Body Fluids Physiology Flashcards
What percentage is the body is total body water?
About 55-60%
What 4 factors make TBW have variations?
Body fat content, age, herbivores v. carnivores (diet), sex
What are 5 basic functions of aqueous solutions in the body?
Glomerular filtration in the kidney
Establishment of a solute concentration gradient
Maintaining cell size
Excitability of cell membrane
Generation of a nerve impulse
What percent of TBW is extracellular fluid? (as a whole)
33%
What percent of TBW is intracellular fluid?
67%
What percent of TBW is plasma?
8%
What percent of TBW is interstitial fluid?
25%
Sucrose is a marker for _______.
ECF
tritium oxide is a marker for ____.
TBW
Radioactive albumin (125- Albumin) is a marker for _____.
Plasma
Can ICF be measured directly or indirectly?
Indirectly, by calculating TBW - ECF
ICF is / of TBW
2/3
ECF is / of TBW
1/3
ISF & other transcellular fluid are / of TBW or _% of ECF
1/4, or 75% of ECF
Plasma is / of TBW or _% of ECF
1/12.5, or 25%
What is SID?
Significant/strong ion difference- The calculated difference between the concentration of positively charged “strong cations” and negatively charged “strong anions” (mainly chloride) in a solution.
What is the most exchangeable ion?
K+
What do electrolytes do?
They control the likelihood for a cell to be excited
What are the major ICF electrolytes?
Potassium (K+), magnesium (Mg), and phosphorus (P)
What are the major ECF electrolytes?
Sodium (Na), chloride (Cl-), and bicarbonate (HCO3-)
Urine & feces are _____ routes of water loss
Sensible
Insulin is a marker for_____.
ECF
Deuterium oxide (D20) is a marker for ______.
TBW
Evans blue is a marker for _______.
Plasma
What is the equation for total blood volume?
Plasma x 100/ 100- HCT (hematocrits)
What happens to blood when the significant ion difference decreases?
Blood becomes more acidic
What happens to blood when the significant ion difference increases?
Blood becomes more alkaline
The amount by which the strong positive ions (cations) are in excess of the strong negative ions (anions).
SID (significant/strong ion difference)
Diffusion, respiration, and sweat are ______ routes of water loss.
insensible
If the water content of the blood was low due to too much salt or sweating, what would happen to the brain and urine output?
The brain would produce more ADH, and a high volume of water is absorbed by the kidney, resulting in a low urine output.
If the water content of the blood was high due to overconsumption of water, what would happen to the brain and urine output?
The brain would produce less ADH, and a high volume of water is absorbed by the kidney, resulting in a high urine output.
What is edema?
The excessive accumulation of H2O in interstitial fluid. It is mostly extracellular and may develop due to factors like:
- Incr. of hydrostatic pressure in the capillaries
- Decr. colloidal osmotic pressure
- Failure of the kidney to excrete excess water
- Lymphatic obstruction
What are the 3 types of dehydration?
Isosmotic
Hyperosmotic
Hypoosmotic
Which dehydration occurs when proportionally the same amount of water and sodium is lost from the body?
Isosmotic dehydration
Which dehydration occurs when proportionally more water than sodium is lost from the body?
Hyperosmotic dehydration
Which dehydration occurs when proportionally more sodium than water is lost from the body?
Hypoosmotic dehydration
What causes hyperosmotic overhydration?
Oral or parenteral intake of large amounts of hypertonic fluid (high levels of solute, like salt)
What type of overhydration involves:
- Incr. of plasma osmolality
- Water shift from ISF to plasma
- Incr. of plasma volume
- Decr. in osmolality of the ECF (plasma), and incr. of osmolality of the ISF (2nd effect)
- Water shift from ICF to ECF
- Decr. in ICF volume
Hyperosmotic overhydration
What type of overhydration involves:
- Decr. in plasma osmolaliry
- Water shift from plasma to ISF
- Decr. in ISF osmolality
- Water shifts from ISF to ICF
Hypoosmotic overhydration
What is increased serum potassium concentration well above normal?
