N5315 Advanced Pathophysiology
Fluid and Electrolytes
Core Concept and Objectives with Advanced Organizers
Fluid and Electrolytes
1. Analyze the pathologic consequences of fluid volume disorders on the mechanisms of
fluid homeostasis.
a. Explain the three main fluid compartments and describe how fluid shifts between
the compartments and the implications for clinical practice.
Fluid Compartments Definition Pattern of Fluid Shifts Clinical Implications
Extracellular Fluid -total volume of fluid
(ECF) outside of the cells
1/3 of body’s fluid
Intravascular TBW 20% in the Both in and out of the Volume overload
-main ECF vessels interstitial and Venous retention
compartment intracellular spaces Increased venous
pressure
Hypertonic IV edema
solution, when
administered, will
increase the solute
concentration in the
intravascular space
Interstitial -total volume of Hydrostatic (movement Edema
-main ECF ECF outside of the by force) and osmotic
compartment blood vessels and is (concentration of Fluid will shift from
separated from solutes movement of intracellular into the
fluid) pressures cause extracellular space
plasma by walls of
movement of fluid
body’s vasculature
*capillary hydrostatic
-contins 20% of
pressure
TBW
*capillary oncotic
pressure
*interstitial
hydrostatic pressure
*interstitial oncotic
pressure
*Intracellular -fluid present inside Controlled by Possible cellular
Space/Fluid (ICF) of the cells and osmotic pressure with injury r/t oncosis
40% total body of considered sum total Na/K concentrations
water of the fluid volume in The cell will continue
all of the body’s cells Fluid flows via to shrink
2/3 of body’s fluid
-separated from osmosis from the
ECF by plasma intracellular space
membrane into the extracellular
space to equalize the
concentration of
, N5315 Advanced Pathophysiology
Fluid and Electrolytes
Core Concept and Objectives with Advanced Organizers
solutes. This will
cause the cell to
shrink. Water will
continue to flow into
the intravascular
space from the
extracellular space if
the intravascular
space still remains
more concentrated
than the extracellular
space
b. Analyze the principles of fluid balance and describe the implications for clinical
practice.
Mechanisms of Fluid Definition Clinical Implications
Balance
Osmolality Measure of solute concentration May be altered by IVF
in a solution concentrations fluid shifts
Plasma osmolality normal
Is 280-295mmOskg
Low potentially 275
Osmosis Movement of water between Hypertonic solutions can pull
compartments from an area of fluid into the intravascular
low concentration of solutes to space, while hypotonic
one that has a high concentration solutions may cause fluid to be
of solutes pulled out of the vasculature
-passive force (low to high)
*Does not require energy
*Where Na+ goes H2O follows
Osmotic Pressure Amount of pressure or force that Hypertonic solutions increase
is exerted by solute molecules of osmolality, increases fluid
a given compartment absorbed in vessels
-The higher the osmolality the
higher the osmotic pressure
(pulling force that will pull water
into a compartment)
*may be overcame by hydrostatic
pressure
Hydrostatic Pressure Force within a fluid Effects of Blood pressure
compartment-the mechanical
force of fluid against the walls of
the compartment
-pushing force and pushes fluid
Fluid and Electrolytes
Core Concept and Objectives with Advanced Organizers
Fluid and Electrolytes
1. Analyze the pathologic consequences of fluid volume disorders on the mechanisms of
fluid homeostasis.
a. Explain the three main fluid compartments and describe how fluid shifts between
the compartments and the implications for clinical practice.
Fluid Compartments Definition Pattern of Fluid Shifts Clinical Implications
Extracellular Fluid -total volume of fluid
(ECF) outside of the cells
1/3 of body’s fluid
Intravascular TBW 20% in the Both in and out of the Volume overload
-main ECF vessels interstitial and Venous retention
compartment intracellular spaces Increased venous
pressure
Hypertonic IV edema
solution, when
administered, will
increase the solute
concentration in the
intravascular space
Interstitial -total volume of Hydrostatic (movement Edema
-main ECF ECF outside of the by force) and osmotic
compartment blood vessels and is (concentration of Fluid will shift from
separated from solutes movement of intracellular into the
fluid) pressures cause extracellular space
plasma by walls of
movement of fluid
body’s vasculature
*capillary hydrostatic
-contins 20% of
pressure
TBW
*capillary oncotic
pressure
*interstitial
hydrostatic pressure
*interstitial oncotic
pressure
*Intracellular -fluid present inside Controlled by Possible cellular
Space/Fluid (ICF) of the cells and osmotic pressure with injury r/t oncosis
40% total body of considered sum total Na/K concentrations
water of the fluid volume in The cell will continue
all of the body’s cells Fluid flows via to shrink
2/3 of body’s fluid
-separated from osmosis from the
ECF by plasma intracellular space
membrane into the extracellular
space to equalize the
concentration of
, N5315 Advanced Pathophysiology
Fluid and Electrolytes
Core Concept and Objectives with Advanced Organizers
solutes. This will
cause the cell to
shrink. Water will
continue to flow into
the intravascular
space from the
extracellular space if
the intravascular
space still remains
more concentrated
than the extracellular
space
b. Analyze the principles of fluid balance and describe the implications for clinical
practice.
Mechanisms of Fluid Definition Clinical Implications
Balance
Osmolality Measure of solute concentration May be altered by IVF
in a solution concentrations fluid shifts
Plasma osmolality normal
Is 280-295mmOskg
Low potentially 275
Osmosis Movement of water between Hypertonic solutions can pull
compartments from an area of fluid into the intravascular
low concentration of solutes to space, while hypotonic
one that has a high concentration solutions may cause fluid to be
of solutes pulled out of the vasculature
-passive force (low to high)
*Does not require energy
*Where Na+ goes H2O follows
Osmotic Pressure Amount of pressure or force that Hypertonic solutions increase
is exerted by solute molecules of osmolality, increases fluid
a given compartment absorbed in vessels
-The higher the osmolality the
higher the osmotic pressure
(pulling force that will pull water
into a compartment)
*may be overcame by hydrostatic
pressure
Hydrostatic Pressure Force within a fluid Effects of Blood pressure
compartment-the mechanical
force of fluid against the walls of
the compartment
-pushing force and pushes fluid
