On 9 Nov 2004 21:04:01 GMT, (Nick Maclaren) wrote:



My understanding is that normal saline as used in hospitals contains
potassium as well as sodium, and perhaps magnesium and calcium as
well, because it is more general and safer.

Absolutely not. Calcium and magnesium are rarely given. If you looked
on a normal UK hospital ward you would find glucose 5% and 0.9 %
sodium choride. Some bags would have added potassium. You would
perhaps find 50% and 10% glucose and maybe 1.4% sodium bicarbonate.
anything else is a rarity. Magnesium and calcium would be present in
TPN ( Total Parenteral Nutrition) which you can in theory live on for
months or years.



For example, if someone is admitted suffering from dehydration and
is actually short of potassium, it is NOT good to rehydrate them with
a potassium-free saline! You need a blood analysis to be certain,
and there often isn't time.

If needed any AED should be able to get a reading of sodium, potassium
and a full blood gas analysis ( pH and oxygen/CO2 levels) as fast as
the sample can be run to the lab and very likely done in the same room
as the patient if they are in the resuscitation bay. Glucose readings
take 1 minute at the bedside or 5 minutes in the lab if you want high
precision.