayed ventricular repolarization and increased susceptibility to arrhythmias, which are reflected in the ECG as changes in ST segments and T-waves. Severe hypokalemia can predispose to life-threatening arrhythmias, contributing to the patient's symptoms of palpitations and "strange heartbeat."

__________ hormone, or vasopressin, plays a central role in the maintenance of water balance.

Antidiuretic

Metabolic alkalosis would be represented by which laboratory results? pH of 7.45 and HCO3- of 24 mEq/L pH of 7.50 and HCO3- of 45 mEq/L pH of 7.35 and HCO3- of 22 mEq/L pH of 7.25 and HCOs- of 18 mEq/L

pH of 7.50 and HCO3- of 45 mEq/L Metabolic alkalosis would be diagnosed based on increased pH (7.50) and HCO3- (45 mEq/L) levels. The pH of 7.25 and HCO3- of 18 mEq/L represents metabolic acidosis, while the remaining options represent normal levels.

The newly admitted client has a diagnosis of emphysema and the following blood gas levels: pH 7.32, PaCO2 55, HCO3 22. The nurse understands that these blood gases demonstrate respiratory acidosis because the client is retaining which substance?

Carbon dioxide Airway collapse with emphysema results in the client retaining carbon dioxide.

Which are signs of metabolic alkalosis? Chvostek sign Hyperkalemia Cullen sign Hypernatremia

Chvostek sign Signs of hypocalcemia, including Chvostek and Trousseau signs, may appear with metabolic alkalosis. Hypokalemia is expected. Cullen sign and hypernatremia are not expected.

A patient has a sodium level of 124 mEq/dL. Which assessment finding is expected? Cardiac arrythmias Pressured speech Confusion Petechiae

Confusion When the sodium level is outside of normal limits, look for neurologic side effects, such as lethargy, confusion, dizziness, or seizures. Cardiac arrhythmias, pressured speech, and petechiae would not be expected.

Which are treatments for respiratory acidosis? Select all that apply. Reversing sedative medication Intubation or BiPAP Diuresis Sodium bicarbonate tablets Hydration

Reversing sedative medication, Intubation or BiPAP, Hydration Respiratory acidosis can be caused by sedatives or anything causing hypoventilation. Therefore, reversing sedatives, providing respiratory support via intubation or BiPAP, and hydration are indicated. Diuresis and sodium bicarbonate tablets are not typically treatments for respiratory acidosis.

What is the difference between crystalloids and colloids? Crystalloids are thicker and more viscous, and colloids are clear fluids. Crystalloids are used to correct sodium levels, and colloids are used to correct potassium levels. Crystalloids are clear fluids, and colloids are thicker and more viscous. Crystalloids are used correct potassium levels, and colloids are used to correct sodium levels.

Crystalloids are clear fluids, and colloids are thicker and more viscous. Crystalloids are crystal clear intravenous fluids while colloids are more viscous, such as albumin and blood products. Neither product completely addresses electrolyte abnormalities or adds electrolytes to the blood.

Which is not a cause of metabolic acidosis? Diarrhea Diuretics Kidney failure Vomiting

Vomiting Metabolic acidosis occurs from either too much acid being produced or a loss of base. Diarrhea, use of diuretics, and kidney failure can all cause a metabolic acidosis. Vomiting can cause metabolic alkalosis.

The most serious manifestations of potassium imbalances are neurological and musculoskeletal. T/F

False

Vitamin C is essential to the maintenance of calcium levels. T/F

False

Potassium is the major anion within the cell. T/F

False It's a cation.

When serum magnesium levels increase, so do serum calcium levels. T/F

False They have an inverse relationship.

The ED nurse is reviewing arterial blood gas results for a client who has been vomiting for the last 2 days. Findings include pH 7.50, PaCO2 37, HCO3 47. The nurse suspects a metabolic alkalosis due to the loss of which substance?

Gastric acid One cause of alkalosis is a loss of stomach acid. Vomiting would cause excessive loss of gastric acid that would lead to metabolic alkalosis.

Upon assessment, a patient has Trousseau and Chvostek signs. Which electrolyte abnormality does this indicate? Hypocalcemia Hypercalcemia Hyperkalemia Hypokalemia

Hypocalcemia Trousseau and Chvostek signs indicate low calcium, or hypocalcemia. They are not associated with hypercalcemia or with an imbalance of potassium.

You are treating an 11-year-old patient in the emergency department whose parents report the child has been vomiting for 5 days. An arterial blood gas analysis obtained on admission reveals: pH 7.5; PaCO2 48mmHg; HCO3- 39mEq/L; and PaO2 110 mmHg. Which mechanism of compensation has occurred in this patient? Decreased HCO3- Decreased PaO2 Increased PaCO2 Increased HCO3-

Increased HCO3-

Your 65-year-old patient is experiencing shortness of breath and an increased respiratory rate with a pH level of 7.10 and an HCO3 - level of 18 mEq/L. Based on these findings, which condition does this patient likely have?

Metabolic acidosis

Your 82-year-ld patient has been diagnosed with renal failure and you've noticed a lack of appetite and diarrhea. The patient also complains of headache, lethargy, and weakness. His arterial blood gas results are PaO2 88%; SaO2 94%; pH 7.31; PaCO2 30mmHg; and HCO3 18 mEq/L. Based on these findings, which condition does this patient likely have?

Metabolic acidosis

What does a pH of 7.14, a CO2 of 36 mEq/L, and an HCO3 of 9 mEq/L indicate? Respiratory acidosis Respiratory alkalosis Metabolic acidosis Metabolic alkalosis

Metabolic acidosis The pH is low, indicating acidosis, the CO2 is normal, and the HCO3 is low, indicating a metabolic problem. The pH and HCO3 are going in the same direction.

