Chapter 16: Caring For Clients With Fluid, Electrolyte, And Acid-Base Imbalances

a Normal serum concentration level ranges from 135 to 145 mEq/L (135-145 mmol/L). When the level dips below 135 mEq/L (135 mmol/L), hyponatremia occurs. Manifestations of hyponatremia include mental confusion, muscular weakness, anorexia, restlessness, elevated body temperature, tachycardia, nausea, vomiting, and personality changes. Convulsions or coma can occur if the deficit is severe. Values of 140, 142, and 145 mEq/L (mmol/L) are within the normal range.

b Metabolic alkalosis is a clinical disturbance characterized by a high pH and high plasma bicarbonate concentration. The HCO value is below normal. The PaCO value and the oxygen saturation level are within a normal range.

a Osmosis is the movement of water through a semipermeable membrane; one that allows some but not all substances in a solution to pass through from a diluted area to a more concentrated area. Filtration promotes the movement of fluid and some dissolved substances through a semipermeable membrane according to pressure differences. Evaporation is the process of converting water into a vapor. Active transport requires the energy source ATP to drive dissolved chemicals from an area of low concentration to an area of higher concentration; the opposite of passive diffusion.

a Dehydration results when the volume of body fluid is significantly reduced in both extracellular and intracellular compartments. In dehydration, all fluid compartments have decreased volumes; in hypovolemia, only blood volume is low. The most common fluid imbalance in older adults is dehydration. Hypervolemia is caused by fluid intake that exceeds fluid loss, such as from excessive oral intake or rapid IV infusion of fluid. Early signs of hypervolemia are weight gain, elevated BP, and increased breathing effort. Hypercalcemia occurs when the serum calcium level is higher than normal. Some of its signs include tingling in the extremities and the area around the mouth (circumoral paresthesia) and muscle and abdominal cramps. Hyperkalemia is an excess of potassium in the blood. Symptoms include diarrhea, nausea, muscle weakness, paresthesias, and cardiac dysrhythmias.

b Ideally, both arms and hands are carefully inspected before choosing a specific venipuncture site that does not interfere with mobility. Instruct the client to hold his arm in a dependent position to increase blood flow. Never leave a tourniquet in place longer than 2 minutes. The site does not necessarily need to be devoid of hair.

c Potassium is a major cation that affects cardiac muscle functioning. Chloride, bicarbonate, and phosphate are anions.

b The management goal in hypervolemia is to reduce fluid volume. For this reason, fluid is rationed and the client is advised to take a limited amount of fluid when thirsty. Sweet or dry food can increase the client's desire to consume fluid. Sweet or dry food does not obstruct water elimination or cause dehydration. Weight regulation is not part of hypervolemia management except to the extent it is achieved on account of fluid reduction.

b Alcoholism is currently the most common cause of symptomatic hypomagnesemia. Intravenous drug use, sedentary lifestyle, and burns are not the most common causes of hypomagnesemia.

b Half-strength saline (0.45%) is hypotonic. Hypotonic solutions are used to replace cellular fluid because it is hypotonic compared with plasma. Another is to provide free water to excrete body wastes. At times, hypotonic sodium solutions are used to treat hypernatremia and other hyperosmolar conditions. Lactated Ringer solution and normal saline (0.9% NaCl) are isotonic. A solution that is 5% NaCl is hypertonic.

a After radical neck resection, a client is prone to developing hypocalcemia. Hypocalcemia is defined as a serum value <8.6 mg/dL (<2.15 mmol/L). Signs and symptoms of hypocalcemia include Chvostek sign, which consists of muscle twitching enervated by the facial nerve when the region that is about 2 cm anterior to the earlobe, just below the zygomatic arch, is tapped; and a positive Trousseau sign can be elicited by inflating a blood pressure cuff on the upper arm to about 20 mm Hg above systolic pressure; within 2 to 5 minutes, carpal spasm (an adducted thumb, flexed wrist and metacarpophalangeal joints, and extended interphalangeal joints with fingers together) will occur as ischemia of the ulnar nerve develops. Slurred speech and muscle weakness are signs of hypercalcemia.

