Fluids & Electrolytes

banana, oranges, spinach, tomatoes, potatoes,

What are a few examples of high potassium foods?

Homeostasis

The dynamic process that enable optimum conditions to be maintained for cells, in spite of continual changes taking place internally and externally

Concepts that affect this process include fluid and electrolytes, acid base balance, thermoregulation, cellular regulation, cranial regulation, glucose regulation, nutrition, and elimination

Imbalances can cause chronic and acute illness, chronic and acute illnesses can create imbalances

endocrine, nervous, respiratory, renal

Even though all body systems are involved in maintaining homeostasis, what are the major contributors?

negative

Does the body more commonly use negative or positive feedback loops to restore the body’s ideal conditions?

Negative feedback

Changes in the body from internal or external stimulus are detected by receptors, which send a signal through afferent pathways to a control center. The control center is releases an output of sent along efferent pathways to the effector. The response of the effector returns the variable back to homeostasis

An example of this is the baroreceptors detecting high BP and the brain lowering it through RAAS

effector organ

an organ carrying out the commands to restore balance

Positive Feedback

Feedback loop that increases variables in the same direction, pushing the body to more extremes

This does not work to restore homeostasis

An example is during childbirth, the body stretches causing oxytocin release, which causes more stretching

promote health, prevent disease, treat illness

What are the 3 main goals of healthcare?

60%

How much of the body is made of fluids in healthy adults?

Dynamic

Body systems make adjustments and alterations in what they’re doing to maintain stability and balance so the body is healthy

Bodies out of balance aren’t compatible with life for very long

Body fluids

Water in our body that provides extracellular transportation routes to deliver nutrients to the cells and carry waste products from the cells

Provides a medium in which chemical reactions or metabolism can occur

Aids in digestion

Helps with insulation, lubrication, and temperature regulation

Thirst mechanisms

Factors that make humans want to drink water

osmoreceptors in the hypothalamic thirst center

When the body has decreased volume of extracellular fluid, what is stimulated?

increased osmolality

What in particular stimulates osmoreceptors?

drinking water

How is the osmolality of the extracellular fluid of the body decreased?

intracellular

Is there more intracellular fluid or extracellulr fluid in the body?

42

How many liters of fluid are in the human body?

Intracellular fluid

Contains 2/3 of the body’s fluids along with solutes such as oxygen, electrolytes, glucose, cations, and anions

Extracellular fluid

Contain 1/3 of the bodies fluids outside of the body’s cells

Contains sodium, chloride, bicarbonate

Made of interstitial fluid, intravascular volume, transcellular/lymph fluid

Interstitial Fluid (ISF)

Fluid that surrounds the cells. Very gell like

75% of the ECF

Intravascular Volume

Plasma/blood

20% of the ECF

Transcellular/lymph fluid

Fluid in the lymphatic system that are being filtered. They are self contained in areas such as the pericardial space or CSF space. The levels do not fluctuate very much

Composes 5% of the ECF

what goes in doesn’t always come out within 24 hours and some output can’t be measured

Why isn’t I&Os always completely accurate and is not considered the most reliable method of tracking a patient’s hydration?

Sensible Loss

Measurable output such as feces and urine

Insensible loss

Output that can not be measured because they are are not visible such as through the lungs and skin

12%

How much does the body’s fluid loss increase when it has a fever?

Body weight

Best indicator of gains and losses of fluid

Especially good for OA because other methods of measurement such as skin turgor are not as accurate on them and is good at sensing dehydration that occurs over 1-4 hours

2.2

How many pounds is 1 kg?

daily weight

What is the best practice to assess fluid status?

Osmolarity

Term used to describe the concentration of the body per liter of solution

Usually used for solutions outside of the body such as IV fluids

Osmolality

Term used to describe the concentration of a solution per kg of water

Usually used when referring to solutions in the body and is what labs use to measure concentration of blood and urine

Osmotic Pressure

Pulling force on water created by the concentration of ions in a solution

Higher concentration, higher pull

osmolality

Is osmolality or osmolarity more reliable and exact?

osmolarity

Is osmolarity or osmolality the more practical form of measurement?

