Fluid Therapy Flashcards
define osmosis
the movement of water across a semi-permeable membrane from high water activity to low water activity
define osmolality
the concentration of a solution expressed as the total number of solute particles per litre
what are electrolytes?
minerals dissolved into ions
define tonicity
the measure of osmotic pressure of two solutions separated by a semi permeable membrane
define isotonic
two solutions have the same concentration of impermeable solutes
define hypotonic
the solution contains a lower concentration of impermeable solutes than the body (cell) fluid so will move into the body (cell) and can cause lysis
define hypertonic
the solution contains a higher concentration of impermeable solutes than the body (cell) fluid so will draw water out of body (cell) tissues
name 2 examples of a normal fluid intake
eating and drinking
name 2 examples of normal fluid outgoing
urination and defecation
name 2 examples of abnormal fluid intake
water deprivation and anesthesia
name 2 examples of abnormal fluid outgoing
vomiting and haemorrhage
what may fluid loss be caused by?
dehydration and hypovolaemia
what are two other potential causes of fluid imbalance?
electrolyte imbalance and altered fluid distribution (change in oncotic pressures e.g. loss of albumin)
define dehydration
loss of fluid from extravascular space
what would be the clinical findings of 0-4% dehydration?
none (very few)
what would be the clinical findings of 4-6% dehydration?
tacky mucous membranes
what would be the clinical findings of 6-8% dehydration?
loss of skin turgor (skin tent becomes less elastic), dry mucous membranes
what would be the clinical findings of 8-10% dehydration?
loss of skin turgor (skin tent becomes less elastic), dry mucous membranes, sunken eyes
what would be the clinical findings of 10-12% dehydration?
persistant skin tent, dry mucous membranes, retracted globe, dull corneas, pulse deficits (hypovolaemia)
define hypovolaemia
reduction in blood volume or fluid in the intravascular space
what are the clinical signs of mild (compensated) hypovolaemia?
mild tachycardia, pinker than normal mucous membranes, increased (<1 second) capillary refill time, bounding pulse
define compensating/compensated
patients body is able to correct fluid loss using normal physiological processes (e.g. vasoconstriction, increased HR)
define decompensated/decompensating
body is unable to keep up and maintain fluid volume
what are the clinical signs of severe (decompensated) hypovolaemia?
severe tachycardia, white/grey mucous membranes, >2seconds (prolonged) capillary refill time, poor/thready pulse