c Normal urine pH is 4.5 to 8.0; a value of 4.3 reveals acidic urine pH. A pH above 7.0 is considered an alkaline or basic solution. A pH of 7.0 is considered neutral.

c Loss of fluid from sweat or diaphoresis is referred to as insensible loss because it is unnoticeable and immeasurable. Losses from urination and bowel elimination are measurable. Nausea does not result in fluid loss, however if the client would develop emesis ( vomiting) this would be considered loss of body fluids and would need measured.

c Potassium may be administered through the oral route. Potassium is never administered by IV push or intramuscularly to avoid replacing potassium too quickly. Potassium is not administered subcutaneously.

a Oral intake is controlled by the thirst center located in the hypothalamus. The thirst center is not located in the cerebellum, brainstem, or thalamus.

a For a patient with abnormal losses of sodium who can consume a general diet, the nurse encourages foods and fluids with high sodium content to control hyponatremia. For example, broth made with one beef cube contains approximately 900 mg of sodium; 8 oz of tomato juice contains approximately 700 mg of sodium. The nurse also needs to be familiar with the sodium content of parenteral fluids (see Table 13-5).

a An isotonic solution is 0.9% normal saline (NaCl). Dextran in normal saline is a colloid solution, 0.45% normal saline is a hypotonic solution, and 3% NaCl is a hypertonic solution.

d A serum potassium level of 2.7 mEq/L constitutes hypokalemia. Manifestations of hypokalemia include fatigue, anorexia, nausea, vomiting, muscle weakness, leg cramps, decreased bowel motility, paresthesias (numbness and tingling), arrhythmias, and increased sensitivity to digitalis. Respiratory symptoms, dysphagia, and tetany are not typically associated with hypokalemia.

d Third-spacing fluid shift, which occurs when fluid moves out of the intravascular space but not into the intracellular space, can cause hypovolemia. Increased calcium and magnesium levels are not indicators of third-spacing fluid shift. Burns typically cause acidosis, not alkalosis.

c You can induce Chvostek sign by tapping the client's facial nerve adjacent to the ear. A brief contraction of the upper lip, nose, or side of the face indicates Chvostek sign. Both hypomagnesemia and hypocalcemia may be tested using the Chvostek sign.

b The respiratory system compensates by decreasing ventilation to conserve CO2 and increase the PaCO2.

d This client's pH value is below normal, indicating acidosis. The HCO3- value also is below normal, reflecting an overwhelming accumulation of acids or excessive loss of base, which suggests metabolic acidosis. The PaCO2 value is normal, indicating absence of respiratory compensation. These ABG values eliminate respiratory alkalosis, respiratory acidosis, and metabolic alkalosis.

d This client's above-normal pH value indicates alkalosis. The below-normal PaCO2 value indicates acid loss via hyperventilation; this type of acid loss occurs only in respiratory alkalosis. These ABG values wouldn't occur in metabolic acidosis, respiratory acidosis, or metabolic alkalosis

c Alcoholism is currently the most common cause of symptomatic hypomagnesemia in the United States. Hypomagnesemia is particularly troublesome during treatment of alcohol withdrawal. Therefore, the serum magnesium level should be routinely measured in patients undergoing withdrawal from alcohol. TPN, heart disease, and lymphoma are not identified as central risk factors for the development of hypomagnesemia.

a, b, c, e Severe dehydration is associated with an increased BUN (N = 10 to 20 mg/dL), serum osmolality (N = 275 to 300 mOsm/kg), serum sodium (N = 135 to 145 mEq/L) and urine specific gravity (N = 1.01 to 1.025). Glucose and hematocrit levels would also be elevated but are within normal range for this question.

a Ham (1,400 mg Na for 3 oz) and bacon (155 mg Na/slice) are high in sodium as is tomato juice (660 mg Na/¾ cup) and low fat cottage cheese (918 mg Na/cup). Packaged meals are high in sodium.

d The normal reference range for serum calcium is 8.6 to 10.2 mg/dl. A serum calcium level of 12 mg/dl clearly indicates hypercalcemia. The client's other laboratory findings are within their normal ranges, so the client doesn't have hypernatremia, hypochloremia, or hypokalemia.