Hyperkalemia
What is the false state of increased serum potassium concentration, usually contributed by red cells?
Pseudohyperkalemia
What is the increased serum potassium concentration well above normal, caused by factors that regulate potassium balance- renal and extrarenal factors?
True hyperkalemia
What is the function of diuretics (furosemide)?
increases potassium excretion
What is the increased serum potassium concentration well above normal?
Hyperkalemia
What is the false state of increased serum potassium concentration, usually contributed by red blood cells?
Pseudohyperkalemia
What is the increased serum potassium concentration well above normal, caused by factors that regulate potassium balance- renal and extrarenal factors
True hyperkalemia
What is the function of diuretics (furosemide)?
To increase potassium excretion
What is the function of calcium chloride?
To antagonize the effect of hyperkalemia when given an IV
What is the function of glucose and insulin?
To control the situation in 10 minutes when given an IV
What is the function of sodium bicarbonate?
To stimulate cellular uptake of K+ when given an IV (same as calcium chloride)
(as well as treating metabolic acidosis)
What is the function of GIT potassium binders?
To reduce serum K+ levels via ion exchange mechanisms in the gastrointestinal tract
(cation exchange resins = polystyrene sulfonate)
What are some extrarenal causes of hypokalemia?
- Diarrhea
- Vomiting
- Potassium redistribution
- Insulin administration
- Acute alkalemia
- Folic acid and Epinephrine infusion
- Vitamin B (stimulates cell proliferation and produces hypokalemia)
What is the normal potassium level in dogs and cats?
3.5-5.5 mEq/L
What organs help maintain the water-salt balance?
Lungs, heart, blood vessels, kidneys, brain/pituitary, parathyroids, and adrenal cortex
What are some extrarenal causes of hypernatremia?
- Decreased fluid intake (dehydration)
- Increased skin loss (sweating)
- Increased GIT loss (vomiting, diarrhea)
What are some antidotes for hypernatremia?
- Free water intake
- Intravenous infusion of 5% dextrose solution
- Administration of Vasopressin (ADH)
- Use of thiazide diuretics and drugs that enhance the renal tubular effect of ADH
- Drugs that contribute to the stimulation of ADH release
What is hemolysis?
the breakdown of red blood cells; (RBCs) break down prematurely, releasing their hemoglobin into the bloodstream
hyperproteinemia decreases the amount of ____ in the blood while increasing the amount of ______.
water, proteins
hyperlipidemia decreases the amount of ____ in the blood while increasing the amount of ______.
water, lipids
What is the problem characterized by too much water but not necessarily too little sodium?
hyponatremia
What is the false increase of Na levels?
pseudohypernatremia
What is pseudohyponatremia?
a condition in which the serum sodium concentration (the level of sodium in the blood) appears low, but the body’s fluids are actually at a normal concentration
What is caused by a:
- decreased glomerular filtration rate
- Increased PT (proximal tubule) reabsorption of water seen in diseases with decreased renal perfusion pressure
- Drug-induced SIADH
Hyponatremia
What part of the kidney is responsible for resorption of water and electrolytes?
proximal tubule (65% resorption)
What does SIADH stand for?
Syndrome of Inappropriate Antidiuretic Hormone Secretion.
What is SIADH ?
It is a condition where the body produces too much antidiuretic hormone (ADH), leading to excessive water retention and low sodium levels in the blood (hyponatremia).
What is the drug chlorpropamide used to treat?
Type 2 diabetes mellitus, drug-induced SIADH
What is the drug clofibrate used to treat?
lower cholesterol and triglyceride (fat-like substances) levels in the blood, drug-induced SIADH
What are the normal sodium levels in dogs?
140-154 mEq/L
What are the normal sodium levels in cats?
145-158 mEq/L
What causes variations in NA levels?
age,
diet, hydration status, and health conditions
What is given to patients to combat hyperkalemia?
calcium chloride via IV
Which organs maintain a water-salt balance?
lung, blood vessels, heart, kidney, brain/pituitary, parathyroid glands, and adrenal cortex.
