There have been many new developments in modern medicine. Among these is the application of basic science to medicine and especially to anesthesiology. Recently there have been considerable interest in the metabolic effects of massive transfusions.
Since World War Ⅱ when the use of ACD(Acid Citrate Dextrose) solution was developed, it has been the custom to use banked blood for transfusions in cases requiring large amounts of blood.
However, recently the use of banked blood has been studied to determine the effects of low temperature, lowered pH, and the electrolyte changes with time, on the mortality of patients requiring more than 5,000 cc of blood per 24 hours.
It has been demostrated that warming the blood, elimination of the exogenous calcium, and the addition of a buffer at the time of massive transfusion has reduced the incidence of cardiac arrythmia, of fibrillation, and of cardiac arrest, and has decreased the patient mortality.
Two groups of studies were made: first, the changes in banked blood over time, and second, the changes in patients receiving massive transfusion. Measurements were made of the effect of bicarbonate buffering, of calcium, and of cold blood (as compared with blood) on the incidence of cardiac complications and mortality.
The following results were obtained:
A. A study of 10 pints of banked blood over a 3 week period: (ACD "A" blood was used for the test.)
1. There was a decrease in pH from 6.69 for blood checked 5 hours after being drawn, to 6.46 three week later.
2. p02 decreased slightly from 55.9 mmHg to 52 mmHg.
3. Standard bicarbonate decreased from 7.7 mEq/L to 6.0 mEq/L.
4. Potassium content was significantly increased from 4.12mEq/L to 28.0 mEq/L.
5. There were no significant changes in the calcium and sodium content over the three week period.
B. In the second group, (36 patients all of whom had received at least 5,000 cc of banked blood within 24 hours) there were three sections. The sections were divided as follows:
Section one:- Cold blood plus calcium.
Section two:- Cold blood only.
Section three:- Warmed blood plus sodium bicarbonate.
1. Cardiac Complication.
Section one - 22 patients who were given cold blood and calcium. It has been the custom to give the patient calcium I.V. for every two pints or more of ACD blood to try to avoid citrate intoxication. In this section 7 out of 22 developed cardiac
arrythmia, one had fibrillation.
Section two- There were no cardiac complications.
Section three - 6 patients who were given warm blood which was buffered by adding 44.6 mEq of sodium bicarbonate for every 5 pints of warmed blood given. In this group there were no cardiac complications.
The average pH for the 21 patients was 7.36 before transfusion and the bicarbonate was 20.1 mEq/L.
In section one and two(cold blood plus no buffering) the pH dropped to 7.175 and the bicarbonate to 11.45 mEq/L after massive transfusion. In section three(warmed blood plus buffering) the pH rose to 7.43 and the bicarbonate to 25.13 mEq/L.
In section one the patients receiving less than 19 pints had a 37.7% mortality, while those getting more than 20 pints had a 57% mortality.
In section two the patients receiving less than 19 pints had a 25% mortality, while those getting more than 20 pints had 25% mortality.
In section three the mortality dropped to 0% for those getting 19 pints or less and was only 25% for those getting more than 20 pints. Out of the 20 patients were studied for changes in electrolytes. No significant changes were noted, including
the fact there was no significant increase in serum potassium.
The use of buffered warm blood along with the avoidance of the administration of exogenous calcium has effectively decreased the incidence of cardiac complications and the mortality following massive transfusions.