Roz Gibbs

Does the use of leucocyte depletion during cardiopulmonary bypass affect exhaled nitric oxide production

Fifty patients undergoing elective coronary revascularisation were prospectively randomised to receive either a leucocyte-depleting or a control filter inserted into the arterial line of the cardiopulmonary bypass (CPB) circuit. The concentration of exhaled nitric oxide (NO) was measured 15 min before and 30 min after CPB using a real-time chemiluminescence analyser (Logan Research, Northampton, UK). The baseline rate of exhaled NO production was 2.14±0.83 ppb/s in the control group, and 2.58±0.53 ppb/s in leucocyte-depleted group (p = 0.17). Following CPB, the mean rate of exhaled NO production in the control group had increased by 1.51±0.45 ppb/s to 3.65±0.81 ppb/s and in the leucocyte-depletion group had increased by 1.05±0.45 ppb/s to 3.64±0.62 ppb/s. The increase in exhaled NO production was significantly lower in the leucocyte depleted group (p = 0.002), indicating that leucocyte depletion suppressed the increase in exhaled NO production seen following CPB.

Effect of blood temperature on the efficacy of systemic leucodepletion during cardiopulmonary bypass: a prospective randomized clinical study.

The authors examined the effect of blood temperature within the cardiopulmonary bypass (CPB) circuit on the efficacy of an arterial line filter. Eighty patients undergoing elective, primary coronary artery bypass grafting under CPB were prospectively randomized in two equal groups. Blood temperature was kept at 35°C in the first group and reduced to 28°C in the second group. Twenty patients in each group had an arterial line LG6 filter attached onto CPB circuit. The other 20 patients in each group (controls) had a non–leukocyte-depleting filter. Blood samples (10 ml) were taken before CPB, at 5 minutes on CPB, at 30 minutes on CPB, 5 minutes after aortic clamp removal, and 6 hours postoperatively. Leucocytes were counted under light microscopy. Activated leucocytes were identified using nitroblue tetrazolium staining. Patients undergoing leucodepletion had significantly lower total and activated leukocyte counts than control patients in both groups (p < 0.05). Patients having a leukocyte-depleting filter at a CPB temperature of 35°C had significantly lower total leukocyte counts (p < 0.05) than those having a leukocyte-depleting filter at a CPB temperature of 28°C (p < 0.05). However, there were not statistically significant differences in the activated leukocyte counts between the two leucodepleted groups (p > 0.05). This study shows that warm blood temperature within the CPB circuit has a positive effect on the overall leucodepleting efficacy of the LG6 filter. Activated leucocytes, however, seem to be depleted at similar rates irrespective of the blood temperature in the CPB circuit.

Leukocytes-depleting filters preferentially remove activated leukocytes and reduce the expression of surface adhesion molecules during the simulated extracorporeal circulation of human blood.

The effect of leukocyte-depleting filters on the total and activated leukocyte counts and the expression of surface adhesion molecules CD11b, CD18, and CD62L during the in vitro extracorporeal circulation of human blood was studied. A 200 ml blood sample was taken from 10 patients undergoing CABG surgery. The blood was circulated for 60 minutes within an experimental extracorporeal circuit. A leukocyte-depleting filter was attached in five circuits (filtered group). In five other circuits, no filter was used (controls). Total leukocyte counts were determined manually. Activated leukocytes were identified using nitroblue tetrazolium staining. The expression of CD11b, CD18, and CD62L was measured with flow cytometry. At 60 minutes, total leukocyte counts were reduced by 49% from the baseline values in the filtered group and 10% in the control group (p < 0.0001). Activated leukocyte counts decreased by 86% in the filtered group and increased by 116% in the control group (p < 0.0001). In the filtered group, the expression of CD11b, CD18, and CD612L decreased by 60%, 21%, and 79%, respectively, and in the control group it increased by 24%, 6%, and 28% (p < 0.0001). Leukocyte-depleting filters preferentially remove activated leukocytes and reduce the expression of CD11b, CD18, and CD62L during the in vitro extracorporeal circulation of human blood.

Reference intervals for absolute and percentage immature platelet fraction using the Sysmex XN-10 automated haematology analyser in a UK population

Abstract Background: Immature platelet fraction (IPF) estimation is a non-invasive and sensitive test that is available on recently introduced Sysmex XN-series of automated haematology analysers. It is a direct cellular indicator of thrombopoiesis. The aim of this study was to establish reference intervals for IPF, for both absolute (A-IPF) and percentage (%-IPF) measurements. Material and methods: A total of 2366 samples that met the inclusion criteria were assayed for full blood count on the Sysmex XN-10 and a non-parametric percentile method was used for calculating the reference intervals. Results: After the outliers were excluded, the reference interval for %-IPF and A-IPF on Sysmex XN-10 were 1.6–10.1% and 4.37–23.21 × 109/L in total individuals, respectively. There was a statistical significance noted between the sexes (p = .004) for %-IPF, therefore a sex-specific reference interval was established, which was 1.8–10.0% for the males and 1.5–10.1% for females. No significant difference in sex status for A-IPF and age status for both %-IPF and A-IPF was observed. A very poor correlation was estimated between age versus %-IPF, ρ = 0.0156, and age versus A-IPF, ρ = −0.0023, indicating that there is no overall biological relationship between age and these parameters. As expected, a strong correlation between %-IPF and A-IPF was noted which could be attributed to their inter-relatedness. Conclusions: This large-scale study showed comparable reference intervals with the previous studies for %-IPF and A-IPF in a UK population. It found the need to establish sex-specific reference intervals for %-IPF, but not for A-IPF, whereas reference intervals were found to be stable across the age range.