Fluids & Electrolytes Flashcards
1
Q
what is IV fluid therapy?
A
the infusion of sterile fluids intraveneously into the circulatory system
2
Q
why is IV fluid therapy chosen/used?
A
to maintain fluid and electrolyte balance
3
Q
why would IV fluid therapy be chosen over another route?
A
when oral/enteral routes are inappropriate
4
Q
what is hypernatremia?
A
a comon electrolyte problem; too much sodium in the blood
5
Q
what are electrolytes?
A
chemicals which conduct electricity when in water and are essential to bodily functions
6
Q
list common electrolytes?
A
- sodium (salt/ Na)
- potassium (K)
- calcium
- bicarbonate
- magnesium
- chloride
- phosphate
7
Q
what is osmosis?
A
- movement of water molecules from a solution of high concentration of water molecules to a lower one
- down a concentration gradient
- through a cell’s partially permeable membrane
8
Q
Types of dehydration?
A
- isotonic
- hyponatraemic
- hypernatraemic
9
Q
what is isotonic dehydration?
A
- blood sodium (salt) concentration unchanged
- salt and water is lost in equal proportions
- loss of plasma/ECF
- common in burns & haemorrhaging
- may need to replace losses urgently due to hypovolaemia risk
10
Q
what does the term fluid balance mean?
A
the balance of input and output of fluids in the body, to allow metabolic processes to function properly
11
Q
how much water does the average human body hold?
A
42-45Litres of water
12
Q
how much water does an adult requiere per day?
A
1.5-2.5Litres
- roughly 6-8 cups of water
13
Q
what is ECF and where is is located?
A
- extracellular fluid
- fluid not contained within the cells but which surrounds them
- found in the blood, lymph, and body cavities lined within the serious (moisture-exuding) membranes
- makes up 1/3rd of total body water
14
Q
what is ICF and where is it located?
A
- intracellular fluid
- fluid contained within the cells
- largest component; 2/3rds of total body water
15
Q
what is interstitial fluid and where is it located?
A
- also found out-with the cells, like ECF
- difference between the two; interstitial fluid is found out-with the blood, and which surrounds the cells and tissues
16
Q
what is osmotic concentration?
A
- also known as osmolarity
- the measure of solute concentration, i.e., of the blood
17
Q
what are osmoreceptors?
A
a sensory receptor (brain cells) located primarily in the hypothalamus that detects changes in osmotic pressure
18
Q
what happens to our osmotic concentratin of our blood when we are dehydrated? what impact does this have?
A
the osmotic concentration of our blood when dehydrated increases (not enough water to equalise; think specific gravity), causing osmosis of ICF out of the cells
- this dehydrates specific brain cells called osmoreceptors and stimulates the release of ADH; reducing water loss through retention and therefore concentrated urine
19
Q
what happens when water intake is high?
A
less ADH is released, resulting in the kidneys excreting large quanities of dilute urine
20
Q
what is ADH and what does it do?
A
- anti-diuretic hormone
- produced by the hypothalamus & released by the pituitary gland
- causes the kidneys to release less water by decreasing urine production and excretion
21
Q
what is a diuretic?
A
any substance which promotes diuresis; increased production of urine
22
Q
what is an anti-diuretic?
A
any substance which opposes diuresis and aids retention of fluid
23
Q
what is ADH also known as?
A
human vasopressin & vasopressin hormone
24
Q
what is polyuria and what causes it?
A
the excessive proudction and excretion of urine, caused by;
- diabetes/ hyperglycaemia
- overuse of diuretics
- renal impairment
25
what is the role of calcium?
contracting muscles
signalling nerves
blood clotting
forming and maintaining bones/teeth
26
what is the role of sodium (salt)?
maintain fluid balance
support muscle contractions
help signal nerves
27
what is the role of potassium (K)?
help maintain BP
regulate heart contractions
assist with muscle functions
28
what is the role of magnesium?
support muscle contractions
maintain proper heart rhythms
support nerve functions
help fluid balance
29
what is the role of chloride?
help maintain fluid balance
support muscle contractions and relaxations
30
three types of treatment for dehydration?
mild; oral rehydtration
moderate; oral & IV fluid therapy
severe; accurate IV fluid therapy replacement
31
balance; positive & negative?
input & ouput are the same; balanced fluids/no change
input increased over output; positive balance; increased fluids
output increased over input; negative balance; decreased fluids
32
what is hypovolaemia?
low blood volume circulating in body
33
what is hypERnatraemic and causes?
MORE WATER LOSS than salt loss
* e.g., excesss sweating or water diarrhhoea
* unconscious and unable to drink
34
what is hypOnatraemia and causes?
MORE SALT LOSS than water loss
* loss of sodium-rich fluid from the gut or kidenys
* too much water intake which 'waters down' the sodium
35
two types of IV fluids?
* crystalloids
* colloids
36
what are crystalloids solutions?
* clear solutions that move between the bloodstream and the tissues
* they contain NO plasma proteins
* generally consist of differeing strengths of NaCL, Dextrose, or both
37
what are colloid solutions?
* contain solutes that stay in the blood because they are too big to pass through capillary walls
* used to increase blood volume
38
what are the 5Rs of I.V. fluid therapy?
healthcare professionals should use the 5Rs/5 principles when prescribing and admonistering IV fluid therapy to do so effectively and safely.
Resuscitation
Routine maintenance
Redistribution
Replacement
Reassessment
39
what is Resuscitation?
40
total body water % for males & females?
males; 60% roughly
females; 52% roughly
41
why do females have less body water % than males?
