Chapter 18: Fluid, Electrolyte, and Acid-Base Balances

Chapter 18: Fluid, Electrolyte, and Acid-Base Balances

 

Complete Chapter Questions With Answers

 

Sample Questions Are Posted Below

 

MULTIPLE CHOICE

 

1. A nurse is caring for a patient who is suffering from kidney failure and is receiving peritoneal dialysis. The nurse explains that peritoneal dialysis works by instilling a solution into the abdomen that contains dextrose that will pull extra fluid into the abdominal cavity. What is the name of this process?

a.	Diffusion
b.	Osmosis
c.	Filtration
d.	Active transport

 

 

ANS:   B

Osmosis is movement of water across a semipermeable membrane from a compartment of lower particle concentration to one that has a higher particle concentration. Diffusion is passive movement of electrolytes or other particles from an area of higher concentration to an area of lower concentration. In other words, the electrolytes move down their concentration gradient until the electrolyte concentration is equal in all areas. Electrolytes cannot diffuse across cell membranes unless the membranes have proteins that serve as ion channels. Filtration is the net effect of several forces that tend to move fluid across a membrane. Active transport is the energy-requiring movement of electrolytes or other substances across cell membranes against their concentration gradient (from an area of low concentration to an area of higher concentration).

 

PTS:    1                      DIF:    Cognitive Level: Remembering (Knowledge)

REF:    465

OBJ:    Describe basic physiological mechanisms responsible for maintaining fluid, electrolyte, and acid-base balances.                     TOP:    Nursing Process: Assessment

MSC:   NCLEX: Physiological Integrity

 

2. A patient has been admitted to the postsurgical nursing unit after surgery. The health care provider has ordered the patient to have an IV of 0.9% sodium chloride. The nurse who is caring for the patient recognizes this as what type of solution?

a.	Hypotonic
b.	Isotonic
c.	Hypertonic
d.	Hypnotic

 

 

ANS:   B

Fluids that have the same osmolality as normal blood are called isotonic. Intravenous (IV) solutions are hypertonic, isotonic, or hypotonic. Isotonic solutions such as 0.9% sodium chloride (same osmolality as normal blood) expand the body’s extracellular fluid volume without causing water to shift in or out of cells. There is no hypnotic solution.

 

PTS:    1                      DIF:    Cognitive Level: Remembering (Knowledge)

REF:    465

OBJ:    Describe basic physiological mechanisms responsible for maintaining fluid, electrolyte, and acid-base balances.                     TOP:    Nursing Process: Assessment

MSC:   NCLEX: Physiological Integrity

 

3. The patient is in a coma after a motor vehicle accident. In addition to IV medications, the patient is receiving an isotonic IV fluid. The primary purpose for this fluid infusion is to:

a.	cause cells to shrink and reduce swelling.
b.	move fluid from intravascular space into cells.
c.	pull fluid from cells into the intravascular space.
d.	expand the body’s intravascular fluid volume.

 

 

ANS:   D

Fluids that have the same osmolality as normal blood are called isotonic. Intravenous (IV) solutions are hypertonic, isotonic, or hypotonic. Isotonic solutions such as 0.9% sodium chloride (same osmolality as normal blood) expand the body’s extracellular fluid volume without causing water to shift in or out of cells. Infusion of hypertonic intravenous solutions (more concentrated than normal blood), such as 3% sodium chloride, pulls fluid from cells by osmosis, causing them to shrink. Physiologically hypotonic solutions (less concentrated than normal blood after they are infused) move water from the extracellular compartment into the cells by osmosis, causing them to swell.

 

PTS:    1                      DIF:    Cognitive Level: Understanding (Comprehension)

REF:    465

OBJ:    Describe basic physiological mechanisms responsible for maintaining fluid, electrolyte, and acid-base balances.                     TOP:    Nursing Process: Planning

MSC:   NCLEX: Physiological Integrity

 

4. Two nursing students were having pizza one evening as they were studying. One student remarked that whenever she ate pizza, she was incredibly thirsty. The second student explained that this thirst was caused by:

a.	colloid osmotic pressure.
b.	osmoreceptors.
c.	oncotic pressure.
d.	hydrostatic pressure.

 

 

ANS:   B

Thirst, a conscious desire for water, regulates fluid intake when plasma osmolality increases (osmoreceptor-mediated thirst) or the blood volume decreases (baroreceptor-mediated thirst and angiotensin II–mediated thirst). The thirst-control mechanism is in the hypothalamus of the brain. Osmoreceptors there continually monitor plasma osmolality; when osmolality increases, the hypothalamus stimulates thirst. Colloid osmotic pressure (oncotic pressure) is an inward-pulling force caused by the presence of protein molecules. Hydrostatic pressure is the force of a fluid pressing outward against the walls of its container. Thus capillary hydrostatic pressure is an outward-pushing force.

 

PTS:    1                      DIF:    Cognitive Level: Understanding (Comprehension)

REF:    465 | 466

OBJ:    Describe basic physiological mechanisms responsible for maintaining fluid, electrolyte, and acid-base balances.                     TOP:    Nursing Process: Assessment

MSC:   NCLEX: Physiological Integrity