Obstetric hemorrhage is currently the leading cause of maternal death, especially in patients with massive hemorrhages [20, 21]. Timely and reasonable blood transfusion is one of the most effective measures to reduce maternal mortality, and has been widely performed in obstetric operations . The clinical use of fresh or stocked allogeneic blood has become the main source of blood transfusion therapy, while the safety of allogeneic blood transfusion and the increasing tension of blood sources have attracted attention from medical workers. Although improvements in the blood donor screening system and the storage technology of blood banks have greatly improved the safety of blood transfusion, the occurrence of blood transfusion-related allergic reactions cannot be completely avoided [23, 24]. Therefore, reasonable, safe, and effective blood availability has become an urgent problem.
Intraoperative cell salvage (IOCS) is a blood source protective measure that has gradually become popular in recent years. This is the most effective method for blood transfusion to reduce blood-borne diseases related to blood transfusions . IOCS is a technology that takes the patient's intraoperative bleeding and blood accumulated in the body cavity and this blood is filtered by multiple layers into the blood recovery tank; after separation, washing, purification, the free hemoglobin, cell debris, fat droplets, and other impurities are diverted into the large waste liquid bag to reduce the residual pollutants, and finally the concentrated red blood cell suspension is returned to the patient . With the use of a leukocyte removing filter, the amniotic fluid components from the recovered blood can be almost completely eliminated [18, 27].
Although multiple studies with a large number of clinical samples have confirmed the safety of this technology, there are still some taboos in promoting this technique [2, 28]. In particular, the safety and effectiveness of IOCS during cesarean section is still controversial , and previous studies have reported inconsistent conclusions about the application of IOCS in cesarean section on allogeneic transfusion and the economic benefits to obstetric patients [13, 29]. Currently, IOCS technology has been widely used in obstetrics, and some scholars have reported that IOCS technology is an effective method of reducing transfusion for cases at high risk of obstetric hemorrhage, and which is economically reasonable, while for routine cesarean deliveries, IOCS is not recommended [12, 30]. Therefore, it is necessary to discuss the application guidelines to provide evidence as to the rationale for such use and to increase confidence in its use as an effective application in obstetrics.
In our study, 2621 patients were included, and all patients who received IOCS had no serious adverse outcomes of e.g., amniotic fluid embolism and maternal death; therefore, IOCS is considered relatively safe and economical. However, this study showed that the proportion of patients using autologous blood transfusion was as high as 75.8% in Group A, because some patients in Group A had a small amount of intraoperative recovered blood, this could not reach the reinfusion standard and did not undergo reinfusion, which caused a waste of resources to a certain extent. Therefore, we conducted a multi-factor analysis to explore the clinical application guidelines of IOCS in obstetrics. Multivariate logistic regression analysis was performed by selecting statistically significant indicators in univariate analysis and high-risk factors related to bleeding to construct a bleeding risk scoring system for guiding the rational use of IOCS technology. This identified ten significant independent risk factors, namely, maternal age ≥35 years, number of cesarean sections, placental attachment position, placenta previa, placenta accreta, blood pool in the placenta, abnormal retroplacental myometrium, placenta protruding to the anterior uterine wall, cervical canal invasion, and continuous disruption of the myometrium. Therefore, the above 10 variables were included in the scoring system to predict the risk of intraoperative hemorrhage in patients with IOCS. The results showed that the area under the curve (AUC) of the receiver operating characteristic curve for the scoring system was 0.837, and a total score of 5 points was identified as the optimal cut-off value allowing good differentiation of intraoperative massive bleeding in IOCS patients. Consequently, IOCS technology was not shown to be beneficial for all obstetric patients. From our study, a total score ≥ 5 points indicating a high risk of intraoperative hemorrhage, was recommended to use the IOCS technology.
The strengths of our study are as follows: First, owing to the application of leukocyte filters, IOCS technology has been widely used in obstetric cesarean section, while there is no recommended application guide in the literature about the technology, which leads to excessive use of IOCS and a waste of resources. In our research, we conducted a multivariate analysis in obstetrics patients using the IOCS, designed a bleeding assessment scale, and achieved better and more reasonable usage of IOCS technology, which can to a certain extent, reduce the economic burden on patients. Second, this study focused on patients who used IOCS technology in cesarean section. Finally, the scoring system not only included clinical data, but also included ultrasonographic indicators, which play an important role in the evaluation of hemorrhagic disease (placenta previa, placenta accreta, and vasa previa) in pregnant women. There are however, some limitations to our study. First, this was a retrospective study, which increased the possibility of patient selection bias. Further, the designed scoring system requires validation using a large sample of prospective data before it can be applied to clinical practice.
In conclusion, our study reports that IOCS technology is a safe and effective hemostatic measure in obstetric cesarean section. We developed a risk scoring system based on ultrasound and clinical indicators by evaluating the risk factors of intraoperative hemorrhage in patients using IOCS technology. This system has good sensitivity and specificity, and can better guide the application of IOCS technology in clinical practice. Therefore, a good understanding of the clinical application guidelines of IOCS and reasonable usage of IOCS technology in clinical settings can save medical resources and reduce the economic burden on patients.