lOMoARcPSD|17222949
Edapt w5 - Lecture notes week 5
Fundamentals – Patient Care (Chamberlain University)
Studocu is not sponsored or endorsed by any college or university
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, lOMoARcPSD|17222949
Introduction to fluids and electrolytes: Fluids and Electrolytes are an important part of care in most all
disease processes and in wellness. Understanding of the inter-related relationships between electrolytes
and fluid movement between all the vascular spaces allows for more informed nursing care and
prevention of complications.
Osmolality and tonicity: Understanding of tonicity and osmolality is important when preparing to give
intravenous fluids. These fluids come in a variety of concentrations and may often be picked based on
their osmolality. For example, someone who is dehydrated may benefit more from an isotonic or
hypotonic solution. Whereas someone who has water intoxication (drinking an overabundance of water as
sometimes happens with lithium), might need a hypertonic solution.
Depending on the state of the body, healthcare professionals can use intravenous fluids to adjust the blood
osmolality at times when there is a fluid imbalance. While the body has homeostatic mechanisms to make
some adjustments, fluids can add volume, add concentration, or just add water.
Fluid Volume: Although we are made up of
approximately 60% water, only about 4-6 liters (depending
on the size of the person) of it is in the vascular system.
The rest is in and outside cells within tissue. The vascular
system uses proteins and electrolytes to transport drugs,
nutrients, and waste between tissue. Electrolytes are
responsible for much of the shifting of fluid between cells,
extracellular space, and the vascular system.
Moving through Membranes: Fluid moves back
and forth between all three compartments. Fluid
moves through capillary membranes to get from
the vascular system to the interstitial space. Fluid
moves through the cell membrane to get from the
interstitial space to the intracellular area.
Fluid Imbalances: Fluid imbalances are defined by volume and osmolality.
Volume fluid imbalances include increased or decreased volume. The concentration or osmolality of the
fluid is normal, but there is too much or not enough. Fluid replacement for a low volume, in this case,
would be with isotonic fluids. Increased volume is usually treated with medication (diuretics), or in severe
cases, dialysis (artificial kidneys).
Osmolality imbalances either mean that the blood is too concentrated or is too dilute. A high osmolality
means there is a need for hypotonic fluid. A low osmolality indicates a need for hypertonic fluid.
We measure osmolality in several ways:
-Blood test for osmolality with a normal value between 280-300 mmol/kg. This direct measurement is
most accurate, but because osmolality can change quickly, this isn’t as useful when fluid levels are being
corrected.
-Urine specific gravity (normal is between 1.002 and 1.030, although greater than 1.010 may indicate a
hyperosmolar state (high osmolality) assuming normal kidney function).
-Blood test for hematocrit and hemoglobin, with hematocrit being the percentage of red blood cells in
plasma. The higher the hematocrit, the higher the osmolality. This assumes no other underlying reason for
elevated hematocrit (chronic hypoxemia [lack of oxygen], etc.).
Downloaded by Nelson Awino ()
Edapt w5 - Lecture notes week 5
Fundamentals – Patient Care (Chamberlain University)
Studocu is not sponsored or endorsed by any college or university
Downloaded by Nelson Awino ()
, lOMoARcPSD|17222949
Introduction to fluids and electrolytes: Fluids and Electrolytes are an important part of care in most all
disease processes and in wellness. Understanding of the inter-related relationships between electrolytes
and fluid movement between all the vascular spaces allows for more informed nursing care and
prevention of complications.
Osmolality and tonicity: Understanding of tonicity and osmolality is important when preparing to give
intravenous fluids. These fluids come in a variety of concentrations and may often be picked based on
their osmolality. For example, someone who is dehydrated may benefit more from an isotonic or
hypotonic solution. Whereas someone who has water intoxication (drinking an overabundance of water as
sometimes happens with lithium), might need a hypertonic solution.
Depending on the state of the body, healthcare professionals can use intravenous fluids to adjust the blood
osmolality at times when there is a fluid imbalance. While the body has homeostatic mechanisms to make
some adjustments, fluids can add volume, add concentration, or just add water.
Fluid Volume: Although we are made up of
approximately 60% water, only about 4-6 liters (depending
on the size of the person) of it is in the vascular system.
The rest is in and outside cells within tissue. The vascular
system uses proteins and electrolytes to transport drugs,
nutrients, and waste between tissue. Electrolytes are
responsible for much of the shifting of fluid between cells,
extracellular space, and the vascular system.
Moving through Membranes: Fluid moves back
and forth between all three compartments. Fluid
moves through capillary membranes to get from
the vascular system to the interstitial space. Fluid
moves through the cell membrane to get from the
interstitial space to the intracellular area.
Fluid Imbalances: Fluid imbalances are defined by volume and osmolality.
Volume fluid imbalances include increased or decreased volume. The concentration or osmolality of the
fluid is normal, but there is too much or not enough. Fluid replacement for a low volume, in this case,
would be with isotonic fluids. Increased volume is usually treated with medication (diuretics), or in severe
cases, dialysis (artificial kidneys).
Osmolality imbalances either mean that the blood is too concentrated or is too dilute. A high osmolality
means there is a need for hypotonic fluid. A low osmolality indicates a need for hypertonic fluid.
We measure osmolality in several ways:
-Blood test for osmolality with a normal value between 280-300 mmol/kg. This direct measurement is
most accurate, but because osmolality can change quickly, this isn’t as useful when fluid levels are being
corrected.
-Urine specific gravity (normal is between 1.002 and 1.030, although greater than 1.010 may indicate a
hyperosmolar state (high osmolality) assuming normal kidney function).
-Blood test for hematocrit and hemoglobin, with hematocrit being the percentage of red blood cells in
plasma. The higher the hematocrit, the higher the osmolality. This assumes no other underlying reason for
elevated hematocrit (chronic hypoxemia [lack of oxygen], etc.).
Downloaded by Nelson Awino ()
