Chapter 23: Fluid and Electrolyte Balance

What factor predisposes an infant to fluid imbalances?
a.
Decreased surface area
b.
Lower metabolic rate
c.
Immature kidney functioning
d.
Decreased daily exchange of extracellular fluid

ANS: C
The infant's kidneys are functionally immature at birth and are inefficient in excreting waste products of metabolism. Infants have a relatively high body surface area (BSA) compared with adults. This allows a higher loss of fluid to the environment. A higher metabolic rate is present as a result of the higher BSA in relation to active metabolic tissue. The higher metabolic rate increases heat production, which results in greater insensible water loss. Infants have a greater exchange of extracellular fluid, leaving them with a reduced fluid reserve in conditions of dehydration.

What is the required number of milliliters of fluid needed per day for a 14 kg child?
a.
800
b.
1000
c.
1200
d.
1400

ANS: C
For the first 10 kg of body weight, a child requires 100 mL/kg. For each additional kilogram of body weight, an extra 50 mL is needed.
10 kg ´ 100 mL/kg/day = 1000 mL
4 kg ´ 50 mL/kg/day = 200 mL
1000 mL + 200 mL = 1200 ml/day
800 to 1000 mL is too little; 1400 mL is too much.

An infant is brought to the emergency department with the following clinical manifestations: poor skin turgor, weight loss, lethargy, tachycardia, and tachypnea. This is suggestive of which situation?
a.
Water excess
b.
Sodium excess
c.
Water depletion
d.
Potassium excess

ANS: C
These clinical manifestations indicate water depletion or dehydration. Edema and weight gain occur with water excess or overhydration. Sodium or potassium excess would not cause these symptoms.

What laboratory finding should the nurse expect in a child with an excess of water?
a.
Decreased hematocrit
b.
High serum osmolality
c.
High urine specific gravity
d.
Increased blood urea nitrogen

ANS: A
The excess water in the circulatory system results in hemodilution. The laboratory results show a falsely decreased hematocrit. Laboratory analysis of blood that is hemodiluted reveals decreased serum osmolality and blood urea nitrogen. The urine specific gravity is variable relative to the child's ability to correct the fluid imbalance.

Physiologically, the child compensates for fluid volume losses by which mechanism?
a.
Inhibition of aldosterone secretion
b.
Hemoconcentration to reduce cardiac workload
c.
Fluid shift from interstitial space to intravascular space
d.
Vasodilation of peripheral arterioles to increase perfusion

ANS: C
Compensatory mechanisms attempt to maintain fluid volume. Initially, interstitial fluid moves into the intravascular compartment to maintain blood volume. Aldosterone is released to promote sodium retention and conserve water in the kidneys. Hemoconcentration results from the fluid volume loss. With less circulating volume, tachycardia results. Vasoconstriction of peripheral arterioles occurs to help maintain blood pressure.

What is an approximate method of estimating output for a child who is not toilet trained?
a.
Have parents estimate output.
b.
Document number of wet diapers.
c.
Place a urine collection device on the child.
d.
Have the child sit on a potty chair 30 minutes after eating.

ANS: B
In general, the number of days in life (up to 6-10 days) should be equal to the number of wet diapers per day. Having parents estimate output would be inaccurate. It is difficult to estimate how much fluid is in a diaper. The urine collection device would irritate the child's skin. It would be difficult for a toddler who is not toilet trained to sit on a potty chair 30 minutes after eating.

A school-age child with acute diarrhea and mild dehydration is being given oral rehydration solutions (ORS). The child's mother calls the clinic nurse because he is also occasionally vomiting. The nurse should recommend which intervention?
a.
Bring the child to the hospital for intravenous fluids.
b.
Alternate giving ORS and carbonated drinks.
c.
Continue to give ORS frequently in small amounts.
d.
Keep child NPO (nothing by mouth) for 8 hr and resume ORS if vomiting has subsided.

ANS: C
Children who are vomiting should be given ORS at frequent intervals and in small amounts. Intravenous fluids are not indicated for mild dehydration. Carbonated beverages are high in carbohydrates and are not recommended for the treatment of diarrhea and vomiting. The child is not kept NPO because this would cause additional fluid losses.

What is the most frequent cause of hypovolemic shock in children?
a.
Sepsis
b.
Blood loss
c.
Anaphylaxis
d.
Heart failure

ANS: B
Blood loss is the most frequent cause of hypovolemic shock in children. Sepsis causes septic shock, which is overwhelming sepsis and circulating bacterial toxins. Anaphylactic shock results from extreme allergy or hypersensitivity to a foreign substance. Heart failure contributes to hypervolemia, not hypovolemia.

