Fluid theraphy Flashcards
What is fluid concentration determined by?
The amount of substances contained in the fluid (solution)
What is a solution?
A solute dissolved within a solvent
What is a solute?
A solid portion of a solution
What is a solvent?
Liquid portion of a solution
What is an isotonic solution?
A solution with a concentration equal to plasma
What is a hypertonic solution?
A solution with a concentration higher than plasma
What is a hypotonic solution?
A solution with a concentration lower than plasma
What are electrolytes?
Ions within a solution
What is osmosis?
The movement of water across a semi-permeable membrane from a lower concentrated solution to a more highly concentrated solution, in order to equalise the concentrations.
How is fluid moved within the body?
By hydrostatic pressure
How is fluid lost in the body?
Via the interstitial spaces. The ‘osmotic draw’ brings fluid back into interstitial spaces via the interstitial spaces
Any excess fluid drains off into the lymphatic system
How does water move in capillaries?
High capillary blood pressure - fluid and nutrients go into interstitial tissue - increased concentration of blood - fluid and waste drawn into capillary by osmosis
How does water move in cells?
ECF and cytosol concentration need to be balanced (osmotic pressure within cell prevents excess fluid absorption) - Fluid and nutrients move into cells from ICF - fluid and waste is pushed out of cell to ICF - Fluid not absorbed into capillary taken to lymphatic system
What problems can occur with water movement within cells?
Decreased plasma proteins or ineffective lymphatic drainage = oedema
What happens when plasma osmolarity is increased?
Increase in plasma osmolarity is detected by osmoreceptors in hypothalamus which stimulates thirst
What happens when plasma concentration is increased?
Increase in plasma concentration casues the activation of PPT which stimulates the anti-diruteic hormone which sitmualtes the distal convulted tubules which cause the resorption of water
How is hydration maintained in the body?
The body feels thrist which causes the increase of plasma which stimulates thirst
How is hydration assessed?
1% = slight loss in skin elastic, hair standing on end 5% = dry mucous membrane, slight decreased skin elastic, increased SG 7% = marked loss in skin elastic, increased SG, decreased urine output, sunken eyes, tachycardia, prolonged capillary refill time 10% = skin tenting, sunken eyes, 3rd eyelid profusion, oliguria, weak pulse, anuria, prolonged CRT, shock, lethargy 12% = depression, collapse, shock, morinund, death
What is the normal urine output?
1-2ml/kg/hr
What is the normal specific gravity in both dog and cat?
Dog - 1.015-1.045
Cat - 1.020-1.060
What is the normal PCV in both dog and cat?
dog - 45%
Cat - 35%
Describe pH within body
pH, number of H+ ions
Greater number, more acidic
Normal body pH = 7.4
Several mechanisms to maintain homeostasis
electrolytes affect pH
faecal volume/RR excreted via water vapour
What is a pH imbalance?
Where pH blood becomes abnormal
What is metabolic acidosis?
Where an acid state in the body occurs due to altered metabolism - unable to excrete acid or is losing excess alkali (causes increased acid)