Your 56-year-old patient has normal oxygen levels but increased carbon dioxide with a lower-than-normal respiratory rate of 12 breaths per minute. All other vital signs are within normal ranges. While it is not evident from assessment and diagnostics, the patient's kidneys are maximizing both H+ excretion and HCO3- reabsorption. Based on these findings, which condition does this patient likely have?

Metabolic alkalosis

What does a pH of 7.50, a CO2 of 41 mEq/L, and an HCO3 of 42 mEq/L indicate? Respiratory acidosis Respiratory alkalosis Metabolic acidosis Metabolic alkalosis

Metabolic alkalosis The pH is high, indicating alkalosis, the CO2 is normal, and the HCO3 is high, indicating a metabolic problem. The HCO3 is going in the same direction as pH.

Which type of oxygen mask may be indicated for the patient in respiratory alkalosis? Venturi mask Nasal cannula Non-rebreather mask Simple face mask

Non-rebreather mask A non-rebreather mask is indicated so the patient can rebreathe in their carbon dioxide. This is not the purpose of a Venturi mask, nasal cannula, or simple face mask.

A nurse is evaluating the following arterial blood gas values: pH 7.35, PaO2 95 mm Hg, SaO2 95%, PaCO2 40 mm Hg, and HCO3 24 mEq/L. How does the nurse interpret these results? Normal Respiratory acidosis Metabolic acidosis Technical error

Normal Each blood gas indicator is within its normal range: pH ranges 7.35 to 7.45, PaO2 ranges 80 to 100 mm Hg., SaO2 > 95%, PaCO2 ranges 35 to 45 mm Hg, and HCO3 ranges 22 to 26 mEq/L.

The nurse is concerned about a patient's pH of 7.30 and PCO2 of 49 mm Hg. What should the nurse interpret these results to mean? Respiratory alkalosis Respiratory acidosis Metabolic alkalosis Metabolic acidosis

Respiratory acidosis The low pH and high PCO2 indicate respiratory acidosis with hypoventilation.

What does a pH of 7.25, a CO2 of 56 mEq/L, and an HCO3 of 24 mEq/L indicate? Respiratory acidosis Respiratory alkalosis Metabolic acidosis Metabolic alkalosis

Respiratory acidosis The pH is low, indicating acidosis, and the CO2 is high, indicating a respiratory problem. The HCO3 is normal. CO2 is going in the opposite direction of pH.

What does a pH of 7.17, a CO2 of 75 mEq/L, and an HCO3 of 26 mEq/L indicate? Respiratory Acidosis Respiratory Alkalosis Metabolic Acidosis Metabolic Alkalosis

Respiratory acidosis The pH is low, indicating acidosis, the CO2 is high, indicating a respiratory problem, and the HCO3 is normal. The pH and CO2 are going in opposite directions.

What does a pH of 7.48, a CO2 of 32 mEq/L, and an HCO3 of 22 mEq/L indicate? Respiratory acidosis Respiratory alkalosis Metabolic acidosis Metabolic alkalosis

Respiratory alkalosis The pH is high, indicating alkalosis, the CO2 is low, indicating a respiratory problem, and the HCO3 is normal. The pH and CO2 are going in opposite directions.

You are caring for a 34-year-old patient diagnosed with pneumonia. The patient's respiratory status has progressively worsened. On physical examination, you hear crackles in the lungs. You check the arterial blood gas value that was drawn 30 minutes ago, and the values are PaO2 84%; SaO2 93%; pH 7.40; PaCO2 39mmHg; and HCO3 23 mEq/L. Based on these findings, which condition does this patient likely have?

Respiratory alkalosis The pH of 7.40 is high, indicating alkalosis. The PaCO2 is 39, which is low, indicating the alkalosis in respiratory.

__________ is the most abundant cation in the body.

Sodium

Why does knowing what causes acid-base imbalances and what is happening in the body important? To encourage similar behavior To train the body to live in a different state To guide treatment and prevention efforts To educate families on their risk of inheriting these disorders

To guide treatment and prevention efforts Understanding what is happening on a cellular level can help guide treatment and prevention efforts. The body strives toward homeostasis and does not need to be trained to live in an unbalanced state. Acid-base imbalances are not inherited conditions.

Excessive vomiting or gastric suctioning can cause hypochloremia. T/F

True

Hypermagnesemia can cause cardiac arrhythmias and arrest. T/F

True

Hypoparathyroidism can cause hypocalcemia. T/F

True

Isotonic fluid volume deficit is nearly always a result of loss of body fluids. T/F

True

Prolonged gastric suctioning may cause hypokalemia. T/F

True

The extracellular fluid compartment includes the vascular, interstitial, and transcellular fluid compartments. T/F

True

The kidneys are the organs primarily responsible for maintaining appropriate sodium levels. T/F

True

The two most important assessments to make for evaluating fluid balance are an accurate I & O and daily weight. T/F

True

Chloride deficit may result in metabolic _____________.

alkalosis

Chvostek and Trousseau tests are commonly used to assess for imbalances in the level of __________.

calcium

Swelling caused by excess interstitial fluid volume is known as __________.

edema

Tetany, low BP, and shortening of the QT interval may occur with _________________. hypophosphatemia hyperphosphatemia

hyperphosphatemia

Clinical manifestations of _______________ include anorexia, lethargy, and disorientation. Hyponatremia Hypernatremia Hypokalemia Hyperkalemia

hyponatremia

The blood pressure in a patient who is hypovolemic is usually _______.

low

A serum calcium level of 8.9 mg/dL is ____________.

normal

The movement of water across a semipermeable membrane creates __________ pressure.

osmotic