b A pH over 7.45 with a HCO3- level over 26 mEq/L indicates metabolic alkalosis. Metabolic alkalosis is always secondary to an underlying cause and is marked by decreased amounts of acid or increased amounts of base HCO3-. The client isn't experiencing respiratory alkalosis because the PaCO2 is normal. The client isn't experiencing respiratory or metabolic acidosis because the pH is greater than 7.35.

a A 2-lb weight gain in 24 hours indicates that the client is retaining 1L of fluid.

a Respiratory acidosis is a clinical disorder in which the pH is less than 7.35 and the PaCO2 is greater than 42 mm Hg and a compensatory increase in the plasma HCO3- occurs. It may be either acute or chronic. The ABG of pH: 7.32, PaCO2: 40 mm Hg, HCO3-: 18 mEq/L indicates metabolic acidosis. The ABGs of pH: 7.50, PaCO2: 30 mm Hg, and HCO3-: 24 mEq/L indicate respiratory alkalosis. The ABGs of pH 7.42, PaCO2: 45 mm Hg, and HCO3-: 22 mEq/L indicate a normal result/no imbalance.

a, b Clients at risk for hypervolemia include those who are receiving corticosteroid therapy and those with altered heart function.

a Respiratory acidosis, which may be either acute or chronic, is caused by excess carbonic acid, which causes the blood pH to drop below 7.35. Chronic respiratory acidosis is associated with disorders such as emphysema, bronchiectasis, bronchial asthma, and cystic fibrosis.

a The client is experiencing hypokalemia, most likely due to the diagnosis of bulimia. Hypokalemia is defined as a serum potassium concentration <3.5 mEq/L (3.5 mmol/L), and usually indicates a deficit in total potassium stores. Clients diagnosed with bulimia frequently suffer increased potassium loss through self-induced vomiting and misuse of laxatives, diuretics, and enemas; thus, the client should avoid laxatives and enemas. Prevention measures may involve encouraging the client at risk to eat foods rich in potassium (when the diet allows), including fruit juices and bananas, melon, citrus fruits, fresh and frozen vegetables, lean meats, milk, and whole grains. If the hypokalemia is caused by abuse of laxatives or diuretics, client education may help alleviate the problem.

b The most common cause of acute respiratory alkalosis is hyperventilation. Extreme anxiety can lead to hyperventilation. Acute respiratory acidosis occurs in emergency situations, such as pulmonary edema, and is exhibited by hypoventilation and decreased PaCO2. CNS disturbances are found in extreme hyponatremia and fluid overload.

d Respiratory alkalosis results from alveolar hyperventilation. It's marked by a decrease in PaCO2 to less than 35 mm Hg and an increase in blood pH over 7.45. Metabolic acidosis is marked by a decrease in HCO3? to less than 22 mEq/L, and a decrease in blood pH to less than 7.35. In respiratory acidosis, the pH is less than 7.35 and the PaCO2 is greater than 45 mm Hg. In metabolic alkalosis, the HCO3? is greater than 26 mEq/L and the pH is greater than 7.45.

c Respiratory acidosis is always from inadequate excretion of CO2 with inadequate ventilation, resulting in elevated plasma CO2 concentrations. Respiratory acidosis can occur in diseases that impair respiratory muscles such as myasthenia gravis.

c Infiltration is the administration of nonvesicant solution or medication into the surrounding tissue. This can occur when the IV cannula dislodges or perforates the wall of the vein. Infiltration is characterized by edema around the insertion site, leakage of IV fluid from the insertion site, discomfort and coolness in the area of infiltration, and a significant decrease in the flow rate. Air emboli, phlebitis, and fluid overload are not indications of infiltration.

b Tetany is the most characteristic manifestation of hypocalcemia and hypomagnesemia. Sensations of tingling may occur in the tips of the fingers, around the mouth, and, less commonly, in the feet. Hypophosphatemia creates central nervous dysfunction, resulting in seizures and coma. Hypermagnesemia creates hypoactive reflexes and somnolence. Signs of hyperkalemia include paresthesias and anxiety.

