Zależność ciśnienia tętniczego od ilości oddanej krwi u krwiodawców Relation Between the Amount of Donated Blood and Blood Pressure in Blood Donors

Summary Background The influence of the amount of donated blood by the blood donors on their blood pressure level. Material and methods A group of 49 blood donors was investigated. History, height and weight measurements were obtained from blood donors before donation. Blood pressure measurements were performed three times, before and after blood donation. Only the average value of second and third blood pressure measurement was taken for analysis. The studied group was analysed according to the mean value of blood pressure before donation: a subgroup (n = 28) with higher blood pressure (≥ 140/90) and a subgroup (n = 21) with lower values. Moreover we analysed donors according to median of donated blood (7900 ml): a subgroup with values below (n = 25) and above (n = 24) the median. The Shapiro-Wilk’s W test, Mann-Whitney U test, T-student test for small groups, c 2 test, Spearman’s correlations, multiple regression analysis were used to show differences between groups. Results Slightly greater decrease of blood pressure was observed in a subgroup with initially higher values of blood pressure as compared to the others (9,2/4,1 vs. 4,4/0,8 mm Hg), however the blood pressure was still significantly higher (132,3/93,9 vs. 117,4/78,0 mm Hg) after donation. The subgroups of blood donors with larger and smaller amount of donated blood differed from each other in terms of the amount of donated blood, age, blood pressure before and after donation. A decrease of blood pressure that followed blood donation was comparable in both subgroups (7,5/3,0 vs. 6,7/2,3 mm Hg). There were no significant correlation between values of blood pressure and amount of donated blood. When age was included in the multiple regression analysis, in the subgroup with a smaller amount of given blood, a level of blood pressure didn’t correlate with the amount of donated blood, but in the subgroup with the larger amount of donated blood, systolic (r = –0,15) and especially diastolic (r = –0,59) blood pressure before donation was inversely correlated with the amount of donated blood. Conclusion The amount of donated blood can protect