Antidiuretic hormone

If the body is experiencing increased osmolality, which hormone does the hypothalamus force the posterior pituitary gland to secrete?

Antidiuretic Hormone (ADH)

Hormone that increases the distal tube permeability and causes increased reabsorption of water into the blood leading to decreased urine output

Also decreases osmolality of water in the blood by diluting it

When suppressed, this hormone decreases the distal tubule permeability, leading to increase urine output and increased osmolality of the blood

Tonicity

Concentration of a solution compared to other

Isotonic, hypertonic, hypotonic

275-296

What is the normal osmolarity of blood and other body fluids?

Isotonic

When the solute concentration in the intracellular fluid and the extracellular fluid are the same, thus the pulling force of both are equal

Hypertonic

ECF has a greater tonicity than that of intracellular fluid so with the osmotic pressure being unequal to that of what’s inside the cell there will be movement. The body will try to equal out the concentration inside the cell with the concentration outside the cell, which will cause water to move out the cell and make the cell shrink

Hypotonic

ECF has a tonicity less than what is in the intracellular fluid, causing the ECF to rush into the cell to equal out. This makes the cell swell

IV fluids

Main purpose is to either maintain body fluids or replace body fluids, but it also corrects electrolytes, provides some calories if it contains glucose, and corrects/maintains acid-base balance

250-375

What is the osmolarity of isotonic solutions?

Isotonic fluids

Fluid that stays in the intravascular space to increase volume when infused. Used to increase BP especially in codes, shock, or hemorrhage, and severe fluids

If too much is given, it can cause circulatory overload by over expanding the vascular compartment and diluting the hemoglobin and hematocrit levels

Eg NaCl (NS), LR, D5W (turns hypotonic in body as dextrose is metabolized)

Hypotonic

Fluids that provide more water than electrolytes, used during cellular dehydration, DKA, and hyperosmolar hyperglycemia

DO NOT give to those with hypotension or increased intercranial pressure because you do not want fluids to be moving from the vasculature into the cells

<250

What is the osmolarity of hypotonic solutions?

375

What is the osmolarity of a hypertonic solution?

Hypertonic

Fluid that has more electrolytes than water and cause fluids to move out of the cells

Treats severe hyponatremia and increased intracranial pressure

These are very irritating to the veins and may cause hypertonic circulatory overload so they are often given in central lines and monitored in higher care units such as ICU

stable IV fluids

Since hypertonic solutions are more caustic to the vein, what are they usually given with?

Circulatory overload

When there is too much fluid in the circulatory system, causing the lungs to sound like crackles, struggle to breath, and cyanosis around the mouth, confusion and irritability

confusion and irritability

What is one of the first sign that is seen with hypoxia?

yes

Do you have to have a doctor’s order to use IV fluids?

Colloid Osmotic Pressure

Inward pulling force in the veins is caused by particles in the interstitial and intracellular fluids, mainly controlled by albumin

This pressure stays pretty constant throughout the body

Hydrostatic Pressure

Force of fluids in the veins that pushes out, as if trying to escape the veins

This force is very powerful closer to the heart, but further away in the veins it becomes weaker than orthostatic pressure, allowing for fluids to start entering the veins

closer

Is hydrostatic pressure stronger further or closer to the heart?

60/40/20 Rule

Rule stating that 60% of the body’s weight is water, 40% of that 60 is intracellular fluids, and 20% of that water is extracellular fluid

1.3-2.1

Normal magnesium levels

2.5-4.5

Normal phosphate levels

3.5-5.0

Normal potassium levels

9.0-10.5

Normal calcium levels

95-105

Normal chloride levels

135-145

Normal sodium levels

ECF

What do are we measuring when we draw labs for electrolytes?

muscle relaxation

What is the purpose of magnesium?

muscle contraction

What is the purpose of phosphorous?

intracellular excitation

What is the purpose of potassium?

neuronal excitation/bone pain

What is the purpose of calcium?

acidosis vs alkalosis

What is the purpose of chlorine?

extracellular excitation

What is the purpose of sodium?

sodium

What is the most abundant extracellular electrolyte?

potassium

What is the most abundant intracellular electrolyte?