a Sources of potassium include fruit juices and bananas, melon, citrus fruits, fresh and frozen vegetables, lean meats, milk, and whole grains (Crawford & Harris, 2011b).

b The ABG results reveal respiratory alkalosis. The best intervention to raise the PaCO2 level would be to have the client breathe into a paper bag. Administering a decongestant, offering fluids frequently, and administering supplemental oxygen wouldn't raise the lowered PaCO2 level.

d Early signs of hypervolemia are weight gain, elevated blood pressure, and increased breathing effort. Eventually, fluid congestion in the lungs leads to moist breath sounds. One of the earliest symptoms of hypovolemia is thirst.

a Normal serum concentration ranges from 135 to 145 mEq/L (135-145 mmol/L). Hyponatremia exists when the serum concentration decreases below 135 mEq/L (135 mmol/L). When the serum sodium concentration decreases to <115 mEq/L (<115 mmol/L), signs of increasing intracranial pressure, such as lethargy, confusion, muscle twitching, focal weakness, hemiparesis, papilledema, seizures, and death, may occur. General manifestations of hyponatremia include poor skin turgor, dry mucosa, headache, decreased saliva production, orthostatic fall in blood pressure, nausea, vomiting, and abdominal cramping. Neurologic changes, including altered mental status, status epilepticus, and coma, are probably related to cellular swelling and cerebral edema associated with hyponatremia. Hallucinations are associated with increased serum sodium concentrations.

d Bananas are high in potassium. Apples, fish, and rice are not high in potassium.

b Respiratory alkalosis is always caused by hyperventilation, which is a decrease in plasma carbonic acid concentration. The pH is elevated above normal as a result of a low PaCO2.

a Fluid volume deficit (FVD) occurs when the loss extracellular fluid (ECF) volume exceeds the intake of fluid. FVD results from loss of body fluids and occurs more rapidly when coupled with decreased fluid intake. A cause of this loss is hemorrhage.

a A chest x-ray is needed to confirm the placement of catheter tip before initiating ordered infusions. Consent should be obtained before, not after, the procedure. No BPs should be taken on the extremity where the catheter is placed.

a To gauge a client's magnesium status, the nurse should check deep tendon reflexes. If the reflex is absent, this may indicate high serum magnesium. Tachycardia, flank pain, and cool, clammy skin are not typically associated with hypermagnesemia.

c Extreme anxiety may lead to respiratory alkalosis by causing hyperventilation, which results in excessive carbon dioxide (CO2) loss. Other conditions that may set the stage for respiratory alkalosis include fever, heart failure, injury to the brain's respiratory center, overventilation with a mechanical ventilator, pulmonary embolism, and early salicylate intoxication. Type 1 diabetes may lead to diabetic ketoacidosis; the deep, rapid respirations occurring in this disorder (Kussmaul's respirations) don't cause excessive CO2 loss. Myasthenia gravis and opioid overdose suppress the respiratory drive, causing CO2 retention, not CO2 loss; this may lead to respiratory acidosis, not alkalosis.

a The client is experiencing an elevated serum phosphorus concentration. Hyperphosphatemia is defined as a serum phosphorus that exceeds 4.5 mg/dL (1.45 mmol/L). Because of the reciprocal relationship between phosphorus and calcium, a high serum phosphorus concentration tends to cause a low serum calcium concentration.

a Increased serum sodium causes increased osmotic pressure, increased thirst, and the release of ADH by the posterior pituitary gland. When serum osmolality decreases and thirst and ADH secretions are suppressed, the kidney excretes more water to restore normal osmolality. Levels of potassium, hemoglobin, and platelets do not directly affect ADH release.

a Muscle weakness, bradycardia, nausea, diarrhea, and paresthesia of the hands, feet, tongue, and face are findings associated with hyperkalemia, which is transient and results from transient hypoaldosteronism when the adenoma is removed. Tremors, diaphoresis, and constipation aren't seen in hyperkalemia.

b Metabolic alkalosis is a clinical disturbance characterized by a high pH and a high plasma biacarbonate concentration. The most common cuase of metabolic alkalosis is vomiting or gastric suction with loss of hydrogen and choloride ions. Gastric fluid has an acid pH, and loss of this acidic fluid increases the alkalinity of body fluids.

