Abstract

A solution of gum acacia of 6 to 7 per cent in 0.9 per cent sodium chloride is capable of effectively replacing blood lost, unless the loss amounts to more than 75 per cent of the blood volume. Hence its use in hemorrhage from various causes, whether from injury, disease or in operations.

Its effect is due to the fact that the blood vessels are impermeable to colloids, so that their osmotic pressure is effective in retaining within the circulation the solution that has been injected, a property which salts do not possess, since the vessels are permeable to them.

It has no chemical or drug-like action and can be used in large quantities.

It can also be used with benefit when the blood volume is reduced owing to removal of a part from effective circulation by stagnation in the capillaries, as happens in wound-shock, traumatic toxemia, and probably in other similar conditions. In such cases, its primary object is to maintain a normal circulation until the toxic products are eliminated from the blood, while the blood out of circulation is restored to use.

When fluid has escaped from the blood, owing to the capillaries becoming permeable to colloids, as in the action of tissue toxins and so on, gum-saline restores the normal state, provided that the morbid condition has not lasted too long. In this latter case, even transfusion of blood is of no avail.

When the blood has become concentrated by loss of fluid from the body, gum-saline is more effective than saline alone, even if hypertonic, since it is not lost from the circulation with the rapidity that such solutions are.

It seems probable that gum-saline may be of value in other states of low blood pressure, or decreased volume in circulation. It has been found to be so in toxic anemia, such as black-water fever.

Neither gum nor blood has any permanent effect when the blood vessels are deprived of control by the vaso-motor centers.

Whether there are any conditions, other than that of excessive hemorrhage, in which blood is more effective than gum-saline is uncertain. Experiments on animals have not given proof of such.

Gum acacia does not produce anaphylaxis nor hemolysis. Nor does it agglutinate the blood corpuscles in man, although it does so in vitro in the case of some cats. This latter phenomenon does not appear to occur while the blood is in circulation, and is not followed by hemolysis, even in vitro.

The addition of gum acacia to fluids used for perfusion of organs is to be recommended on account of the relative absence of oedema.