Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Feb 1979
In-line blood warming and microfiltration devices. II. Influence of blood temperature on flow rate and hemolysis during pressure transfusion through microfilters and transfusion sets.
The influence of blood temperature on flow rate and hemolysis was studied. Homogeneous aggregate-free blood was transfused through six different microfilters and transfusion sets, combined with a large-bore venous cannula (Venflon No. 2) at a constant pressure of 20 kPa. Flow rates and plasma hemoglobin for cold (+5 degrees C) and prewarmed (+37 degrees C) blood were determined separately. ⋯ The Fenwal "dry-heat" warmer was found to have a great flow resistance. The pressure transfusion caused only a slight increase in free plasma hemoglobin of cold blood and no increase in prewarmed blood. It seems more practical to warm the entire blood unit before transfusion than to use so-called in-line blood warmers, because prewarming results in a flow rate approximately twice as high as that obtained with coils.
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Acta Anaesthesiol Scand · Feb 1979
In-line blood warming and microfiltration devices. I. Testing of flow and warming properties by pressure transfusion of aggregate-free blood.
Homogeneous microaggregate-free whole blood at +5 degrees C was transfused at constant pressures of 20 and 40 kPa through two micro-filtration and blood warming devices, and the temperature of the blood was recorded before it reached the venous cannula. The flow rates with the Fenwal system were 58 and 139 g/min, whereas the micro-filter MF10B combined with the Portex Coil allowed flow rates of 143 and 224 g/min. The warming capacities of the two warmers were almost equal and this did not prove to be their weak point. ⋯ Increasing the priming volume of the coil would raise the mean infusion temperature. A pressure infusor (Fenwal) was tested, and the internal pressures of the blood bag and the infusor were determined separately. The bag pressure differed significantly from the infusor pressure as the blood bag emptied, making the usefulness of the infusor manometer questionable.