b Potassium is the major intracellular electrolyte. Hypokalemia (below 3.5 mEq/L) usually indicates a deficit in total potassium stores. Potassium deficiency can result in derangements in physiology. Clinical signs include fatigue, anorexia, nausea, vomiting, muscles weakness, leg cramps, decreased bowel motility, and paresthesias. The sodium, chloride and magnesium levels are within normal limits.

a, b, c Calcitonin reduces bones resorption, increasing deposition of calcium and phosphorous in the bones, and increases urinary excretion of calcium and phosphate.

a The client should avoid salt substitutes. The nurse must caution clients to use salt substitutes sparingly if they are taking other supplementary forms of potassium or potassium-conserving diuretics. Potassium-rich foods to be avoided include many fruits and vegetables, legumes, whole-grain breads, lean meat, milk, eggs, coffee, tea, and cocoa. Conversely, foods with minimal potassium content include butter, margarine, cranberry juice or sauce, ginger ale, gumdrops or jellybeans, hard candy, root beer, sugar, and honey. Labels of cola beverages must be checked carefully because some are high in potassium and some are not.

d When PaCO2 chronically exceeds 50 mm Hg, it creates insensitivity to CO2 in the respiratory medulla, and the use of oxygen may result in the client developing carbon dioxide narcosis and hypoxemia. No information indicates the client's calcium will rise dramatically due to pituitary stimulation. No feedback system that oxygen stimulates would create an increase in the client's intracranial pressure and create confusion. Increasing the oxygen would not stimulate the client to hyperventilate and become acidotic; rather, it would cause hypoventilation and acidosis.

b Major functions of the kidneys in maintaining normal fluid balance include regulation of extracellular fluid (ECF) volume and osmolality by selective retention and excretion of body fluids and regulation of electrolyte levels in the ECF by selective retention of needed substances and excretion of unneeded substances. Antidiuretic hormone (ADH) is secreted by the pituitary gland, and angiotensin is ultimately derived from the liver, not the kidneys. Concentration of H+ ions contributes the buffer action of the kidneys, not the maintenance of fluid balance.

a The patient is experiencing respiratory alkalosis. Respiratory alkalosis is a clinical condition in which the arterial pH is >7.45 and the PaCO2 is <38 mm Hg. Respiratory alkalosis is always caused by hyperventilation, which causes excessive "blowing off" of CO2 and, hence, a decrease in the plasma carbonic acid concentration. Causes include extreme anxiety, hypoxemia, early phase of salicylate intoxication, gram-negative bacteremia, and inappropriate ventilator settings.

c Probably the most common cause of metabolic alkalosis is vomiting or gastric suction with loss of hydrogen and chloride ions. The disorder also occurs in pyloric stenosis in which only gastric fluid is lost. Vomiting, gastric suction, and pyloric stenosis all remove potassium and can cause hypokalemia. This client would not be at risk for hypercalcemia; hyperparathyroidism and cancer account for almost all cases of hypercalcemia. The nasogastric tube is removing stomach acid and will likely raise pH. Respiratory acidosis is unlikely since no change was reported in the client's respiratory status.

a Potassium-losing diuretics, such as the thiazides and loop diuretics, can induce hypokalemia. Gastrointestinal (GI) loss of potassium is another common cause of potassium depletion. Vomiting and gastric suction frequently lead to hypokalemia.

a Irritating medications, such as chemotherapeutic agents, can cause pain, burning, and redness at the site. Blistering, inflammation, and necrosis of tissues can occur. The extent of tissue damage is determined by the medication concentration, the quantity that extravasated, infusion site location, the tissue response, and the extravasation duration. Extravasation is the priority over the other listed consequences.

b Magnesium excess (>2.7 mEq/L) is associated with the following symptoms: flushing, hypotension, muscle weakness, drowsiness, hypoactive reflexes, depressed respirations, and cardiac arrest. The respiratory center is depressed when serum magnesium levels exceed 10 mEq/L (5 mmol/L). This is not present in this patient, so the magnesium level is unlikely to be 11 mEq/L. Coma, atrioventricular heart block, and cardiac arrest can occur when the serum magnesium level is greatly elevated and not treated.

