Chapter 45. Fluid, Electrolyte, and Acid-Base Disorders and Therapy
1. The parents of a child with acid-base imbalance ask the nurse about mechanisms that regulate
acid-base balance. Which statement by the nurse accurately explains the mechanisms regulating
acid-base balance in children?
a. The respiratory, renal, and chemical-buffering systems regulate acid-base in
the body.
b. The kidneys balance acid; the lungs balance base.
c. The cardiovascular and integumentary systems work together to control
acid- base.
d. The skin, kidney, and endocrine systems control the bodys acid-base.
ANS: A
The acid-base system is regulated by chemical buffering, respiratory control of carbon dioxide,
and renal regulation of bicarbonate and secretion of hydrogen ions. Both the kidneys and the
lungs, along with the buffering system, contribute to acid-base balance. Neither system
regulates acid or base balances exclusively. The cardiovascular and integumentary systems are
not part of acid-base regulation in the body. Chemical buffers, the lungs, and the kidneys work
together to keep the blood pH within a normal range.
2. A child has a 2-day history of vomiting and diarrhea. He has hypoactive bowel sounds and
an irregular pulse. Electrolyte values are sodium, 139 mEq/L; potassium, 3.3 mEq/L; and
calcium,
9.5 mg/dL. This child is likely to have which of the following electrolyte imbalances?
a. Hyponatremia
b. Hypocalcemia
c. Hyperkalemia
d. Hypokalemia
ANS: D
A serum potassium level less than 3.5 mEq/L is considered hypokalemia. Clinical
manifestations of hypokalemia include muscle weakness, decreased bowel sounds, cardiac
irregularities, hypotension, and fatigue. The normal serum sodium level is 135 to 145 mEq/L. A
level of 139
, mEq/L is within normal limits. A serum calcium level less than 8.5 mg/dL is considered
hypocalcemia. A serum potassium level greater than 5 mEq/L is considered
hyperkalemia.
3. Which statement best describes why infants are at greater risk for dehydration than
older children?
a. Infants have an increased ability to concentrate
urine. b. Infants have a greater volume of intracellular
fluid.
c. Infants have a smaller body surface area.
d. Infants have an increased extracellular fluid volume.
ANS: D
The larger ratio of extracellular fluid to intracellular fluid predisposes the infant to dehydration.
Because the kidneys are immature in early infancy, there is a decreased ability to concentrate
the urine. Infants have a larger proportion of fluid in the extracellular space. Infants have a
proportionately greater body surface area in relation to body mass, which creates the potential
for greater fluid loss through the skin and gastrointestinal tract.
4. Which assessments are most relevant to the care of an infant with dehydration?
a. Temperature, heart rate, and blood pressure
b. Respiratory rate, oxygen saturation, and lung
sounds c. Heart rate, capillary refill, and skin color
d. Diet tolerance, bowel function, and abdominal girth
ANS: C
Changes in heart rate, capillary refill, and skin color are early indicators of impending shock in
the child. Children can compensate and maintain an adequate cardiac output when they are
hypovolemic. Blood pressure is not as reliable an indicator of shock as are changes in heart
rate, sensorium, and skin color. Respiratory assessments will not provide data about
impending hypovolemic shock. Diet tolerance, bowel function, and abdominal girth are not as
important indicators of shock as heart rate, capillary refill, and skin color.
1. The parents of a child with acid-base imbalance ask the nurse about mechanisms that regulate
acid-base balance. Which statement by the nurse accurately explains the mechanisms regulating
acid-base balance in children?
a. The respiratory, renal, and chemical-buffering systems regulate acid-base in
the body.
b. The kidneys balance acid; the lungs balance base.
c. The cardiovascular and integumentary systems work together to control
acid- base.
d. The skin, kidney, and endocrine systems control the bodys acid-base.
ANS: A
The acid-base system is regulated by chemical buffering, respiratory control of carbon dioxide,
and renal regulation of bicarbonate and secretion of hydrogen ions. Both the kidneys and the
lungs, along with the buffering system, contribute to acid-base balance. Neither system
regulates acid or base balances exclusively. The cardiovascular and integumentary systems are
not part of acid-base regulation in the body. Chemical buffers, the lungs, and the kidneys work
together to keep the blood pH within a normal range.
2. A child has a 2-day history of vomiting and diarrhea. He has hypoactive bowel sounds and
an irregular pulse. Electrolyte values are sodium, 139 mEq/L; potassium, 3.3 mEq/L; and
calcium,
9.5 mg/dL. This child is likely to have which of the following electrolyte imbalances?
a. Hyponatremia
b. Hypocalcemia
c. Hyperkalemia
d. Hypokalemia
ANS: D
A serum potassium level less than 3.5 mEq/L is considered hypokalemia. Clinical
manifestations of hypokalemia include muscle weakness, decreased bowel sounds, cardiac
irregularities, hypotension, and fatigue. The normal serum sodium level is 135 to 145 mEq/L. A
level of 139
, mEq/L is within normal limits. A serum calcium level less than 8.5 mg/dL is considered
hypocalcemia. A serum potassium level greater than 5 mEq/L is considered
hyperkalemia.
3. Which statement best describes why infants are at greater risk for dehydration than
older children?
a. Infants have an increased ability to concentrate
urine. b. Infants have a greater volume of intracellular
fluid.
c. Infants have a smaller body surface area.
d. Infants have an increased extracellular fluid volume.
ANS: D
The larger ratio of extracellular fluid to intracellular fluid predisposes the infant to dehydration.
Because the kidneys are immature in early infancy, there is a decreased ability to concentrate
the urine. Infants have a larger proportion of fluid in the extracellular space. Infants have a
proportionately greater body surface area in relation to body mass, which creates the potential
for greater fluid loss through the skin and gastrointestinal tract.
4. Which assessments are most relevant to the care of an infant with dehydration?
a. Temperature, heart rate, and blood pressure
b. Respiratory rate, oxygen saturation, and lung
sounds c. Heart rate, capillary refill, and skin color
d. Diet tolerance, bowel function, and abdominal girth
ANS: C
Changes in heart rate, capillary refill, and skin color are early indicators of impending shock in
the child. Children can compensate and maintain an adequate cardiac output when they are
hypovolemic. Blood pressure is not as reliable an indicator of shock as are changes in heart
rate, sensorium, and skin color. Respiratory assessments will not provide data about
impending hypovolemic shock. Diet tolerance, bowel function, and abdominal girth are not as
important indicators of shock as heart rate, capillary refill, and skin color.
