Types of fluids available for intravenous therapy

Fluids are divided into crystalloids (table 5) and colloids (table 6). Crystalloids are true chemical solutions whereas colloids contain elements that are in suspension and not true solution. If you shine a light through a colloid the light will be scattered (e.g. like a ray of sunlight in a smokey pub), this is termed the Tindel effect.

Table 5: Crystalloid solutions in common use

Name	Na	K	Cl	HCO	Ca	Glucose
Normal Saline N/S 0.9%	150	0	150	0	0	0
Hartman's	131	5	111	29	2	0
Dextrose Saline D/S / solution 18	30	0	30	0	0	43 g/L
Dextrose 5%	0	0	0	0	0	50 g/L

Table 6: Colloids in common use

Name	Pros	Cons
Gelofusin	Made from degraded gelatin (formerly extracted from horses hooves), cheap, no chance of viral transmission, is cleared from the circulation in about 8 hours. No cross match required, on the shelf	Allergic reactions, good for volume but not oxygen carriage
Whole blood	Great for active blood loss,	Hard to come by as the blood bank likes to use this blood to get clotting factors and other goodies. Cross match required, emergency cross match takes 20-40 minutes.
Packed cells	Good to replace haemoglobin,	No clotting factors. Citrate is used as an anticoagulant and binds calcium so the recipient may get citrate toxicity / hypo calcaemia. Risk of viral transmission. Cross match required.
FFP	Replace clotting factors	Expensive, risk of viral transmission. Must be matched to blood type. Once unfrozen has to be given quickly or will go off.