The nurse suspects shock in a child 1 day after surgery. What should be the initial nursing action?
a.
Place the child on a cardiac monitor.
b.
Obtain arterial blood gases.
c.
Provide supplemental oxygen.
d.
Put the child in the Trendelenburg position.

ANS: C
The initial nursing action for a patient in shock is to establish ventilatory support. Oxygen is provided, and the nurse carefully observes for signs of respiratory failure, which indicates a need for intubation. Cardiac monitoring would be indicated to assess the child's status further, but ventilatory support comes first. Oxygen saturation monitoring should be begun. Arterial blood gases would be indicated if alternative methods of monitoring oxygen therapy were not available. The Trendelenburg position is not indicated and is detrimental to the child. The head-down position increases intracranial pressure and decreases diaphragmatic excursion and lung volume.

What explains physiologically the edema formation that occurs with burns?
a.
Vasoconstriction
b.
Reduced capillary permeability
c.
Increased capillary permeability
d.
Diminished hydrostatic pressure within capillaries

ANS: C
With a major burn, capillary permeability increases, allowing plasma proteins, fluids, and electrolytes to be lost into the interstitial space, causing edema. Maximum edema in a small wound occurs about 8 to 12 hr after injury. In larger injuries, the maximum edema may not occur until 18 to 24 hr later. Vasodilation occurs, causing an increase in hydrostatic pressure.

A child is admitted with extensive burns. The nurse notes burns on the child's lips and singed nasal hairs. The nurse should suspect what condition in the child?
a.
A chemical burn
b.
A hot-water scald
c.
An electrical burn
d.
An inhalation injury

ANS: D
Evidence of an inhalation injury includes burns of the face and lips, singed nasal hairs, and laryngeal edema. Clinical manifestations may be delayed for up to 24 hr. Chemical burns, electrical burns, and burns associated with hot-water scalds would not produce singed nasal hair.

What is the most immediate threat to life in children with thermal injuries?
a.
Shock
b.
Anemia
c.
Local infection
d.
Systemic sepsis

ANS: A
The immediate threat to life in children with thermal injuries is airway compromise and profound shock. Anemia is not of immediate concern. During the healing phase, local infection or sepsis is the primary complication.

After the acute stage and during the healing process, what is the primary complication from burn injury?
a.
Shock
b.
Asphyxia
c.
Infection
d.
Renal shutdown

ANS: C
During the healing phase, local infection or sepsis is the primary complication. Respiratory problems, primarily airway compromise, and shock are the primary complications during the acute stage of burn injury. Renal shutdown is not a complication of the burn injury but may be a result of the profound shock.

What finding is the most reliable guide to the adequacy of fluid replacement for a small child with burns?
a.
Absence of thirst
b.
Falling hematocrit
c.
Increased seepage from burn wound
d.
Urinary output of 1 to 2 mL/kg of body weight/hr

ANS: D
Replacement fluid therapy is delivered to provide a urinary output of 30 mL/hr in older children or 1 to 2 mL/kg of body weight/hr for children weighing less than 30 kg (66 pounds). Thirst is the result of a complex set of interactions and is not a reliable indicator of hydration. Thirst occurs late in dehydration. A falling hematocrit would be indicative of hemodilution. This may reflect fluid shifts and may not accurately represent fluid replacement therapy. Increased seepage from a burn wound would be indicative of increased output, not adequate hydration.

Fentanyl and midazolam (Versed) are given before debridement of a child's burn wounds. What is the purpose of using these medications?
a.
Facilitate healing.
b.
Provide pain relief.
c.
Minimize risk of infection.
d.
Decrease amount of debridement needed.

ANS: B
Partial-thickness burns require debridement of devitalized tissue to promote healing. The procedure is painful and requires analgesia and sedation before the procedure. Fentanyl and midazolam provide excellent intravenous sedation and analgesia to control procedural pain in children with burns.

Hydrotherapy is required to treat a child with extensive partial-thickness burn wounds. What is the purpose of hydrotherapy?
a.
Provide pain relief.
b.
Debride the wounds.
c.
Destroy bacteria on the skin.
d.
Increase peripheral blood flow.

ANS: B
Soaking in a tub or showering once or twice a day acts to loosen and remove sloughing tissue, exudate, and topical medications. The hydrotherapy cleanses the wound and the entire body and helps maintain range of motion. Appropriate pain medications are necessary. Dressing changes are extremely painful. The total bacterial count of the skin is reduced by the hydrotherapy, but this is not the primary goal. There may be an increase in peripheral blood flow, but the primary purpose is for wound debridement.

What is the nursing action related to the applying of biologic or synthetic skin coverings for a child with partial-thickness burns of both legs?
a.
Splint the legs to prevent movement.
b.
Observe wounds for signs of infection.
c.
Monitor closely for manifestations of shock.
d.
Examine dressings for indications of bleeding.

