Cell salvage for the management of postpartum haemorrhage.
Postpartum haemorrhage (PPH), defined as a blood loss of 500 mL or more within 24 hours of birth, is the leading global cause of maternal morbidity and mortality. Allogenic blood transfusions are a critical component of PPH management, yet are often unfeasible, particularly in resource-poor settings where maternal morbidity is highest. Autologous cell salvage in the management of PPH has been proposed to combat limitations in access to allogenic blood and potential transfusion-related risks. This review examines the benefits and harms of using cell salvage for pregnant women during birth.
To assess the benefits and harms of cell salvage when used during birth.
We searched the CENTRAL, MEDLINE, Ovid Embase, and Global Index Medicus databases and the ICTRP and ClinicalTrials.gov trials registers. We also carried out reference checking and citation searching, and contacted study authors to identify all relevant studies. The latest search date was 8 February 2024.
We included randomised controlled trials (RCTs) in pregnant women (24 weeks or more gestation) comparing use of cell salvage following caesarean or vaginal birth with routine care (defined as no cell salvage). We did not place any restrictions on mode of birth, ethnicity, race, socioeconomic status, education level, or place of residence.
Critical outcomes for this review were risk of allogenic blood transfusion, risk of transfusion-related adverse reactions, risk of haemorrhage, transfer to higher level of care, length of hospitalisation, length of operation, and risk of sepsis. Important outcomes were estimated blood loss, blood loss ≥ 500 mL, blood loss ≥ 1000 mL, use of additional uterotonics or tranexamic acid, maternal death, postpartum haemoglobin concentration, change in haemoglobin, major surgery including hysterectomy, future major surgery, end-organ dysfunction or failure, amniotic fluid embolism, side effects, clotting abnormalities, maternal experience/satisfaction, maternal well-being, and breastfeeding.
We assessed risk of bias using the Cochrane risk of bias tool (RoB 1) for each critical outcome from each RCT.
We conducted a meta-analysis for each outcome where data were available from more than one study using a random-effects model. If data could not be analysed using meta-analysis, we synthesised results narratively using the Synthesis Without Meta-analysis (SWiM) guidance. We used GRADE to assess the certainty of evidence for each outcome.
We included six RCTs with 3476 participants. All trials involved pregnant women having a caesarean birth. Three trials were conducted in high-income countries, and three were conducted in an upper-middle-income country.
Allogenic blood transfusion Intraoperative cell salvage at caesarean birth may reduce the need for allogenic transfusions received by participants, although the 95% confidence interval (CI) includes the possibility of an increase in effect. Low-certainty evidence from three studies found the risk of donor transfusions was possibly lower in participants with cell salvage (risk ratio (RR) 0.45, 95% CI 0.15 to 1.33; P = 0.15, I2 = 33%; 3 RCTs, 3115 women; low-certainty evidence). The absolute risk of transfusion was very low in the studies (4% in women not treated with cell salvage and 2% in women treated with cell salvage). Transfusion-related adverse reactions The evidence is very uncertain about the risk of transfusion-related adverse reactions in participants with intraoperative cell salvage (RR 0.48, 95% CI 0.09 to 2.62; P = 0.39; 4 RCTs, 3304 women; very low-certainty evidence). Haemorrhage Two studies reported risk of haemorrhage and found that there was probably no difference between arms (RR 0.88, 95% CI 0.67 to 1.15; P = 0.36, I² = 0%; 2 RCTs, 3077 women; moderate-certainty evidence). Length of hospitalisation The evidence is very uncertain about whether interoperative cell salvage at caesarean birth affects length of hospitalisation. Three studies reported length of hospitalisation (MD -2.02 days, 95% CI -4.73 to 0.70; P = 0.15, I2 = 100%; 3 RCTs, 3174 women; very low-certainty evidence). Length of operation Two studies reported on length of operation. However, meta-analysis was not possible due to statistical heterogeneity and divergence of study findings; the direction of effect could not be determined. We evaluated the evidence as very low certainty. Sepsis One study reported risk of sepsis, finding that there was possibly no difference between arms (RR 1.00, 95% CI 0.43 to 2.29; P = 0.99; 1 RCT, 2990 women; low-certainty evidence). Estimated blood loss Cell salvage at caesarean birth may reduce blood loss. Two studies reported that estimated blood loss was possibly lower in women who had cell salvage compared to those who did not (MD -113.59 mL, 95% CI -130.41 to -96.77; P < 0.00001, I2 = 0%; 2 RCTs, 246 women; low-certainty evidence). Postpartum haemoglobin concentration Cell salvage at caesarean birth may increase day one postpartum haemoglobin. Three studies reported day one postpartum haemoglobin levels (MD 6.14 g/L, 95% CI 1.62 to 10.65; P = 0.008, I2 = 97%; 3 RCTs, 3070 women; low-certainty evidence). Amniotic fluid embolism Three trials reported risk of amniotic fluid embolism and no cases were observed (n = 3226 women).