How do the lungs maintain a water-salt balance?
Gaseous exchange in the epithelium at the alveolar level
What hormone is PTH?
parathyroid hormone
How does the parathyroid maintain a water-salt balance?
PTH controls the calcium and phosphorus through;
1) release of calcium from bones into the bloodstream
2) absorption of calcium from the intestines
3) reabsorption of calcium in the kidneys
What are the 4 roles of electrolytes in the body?
1) Conduct electricity across cell membranes; they are needed for life processes to occur.
2) Maintain osmolality of body fluid compartments.
3) Regulate balance of acids and bases.
4) Aid in neurological and neuromuscular conditions.
What must be present for a homeostatic condition to exist?
Equal amounts of anions and cations must be present
on either side of the cell membrane
Where are extracellular electrolytes found?
The interstitial and intravascular fluids where there is a balance of anions and cations.
What are the kinds of IV fluids?
1) Colloids
2) Crystalloids
3) Blood and blood products
4) Oxygen-carrying solutions
What do colloid IV fluids help?
Improves the oncotic pressure in blood.
How do colloids maintain blood volume?
They contain proteins and molecules that are too large to pass through the capillary walls, so they have to stay in the blood stream for a long time, which increases the intravascular volume.
What nonclinical factors should be considered before using colloids for IV fluids?
They are expensive, have specific storage requirements, and have a short shelf life.
What strengths are available for albumin?
Albumin 5% and 25%
What is albumin made from?
Pooled human plasma
What do colloidal fluids treat or prevent by increasing the intravascular volume?
Edema
Describe Albumin 5%?
Slightly yellow tint, contains no preservatives, and slightly viscous.
(Albumin 5% is composed of 154 mEq’s of Sodium and 50 grams of albumin and has a pH level of 6.6 as well as an osmolarity of
290)
What is Albumin 25% used primarily to treat?
hypoproteinemia
What is another type of plasma expander that is similar in properties to Albumin.
Hetastarch (Hespan); It is composed of 154 mEqs of Sodium with a pH level of 5.5 as well as an osmolarity of 310
Name 3 conditions when you would want to use colloidal solutions?
1) Edema
2) Liver dysfunction
3) Low blood sugar
Name 3 plasma expanders?
Albumin, Hespan, and Dextran
What are the strengths (#) of Dextran?
Dextran 40 and 70
What are the 2 basic compounds that regulate osmotic pressure in plasma?
electrolytes and proteins
What type of solutions are primarily used in pre-hopsital therapy?
Crystalloids
Crystalloids contain electrolytes (e.g., sodium, potassium, calcium, chloride) and are classified according to their ________?
tonicity
What is crystalloid tonicity?
the concentration of electrolytes (solutes) dissolved in the water, as compared with that of body plasma fluid surrounding the cells
Give examples of crystalloids
normal saline, lactate ringers, dextrose 5% in water
What is the main solution of choice when administering a blood product?
Normal saline
Which crystalloid is considered isotonic in the bag before it is administered?
D5W (Dextrose 5% in water)
What are the most desirable/precious fluids for replacement for intravascular volume?
blood and blood products
Why use blood and blood products for intravascular volume replacement?
Because they carry oxygen to the cells
Which type of blood is universally compatible in humans?
0-negative
When considering blood typing and cross matching, what is special about ruminants?
They rarely require type and cross matching prior to receiving blood products.
Why does blood transfusion only briefly provide relief from signs of anemic anoxia in animals?
The erythrocytes have extremely short half-lives in the recipients.
Dogs that have __________can be considered to be universal recipients while ___________ are universal donors
DEA 1.1 positive ; DEA 1.1 negative
Why is it difficult to harvest plasma from ruminant blood without access to a large centrifuge or equipment for plasmapheresis?
Ruminant blood does not separate out naturally on standing, unlike equine blood.
What is the easiest way to give a plasma transfusion to ruminants?
Administer whole blood.
