Screen filtration pressure method and adhesiveness and aggregation of blood cells

Abstract

An apparatus is described which measures the resistance to flow of blood through a screen with multiple openings 20 μ square. This apparatus is especially sensitive to presence in blood of aggregated blood elements and adhesive materials. It is much less sensitive to changes in hematocrit. The structural features and operation, as well as interpretation of pressure curves are described. viscosity of blood; suspension stability of blood; aggregation of platelets and leucocytes; aggregation of red blood cells; adhesiveness of platelets; adhesiveness of blood elements Submitted on August 5, 1963

No Deleterious Pulmonary Effects from Moderate Transfusions of Microaggregate-Rich Blood in Dogs

“…The screen filtration pressure (SFP) of each blood unit was determined according to Swank's method [27], If the SFP was significantly elevated after passage through a commercial standard filter, the blood was used for transfusion. Prior to transfusion, the blood was checked for blood group incompatibili ties by a cross-match test.…”

Platelet Behaviour in Dogs During and After Moderate and Severe Haemorrhage

“…The screen filtration pressure (SFP), the pressure required for the passage of 4 ml blood at a constant rate through a screen (diameter 2.4 mm) with multiple micropores 20 fi square was measured with a strain gauge as described by Swank [1964] using citrated arterial and mixed venous blood within 3 minutes of withdrawal. 3 microscope slides were prepared from each sample of arterial and mixed venous blood using siliconised cover-slips and glass slides and examined immediately with a phase contrast microscope for the presence of formed aggregates.…”

Effect of Adrenaline Infusion on Platelet Aggregation in the Cat as Determined Using the Screen Filtration Pressure Method

“…Screen Filtration Pressure (SFP): The SFP has been described as a suitable procedure for the determination of the forces holding together the formed elements of blood when aggregated. According to this procedure, as described by Swank [19,20), the pressure required to force blood through a metal screen whose pores are precisely 20 micron square, is recorded. The blood is forced at a constant rate of 4 ml/10 sec through an area of 2.4 mm diameter.…”

“…in vitro. Similar results were obtained by Glynn [5] when comparing different methods, and Nordoy [12] reported an adrenaline induced increase in rat platelet adhesiveness.The secretion of adrenaline in vivo leads to changes in the physiological responses of the body that have sometimes been related to an increased thrombotic tendency [18].In the present experiments we adapted the screen filtration pressure method [20][21] to evaluate the different stages in the effect of adrenaline on platelet aggregation, when infused at a constant rale in vivo. …”