Cell salvage may reduce the need for allogenic blood transfusion, may reduce blood loss, and may increase day one postpartum haemoglobin in pregnant women having caesarean birth (low certainty). Cell salvage may make little to no difference to the risk of sepsis (low certainty) and probably makes little to no difference to the risk of haemorrhage (moderate certainty). The effect of cell salvage on risk of transfusion-related adverse reactions is very uncertain. The effect of cell salvage on the length of hospital stay was both clinically and statistically heterogenous, with a very low certainty of evidence. The effect of cell salvage on length of operation is divergent and meta-analysis was not possible due to significant statistical heterogeneity; the evidence is of very low certainty. No cases of amniotic fluid embolism were reported among the included trials. Studies in low- and middle-income settings are needed.
This review had no dedicated funding.
This review was registered with PROSPERO (CRD42024554204).
Dey T
，Brown D
，Cole MG
，Hill RA
，Chaplin M
，Huffstetler HE
，Curtis F
... -
《Cochrane Database of Systematic Reviews》
Tranexamic acid for preventing postpartum haemorrhage after caesarean section.
Postpartum haemorrhage (PPH) is common and potentially life-threatening. The antifibrinolytic drug tranexamic acid (TXA) is recommended for treating PPH; it reduces the risk of death from haemorrhage by one-third when given soon after bleeding onset, but not overall risk of death. Interest in whether TXA may be effective in preventing PPH is growing. Evidence indicates that TXA given more than three hours after injury to bleeding trauma patients increases mortality. Potential harm becomes critical in prophylactic use of TXA. Reliable evidence of the effect and safety profile of TXA is required before widespread prophylactic use can be considered.
To assess the effects of TXA for preventing PPH compared to placebo or no treatment (with or without uterotonic co-treatment) in women during caesarean birth.
We searched CENTRAL, MEDLINE, Embase, and WHO ICTRP to 20 February 2024 and searched reference lists of retrieved studies.
We included randomised controlled trials (RCTs) evaluating the use of TXA alone or plus uterotonics during caesarean birth for preventing PPH. Trials needed to be prospectively registered (i.e. before starting recruitment). We applied a trustworthiness checklist.
The critical outcome was blood loss ≥ 1000 mL, measured using estimated or calculated methods. Important outcomes included maternal death, severe morbidity, blood transfusion, the use of additional surgical interventions to control PPH, thromboembolic events, use of additional uterotonics, hysterectomy, maternal satisfaction, and breastfeeding at discharge.
We assessed risk of bias in the included studies using Cochrane's RoB 1 tool.
Two review authors independently selected trials, extracted data, and assessed risk of bias and trial trustworthiness. We pooled data using random-effects meta-analysis. We assessed the certainty of the evidence using GRADE.
We included six RCTs with 15,981 participants. All 12 trials in the previous version of this review were not included after review of trial registrations and trustworthiness checklists. Most included studies involved women at low risk of PPH and were conducted in high-resource settings.
