Biomedical subjects

K Linko

Publications and source records attributed to K Linko.

39 records · Page 3Linked to original sources

PubMed1979

Erythrocyte damage caused by the Haemotherm microwave blood warmer.

Blood units (59) were warmed with the Haemotherm microwave blood warmer and seven units were warmed in a water bath for comparison. The influence of the final blood temperature, the size and the hematocrit of the units on the erythrocyte lesion was studied. Extracellular hemoglobin and potassium, hematocrit, osmotic fragility and mean cellular volume were used as indicators of red cell damage. Warming in the water bath caused no erythrocyte damage at temperatures below +46.8 degrees C. Higher temperatures caused progressive morphological changes and hemolysis. Units of red cells in saline warmed to temperatures above +46.3 degrees C with the Haemotherm showed intense hemolysis and changes in all parameters used. Below this temperature no erythrocyte damage occurred. When the amount of blood warmed was less than 300 g or when the hematocrit exceeded 0.70, the blood mixing mechanism became insufficient, leading to local overheating and hemolysis. Therefore, erythrocyte concentrates in a Fenwal blood bag should never be warmed by the Haemotherm. The mean plasma hemoglobin increase of the ten whole blood units warmed by the Haemotherm to +36.0-36.8 degrees C was 123 mg/l. The results of the present study indicate that microwaves per se are not harmful to erythrocytes but that poor penetrance of microwaves, together with insufficient blood mixing during warming, are the critical factors leading to hemolysis.

Blood Transfusion↗

PubMed1979

An in vitro comparison of six microaggregate blood filters.

The latest models of six blood microfilters were tested by filtering large amounts of pooled blood at various driving pressures. For determination of the amount and size of microaggregates in stored blood, a simple method was developed, based on consecutive nylon screens. The amount of aggregates was also determined by a modification of the screen filtration pressure method. Filtration efficiency was tested by transfusing blood from the same pool through each of the microfilters. The Pall (SQ40KL) filtered only particles with a diameter greater than 40 micrometers. Small aggregates passed also through Bentley (PFF-100). The Biotest (MF10B) filter removed large aggregates efficiently, but some small particles were not filtered. Fenwal (4C2423), Swank (6010-3) and Intersept (HRI8137-00) were the most effective filters. All filters were also tested by pressure transfusion of pooled blood (9 units, 21 days old). The efficiency of Biotest, Pall and especially Bentley improved considerably during the transfusion. Bentley and Fenwal had the highest capacities. A high flow rate was maintained with Pall, but small aggregates were not removed by this filter. Intersept, Swank and Biotest became occluded rapidly. Filtration of four units through Intersept released 2218-2454 mg of hemoglobin from the erythrocytes.

Blood↗

PubMedDate not supplied

Observations on the removal of microaggregates from stored blood by centrifugation and filtration through a standard 170 micron transfusion filter.

The effect of centrifugation (5 minutes, 6900 X g) on the amount and particle size of blood microaggregates was studied in order to assess whether centrifugation and filtration by a standard (170 micron) transfusion set filter could be used for aggregate removal instead of microfiltration. Aggregates were quantitated using a method based on nylon screens with graded pore sizes. At the beginning of storage, centrifugation increased the particle size of aggregates only slightly. In 7-day-old blood, aggregates capable of passing a 160 micron screen amounted to 308 +/- 107 (SD) mg of debris protein per liter of blood before and 55 +/- 26 (SD) mg of protein (n = 10) after centrifugation. In 14-day-old blood centrifugation increased the size of aggregates even more effectively: 311 +/- 81 (SD) before and 29 +/- 14 (SD) mg of protein following centrifugation. Microaggregates can thus be removed effectively by the centrifugation and filtration method from blood stored for more than 1 week. A standard transfusion set filter can be used instead of a micropore filter.

Blood↗