Magnesium

Electrolyte that keeps muscles calm and functioning properly mainly in the heart, uterus, and deep tendon reflexes

Required for calcium and vitamin D absorption

Hypermagnesemia

Electrolyte imbalance that slows all the muscles, especially heart (bradycardia, hypotension), hyporeflexia/decreased DTR, depression shallow respirations, constipation and hypoactive bowel sounds,

Hypomagnesemia

Electrolyte imbalance which causes the heart to go wild, torsades de pointes, hyperflexia (increased DTR), nystagmus, and diarrhea

Hyperkalemia

Electrolyte imbalance that causes the heart to get tight and contracted so it can’t effectively pump, hypotension, cardiac standstill, diarrhea, hyperactive bowel sounds, paralysis in the extremities because the muscles are too tightly contracted, increased DTR, profound muscle weakness because they’re too tight to move

MUSCLE WEAKNESS OF THE LEG IS VERY COMMON

Hypokalemia

Electrolyte imbalance that causes the heart to start going very slow, there’s decreased DTRs, muscle cramping, flaccid paralysis, decrease in motility with hypoactive bowel sounds that cause constipation, and abdominal distention causing paralytic ileus leading to small bowel obstruction

VERY COMMON FOR THEIR TO BE MUSCLE WEAKNESS OF THE LUNGS

Calcium

Electrolyte that affects bones, blood (clotting factors), and heart beats

Hypercalcemia

Electrolyte imbalance that cause swollen and slow such as constipation, bone pain, kidney stones, and decreased/severely weakened DTR

Hypocalcemia

Electrolyte imbalance that causes Trousseau’s sign, Chvostek’s sign, diarrhea, problems with blood clotting, arrhythmias, and circumoral tingling

Chvostek’s sign

Twitching of the facial muscles in response to tapping over the area of the facial nerve

Trousseau’s sign

Carpopedal spasm (of the arms) caused by inflating the blood pressure cuff to a level above systolic pressure for 3 minutes

circumoral tingling

tingling around the mouth

blood pressure, blood volume, pH balance

What are the 3 functions of sodium?

Hypernatremia

Electrolyte imbalance that causes flushed skin, edema, low grade fever, and polydipsia.

Late and serious signs consist of swollen dry tongue, increased muscle tone, nausea and vomiting

Hyponatremia

Electrolyte imbalance that causes seizures, coma, tachycardia, weak and thready pulses, and respiratory arrest

Edema

Accumulation of fluid within the interstitial space

Caused by an increase in capillary hydrostatic pressure, (pushes fluid too strongly out of the cells) decrease in plasma oncotic (or osmotic) pressure, increase in capillary permeability, lymph obstruction or leakage

First Spacing

Normal distribution of fluid in the ICF and ECF

Second Spacing

Abnormal accumulation of fluid (edema) in the interstitial space

“normal” edema

Third Spacing

Fluid accumulation in a part of body that is not in the ICF or ECF and does not contribute to equilibrium between ICF and ECF

Commonly seen with ascites, burns, bowel obstruction, peritonitis, and massive bleeding

Fluid seeps into areas that aren’t easily pulled back into the vascular space

Diuretics

Medication used to combat edema by pulling fluid back into intravascular space and then letting the kidneys flush it out of the body

Compression Stockings

Device used to combat edema (particularly peripheral) by creating pressure to make it difficult for fluid to enter the interstitial space via hydrostatic pressure to begin with

Ascites

Fluid collection in the abdominal cavity when the capillaries secrete fluid into the abdominal peritoneum, causing fluid to leak out into the peritoneal cavity

This can actually cause depletion of fluid from the intracellular, interstitial, or vascular compartments

Hypothalamus

Part of the brain that has the thirst mechanism, which is the primary regulator of fluid intake

thirst mechanism

What is the primary regulator of fluid intake?

urine

What is the biggest cause of fluid loss?

Aldosterone

Hormone that affects BP by causing release of sodium in vascular system, excretion of potassium in urine, and water reabsorption in order to main BP

1-2%

How much must osmolality increase to stimulate the thirst mechanism?

Angiotensin II and III, increased osmolality, decreased plasma volume, dry mucous membranes, psychological factors

What causes activation of the thirst mechanism?