NUR 334 EXAM 4
STUDY GUIDE: FLUID, ELECTROLYTES, AND GI
DISORDERS
2026 UPDATE WITH COMPLETE SOLUTIONS
INSTITUTION
UNIVERSITY OF ARIZONA COLLEGE OF NURSING
,NUR 334 Exam 4 Study Guide: Modules 7 s 8
Module 7 - Fluid and Electrolytes
Body Fluid Compartments:
• Fluids are continuously exchanged across semipermeable membranes between
intracellular (inside cells - 2/3 of total body fluid) and extracellular (outside cells -
1/3 of total body fluid) fluid compartments
• Extracellular fluid (ECF) is further divided into 2 parts: fluid in the plasma or
intravascular space, and fluid in the interstitial spaces between cells
• 3 solutes determine osmolarity: usually sodium, glucose, and urea
o Sodium is the greatest contributor to osmolarity because it is abundant in
most body fluids
o Changes in osmolality can cause water to move to different compartments
o Tonicity is the relative concentration of intravenous fluid
▪ General term, not a precise measurement, as osmolality is
▪ Tonicity is the ability of a solution to cause a change in water
movement across a membrane due to osmotic forces
▪ Normal plasma is considered isotonic; solutions that have the same
concentration of solutes as plasma are called isotonic
Intravenous Therapy
• Crystalloids
o IV solutions with electrolytes and other substances that closely resemble
the body’s ECF
o Used to replace fluids and promote urine output
o Capable of leaving plasma and moving to interstitial spaces and intracellular
fluid
o Compartment entered depends on tonicity of intravenous fluid
▪ Isotonic - replace fluid lost
▪ Hypertonic- expands plasma volume by drawing water away from
cells and tissues. Can relieve cellular edema
▪ Hypotonic- cause water to move out of plasma to the tissues and
cells; hypernatremia and cellular dehydration
• Colloids
, o Proteins, starches, or other large molecules that remain in the blood for a
long time because they are too large to easily cross capillary membranes
▪ Stay in intravascular space
▪ Rapidly expand plasma volume
o When in the blood, they have the same effect as hypertonic solutions; draw
water from intracellular fluid and interstitial spaces into plasma to increase
plasma osmolarity and osmotic pressure
o Important in treating hypovolemic shock caused by burns, hemorrhage, and
surgery
o Most frequently used colloid - normal serum albumin; helps keep fluid from
leaking out of the blood into the tissues
Prototype Drug: Dextran 40 (Gentran 40, Others)
• Therapeutic Class: Plasma volume expander
• Pharmacologic Class: Colloid
• Action and uses: Dextran 40 is a polysaccharide that is too large to pass through
capillary walls. It is similar to dextran 70, except dextran 40 has a lower molecular
weight. Dextran 40 acts by raising the osmotic pressure of the blood, thereby
causing fluid to move from the interstitial spaces of the tissues to the intravascular
space (blood). Given as an IV infusion, it has the capability of expanding plasma
volume within minutes after administration. Cardiovascular responses include
increased blood pressure, increased cardiac output, and improved venous return to
the heart. Dextran 40 is excreted rapidly by the kidneys.
• Administration:
o Emergency administration may be given 1.2 to 2.4 g/min.
o Nonemergency administration should be infused no faster than 240 mg/min.
o Unused portions should be discarded once opened because dextran
contains no preservatives.
o No definitive data are available on the use of this drug during pregnancy or
lactation.
• Pharmacokinetics:
o Onset: Several minutes
o Peak: Unknown
o Duration: 12–24 hours
• Adverse effects: Vital signs should be monitored continuously during dextran 40
infusions to prevent hypertension caused by plasma volume expansion. Signs of
fluid overload include tachycardia, peripheral edema, distended neck veins,
STUDY GUIDE: FLUID, ELECTROLYTES, AND GI
DISORDERS
2026 UPDATE WITH COMPLETE SOLUTIONS
INSTITUTION
UNIVERSITY OF ARIZONA COLLEGE OF NURSING
,NUR 334 Exam 4 Study Guide: Modules 7 s 8
Module 7 - Fluid and Electrolytes
Body Fluid Compartments:
• Fluids are continuously exchanged across semipermeable membranes between
intracellular (inside cells - 2/3 of total body fluid) and extracellular (outside cells -
1/3 of total body fluid) fluid compartments
• Extracellular fluid (ECF) is further divided into 2 parts: fluid in the plasma or
intravascular space, and fluid in the interstitial spaces between cells
• 3 solutes determine osmolarity: usually sodium, glucose, and urea
o Sodium is the greatest contributor to osmolarity because it is abundant in
most body fluids
o Changes in osmolality can cause water to move to different compartments
o Tonicity is the relative concentration of intravenous fluid
▪ General term, not a precise measurement, as osmolality is
▪ Tonicity is the ability of a solution to cause a change in water
movement across a membrane due to osmotic forces
▪ Normal plasma is considered isotonic; solutions that have the same
concentration of solutes as plasma are called isotonic
Intravenous Therapy
• Crystalloids
o IV solutions with electrolytes and other substances that closely resemble
the body’s ECF
o Used to replace fluids and promote urine output
o Capable of leaving plasma and moving to interstitial spaces and intracellular
fluid
o Compartment entered depends on tonicity of intravenous fluid
▪ Isotonic - replace fluid lost
▪ Hypertonic- expands plasma volume by drawing water away from
cells and tissues. Can relieve cellular edema
▪ Hypotonic- cause water to move out of plasma to the tissues and
cells; hypernatremia and cellular dehydration
• Colloids
, o Proteins, starches, or other large molecules that remain in the blood for a
long time because they are too large to easily cross capillary membranes
▪ Stay in intravascular space
▪ Rapidly expand plasma volume
o When in the blood, they have the same effect as hypertonic solutions; draw
water from intracellular fluid and interstitial spaces into plasma to increase
plasma osmolarity and osmotic pressure
o Important in treating hypovolemic shock caused by burns, hemorrhage, and
surgery
o Most frequently used colloid - normal serum albumin; helps keep fluid from
leaking out of the blood into the tissues
Prototype Drug: Dextran 40 (Gentran 40, Others)
• Therapeutic Class: Plasma volume expander
• Pharmacologic Class: Colloid
• Action and uses: Dextran 40 is a polysaccharide that is too large to pass through
capillary walls. It is similar to dextran 70, except dextran 40 has a lower molecular
weight. Dextran 40 acts by raising the osmotic pressure of the blood, thereby
causing fluid to move from the interstitial spaces of the tissues to the intravascular
space (blood). Given as an IV infusion, it has the capability of expanding plasma
volume within minutes after administration. Cardiovascular responses include
increased blood pressure, increased cardiac output, and improved venous return to
the heart. Dextran 40 is excreted rapidly by the kidneys.
• Administration:
o Emergency administration may be given 1.2 to 2.4 g/min.
o Nonemergency administration should be infused no faster than 240 mg/min.
o Unused portions should be discarded once opened because dextran
contains no preservatives.
o No definitive data are available on the use of this drug during pregnancy or
lactation.
• Pharmacokinetics:
o Onset: Several minutes
o Peak: Unknown
o Duration: 12–24 hours
• Adverse effects: Vital signs should be monitored continuously during dextran 40
infusions to prevent hypertension caused by plasma volume expansion. Signs of
fluid overload include tachycardia, peripheral edema, distended neck veins,