* muscles are made of 75% of water whereas adipose (fat) tissue is oly 10%
* females have a higher percentage of body fat than males, meaning females therefore hold less body water %
42
what is the enteral route?
routes in which the drug is absorbed in the GI tract, e.g., PO, sublingual, buscal, rectal
43
what is tissue fluid/also known as?
* fluid between body cells
* also known as interstitial fluid
44
Fluid Compartments
Intracellular fluid (ICF); located within cells 2/3rds of total body water
Extracellular fluid (ECF); located outwith the cells, surrounding and bathing them 1/3rd total body water
Interstitial fluid (IF); the other constituent/part of ECF, that is not located in the blood like the rest of ECF, but is located around/bathing the cells. IF is the medium through which substances diffuse from blood to cells
45
what are the two constituents of ECF?
* Blood plasma; fluid component of the blood
* Interstitial fluid (IF); surrounds all the cells but is not in the blood
46
signs of electrolyte imbalance
* confusion
* dizziness
* irritability
* muscle spasms
* anxiety
* changes in heartbeat
47
what are osmoles?
an individual ion within a solution
48
what is osmolality?
the concentration of osmoles in the mass of a solvent (e.g., a liquid)
49
what is osmoregulation?
the process of maintaining salt and water balance (osmotic balance)
50
what is saline?
* a mixture of sodium chloride (salt) and water
* abbreviated; NaCL (normal saline)
* used to clean wounds, treat drye eyes, maintain contact lenses
* used to treat dehydtration intraveneously
51
what is dextrose?
* a suguar substitute that is chemically identical to glucose
* abbreivated; C₆H₁₂O₆
* used to treat dehydtration, hypoglycaemia, insulin shock and also provides nutritional support to those unable to eat
52
what does Resuscitation refer to?
* refers to pts requiering IV fluids urgently to restore circulation to vital organs following a loss of blood plasma
* can be caused by excessive external fluid and electrolyte losses, haemmorage and plasma loss
53
what does Routine Maintenance refer to?
* refers to pts unable to maintain normal fluid levels orally or via other enteral route(s)
* these pts are otherwise well in terms of fluid and electrolyte balance. they are haemodynamically stable
* some pts requiering routine maintenance may be unable to eat/drink properly and therefore need electrolyte supplementation
* calculating pt's weight, oral intake and ither IV output is vital for pts requiering routine maintenance IV fluid therapy, to prevent fluid overload
54
what does Replacement refer to?
* for pts needing fluid to correct water and/or electrolyte deficits or ongoing abnormal losses
* e.g., from high-ouput ileostomies, diarrhoea, vomitting, etc.
55
what does Redistribution refer to?
* some pts have complex fluid & electrolyte balance issues, due to the shift/lack of shift of fluid between different body compartments
* e.g., in pts who are septic, critically ill following surgery, have major comorbidities, etc.
* healthcare pros shuld consider if a pt requieres IV fluids to for their natural fluids to be redistributed correctly
56
what does Reassessement refer to?
* pts should be reassessed continiously regarding their IV fluid therapy to avoid under and over administering fluid intraveneosly
57
difference between dehydtration and depletion?
* dehydration; usually describes a greater proportion of water loss than salt loss fron the body, e.g., during diarrhoea and vomitting
* depletion (hypovolaemia); reduction in circulatory volume, i.e., loss of blood or blood plasma
58
can dehydtration and depletion occur together?
they can occur together or independently
59
what happens when too much IV fluid is administered?
* can cause odema and fluid overload
* tachycardia will present as the heart must work harder to pump normal & excess fluid around body
60
what happens when not enough IV fluid is administered?
* dehydtration and therefore renal insufficency more likely
61
what are ascites?
a condittion where fluid collects in the abdomen, and cause the following symptoms;
* abdominal pain
* abdominal swelling
* naseua & vomitting
* impacts other organs, e.g., heart, lungs, kidneys
62
most common electrolytes found in ECF?
* sodium (Na)
* Chloride (CI-)
this means that blood plasma and tissue fluid (IF) are salty
63
most common electrolytes found in ICF?
* potassium (K+)
* magnesium (Mg++)
* phosphate
64
why is electrolyte composition different inside and outside of cells?
the cell membrane is selectively permeable to ions, and some ions are too big to cross cell membranes
65
three reasons why 0.9% saline is a good choice as a Resuscitation fluid?
1.) it is isotonic to ECF; meaning it will not upset interal fluid balance
2.) it will increase plasma volume (blood volume)
3.) it is safe; no transfusion reactions, allergies, viruses risks, etc.
66
isotonic fluid?
IV fluids that have a similair concentration of dissolved particles as the blood. an example of an isotonic fluid is 0.9% NaCL!
cells placed into an isotnic fluid will not shrink or shirvel by osmosis as a result
67
difference between hypotonic solutions and hypertonic solutions
* hypotonic solution; has a lower concentration of solutes than the blood. solution is dilute and therefore RBCs will swell due to osmosis
* hypertonic solution; has a greater concentration of solutes than the blood. solution is concentrated and RBC will shrunk due to osmosis
68
can Na+ and CI- readily cross cell membranes into cells?
no
69
why would a post-op 'nil by mouth' pt be given 5% dextrose (glucose) as part of their fluid maintenance regime?
1.) to prodive a source of energy (calories) for cells in the absence of nutrition (food)
2.) ^ to prevent the rapid breakdown of bdoy fat for energy, as this can produce ketone bodies and acidosis
3.) this replacement 5% dextrose fluid will behave as a hypotonic fluid, distirbute into cells and correct dehydtration in pt not drinking
