VETS3050 Fluids & Pharmacology

List the fluid compartments & their percentages
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List the fluid compartments & their percentages
- Total body water = 60%
- Intracellular fluid = 66%
- Extracellular fluid = 33%
Of the ECF:
- Interstitial fluid = 75%
- Plasma (intravascular) = 25%
What is the most common electrolyte for the ECF vs ICF
ECF = Na
ICF = K
The cell membrane is permeable to:

whilst the vascular endothelium is permeable to:
Cell membrane = water only
Vascular endothelium = water & electrolytes
Define osmolality vs. osmolarity
Osmolality = concentration of particles per kg of solvent
Osmolarity = number of particles per L of solvent
What is the formula for osmolality?
2 (Na+K) + Glucose + Urea
Which of the following is NOT an effective osmole?
a. Sodium
b. Urea
c. Potassium
d. Glucose
b
What are Starling's forces and what is their aim?
Aim: maintaining vascular volume

1. Hydrostatic pressure
2. Colloid osmotic pressure
3. Endothelial permeability
List three ways we lose fluids and what compartment the fluid is lost from as well as the type of loss.
1. Hypovolaemic shock = intravascular & isotonic loss

2. Dehydration = interstitial & isotonic

3. Free water loss = loss from all 3 spaces
How do we detect these fluid losses?
1. Hypovolaemia = perfusion parameters eg. mentation, CRT, MM colour, temperature, HR & pulse

2. Dehydration = hydration parameters eg. skin turgor, tacky MM's, ocular position, tear film

3. Free water loss = high serum Na
Dehydration should be correct rapidly - true/false?
False - it occurs slowly and therefore should be replaced slowly
What is the normal IN amount for drinking water for cats & dogs? a. 40 - 60ml/kg/day b. 70 ml/kg/day c. 2.5ml/kg/day d. 10 - 20 ml/kg/dayaWhat are sensible losses?- Water lost in normal processes eg. urine, faeces, salivaHow do we tx dehydration?1. ALWAYS TREAT SHOCK FIRST - Assess perfusion & tx rapidly with isotonic crystalloids 2. ESTIMATE THE DEFICIT AS A % OF BW eg. 15kg x 5% (dehydration; 0.05) = 750 ml 3. CHOOSE FLUID TYPE, RATE & ROUTE 4. CALCULATE MAINTENANCE BASED ON BW - Cats & large dogs = 2ml/kg/hr - Small dogs = 3 - 4 ml/kg/hr 5. CALCULATE ONGOING LOSSESList the two methods of hypernatraemia & TWO examples of things that cause these pathogeneses1. Decreased free water = Decreased intake (lack of access to water) = Increased loss (excessive panting or diabetes insipidus) 2. Increased salt = Salt ingestion (licks, jerky, playdough) = Iatrogenic (hypertonic saline)Which of the following is NOT a clinical sign of hyper-natraemia? a. Lethargy b. Confusion c. Decreased mentation d. Head pressing e. DiarrhoeaeWhat are idiogenic osmoles?- If hypernatraemia > 24 - 48 hrs - Brain produces these osmoles which increase the osmolality of the ICF to draw fluid back into the brain (protective) - If tx occurs too quickly >> water influx into brain = cerebral oedemaHow do we tx hypernatraemia- 5% dextrose (free water) SLOWLY < 0.05 - 1mmol/L/hrList the pathogenesis of hyponatraemia & LIST TWO conditions that cause these pathogenesis1. Increase free water - Pseudohyponatreamia - Diuretics (chronic) - Excessive water ingestion 2. Decreased sodium - Haemorrhage - ADH secretion & increased PD >> no salt replacedWhat is NOT a clinical sign of hyponatraemia? a. No signs b. Severe obtundation c. Headpressing d. VomitingdHow do we tx hypo-natraemia?- Treat underlying cause and it will self-correct in most cases - If symptomatic can raise sodium with isotonic crystalloid >> treat slowly as can cause osmotic demyelinationWhat can cause abnormalities in Cl-1. Change in water balance = Loss of free water = HyperCl eg. diabetes insipidus, lack of access = Gain of free water = HypoCl eg. excessive drinking, iatrogenic 2. Gain or loss of Cl- = Gain of Cl - >> hyperCl & acidaemia >> body dumps bicarb = Loss of Cl- >> hypoCl & alkalaemia >> body retains bicarb 3. Changes in bicarb 4. Pseudohyperchloraemia - Meds with K+ Bromide & iodides leads to incorrect readingPotassium is important for the regulation of ALL the following EXCEPT: a. Transmission of action potentials. b. Homeostasis of cell volume. c. Maintenance of resting membrane potential. d.Vascular fluid volume.dWhat happens with hyper-kalaemia?- Slows myocardial conductance - Tachycardia FIRST >> bradycardia & atrial arrest >> deathWhat can cause pseudohyperkalaemia?- Collecting a sample into EDTA tube - Severe thrombocytosisHow do you tx hyperkalaemia?- Address underlying problem - 10% calcium gluconate IV slowly - Glucose & insulin all drive K+ into cells (short fix ONLY!)Csx of hypokalaemia- Muscle weakness - Arrhythmias - RhabdomyolysisHow do you tx hypokalaemia?- Treat underlying cause - Infusion no faster than 0.5mmol/kg/hrQuestion 17. An intravenous fluid is said to be BALANCED if: a. All electrolytes are present in equal proportions b. Its composition mimics that of the extracellular fluid c. Sodium and potassium equal each other d. Sodium and chloride equal each otherbMatch these fluids to their description: 1. Hartmanns 2. 0.9% saline 3. 50% dextrose 4. 5% dextrose 5. Hypertonic saline a. Useful for traumatic brain injury in reducing cerebral oedema in patients as steals fluid from the interstitium (non-balanced) b. Balanced isotonic crystalloid useful for volume expansion with alkalinising effect c. Primarily used for correction of hypoglycaemia d. Non-balanced maintenance fluid useful for controlling free water loss and acidifying effect e. Non-balanced and acidifying solution for volume expansion & rehydration1. b 2. e 3. c 4. d 5. a.Possible side effects of synthetic colloids, such as Voluven, include the following EXCEPT: a. Glaucoma. b. Acute kidney injury. c. Decreased fibrin polymerization. d. Decreased factor VIII and vWB factor.A