What are synthetic fluids that carry and deliver oxygen to the cells?
oxygen-carrying solutions
When would you use oxygen-carrying solutions if blood products are not available?
severe blood loss or hypovolemia
What are the 3 types of fluid classifications?
maintenance fluids, replacement fluids, and special fluids
What is the function of maintenance fluids?
replace insensible fluid losses
What is the function of replacement fluids?
correct body deficits due to gastric drainage, vomiting, diarrhea, infection, trauma, burns, etc.
What are 3 conditions and treatments with special fluids?
1) Hypoglycemia - 25 % dextrose
2) Hypokalemia —- inj. KCl
3) Metabolic acidosis – inj. of sodium bicarbonate
Where do fluids distribute?
1) IV goes to → ________.
2) Subcutaneous goes to → ________, then → _______.
3) Oral goes to → _______ then → _____, and then ______.
1) plasma
2) interstitial space, blood
3) intestines, ISF, and blood
What 5 factors determine which IV solution to use?
1) Tonicity
2) Osmolarity
3) Osmolality
4) Type of dehydration
5) Type of electrolyte imbalance
What are the 6 routes of fluid administration?
1) Oral
2) Intravenous
3) Intraperitoneal
4) Subcutaneous
5) Intramedullary (IO or bone marrow)
6) Rectal
What are 4 advantages of oral rehydration?
Simple & inexpensive, owners can do this at home, large volumes can be administered, and most types of fluids can be used due to selective absorption.
What are 7 disadvantages of oral
rehydration
1) Slow absorption rate,
2) Not good for vomiting patients
3) Can’t use for circulatory shock
4) Time consuming
5) Stressful if the patient is forced
6) Risk of aspiration pneumonia when forced by syringe
7) Only effective with mildly dehydrated animals.
What are the 2 advantages of
subcutaneous fluid therapy?
1) Simple, quick and inexpensive.
2) Useful in small animals such as hamsters where intravenous fluid therapy is impossible
What are the 7 disadvantages of
subcutaneous fluid therapy
1) Slow rate of absorption.
2) Can’t use for circulatory shock.
3) Painful. Irritation and sepsis may result.
4) Contraindicated if the skin is devitalized.
5) Limited type of fluids, (isotonic only).
6) Only small volumes of fluid can be administered (10-12mls/kg per injection site).
7) Mild dehydration only.
What are the 2 main dangers associated with intraperitoneal fluid administration
Peritonitis and risk of puncturing an abdominal organ.
What are the 2 main risks associated with intravenous fluid therapy?
Thrombophlebitis (vein swells and forms a blood clot or thrombus) and over-transfusion if kidney damage exists
What are 9 conditions where IV fluids are administered?
- Coma
- Anesthesia
- Severe vomiting
- Diarrhea
- Dehydration
- Shock
- Hypoglycemia
- It is a vehicle for antibiotics, chemotherapy agents
- Critical problems (anaphylaxis, status asthmaticus (asthma)
or epilepticus (seizures), cardiac arrest, forced diuresis in drug overdose, poisoning etc.)
What things are considered to determine the appropriate IV fluid to administer?
- the pathology / histology
- the patient’s underlying problem
- estimated fluid loss
- the primary fluid compartment involved
- the physiological and hemodynamic impact of the IV solution
Some complications of IV fluids are categorized into what 2 types?
local and systemic
What are the local complications of IV fluids?
hematoma (blood in the ISF) and phlebitis (inflammation of the veins)
What are 7 systemic complications of IV fluids?
1) Circulatory overload in large volumes
2) Hyper-coagulation due to reduction in AT3 (antithrombin III protein, natural defense)
3) Rigors (shivering due to large amounts of cold IV fluids)
4) Air embolism, delayed healing of anastomosis
5) Inhibition of GI motility (peristalsis)
6) Septicemia
7) Others: fluid contamination, mixing of incompatible drugs
What are the names of 4 types of isotonic IV fluids used all the time?