Prophylactic TXA in addition to standard care compared to placebo in addition to standard care or standard care alone TXA results in little to no difference in estimated blood loss ≥ 1000 mL (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.79 to 1.11; 4 RCTs; n = 13,042; high certainty evidence), resulting in 8 fewer per 1000 women having estimated blood loss ≥ 1000 mL (from 30 fewer to 16 more). TXA likely results in a slight reduction in calculated blood loss ≥ 1000 mL (RR 0.83, 95% CI 0.76 to 0.92; 2 RCTs; n = 4327; moderate certainty evidence), resulting in 53 fewer per 1000 having calculated blood loss ≥ 1000 mL (from 75 fewer to 25 fewer). The evidence is very uncertain about the effect of TXA on maternal death (one event in placebo group, none in TXA group). No trials measured severe morbidity. TXA likely results in little to no difference in blood transfusion (RR 0.88, 95% CI 0.72 to 1.08; 5 RCTs; n = 15,740; moderate certainty evidence), resulting in 4 fewer per 1000 women requiring a blood transfusion (from 10 fewer to 3 more). TXA results in little to no difference in additional surgical interventions to control PPH (RR 1.02, 95% CI 0.86 to 1.22; 4 RCTs; n = 15,631; high certainty evidence), resulting in 1 more per 1000 women requiring additional surgical intervention (from 4 fewer to 7 more). The evidence is very uncertain about the effect of TXA on thromboembolic events (RR 1.40, 95% CI 0.22 to 8.90; 4 RCTs; n = 14,480; very low certainty evidence), resulting in 1 more per 1000 women having a thromboembolic event (from 2 fewer to 17 more). TXA results in little to no difference in the need for additional uterotonics (RR 0.88, 95% CI 0.78 to 1.00; 4 RCTs; n = 15,728; high certainty evidence), resulting in 15 fewer per 1000 women requiring additional uterotonics (from 27 fewer to 0 fewer). The evidence is very uncertain about the effect of TXA on hysterectomy (RR 0.80, 95% CI 0.20 to 3.29; 2 RCTs; n = 4546; very low certainty evidence), resulting in 3 fewer per 10,000 women requiring a hysterectomy (from 11 fewer to 31 more). One trial measuring maternal satisfaction reported no difference between groups at day two postpartum. No data were available on breastfeeding. Overall, studies had low risk of bias. We downgraded the certainty of evidence mainly for imprecision.
Prophylactic TXA in addition to standard care during caesarean birth results in little to no difference in estimated blood loss ≥ 1000 mL and likely results in a slight reduction in calculated blood loss ≥ 1000 mL compared to placebo. There were no data for severe morbidity due to PPH. Event rates for further interventions to control PPH were low and similar across groups. Prophylactic TXA thus results in little to no difference between groups for additional surgical interventions (32 versus 31 per 1000), and likely results in little to no difference between groups for blood transfusions (31 versus 36 per 1000) and use of additional uterotonics (107 versus 121 per 1000). There were very few events for the outcomes maternal death (1 in placebo group), thromboembolic events (2 versus 3 per 1000), and hysterectomy (1 per 1000 in each group). Evidence for these serious adverse events is therefore very uncertain. Decisions about implementing routine prophylactic TXA during caesarean birth should not only consider outcomes related to blood loss, but also the relatively low rates of PPH morbidity and uncertainty of serious adverse events. Most studies included women at low risk of PPH, thereby precluding any conclusions about women at high risk of PPH. Cost associated with routine use of an additional drug for all caesarean births needs to be considered.
This Cochrane review was funded in part by the World Health Organization.
The published protocol and updates to the review can be accessed: Protocol (2009) DOI: 10.1002/14651858.CD007872 Original Review (2010) DOI: 10.1002/14651858.CD007872.pub2 Review Update (2015) DOI: 10.1002/14651858.CD007872.pub3.
Rohwer C
，Rohwer A
，Cluver C
，Ker K
，Hofmeyr GJ
... -
《Cochrane Database of Systematic Reviews》
ResearchGate
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