Filtration of the microaggregates in stored blood

A clinical experience with intraoperative autotransfusion

Utilizing a disposable unit, intraoperative autotranfusion was employed during surgery in 53 patients admitted to the Bexar County Teaching Hospital at the University of Texas Health Science Center at San Antonio. During the two-year period of study, 26 patients underwent surgery for major traumatic injuries, 8 for ruptured ectopic pregnancy and 19 for miscellaneous emergency or elective conditions. The indication for intraoperative autotransfusion was an anticipated blood loss of 1,000 ml or more. Contraindications for its use were colon injury or localized infection. Over 325 units of blood were salvaged and returned directly to these patients during surgery. One death related to the use of the autotransfusor unit was due to massive air embolism. Twenty other deaths were associated with severe injuries and irreversible shock requiring greater than 3,600 ml of both autologous and homologous blood. Eight of these patients demonstrated severe pancoagulopathies. In the remaining patients, clotting factors and plasma or urine hemoglobin levels were transiently abnormal. However, there were no clinically apparent bleeding defects or renal problems detected. Postoperative blood cultures were consistently negative. It is concluded that intraoperative autotransfusion, when properly employed, is a safe, practical and technically feasible procedure.

Dacron wool filtration and hypotensive shock: an electron microscopical study

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Microaggregates in frozen and saline washed red blood cells

The microaggregates which accumulate in stored blood have been implicated in the development of posttraumatic pulmonary insufficiency. These particles are known to be composed of degenerated leukocytes and platelets. Because frozen and saline washed red blood cells contain small numbers of leukocytes and platelets, they were studied as a possible source of microaggregate-free red blood cells. Using a Model T Coulter Counter to quantitate all particles 13-80 microns in size, it was shown that freezing and deglycerolization, or simple saline washing (manual or automated), could reduce the number of microaggregates in stored blood by 80 to 90 per cent. These findings add to a growing list of potential advantages in the routine use of frozen red cells for patients requiring transfusion.

Pulmonary gas exchange following hemorrhagic shock and massive blood transfusion in the baboon

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