a Evaluation of arterial blood gases reveals a pH greater than 7.45 and a serum bicarbonate concentration greater than 26 mEq/L.

a The client is experiencing an elevated serum phosphorus concentration. Hyperphosphatemia is defined as a serum phosphorus that exceeds 4.5 mg/dL (1.45 mmol/L). Because of the reciprocal relationship between phosphorus and calcium, a high serum phosphorus concentration tends to cause a low serum calcium concentration.

c Diuretics cause potassium loss, and it is important to maintain adequate intake during therapy. Hyponatremia is more of a risk than hypernatremia, so a low-sodium diet does not address the risk for electrolyte disturbances. There is no direct need for extra calcium intake and increased fluid intake does not reduce the client's risk for electrolyte disturbances.

a Third-spacing describes the translocation of fluid from the intravascular or intercellular space to tissue compartments, where it becomes trapped and useless. The client manifests signs and symptoms of hypovolemia with the exception of weight loss. There may be signs of localized enlargement of organ cavities (such as the abdomen) if they fill with fluid, a condition referred to as ascites. Pitting edema occurs when indentations remain in the skin after compression. Anascara is another term for generalized edema, or brawny edema, in which the interstitial spaces fill with fluid. Hypovolemia (fluid volume deficit) refers to a low volume of extracellular fluid.

b In healthy adults, normal serum osmolality is 270 to 300 mOsm/kg (Crawford & Harris, 2011c).

d Although changes in all these findings are seen in hyperkalemia, ECG results should take priority because changes can indicate potentially lethal arrhythmias such as ventricular fibrillation. It wouldn't be appropriate to assess the client's neuromuscular function, bowel sounds, or respiratory rate for effects of hyperkalemia.

a Extracellular fluid includes the water between cells (interstitial fluid) and in the plasma (serum) portion of blood (intravascular fluid). The body weight of a healthy infant is 77% water, with the following percentages: 4% intravascular, 25% interstitial, and 48% intracellular.

a Hypokalemia causes fatigue, weakness, anorexia, nausea, vomiting, cardiac dysrhythmias, leg cramps, muscle weakness, and paresthesias. Many diuretics, such as ethacrynic acid (Edecrin), also waste potassium. Symptoms of hyperkalemia include diarrhea, nausea, muscle weakness, paresthesias, and cardiac dysrhythmias. Signs of hypocalcemia include tingling in the extremities and the area around the mouth and muscle and abdominal cramps. Hypercalcemia causes deep bone pain, constipation, anorexia, nausea, vomiting, polyuria, thirst, pathologic fractures, and mental changes.

c Failure of the kidneys results in multiple fluid and electrolyte abnormalities including fluid volume overload. If renal function is so severely impaired that pharmacologic agents cannot act efficiently, other modalities are considered to remove sodium and fluid from the body.

a Chronic alcohol abuse is a major cause of symptomatic hypomagnesemia in the United States. The serum magnesium concentration should be measured at least every 2 or 3 days in clients undergoing alcohol withdrawal. The serum magnesium concentration may be normal at admission but may decrease as a result of metabolic changes, such as the intracellular shift of magnesium associated with intravenous glucose administration.

a The client is at risk for developing metabolic acidosis. Metabolic acidosis is caused by diarrhea, lower intestinal fistulas, ureterostomies, and use of diuretics; early renal insufficiency; excessive administration of chloride; and the administration of parenteral nutrition without bicarbonate or bicarbonate-producing solutes (e.g., lactate).

c Probably the most common cause of metabolic alkalosis is vomiting or gastric suction with loss of hydrogen and chloride ions. The disorder also occurs in pyloric stenosis in which only gastric fluid is lost. Vomiting, gastric suction, and pyloric stenosis all remove potassium and can cause hypokalemia. This client would not be at risk for hypercalcemia; hyperparathyroidism and cancer account for almost all cases of hypercalcemia. The nasogastric tube is removing stomach acid and will likely raise pH. Respiratory acidosis is unlikely since no change was reported in the client's respiratory status.

