An autologous fibrinogen-based adhesive for use in otologic surgery.

Successful middle ear surgery requires the availability of a safe, effective bonding material. Side effects caused by synthetic materials have led to the use of biologic adhesives; however, they carry the risk of transmission of infectious disease if they are prepared from pooled human blood. A procedure for the production of an autologous fibrinogen-based adhesive using polyethylene glycol to precipitate the fibrinogen-factor XIII component from plasma is described. This procedure requires 40 ml of whole blood and approximately 3 hours' preparation time, and it can be performed in any blood bank with the facilities for sterile techniques. This adhesive has been used successfully for otologic surgery in 12 patients, and further study of the use of this biologic adhesive for other microsurgical techniques should be undertaken.

Rapid estimation of the glycerol concentration of frozen-thawed red cells prepared by the agglomeration technique.

The glycerol concentration of frozen-thawed red cells must be less than 2 percent to prevent hemolysis upon transfusion. Three methods were investigated for monitoring the glycerol concentration of frozen-thawed red cells prepared by the agglomeration technique. The supernatant osmolality and glycerol concentration were determined on 47 units of frozen-thawed red cells prepared by agglomeration, and were found to be linearly related (r = 0.83, p less than 0.001). The supernatant refractive index was determined on 29 of the same units. There also was a linear relationship between the refractive index and the glycerol concentration (r = 0.74, p less than 0.001). The relationships were different from those previously reported for red cells prepared by other methods. The simulated transfusion test was done on red cells from three units whose glycerol concentration had been artificially elevated. The simulated transfusion test was found to be sensitive to glycerol concentrations above 2 percent. All three of the methods evaluated can be used to estimate the glycerol concentration of frozen-thawed red cells prepared by the agglomeration technique.

Evaluation of erythrocyte washing using the Haemonetics Model 102 Cell Washer.

The Haemonetics Model 102 Cell Washer was evaluated for efficiency of leukocyte removal and erythrocyte recovery. Groups of 25 units of blood were washed using five different protocols, including the methods recommended by the manufacturer. Mean erythrocyte recovery ranged from 83% to 91% and median residual leukocytes ranged from 1% to 4% for the five protocols. The mean erythrocyte recovery for units washed with 30 sec of increased pump speed was 95%, while it was 84% for units washed with 90 sec of increased pump speed (P less than 0.001). The median residual leukocytes was 1% for units washed after buffy coat removal and 4% for all other units (P less than 0.001). There was no other significant difference among the different protocols. These findings could not be explained on the basis of age of units, prewash erythrocyte mass, or prewash total leukocytes.