1) 9% NaCl, normal saline
2) LRS, lactate ringers
3) Plasmalyte
4) Normosol
How to calculate the daily metabolic water requirement?
mL/day=(30 x BWkg) + 70
How to calculate the amount of fluid deficit in liters (dehydration)?
BWkg x estimated % dehydration x 1,000 ml/L
How to calculate the percentage of dehydration (%)
Well wt (kg) - Current wt (kg) ÷ Well wt (kg) x 100
How to calculate the infusion rate or how fast (flow rate)?
total fluid volume x drop factor ÷ time (4 hrs? 6hr? 8hr?)
How to calculate infusion time or how long?
time = total quantity bag ÷ flow rate (ml/ hr)
what is the number of drops it takes to make up one milliliter (ml) of fluid called?
drop factor or IV drip rate
What are the 2 common sizes for drip rates? and for which fluids?
“gtts” is the medical abbreviation means drops
20 drops/mL for clear fluids
15 drops/mL for thicker substances such as blood.
What are the 2 types of tubing infusions?
microdrip and macrodrip
How is the IV fluid drip rate (gtt/min) calculated?
IV Drip Rate (gtt/min) = Total Volume
÷ Time (min) x Drop Factor (gtt/mL)
How to calculate the daily water intake?
Body wt x 2/3 (or 67%)
What is necessary for hydration to be calculated?
No ongoing losses
How to calculate the total fluid deficit?
Deficit (ml) = premorbid wt- current wt (kg) x 1000
For IV fluids, use the ______ diameter and the _______ catheter.
largest; shortest
What is the name of the physic law for pressure?
Poiseuille’s Law
Delta p = pressure difference between the two ends
N = dynamic viscosity
L = length of tube
Q = volumetric flow rate
R = tube radius
What is the state of poor perfusion to tissues called?
shock
What 3 things are needed for perfusion?
pump (heart), tubes, (vessels) , fluid (blood)
Poor perfusion leads to what?
Organ dysfunction
What are the signs of shock?
Pallor (pallness), tachycardia, tachypnea, prolonged CRT (capillary refill time), hypothermia – Cats—bradycardia??
Signs of shock in dogs?
Rapid heart rate and weak pulse: The body is trying to pump more blood to vital organs.
Rapid and shallow breathing: The body is trying to get more oxygen to the tissues.
Pale or bluish gums, lips, and tongue: Reduced blood flow causes a lack of oxygen.
Cold extremities: The body is shunting blood away from non-essential areas to preserve vital organs.
Low blood pressure: The body is not circulating enough blood.
Lethargy, confusion, or unresponsiveness: The brain is not getting enough oxygen.
Vomiting or diarrhea: The body may try to expel toxins or reduce blood volume.
Seizures or tremors: In severe cases, shock can affect the nervous system.
What sign of shock might be different in cats?
bradycardia (slow heartrate)
What is the treatment for shock?
– Oxygen
– IV fluids (unless cardiogenic shock)
– Pain management
What is oedema (edema)? Special types?
Accumulation of fluid in the interstitial spaces
* Special types: ascites, hydrothorax
What is ascites?
a type of edema where the interstitial fluid is in the peritoneal cavity of the abdomen
What is hydrothorax?
a type of edema where there is a n abnormal accumulation of fluid in the pleural space between the lungs and chest wall
What are the causes of oedema?
- Increased Pcap (capillary
hydrostatic pressure) - Decreased πcap (oncotic pressure)
- Blocked lymphatics
- Increased capillary permeability
(inflammation, histamine
What is Starlings’ Law of capilllaries?
the movement of fluid between
the capillaries and interstitial fluid is due to the net effect of all four
pressures operational within and around the capillaries
What is the equation used to calculate the NFP (net filtration pressure) and determine the direction of movement?
NFP = (BHP + IFCOP) (favour filtration) –(BCOP + IFHP) (oppose
filtration).
