Haemolysis Rates Research Articles

Randomized, single blinded control trial comparing haemolysis rate between two cannula aspiration techniques

Blood aspiration through i.v. cannulae is a common ED sampling method. It is, however, associated with increased haemolysis rates when compared with direct venipuncture. Our ED utilizes two common methods of sampling through cannulae. The aim of the present study was to examine the haemolysis rates for these two techniques. A randomized, single blinded prospective study was performed. From a convenience sample patients were randomized to either 'Method one' (blood taken directly from cannula hub) or 'Method two' (blood taken using an Interlink device through cannula cap). For each group patient demographics, clinical information and haemolysis were analysed. chi(2)-analysis and a multivariate logistic regression model were applied to determine significant relationships. A total of 1390 patients were enrolled, 694 had blood collected by 'Method one' and 696 by 'Method two', with haemolysis rates of 6.5% and 7.2%, respectively. Univariate analysis showed ease of aspiration to be the only variable to have a strong association with haemolysis (P < 0.0001). After allowing for ease of aspiration the technique used did not significantly affect haemolysis rate (P = 0.7). The rate of haemolysis is unrelated to the technique of blood aspiration. However, haemolysis rates increase significantly with perceived difficulty of blood draw.

Fragility of red cells during exercise is affected by blood pH and temperature.

We examined the relationship in horses between osmotic fragility of erythrocytes (OFE) measured as the red cell haemolysis rates (HLR) in 0.56% NaCl and certain physiological characters. Animals were exercised on a treadmill: warmed up at 30% VO2max for 5 min or at 105% VO2max for 1 min, given an exercise test at 80 or 105% VO2max until fatigued, and then cooled down. The pH and temperature of the blood had a significant correlation for the HLR: r = 0.93 and 0.92 (P < 0.01) on arterial and mixed venous blood, respectively. In multiple regression analysis, heart rate and packed cell volume showed lower coefficients for the HLR. The present study suggested that, in exercising horses, 1) the increase of blood flow and release of erythrocytes from the spleen into the circulation have little effect on changes of OFE; 2) the decrease of blood pH promotes OFE; 3) the increase of the pH causes osmotic resistance in the cells and 4) an increase of blood temperature during exercise is associated with the decrease in the OFE.

Effects of exercise on erythrocytes in normal and splenectomised Thoroughbred horses

SummaryChanges in erythrocyte quality during exercise were determined in 3 control (Group C) and 3 splenectomised (Group 5) horses that performed an incremental exercise test on a treadmill until the point of fatigue. Venous blood samples were drawn before the exercise test and immediately after warming‐up and incremental exercise test. Incremental exercise increased erythrocyte count and haemoglobin concentration by 46 and 37% respectively in control horses and by 15 and 17% respectively inGroup Sanimals. Packed cell volume (PCV) increased by 48% in controls but there was no change inGroup Sanimals. Warming‐up decreased mean cell volume (MCV), mean cell Hb (MCH) and mean cell Hb concentration (MCHC) by 9, 19 and 7% in control horses. Incremental exercise restored MCV and MCHC but MCH remained lower than the resting level. InGroup Shorses, warming‐up and incremental exercise decreased MCV by 6 and 9% respectively, did not change MCH, but increased MCHC by 4 and 15% respectively. Incremental exercise increased erythrocyte density (ED) inGroup Cbut not inGroup Shorses. Osmotic fragility of erythrocytes measured as the red cell haemolysis rates in 0.56% NaCl (HL) were significantly higher inGroup Cthan inGroup Shorses regardless of exercise. Warming‐up decreased HL by 7% inGroup Cvs 19% inGroup Shorses, but exercise increased HL by 26% inGroup Cvs 38% inGroup Shorses. These results suggest that: 1) exercise causes shrinking of erythrocytes; 2) erythrocyte indices are dependent on the intensity of the exercise; 3) release of erythrocytes from the spleen is associated with an increase in osmotic fragility; and 4) exercise changes osmotic fragility regardless of the release of erythrocytes from the spleen into circulation.

Rates of chlorpromazine‐induced hemolysis in seven species of animals

Chlorpromazine (CPZ) affects the hemolytic process in vitro. Hemolysis rates induced by CPZ at 10‐3 M concentration were measured in blood from humans, monkeys, horses, cattle, goats, rats and dogs. Hemolysis data were plotted in the form of Lineweaver‐Burke plots and the kinetics considered. The canine red cell was markedly more resistant than the other species as represented by a smaller Vmax. Basal glutathione peroxidase levels of the red cell were assayed in an attempt to correlate the enzyme activity with the haemolysis rates in the species studied. A strong correlation would have explained the dog's high resistance and would have strongly indicated lipid peroxidation as the mechanism of CPZ‐induced in vitro hemolysis. No such correlation was found.

Biochemical and physiological studies of certain ticks (Ixodoidea). Haemolysis rate and meal size in the interactions between Argas (Persicargas) arboreus Kaiser, Hoogstraal and Kohls, A. (P.) persicus (Oken) (Argasidae) and some avian hosts.

Bloodmeal volumes and haemolysis rates were determined in male Argas (Persicargas) arboreus and A. (P.) persicus fed on pigeons, domestic fowl, and adult and fledgling herons. Erythrocyte osmotic fragility curves were prepared for the host species.