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)
Give examples of causes of metabolic acidosis
Vomiting - brings up stomach acid then alkali. Due to decrease in alkali causing a relative acid increase
Diarrhoea - similar to vomiting
Renal failure - dysfunction in kidney, can’t excrete acid causing relative acid increase due to build up
Shock - decreased BP to kidney can’t function so same as renal failure occurs
What is metabolic alkalois?
Where an alkaline state in the body occurs due to altered metabolism - losing excess acid (causing increased alkaline)
Give examples of cause of metabolic alkalois
Vomiting stomach contents only - stomach acid lost, cause relative increase in alkaline
Over admin of bicarbonate - increases alkaline in the body
What is respiratory acidosis?
Where an acid state in the body occurs in the body when respiratory system can’t excrete acid (increased acid)
What can cause respiratory acidosis?
Repsiratory obstruction - can’t excrete acid, causes a build up of acid
Acute respiratory - can’t excrete acid, causes a build up of acid
Acute respiratory failure - breathing is stopped, cant excrete acid causing a build up
Hypoventilation - breathing slowed, causes build up of acid
Anaesthetic problems - wrong size circuit, causes acid build up due to restricted breathing
What is respiratory alkalosis?
Where an alkaline state in the body occurs when respiratory system losses excess acid (increased alkaline)
What can cause respiratory alkalosis?
Hyperventilation - heatstroke, loss of acid causes relative build up of alkaline
Pain, stress - increased respiration, build up of alkaline
Hyperthermia - increased respiration, build up of alkaline
Excessive IPPV
What can cause fluid losses?
Urine
Diarrhoea
Vomit
Blood
What are the types of fluid losses?
Water only - plasma becomes hypertonic, fluid moves from ICF to ECF by osmosis
Water + electrolytes - loss hypotonic or hypertonic, movement depends on tonicity of fluid, hypetonic dehydration - water only loss, hypotonic dehydration - fluid moves from ECF to ICF by osmosis, isotonic dehydration - no fluid movement
Blood - most serious, isotonic loss therefore no fluid movement
Plasma - increased PCV, loss of plasma proteins, proteins need to be replaced
What should be considered before giving fluid therapy?
Amount of fluid required
Type of fluid required
Type of dehydration
pH of the body
What are the categories of fluid?
Chrystalloids
Colloids
Blood/blood products
Describe chrystalloids
Variety of solutions available
Used to retify fluid and electrolyte loss
Also to balance abnormal body pH
Describe Colloids
A number of products available
Contain large molecules - create fluid shift from ICF to plasma
Do not provide any O2 carrying capacity - consider concurrent O2 admin
Describe Blood/blood products
whole blood - haemorrhage, anaemia, haemolysis
plasma - burns, hypovolaemia
packed red cells - anaemia
Cryo-precipate - clotting /bleeding disorders
DEscribe the management of a drip line
use unopened srelike materials
prepare aseptically
Insert catheter up to the hilf
Ensure catheter is taped in dry
Change catheters (every 48-72hrs)
Use heparinised saline to provide patent catheter
Check bag is right fluid, in date and clear
Check admin site for swelling, brusing, pain and perivascular fluid
Check line regularly for kinks, blockages and interference
What patient monitoring occurs with a patient on fluid therapy?
check clinical signs for hydration level Monitor TPR and mm Record urine output and SG Monitor PCV Monitor ongoing losses
What does central venous pressure measure?
Measurement of blood pressure within a central vein
Not commonly used in practice
What can overhydration cause?
causes patient to be ‘soggy’. water gets into aveloi causing soft, moist cough - pulmonary oedema
Dyspnoea, tachypnoea
Tachycardia, lethargy
runny nose, decreased PCV, increased urine output
