(2) Blood should be examined routinely to detect evidence of bacterial
contamination; look for an unusual color or the presence of hemolysis. If bacteria are
suspected to be the cause of a transfusion reaction, the blood from the bag, the patient,
and all IV solutions used should be cultured. Although the appearance of
microorganisms on a gram-stained smear provides proof of bacterial presence, the
absence of visible microorganisms does not rule out the possibility of contamination of a
f. Other Untoward Effects of Transfusion.
The rapid administration of a large volume of blood may be associated with
(1) Hypothermia. If blood is not warmed before massive transfusion,
ventricular arrhythmia and cardiac arrest may occur secondary to acute hypothermia.
Blood may be warmed by passing it through a coil of tubing in a water bath maintained
at less than 38C or with one of the commercially available blood warmers. The use of
(2) Bleeding diathesis. Another consequence of massive transfusion of
stored blood may be the development of a bleeding diathesis, brought about by lack of
platelets or certain coagulation factors. Platelets, although present in bank blood, are
not very functional after 2 days of storage, while factors V and VIII have relatively short
"in vitro" half-Iives. Fresh-frozen plasma and/or platelet concentrates should be used
for specific replacement therapy, when necessary.
(3) Hyperkalemia. During storage of blood, potassium slowly leaks from the
cells into the plasma, increasing the plasma potassium concentration to about 17 mEg
per liter by day 14 and about 21 mEg per liter by day 21. Although most recipients
tolerate the potassium load without difficulty, patients with renal failure or those
receiving exchange transfusion or other massive transfusion may develop acute
hyperkalemia. This can be prevented by using blood less than 5 days old or by
removing as much as possible of the potassium-rich plasma.
(4) Microemboli. A moderate amount of debris derived from platelets, fibrin,
and leukocytes collects in bank blood during storage. Much of this particulate material
is not filtered out by conventional 170-u blood administration set filters; this may cause
pulmonary microemboli, leading to impaired oxygen transport ability in patients who
receive large volumes of banked blood. Several filters capable of removing much of this
material are commercially available and their use might be considered whenever the
administration of large amounts of blood is anticipated.