Abnormal placentation, i.e. various grades of placental attachment to the myometrium, frequently leads to high or excessive blood loss after birth. Especially in cases of placenta accreta and increta, blood loss is often unpredictable and, if bleeding cannot be controlled, emergency hysterectomy is the final consequence. Needless to say, women undergoing this procedure are facing an increased risk for blood transfusion. Personally, I remember a case which ended up requiring around 50 units of allogeneic blood and 70 units of fresh frozen plasma.
The study by Elagamy et al. investigates the use of cell salvage in women who underwent cesarean hysterectomy due to placental retention. The concept of cell salvage is not new and is widely used outside pregnancy. However, the technique is not widely used in obstetrics since there is the fear of amniotic fluid embolism (AFE) due to reinfusion of fetal and maternal cell debris via the cell salvage system. The authors used a combination of a cell salvage system and a leukocyte depletion filter (LDF) and showed that, with this system, chances of transfusing fetal maternal cells is very low. In fact, in 15 women who were reinfused there was no case of AFE or other major complications due to the reinfusion. In addition, the authors show that only 2 of 15 women were severely anemic (Hb < 8.0 g/dL), while the others had moderate anaemia after autologous blood (Hb > 9.0 g/dL). Thirteen of 15 women did not require additional blood transfusion. Finally there were no significant negative effects on electrolytes or coagulation.
The authors conclude that the system is safe in their setting, acknowledging that the number of patients was low and that the risks and benefits would certainly show up more clearly if more women were treated in the same way. However, due to a carefully conducted study, a homogenous patient population and still a higher number of patients compared to other studies, the results are, for this reviewer, very relevant. Cell salvage systems should be introduced and investigated in these patients in major hospitals in the near future. Regarding the important concept of patient blood management, I am convinced that a clear positive cost and benefit ratio could be shown. Having said that, we must not forget that the salvage system will be mainly used in highly equipped settings which can sustain and afford these devices. For hospitals with lower resources, “aggressive” treatment of anemia prior to birth, prospective planning and blood sparing surgery in experienced hands will be the main modalities for the prevention of maternal mortality.
– Christian Breymann
In this prospective observational study, intraoperative cell salvage was performed in 20 cesarean hysterectomies for placenta accreta. Salvaged blood was collected and washed in 18 women and re-infused through a leukocyte depletion filter in 15 women (1476 ± 247 mL), and only 2 required allogeneic blood transfusion. Compared to prewash values, squamous cell counts were significantly lower post-filtration, although fetal Hb was still present (0.7 g/dL). There were no complications due to intraoperative or postoperative amniotic fluid embolism, hypotension, sepsis or coagulopathy.
As recently reviewed by Liumbruno et al. (Transfusion 2011;51:2244-56), in over 800 documented procedures and more than 400 patients transfused with salvaged blood, the procedure is useful and carries low risks. The risk for amniotic fluid embolism is preventable by washing salvaged blood and using leukoreduction filters for reinfusion. There are low risks for alloinmunization due to contamination by fetal Rh-mismatched red blood cells, since anti-Rh immunoglobulin is available, or ABO incompatibility, as ABO antigens are not fully developed at birth. In addition, the risk of alloimmunization from allogeneic transfusion is probably even greater.
This small study adds to the feasibility, efficacy and safety of intra-operative cell salvage for minimizing allogeneic transfusion in cesarean procedures at high risk for hemorrhage, as is the case for placenta accreta.
– Manuel Muñoz