ANS: B
When applied early to a superficial partial-thickness injury, biologic dressings stimulate epithelial growth and faster wound healing. If the dressing covers areas of heavy microbial contamination, infection occurs beneath the dressing. In the case of partial-thickness burns, such infection may convert the wound to a full-thickness injury. Infection is the primary concern when biologic dressings are used.

The nurse is teaching a group of female adolescents about toxic shock syndrome and the use of tampons. What statement by a participant indicates a need for additional teaching?
a.
"I can alternate using a tampon and a sanitary napkin."
b.
"I should wash my hands before inserting a tampon."
c.
"I can use a superabsorbent tampon for more than 6 hr."
d.
"I should call my health care provider if I suddenly develop a rash that looks like sunburn."

ANS: C
Teaching female adolescents about the association between toxic shock syndrome and the use of tampons is important. The teaching should include not using superabsorbent tampons; not leaving the tampon in for longer than 4 to 6 hr; alternating the use of tampons with sanitary napkins; washing hands before inserting a tampon to decrease the chance of introducing pathogens; and informing a health care provider if a sudden high fever, vomiting, muscle pain, dizziness, or a rash that looks like a sunburn appears.

The nurse is preparing a presentation on compensated, decompensated, and irreversible shock in children. What clinical manifestations related to decompensated shock should the nurse include? (Select all that apply.)
a.
Tachypnea
b.
Oliguria
c.
Confusion
d.
Pale extremities
e.
Hypotension
f.
Thready pulse

ANS: A, B, C, D
As shock progresses, perfusion in the microcirculation becomes marginal despite compensatory adjustments, and the signs are more obvious. Signs include tachypnea, oliguria, confusion, and pale extremities, as well as decreased skin turgor and poor capillary filling. Hypotension and a thready pulse are clinical manifestations of irreversible shock.

In what condition should the nurse be alert for altered fluid requirements in children? (Select all that apply.)
a.
Oliguric renal failure
b.
Increased intracranial pressure
c.
Mechanical ventilation
d.
Compensated hypotension
e.
Tetralogy of Fallot
f.
Type 1 diabetes mellitus

ANS: A, B, C
The nurse should recognize that conditions such as oliguric renal failure, increased intracranial pressure, and mechanical ventilation can cause an increase or a decrease in fluid requirements. Conditions such as hypotension, tetralogy of Fallot, and diabetes mellitus (type 1) do not cause an alteration in fluid requirements.

What clinical manifestations should be observed in a 2-year-old child with hypotonic dehydration? (Select all that apply.)
a.
Thick, doughy feel to the skin
b.
Slightly moist mucous membranes
c.
Absent tears
d.
Very rapid pulse
e.
Hyperirritability

ANS: B, C, D
Clinical manifestations of hypotonic dehydration include slightly moist mucous membranes, absent tears, and a very rapid pulse. A thick, doughy feel to the skin and hyperirritability are signs of hypertonic dehydration.

The nurse is caring for a child with hypokalemia. The nurse evaluates the child for which signs and symptoms of hypokalemia? (Select all that apply.)
a.
Twitching
b.
Hypotension
c.
Hyperreflexia
d.
Muscle weakness
e.
Cardiac arrhythmias

ANS: B, D, E
Signs and symptoms of hypokalemia are hypotension, muscle weakness, and cardiac arrhythmias. Twitching and hyperreflexia are signs of hyperkalemia.

The nurse is caring for a child with hypercalcemia. The nurse evaluates the child for which signs and symptoms of hypercalcemia? (Select all that apply.)
a.
Tetany
b.
Anorexia
c.
Constipation
d.
Laryngospasm
e.
Muscle hypotonicity

ANS: B, C, E
Signs and symptoms of hypercalcemia are anorexia, constipation, and muscle hypotonicity. Tetany and laryngospasm are signs of hypocalcemia.

The nurse is caring for a child with hypernatremia. The nurse evaluates the child for which signs and symptoms of hypernatremia? (Select all that apply.)
a.
Apathy
b.
Lethargy at rest
c.
Oliguria
d.
Intense thirst
e.
Dry, sticky mucus

ANS: B, C, E
Signs and symptoms of hypernatremia are nausea; oliguria; and dry, sticky mucus. Apathy and lethargy are signs of hyponatremia.

A health care provider prescribes dopamine (Intropin), 5 mcg/kg/min in a continuous intravenous (IV) infusion for a child in shock. The child weighs 25 kg. The medication is available as dopamine 400 mg in 250 mL. The nurse prepares to calculate the rate. How many milliliters per hour will the nurse set the IV infusion pump to deliver 5 mcg/kg/min? Fill in the blank. Round to one decimal place.
________________

ANS:
4.7