Interpretation
Suspicion of a placental insertion abnormality is identified by
national15 and international6,7guidelines as an indication for implementing ICS. Our results support
the idea that an optimal transfusion strategy based on ICS should be set
up during cesarean section in women with placenta accreta.
In our study, placenta previa was not associated with autotransfusion.
It is likely that ICS is not effective in this indication because a part
of the bleeding is externalized through the vagina. Moreover, when
trans-placental incision is performed, a significant proportion of
bleeding is removed with amniotic fluid. In these cases, using a
single-aspiration strategy may optimize the collection of the bleeding
and the efficiency of ICS. This strategy is supported by the work of
Sullivan et al.16 and is being developed in English
centers17. As proposed in the guidelines of the Royal
College of Obstetricians and Gynaecologists (RCOG)18,
in placenta previa situations, it may be appropriate to reserve ICS for
patients with prepartum anemia, in particular in women who would decline
blood products (grade D).
The presence of uterine fibroid(s) was also identified as a risk factor
for autotransfusion with ICS. These patients are considered to be at
high risk of PPH. The size and location of the fibroid(s) appear to
correlate with the occurrence of PPH19. From the
pathophysiological viewpoint, the existence of a fibroid in the cavity
may lead to incomplete uterine retraction and a reduced response to
oxytocics, which may lead to uterine atonia20.
However, no studies have evaluated the use of ICS for this indication.
We found a strong association between postoperative bleeding and
autotransfusion (OR 10.15, 95% CI 2.6–38.53). The good performance of
autotransfusion in this situation can be explained by the large volume
of blood contained in a hemoperitoneum, which can be easily collected
during revision surgery. In our cohort, 8 patients who did not receive
autotransfusion during their cesarean section received a homologous
transfusion for postoperative bleeding. ICS had not been set up in these
patients even though 5 had undergone revision surgery. Our results
suggest that the use of ICS would have allowed autotransfusion in 77%
of these patients, thus reducing the need for homologous transfusion in
3–4 women.
The existence of a uterine scar did not appear to influence the need for
autotransfusion. However, in patients with multiple scars, it is
essential not to ignore the possibility of an associated placenta
accreta, which should be suspected when a uterine scar is associated
with placenta previa. In 2006, a large prospective cohort found placenta
accreta spectrum rates of 40%, 60%, and 67% in patients with placenta
previa and 3, 4, and ≥5 anterior cesarean section scars,
respectively21.
Despite uterine overdistension associated with a multiple pregnancy,
this indication was not associated with autotransfusion in our cohort.
We did not study the factors influencing uterine distension, such as
fetal weight and quantity of amniotic fluid.
The group of patients with transfusion difficulties (e.g., rare blood
groups, Jehovah’s Witness, and sickle cell disease) had a lower risk of
autotransfusion in our series. This result was expected given that ICS
is implemented in women with variable bleeding risk. In these patients,
access to blood products is limited by the scarcity of compatible
homologous RBCs or transfusion may be refused because of personal
beliefs. ICS makes it possible for these women to access transfusion in
the event of haemorrhage. Despite the lack of association, it seems
justified to continue using ICS in these women.
In our study, 47% of the women who received autologous transfusion
avoided homologous transfusion. This result is consistent with the
literature13,17. The rate of autotransfusion in our
cohort (33.1%) is lower than that in other studies of populations at
risk of bleeding. This may be explained by the heterogeneity of our
indications, which argue in favor of our main objective.
To help decide more easily when implementing ICS, we studied the
association between the bleeding volume and autotransfusion. We found a
predictive autotransfusion threshold at 936 mL of bleeding, with high
PPV and NPV (77.4% and 95.5%, respectively). This finding is
consistent with the 1000 mL threshold suggested in the review by
Grainger and al.22. However, this volume is less than
the 1500 mL threshold proposed by the French guidelines for the
management of placenta accreta (grade C)15.
Clinical implications
Our study confirms, through a large cohort, the effectiveness of ICS in
patients with placenta accreta spectrum. We also provide a new point of
view about the transfusion management of women with uterine fibroma. In
these patients, it seems justified to plan cesarean section in an
obstetric department equipped with an ICS device.
Postoperative bleeding cannot be anticipated and is likely to occur in
any maternity ward. ICS devices are used mainly in the USA and the UK,
where 49% of obstetric departments were equipped with an ICS device in
201123. In France, several factors are slowing the
uptake of ICS devices, starting with the economic cost. Regular use of
ICS is essential for assessing the abilities of anesthetic and obstetric
teams. However, it is not suitable within the practice of maternity
wards with a smaller volume of deliveries.
In Lille University Hospital’s obstetric department, the
cost-effectiveness of the ICS system is ensured because of a large
number of cesarean sections in women at high risk of bleeding. The CATS
device is provided by Fresenius Health Care Group, which ensures its
maintenance. Each collection kit costs 34 \euro, and the treatment kit
is invoiced at 63 \euro. The average cost for a homologous RBC unit in
our hospital is 193 \euro. The equivalent of 170 autologous RBC units
was transfused during our study. Although we did not design this study
to be a medicoeconomic analysis, our work seems to support the idea that
ICS is cost-effective for cesarean sections in women at high risk of
bleeding, as reported by international studies24,25.
Team training was fast and our hospital ensures access to ICS 24 h a
day. The estimated assembly time is 3 min.
The implementation of ICS in our department has revolutionized the
management of women suspected of having placenta accreta spectrum.
Before the implementation of ICS, our transfusion strategy for these
patients involved ordering a large number of RBC units from the blood
bank. This led to the loss of vital resources.
Strengths and limitations
This work provides new data in a field with few published studies. As a
clinical study, our findings may provide reassurance about the safety of
ICS in terms of serious adverse effects of autotransfusion, in
particular amniotic fluid embolism. Our study included 5 women with
sickle cell disease (4 homozygous SS and 1 compound heterozygote SC) who
were reinfused safely after ICS. Hemoglobinopathy is listed in some
reports as a contraindication to ICS26,27 but the data
on these patients remain limited. Given the transfusion difficulties
encountered by these patients, most of whom were severely anemic, we
considered it reasonable to offer them ICS. The volume of reinfusion was
often low because of hemolysis of sickle RBCs, but the transfusion
efficiency remained good. Despite the small number of patients in our
study, the absence of autotransfusion side effects is reassuring and
should encourage further study on ICS in this population.
The small number of patients in some of the groups made some of the
analyses impossible. For example, we could not analyze the data for
women with a retroplacental hematoma or hemostatic disorder. In terms of
adverse effects of autotransfusion, we do not conclude on concerns about
alloimmunization because we were enable to collect the necessary data.