Page 320 - Haematologica April 2020

N.H. Saadah et al.
Table 2. Comparison of the number of transfusion reactions and transfusion reaction risk for fresh frozen plasma and solvent/detergent plasma using national hemovigilance data.
Transfusion reaction
allergic (other) reaction
allergic (anaphylactic) reaction non-hemolytic transfusion reaction
febrile non-hemolytic transfusion reaction transfusion associated circulatory overload transfusion related acute lung injury
other
FFP (209,681 units)
114
37
9
8
2
1
24
SD plasma (137,028 units)
14
9
1
1
2
1*
5
Risk Ratio (95% CI) riskSD/riskFFP
0.19 [0.11 to 0.33]
0.37 [0.18 to 0.77]
0.17 [0.02 to 1.34]
0.19 [0.02 to 1.53]
1.53 [0.22 to 10.86]
1.53 [0.10 to 24.46]
0.32 [0.12 to 0.84]
Significance
P<0.01 P<0.01 P=0.10 P=0.10 P=0.65 P=0.71 P=0.01
*Upon review, the expert panel tasked with evaluating debatable cases could not rule out TACO.TACO: transfusion associated circulatory overload; FFP: fresh frozen plasma; SD plasma: solvent/detergent treated pooled plasma.
fSD – fFFP. In the Online Supplementary Table S1, the numeric results of our entire blood product use analysis are shown. In our second sensitivity analysis, involving use of vary- ing hierarchies for cohort selection, we found changing the hierarchy yielded nearly identical results as only a few transfusion episodes were coded with diagnostic codes
from two different treatment wards (data not shown).
Comparison of plasma transfusion reaction risk
During the period from 2012 to 2016, Sanquin distrib- uted 209,681 units of FFP and 137,028 units of SD plasma. During the same period, the National Hemovigilance Office received reports of 46 allergic (anaphylactic) reac- tions, 128 allergic (other) reactions, 10 mild non-hemolytic febrile reactions (mild NHFR), nine non-hemolytic trans- fusion reactions (NHTR), four cases of transfusion associ- ated circulatory overload (TACO), two cases of transfu- sion related acute lung injury (TRALI), and 29 ‘other’ plas- ma transfusion reactions in association with transfusion of one or more plasma units. Table 2 shows risk ratios com- paring SD plasma and FFP for the seven plasma transfu- sion reaction types reported during the study period with an imputability of ‘certain’, ‘probable’, or ‘possible’. SD plasma was associated with fewer allergic (other) reac- tions (RR=0.19 [95% CI: 0.11 - 0.34]; P<0.01) and allergic (anaphylactic) reactions (RR=0.38 [0.18 - 0.79]; P<0.01), as well as fewer ‘other’ plasma transfusion reactions (RR=0.33 [0.13 - 0.86]; P=0.02) than FFP. No bacterial transfusion reactions were attributed to transfusion of either plasma during the study period.
Discussion
We compared the plasma/RBC units ratio, number of RBC units concurrently transfused, and transfusion reac- tion risks for SD plasma (200 mL) and FFP (~300mL) units in the Netherlands in the years surrounding the Dutch switch to SD plasma in 2014 and compared plasma unit use for transfusion episodes involving the two plasma types for the same period. The mean number of plasma and RBC units transfused per episode decreased signifi- cantly in the aneurysm and gynecological groups, and the decrease in overall plasma use continued despite the switch to the smaller SD plasma units. Despite the signif- icantly (one third) smaller volume of SD plasma units, the plasma/RBC units ratio remained constant across all
patient cohorts with the switch from FFP to SD plasma units. The risk of most plasma transfusion reactions decreased.
The SD process involves pooling FFP, treating the pool to disrupt lipid-coated viruses, and running the pool through a filter designed to remove prions. This process normalizes coagulation factor levels and dilutes proteins/cytokines from the individual donations, and is thus expected to reduce the incidence of some transfusion reactions (e.g. allergic, FNHTR). However, no aspect of the SD process is expected to increase the product efficiency, suggesting equal volumes of the two would be needed to affect the same reduction in active bleeding. In the Netherlands, a 200 mL unit of SD plasma is smaller than a unit of FFP which typically contains between 300 and 330 mL of plasma,3 meaning transfusing equal volumes of the two plasma products requires transfusing more units of SD plasma.
At the national level, we observed no such increase in units issued, with the switch to SD plasma not interrupt- ing the downward trend in plasma use over the period. At the transfusion episode level, we observed only a small increase in mean plasma units transfused per episode for the cohort as a whole. Rather than a large increase of SD plasma being transfused – an increase of 50% in the num- ber of transfused units could have been expected - this small increase is likely due to plasma exchange patients who, being exchanged with a specific volume, were trans- fused with more units of SD plasma (Table 1). The changes in the plasma use for the ward-based patient groups and diagnosis-based sub-cohorts varied, but did not show the trend we expected to see were the number of plasma units transfused systematically different for FFP versus SD plasma. When the changes in mean plasma units per episode did reach the level of statistical signifi- cance (e.g. cardiothoracic surgery + cardiology group), the effect sizes were in line with those of the other cohorts and the statistical significance resembles the result of the larger size of these cohorts. Given that the change in plas- ma/RBC ratio (f) was not significant for any of the cohorts, we interpret these results as showing continued transfusion of SD plasma units in the same proportion to RBC units as FFP plasma. We have found no previous studies comparing the plasma/RBC units ratio for FFP and SD plasma. In broad terms, plasma is transfused to replen- ish plasma proteins during active bleeding (e.g. during sur- gery) or to remove a harmful entity/constituent via plasma
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haematologica | 2020; 105(4)