Page 435 - WSAVA2018
P. 435

· Colloids
· Blood and blood products
Crystalloids
Crystalloids are water-based solutions that contain small particles (ions and molecules). Common constituents include electrolyes (e.g. sodium, potassium, calcium, magnesium and chloride to replace or maintain plasma levels), glucose or dextrose (to provide energy) and sometimes a buffer (to correct or maintain the normal acid-base balance of the plasma).
These small particles readily pass through membranes and into all body compartments. The fluid is rapidly redistributed through the body. Generally, 75% of crystalloid fluids given will leave the intravascular space within 30 minutes of administration.
Crystalloid solutions can be: · Isotonic
· Hypotonic
· Hypertonic
Colloids
Colloids contain large molecules that do not readily pass through membranes. Fluid is drawn into blood vessels.
Colloid solutions refer to solutions that have an osmolality greater than the extracellular space; they contain large molecules which are designed to stay in the intravenous space longer than crystalloids. They are sometimes referred to as ‘plasma expanders’ due to their ability to draw fluid out of the interstitial and intracellular spaces into plasma and thus maintain vascular volume more effectively.
Much smaller volumes of colloids are just as effective as large amounts of crystalloids.
Their main indications for use are: · Hypovolaemic shock
· Hypoproteinaemia
They are often administered as a bolus (supported with crystalloid fluids) or over several hours.
Examples of Synthetic colloids include:
Voluven 6%
Voluven 6% contains 6% hydroxyethyl starch in 0.9% NaCl. Its main use is as a plasma volume replacement. It does NOT replace red blood cells or clotting factors. It is a clear colourless solution. It should be stored below 25oC and should not be frozen.
Contraindications
· Do not use in patients with pre-existing disorders of haemostasis and coagulation
· Do not use in patients with established renal failure
Side-effects
· Minor allergic reactions due to histamine release
· Transient increase in bleeding time may occur
· Hypersensitivity reactions may occur including, rare-
Your Singapore, the Tropical Garden City
ly, severe anaphylactic reactions
Voluven dose rates (as per manufacturers
recommendations):
· Up to 50ml/kg/day – maximum due to coagulation problems if larger amounts given
· Continuous infusion can be calculated at 1-2 ml/kg/hr although not recommended to use as a CRI now due to adverse renal effects
Or
· Larger bolus over shorter period can be given at 20-40ml/kg per day (so larger amount given over 2 hrs instead of smaller amount of 8 hrs but must not exceed 50ml/kg/day)
Monitoring of and Care of Intravenous Catheters
It must be remembered that intravenous catheters can be a port of entry for bacteria into the vein. The catheter and the dressing must be checked regularly.
Intravenous catheter checks should be performed
frequently (at least four times a day) and includes:
· Remove and replace immediately if contaminated in any way (dirty, wet, chewed etc).
· Check for swelling of the distal paw
· Check for swelling or heat proximal to the bandage · Ensure catheter is not leaking
At least once a day the following check should be
employed:
· Remove the catheter bandage
· Visualise the insertion site of the catheter and check for:
· Any redness
· Any heat or swelling
· Any discharge (note colour and amount) · Catheter dislodgement
· Adhesive tape or padding dislodgement · Pain on palpation of area
Re-bandage and note catheter check performed and findings
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