Intraoperative Cell Salvage In Obstetrics

ObjectiveThe process of intraoperative blood salvage consists of blood collection (aspiration of blood from the surgical field), blood processing (centrifugation and washing with heparinized saline solution) and reinfusion. The use of ICS has increased substantially during the past decades. It avoids the hazards of allogeneic blood transfusion and has been well established in cardiac, vascular and orthopaedic surgery. Haemorrhage is a leading cause of perinatal mortality. Placenta praevia and placenta accreta can present as obstetric massive haemorrhage during caesarean section. In china, ICS has not been adopted in the obstetric field. The safety has been questioned because of the presumed risk of precipitating amniotic fluid embolism and maternal alloimmunisation.Internationally, ICS in obstetrics has been proven to be safe in light of new research and experience and endorsed by many guidelines. At present there is no related research at home. In this study, intraoperative cell salvage was combined with blood filtration using a leukocyte depletion filter. A comparison of this washed, filtered product was then made with maternal central venous blood. Next, this is the first study to make model combined amniotic fluid embolism with autologous transfusion in animal. Self-controlled was applied in the research to find the related adverse reactions of cell salvage when the blood was contaminated by amniotic fluid and meconium. At last, we show our experience and results of the implementation of intraoperative cell salvage during cesarean section in patients by a retrospective analysis.Materials and Methods1. In vitro studyOperative blood loss was collected and processed using the Dideco Electa (Sorin,Italy) cell salvage machine and filtered by RF 400 leucocyte depletion filtration. The fetal squamous cell, a-fetoprotein, tissue factor, endothelin-1, histamine and fetal red blood cell concentration were measured in four sequential blood samples collected from 30 women undergoing cesarean section. The blood samples collected included unwashed blood from the surgical field (prewash), washed blood (postwash), washed and filtered blood (postfiltration), and maternal central venous blood drawn from a internal jugular vein catheter at the time of placental separation.2. Animal Experiment12 adult nonpregnant female Beagle dogs were divided into three groups, the amniotic fluid group(n=4), meconium group(n=4), the meconium stained amniotic fluid mixed group n=4. In the first stage, human amniotic fluid, meconium, mixed liquid (10ml/kg) were mixed with animal steriled blood 100ml in the storage tank. After washing and filtering, recycling blood was re-transfused.30 days later, in the second stages, amniotic fluid, meconium and mixture of the same specimen (10Oml/kg) were injected into the animals above. The change of life signs including MAP, HR, RR and adverse reactions were recorded before anesthesia(T0), after anesthesia(T1), after transfusion immediately(T2),3min(T3),10min(T4),30min(T5) and 100min(T6). One milliliters of femoral arterial blood was placed into a purple-top tube to make alcohol-fixed and HE-stained slide for screened for the presence of squamous epithelial cells, amniotic fluid and meconium.3. Cases reportFrom 2013 to 2014 intraoperative blood salvage was used for 4 patients of pernicious placenta previa complicated with placenta accreta undergoing cesarean section. The clinical data were retrospectively analyzed. A comparation of Hb, Hct, PT, APTT, FIB, INR and Plt were made between before anesthesia with 2h after anesthesia.Results1. In vitro studyThe volume of the blood loss was (2150.3±223.4)ml and salvaged blood was (1476.5±250.9)ml. The hct was (31.3±4.8)%. None of the cases were re-transfused. 88U of heterologous blood was transfused. Compared with maternal central venous blood, a-fetoprotein, tissue factor, endothelin-1 and histamine of the postwash and postfiltration samples were effectively removed by cell salvage processing (P<0.05);Compared with the postwash samples, fetal squames, fetal red blood cells and a-fetoprotein levels of postfiltration samples were decreased (P<0.05).2. Animal ExperimentThe first stage:For the three groups, compared with TO of MAP, HR and RR, T1-5 decreased significantly (P<0.05). Compared with T2 of MAP, HR and RR, T3-5 had no significant change (P>0.05), but T6 increased significantly (P<0.05). The reinfusion of salvaged blood had not produced the related symptoms of AFE. Amniotic fluid and meconium components were not found in the blood samples observed under microscope.The second stage:For the amniotic fluid group and mixed group, compared with T0, Tl-2 of MAP, HR and RR significantly decreased, T3-5 of MAP significantly decreased, and HR, RR significantly increased (P<0.05). Compared with T2, T3-5 of MAP significantly decreased, T6 of MAP significantly increased, while T3-6 of HR and RR increased significantly (P<0.05). For the meconium group, compared with T0, T1-5 of MAP, HR decreased significantly (P<0.05), while of RR, T1 and T2 decreased, T3 and T4 increased significantly (P< 0.05). Compared with T2, T3-6 of RR significantly increased (P<0.05), T6 of MAP, HR increased significantly (P<0.05). The infusion had produced the various symptoms including cough, convulsions, opisthotonus, lung wet rales and so on during the process. Amniotic fluid or meconium components were found obviously in the blood samples observed under microscope.3. Cases reportThe cell salvage was used for 4 patients. Compared with those before anesthesia, Hb, Hct, FIB and Plt had downward trend. PT, APTT and INR had rising trend. But the differences were not statistically significant (P>0.05). Blood loss ranged 1800-3900ml and the volume of re-transfused ranged 991～1920ml. All the process of retransfison used leukocyte depletion filter and the quantity ranged 2-8. The operation time ranged 60-260min. Interventional therapy was combined in 3 patients. Two patients received total heterologous red blood 4U. No complications resulting from the retransfusion of salvaged blood were recorded in our research. Conclusions1. Leukocyte depletion filtering of cell-salvaged blood obtained from cesarean section significantly reduces amniotic fluid contaminants, a-fetoprotein, tissue factor, endothelin-1 and histamine to a concentration equivalent to maternal venous blood.2. After processing using the cell salvage machine, the re-infusion of salvaged blood was safe for the animals without related complication, though the blood loss was contaminated by human amniotic fluid or meconium.3. Intraoperative cell salvage has no obvious effect on the level of Hb, hct and coagulation function for placenta previa/increta patients.4. In cases of intractable massive hemorrhage, Leukocyte depletion filtering of intraoperative cell salvage should be considered if available. The intraoperative cell salvage can be used with relative safety as a cost-effective practice to minimize allogeneic transfusion in women undergoing cesarean section.