Fluids and Electrolytes PP Flashcards
Major Intracellular Ions
K, Mag, Phosphate
Major Extracellular Ions
Na, Calcium, Chloride, Bicarb
Primary Cation and Anion in ECV (extracellular volume)
Cation: Na+
Anion: Cl -
Primary Cation and Anion in ICV (intracellular volume)
Cation: K+
Anion: PO4-
Extracellular Volume can be divided into two fluid systems
Interstitial Fluid (more % of fluid)
and
Plasma
Neonates have the _____ TBW, and females, the elderly, and the obese have the _____ TBW
Highest
Lowest
What mechanism and structure determine the net movement of fluid between the intravascular and interstitial spaces?
Starling Forces and Glycocalyx
What are two forces that move fluid from the capillary to the interstitial space?
Pc = Capillary hydrostatic pressure (pushes fluid out of capillary)
Pi If = Interstitial oncotic pressure (pulls fluid of capillary
What are two forces that move fluid from the interstitial space into the capillary
Pif = interstitial hydrostatic pressure (pressure fluid into capillary)
Pi C = Capillary oncotic pressure (pulls fluid into capillary)
What is the endothelial glycocalyx?
Forms a protective layer on the interior wall of the blood vessel. It acts as a gatekeeper to determine what can pass form the vessel into the interstitial space. Disruption of the glycocalyx contributes to capillary leak.
RBCs are considered about of which compartment?
Intracellular compartment because they are contained by a membrane.
What is hematocrit?
Faction of the blood volume that is occupied by RBCs
Edema occurs when the rate of interstitial fluid accumulation ____ the rate of fluid removal by the ______ system
Exceeds
Lymphatic
Which thoracic duct is smaller? What areas does it drain lymph from?
The right thoracic duct is much smaller than the left—drains lymph from the Right upper extremity, right thorax, and right side of head and neck at the junction of the right IJ and SC veins.
What is osmosis
Net movement of water across a semipermeable membrane
What is osmolALity
Number of osmoles per kilogram of solution
What is OsmolARity
Number of osmoles per liter of solution
Water tends to move from areas of ____ solute concentration to areas of _____ solute concentration
lower solute to HIGHER solute
What is diffusion?
The net movement of a substance (solute) from an area of higher concentration to an area of lower concentration across a FULLY (not semi) permeable membrane. Both water and solute can pass through.
Solute moves down its concentration gradient.
What is Osmotic Pressure?
The pressure of a solution against a semipermeable membrane prevents water from diffusing across that membrane.
It is a COLLIGATIVE property. This means it is a function of the number of osmotically active particles in the solution, NOT a function of their molecular weights.
What is normal plasma osmolarity?
280-290 mOsm/L
What is the formula for plasma osmolarity?
Plasma Osmo = (Na x 2) + (Glucose/18) + (BUN/28)
Hypotonic solutions have an osmolarity ____ than plasma
Lower
Isotonic solutions have an osmolarity ______ to plasma
roughly equal
Hypertonic solutions have an osmolarity _____ than the plasma
Higher
Tonicity compares what to what
Compares the osmolarity of a solution relative to the osmolarity of the plasma
Assuming normal plasma osmolarity, what will the administration of a hypotonic solution do to the cell?
The solution is hypotonic to the cell. Water enters, and the cell swells.
Assuming normal plasma osmolarity, what will the administration of a hypertonic solution do to the cell?
The solution is hypertonic to the cell. Water exits, and the cell shrinks.
What are two hypotonic crystalloid solutions?
NaCL 0.45%
D5W
What are three isotonic crystalloid solutions?
NaCL 0.9%
LR
Plasma-Lyte A
Is Albumin 5% hypo, iso, or hypertonic
Isotonic
What are four hypertonic crystalloid solutions
NaCL 3%
D5 NaCl 0.9%
D5 NaCl 0.45%
D5 LR
How does giving a hypotonic solution affect intracellular and extracellular fluid volume?
Increases the ECF and ICF volumes
How does giving a hypotonic solution affect intracellular and extracellular fluid osmolarity?
Decreases plasma osmolarity.
Hypotonic solutions distribute where?
Throughout all body compartments. This is why it is a POOR intravascular volume and why you should never give it to someone with increased ICP.
How does giving an isotonic solution affect intracellular and extracellular fluid volume?
ICF remains the same and expands ECF and plasma volume.
How does giving an isotonic solution affect intracellular and extracellular osmolarity?
Stays the same.
How does giving a hypertonic solution affect intracellular and extracellular fluid volume?
Reduces ICF. Expands intravascular volume by pulling fluid from the ICF into the ECF.
How does giving a hypertonic solution affect intracellular and extracellular osmolarity?
Osmolarity increases in both ICF and ECF
What are two conditions that hypertonic solutions can be used to treat?
Cerebral edema and hyponatremia
What condition can occur is serum sodium rises too quickly?
Central Pontine Myelinolysis
Total Body Water is around what percent in the elderly?
~50%
Does muscle have more or less water than adipose?
More. Patients who have more adipose tissue will have a lower body water percentage.
Around puberty to adulthood, total body water is about what percent? How much is ICV and how much is ECV?
TBW = ~ 60%
ICV about 2/3 (40%)
ECV about 1/3 (20%)
How is the charge gradient of primary cations and anions between the ICV and ECV maintained?
Maintained by the Na+/K+ ATPase pump in the cell membrane. Requires energy
Assuming a healthy adult, normothermic, and standard metabolic function - how much fluid intake does someone need to take in to remain normovolemic?
About 25-35 ml/kg/day which is about 2-3L
The ECV is made up of ____ compartments and separated by vascular endothelium. What are the components, and what is the volume ratio?
2 compartments.
Intravascular (Plasma volume) = ~1/4
Extravascular (Interstitial) = ~3/4
What pressure influences vascular tone / cardiac output?
Capillary Hydrostatic Pressure (Pc)
What pressure relates to lymphatic drainage? Is it positive or negative?
Interstitial fluid Pressure (Pif) - slightly negative due to drainage of the lymphatic system
What pressure holds some of the water in the intravascular space to maintain plasma volume or to pull fluid from the interstitial space?
Plasma Oncotic Pressure (πif) via colloid proteins. Mainly Albumin
What pressure maintains interstitial volume and pulls fluid from the intravascular space into the interstitial?
Interstitial Oncotic Pressure (πif)
the surrounding tissue can attract water from the capillaries into the interstitial space, promoting movement out of the blood vessels.
What is the glycocalyx?
A thin gel-like structure is on the inner surface of the vascular endothelium.
It is a selectively permeable surface that modules fluid hemostasis, preserves laminar flow, and regulates the immune response and coagulation process.
What can occur when the glycocalyx is damaged?
The vessel wall becomes leaky and allows more fluid than usual into the interstitial space, causing edema
Do crystalloids hydrate just the intravascular/plasma volume or the entire ECV, including the interstitial volume?
The ENTIRE ECV. both plasma and interstitial
While crystalloid will expand the intravascular space, it is transient. About what percentage will filtrate to the interstitial space relatively quickly?
~75-80%
What acid-base balance can occur with