What does NFP stand for?
net filtration pressure
What does BHP stand for?
blood hydrostatic pressure
What does BCOP stand for?
blood colloid osmotic pressure
What does IFHP stand for?
interstitial fluid hydrostatic
pressure
What does IFCOP stand for?
interstitial fluid colloid osmotic pressure
_______ and ________promote the movement of fluid out of the
capillaries or filtration. _______ and __________ promote the movement of fluid into the capillaries or reabsorption.
BHP and IFCOP
BCOP and IFHP
If the filtration pressure is greater than resorption pressure, then the NFP will be what
postive
If the resorption pressure is greater than the filtration pressure, then the NFP will be what?
negative
Under normal conditions physiologically, which factors of Starling’s Law do not significantly vary?
IFHP, IFCOP, and BCOP
In most tissues, the rate of filtration and reabsorption comes down to ______?
BHP, blood hydrostatic pressure
What is condition in sheep characterized by a swelling of the submandibular lymph nodes, located under the jaw that is caused by a worm that destroy Albumin?
bottle jaw sheep, interstitial edema of the lower jaw
What condition is a painful swelling of the lymphatic vessels in a limb, usually in the horse’s hind leg. It’s often caused by a bacterial infection.
lymphangitis of the horse
How do you tell when an animal is dehydrated? (Initial Assessment and blood work?)
- Eyes
- Skin
- Mouth – CRT (capillary refill time)
- Hematocrit
- Range of dehydration– 5- 12%
What is the range of fluid loss to diagnose an animal with dehydration?
5% to 12% difference from their initial body weight
What do I have to consider when rehydrating an animal?
Replacement [90ml/kg/h in dogs; 45ml/kg/h in cats] Severe
* Maintenance [60-80ml/kg/day]
* Compensate for ongoing excess loss of fluids
What is the equation for Total Body Volume? (TBV)
TBV = ICF + EFC
What are some antidotes for hyperkalemia?
Calcium Chloride
Glucose & Insulin
Diuretics
Dialysis
What are some symptoms of hyperkalemia?
Arrhythmias and neuromuscular disorders
What kind of fluids would you give
a dog with hypernatremia?
3% sodium chloride (NaCl): 2 mL/kg of 3% NaCl IV over 10 to 60 minutes
Lactated Ringer’s solution (LRS): A fluid and electrolyte replacement solution
Plasmalyte-A: A balanced isotonic crystalloid solution
Hypertonic saline: 3% or 5%
What kind of fluids would you give a cow with hypoalbuminemia?
Colloids
What kind of fluids would you give a dog with hyperosmotic dehydration?
Isotonic crystalloid
What kind of fluids would you give a cat with hypokalemia?
Hyperosmotic crystalloids
What kind of fluids would you give a hypoglycemic dog?
> 5% dextrose solution
What are some examples of blood and blood products?
Plasma, platelets, Packed RBCs
What situations are oxygen-carrying solutions used in?
Severe blood loss or hypovolemia
What is the replacement fluid rate in dogs?
90 mL/kg/h
What is the replacement fluid rate in cats?
45 mL/kg/h
What is the maintenance fluid rate in cats?
60 mL/kg/day
What is the maintenance fluid rate in dogs?
60 mL/kg/day
What would happen if you give a DEA 1.1-negative dog more than one blood transfusion of DEA 1.1-positive blood?
The antibodies will attack the blood.
How is the hypothalamus stimulated during dehydration and why?
The osmoreceptors in the hypothalamus detect increased concentration of blood. It sends signals toincrease thirst and increase ADH to conserve water in the kidneys
If the solute concentration (osmolarity) in the extracellular fluid increases, what do osmoreceptors in the hypothalamus do?
generate an output signal to increase the release of ADH from the posterior pituitary.
If the solute concentration (osmolarity) in the extracellular fluid decreases, what do osmoreceptors in the hypothalamus do?
there is a decrease in the release of ADH.
Where is ADH released from?
The posterior pituitary in the brain
What is the most abundant cation in the extracellular fluid?
NA +
What is the most abundant cation inside the cell?
K+
Which water is produced by the mitochondria?
metabolic water