a Normal urine osmolality is 200 to 800 mOsm/kg, so 980 mOsm/kg is elevated. Acidosis is a factor that increases urine osmolality. Fluid volume excess, diabetes insipidus, and hyponatremia are all factors that decrease urine osmolality.

b Major functions of the kidneys in maintaining normal fluid balance include regulation of extracellular fluid (ECF) volume and osmolality by selective retention and excretion of body fluids and regulation of electrolyte levels in the ECF by selective retention of needed substances and excretion of unneeded substances. Antidiuretic hormone (ADH) is secreted by the pituitary gland, and angiotensin is ultimately derived from the liver, not the kidneys. Concentration of H+ ions contributes the buffer action of the kidneys, not the maintenance of fluid balance.

a, b, c Clinical manifestations of FVE include distended neck veins, crackles in the lung fields, shortness of breath, increased blood pressure, and tachycardia.

a The lactated Ringer intravenous (IV) fluid is contributing to both the fluid volume excess and the hyperkalemia. In addition to the volume of IV fluids contributing to the fluid volume excess, lactated Ringer solution contains more sodium than daily requirements, and excess sodium worsens fluid volume excess. Lactated Ringer solution also contains potassium, which would worsen the hyperkalemia.

a The client is experiencing an elevated serum phosphorus concentration. Hyperphosphatemia is defined as a serum phosphorus that exceeds 4.5 mg/dL (1.45 mmol/L). Because of the reciprocal relationship between phosphorus and calcium, a high serum phosphorus concentration tends to cause a low serum calcium concentration.

a The client's ABG would likely demonstrate metabolic alkalosis. Metabolic alkalosis is a clinical disturbance characterized by a high pH (decreased H+ concentration) and a high plasma bicarbonate concentration. It can be produced by a gain of bicarbonate or a loss of H+. A common cause of metabolic alkalosis is vomiting or gastric suction with loss of hydrogen and chloride ions. The disorder also occurs in pyloric stenosis, where only gastric fluid is lost. The other results do not represent metabolic alkalosis.

c Loss of fluid from sweat or diaphoresis is referred to as insensible loss because it is unnoticeable and immeasurable. Losses from urination and bowel elimination are measurable. Nausea does not result in fluid loss, however if the client would develop emesis ( vomiting) this would be considered loss of body fluids and would need measured.

a Hypokalemia causes fatigue, weakness, anorexia, nausea, vomiting, cardiac dysrhythmias, leg cramps, muscle weakness, and paresthesias. Many diuretics, such as ethacrynic acid (Edecrin), also waste potassium. Symptoms of hyperkalemia include diarrhea, nausea, muscle weakness, paresthesias, and cardiac dysrhythmias. Signs of hypocalcemia include tingling in the extremities and the area around the mouth and muscle and abdominal cramps. Hypercalcemia causes deep bone pain, constipation, anorexia, nausea, vomiting, polyuria, thirst, pathologic fractures, and mental changes.

b Potassium is the major intracellular electrolyte. Hypokalemia (potassium levels lower than 3.5 mEq/L) usually indicates a deficit in total potassium stores. Potassium deficiency can result in derangements in physiology. Clinical signs include fatigue, anorexia, nausea, vomiting, muscles weakness, leg cramps, decreased bowel motility, and paresthesias. The sodium, chloride, and magnesium levels listed are within normal limits.

a Acids are substances that release hydrogen into fluid. The delicate balance of fluid, electrolytes, acids, and bases is ensured by an adequate intake of water and nutrients, physiologic mechanisms that regulate fluid volume, and chemical processes that buffer the blood to keep its pH nearly neutral.

d Third-spacing fluid shift, which occurs when fluid moves out of the intravascular space but not into the intracellular space, can cause hypovolemia. Hypertension, bradycardia, and hypervolemia are not indicators of third-spacing fluid shift.

