Material and Methods
We conducted a retrospective observational study at Lille University
Hospital, France. All women who received ICS to reduce the need for
allogeneic blood transfusion during a scheduled or urgent cesarean
section or postoperative PPH were included. Women transferred because of
postoperative PPH whose cesarean section was performed in a primary
hospital were not included. The inclusion period extended from June 2007
to September 2018.
ICS protocol
Our device was a continuous autotransfusion system (CATS, Fresenius
Laboratory, Germany), which performed the blood washing and salvage.
Women identified at high risk of PPH, those with a rare blood type, and
those who refused the use of allogeneic products in the event of
cesarean section were eligible for ICS. In cases of emergency, the
anesthesiologist could implement ICS during PPH.
The blood-collecting system was set up as the patient entered the
operating theater. Two separate suction
utotransfusion
depended on clinical parameters, bleeding flow, and hemoglobin level. In
case of contamination of the surgical site with methylene blue or iodine
antiseptics or in case of maternal sepsis at the time of the cesarean
section, the collected blood was not reinfused. Autotransfusion was
performed using a transfusion filter after passing the fluid through a
second standard 40 µm filter.
A transfusion traceability sheet was sent to the hospital’s
hemovigilance service. Women with rhesus (Rh) incompatibility received
an injection of Rh immune globulin, whose dose was adapted to the
Kleihauer test result and cell count. An antiglobulin test was
recommended for each patient 2 months after autotransfusion.
ICS could be used during a scheduled or urgent cesarean section. The
severity of the urgent need for cesarean section was classified
according to the color coding used in our maternity ward. Each color is
defined by a decision-to-delivery interval: ≤20 min is coded as red; ≤30
min as orange, and no time limit as green11. PPH was
defined as a rate of bleeding >500 mL within 24 h and was
considered to be severe when blood loss was >1000 mL.
Indications for ICS
The women included in our study could have 1, 2, or 3 of the following
indications for ICS: placenta abnormality, such as placenta accreta
spectrum or placenta previa; risk factors for uterine atony, such as
uterine fibroids, multiple pregnancy or fetal macrosomia; uterine
scarring caused by myomectomy or anterior cesarean section scar(s);
postoperative bleeding, defined as PPH within 24h after caesarean
section delivery; maternal heart disease; pregnancy-related vascular
disorders such as preeclampsia, HELLP syndrome, or retroplacental
hematoma; transfusion difficulties, such as having a rare blood group or
sickle cell disease, or being a Jehovah’s Witness; hemostasis disorder;
severe prepartum anemia, defined as hemoglobin concentration
<10 g/dL; history of severe postpartum haemorrhage; or other
indications, such as uterine rupture, acute fatty liver of pregnancy or
a maternal disease.
Assessment criteria
The primary outcome for assessing the effectiveness of ICS was its
ability to enable the reinfusion of autologous blood. Data about ICS
management were collected prospectively during cesarean section on
autologous-transfusion traceability sheets. Anthropometric, obstetric,
and anesthetic variables were collected retrospectively from patients’
medical records.
Statistical analysis
The frequency of the different indications of ICS was compared between
two groups of women: those who received ICS and autotransfusion and
those who received ICS without autotransfusion.
Qualitative variables were described as frequency and percentage, and
quantitative variables as median and interquartile interval.
Bivariate analyses were performed using the chi-squared test or exact
Fisher test (in case of theoretical numbers <5) for
qualitative variables.
Multivariate analysis was performed using a multivariate logistic
regression model with a step-by-step backward selection procedure. The
logistic regression model was performed for variables with a P value
< .1 in the bivariate analysis.
A receiver operating characteristic (ROC) curve was created to study the
interrelationship between autotransfusion and the bleeding volume and,
predict a bleeding threshold.
Statistical analyses were performed using SAS software, version 9.4. The
level of significance was set at P < .05.
Ethics
A statement was submitted to the National Commission on Informatics and
Liberties. Patients consented to the collection of their clinical data.
Our research received approval number CEROG 2019-OBST-1001 from the
Ethical Review Committee “Comité d’éthique de la recherche en
obstétrique et gynécologie”.