a Hemoconcentration, a high ratio of blood components in relation to watery plasma, increases the potential for blood clots and urinary stones and compromises the kidney's ability to excrete nitrogen wastes. Metabolic acidosis is a condition that results in decreased plasma pH because of increased organic acids (acids other than carbonic acid) or decreased bicarbonate. Accumulation of acids also may follow renal failure, aspirin (acetylsalicylic acid) over dosage, or profuse diarrhea. Metabolic alkalosis results in increased plasma pH because of accumulated base bicarbonate or decreased hydrogen ion concentrations. Risk factors include excessive oral or parenteral use of bicarbonate-containing drugs or other alkaline salts, a rapid decrease in extracellular fluid volume, and loss of hydrogen and chloride ions through vomiting or other GI conditions. Hemodilution is a reduced ratio of blood components to watery plasma, which causes a low blood cell count and hematocrit level.

a In healthy adults, oral fluid intake averages about 2500 mL/day; however, it can range between 1800 and 3000 mL/day, with a similar volume of fluid loss. Based on the standard formula for calculating daily fluid intake, this client requires about 2220 ml of oral fluid intake based on the weight of 150 lb.

a Chloride is a major anion found in extracellular fluid. Potassium, sodium, and calcium are cations.

a An isotonic solution is 0.9% normal saline (NaCl). Dextran in normal saline is a colloid solution, 0.45% normal saline is a hypotonic solution, and 3% NaCl is a hypertonic solution.

b Osmosis is the movement of fluid from a region of low solute concentration to a region of high solute concentration across a semipermeable membrane. Hydrostatic pressure refers to changes in water or volume related to water pressure. Diffusion is the movement of solutes from an area of greater concentration to lesser concentration; the solutes in an intact vascular system are unable to move so diffusion normally should not be taking place. Active transport is the movement of molecules against the concentration gradient and requires adenosine triphosphate (ATP) as an energy source; this process typically takes place at the cellular level and is not involved in vascular volume changes.

a Muscle weakness, bradycardia, nausea, diarrhea, and paresthesia of the hands, feet, tongue, and face are findings associated with hyperkalemia, which is transient and results from transient hypoaldosteronism when the adenoma is removed. Tremors, diaphoresis, and constipation aren't seen in hyperkalemia.

c Extreme anxiety may lead to respiratory alkalosis by causing hyperventilation, which results in excessive carbon dioxide (CO2) loss. Other conditions that may set the stage for respiratory alkalosis include fever, heart failure, injury to the brain's respiratory center, overventilation with a mechanical ventilator, pulmonary embolism, and early salicylate intoxication. Type 1 diabetes may lead to diabetic ketoacidosis; the deep, rapid respirations occurring in this disorder (Kussmaul's respirations) don't cause excessive CO2 loss. Myasthenia gravis and opioid overdose suppress the respiratory drive, causing CO2 retention, not CO2 loss; this may lead to respiratory acidosis, not alkalosis.

c Hyperkalemia is a common complication of acute renal failure. It's life-threatening if immediate action isn't taken to reverse it. Administering glucose and regular insulin, with sodium bicarbonate if necessary, can temporarily prevent cardiac arrest by moving potassium into the cells and temporarily reducing serum potassium levels. Hypernatremia, hypokalemia, and hypercalcemia don't usually occur with acute renal failure and aren't treated with glucose, insulin, or sodium bicarbonate.

b Half-strength saline (0.45%) is hypotonic. Hypotonic solutions are used to replace cellular fluid because it is hypotonic compared with plasma. Another is to provide free water to excrete body wastes. At times, hypotonic sodium solutions are used to treat hypernatremia and other hyperosmolar conditions. Lactated Ringer solution and normal saline (0.9% NaCl) are isotonic. A solution that is 5% NaCl is hypertonic.

b, c, e To assess for FVE the nurse measures blood pressure, heart rate and rhythm, and breath sounds; inspects the skin to look for edema and turgor; and inspects neck veins. Intake and output, daily weight, urine volume and color, dyspnea, and thirst are assessments that will assist the nurse in identifying improvement or worsening of the fluid volume excess. In addition, the nurse will be able to identify potential fluid volume deficit from overtreatment of the fluid volume excess.

d Tetany is a symptom of hyperphosphatemia. Bone pain, peresthesia, and seizures are associated with hypophosphatemia.