Interventions for reducing red blood cell transfusion in adults undergoing hip fracture surgery: an overview of systematic reviews.

Following hip fracture, people sustain an acute blood loss caused by the injury and subsequent surgery. Because the majority of hip fractures occur in older adults, blood loss may be compounded by pre-existing anaemia. Allogenic blood transfusions (ABT) may be given before, during, and after surgery to correct chronic anaemia or acute blood loss. However, there is uncertainty about the benefit-risk ratio for ABT. This is a potentially scarce resource, with availability of blood products sometimes uncertain. Other strategies from Patient Blood Management may prevent or minimise blood loss and avoid administration of ABT. To summarise the evidence from Cochrane Reviews and other systematic reviews of randomised or quasi-randomised trials evaluating the effects of pharmacological and non-pharmacological interventions, administered perioperatively, on reducing blood loss, anaemia, and the need for ABT in adults undergoing hip fracture surgery. In January 2022, we searched the Cochrane Library, MEDLINE, Embase, and five other databases for systematic reviews of randomised controlled trials (RCTs) of interventions given to prevent or minimise blood loss, treat the effects of anaemia, and reduce the need for ABT, in adults undergoing hip fracture surgery. We searched for pharmacological interventions (fibrinogen, factor VIIa and factor XIII, desmopressin, antifibrinolytics, fibrin and non-fibrin sealants and glue, agents to reverse the effects of anticoagulants, erythropoiesis agents, iron, vitamin B12, and folate replacement therapy) and non-pharmacological interventions (surgical approaches to reduce or manage blood loss, intraoperative cell salvage and autologous blood transfusion, temperature management, and oxygen therapy). We used Cochrane methodology, and assessed the methodological quality of included reviews using AMSTAR 2. We assessed the degree of overlap of RCTs between reviews. Because overlap was very high, we used a hierarchical approach to select reviews from which to report data; we compared the findings of selected reviews with findings from the other reviews. Outcomes were: number of people requiring ABT, volume of transfused blood (measured as units of packed red blood cells (PRC)), postoperative delirium, adverse events, activities of daily living (ADL), health-related quality of life (HRQoL), and mortality. We found 26 systematic reviews including 36 RCTs (3923 participants), which only evaluated tranexamic acid and iron. We found no reviews of other pharmacological interventions or any non-pharmacological interventions. Tranexamic acid (17 reviews, 29 eligible RCTs) We selected reviews with the most recent search date, and which included data for the most outcomes. The methodological quality of these reviews was low. However, the findings were largely consistent across reviews. One review included 24 RCTs, with participants who had internal fixation or arthroplasty for different types of hip fracture. Tranexamic acid was given intravenously or topically during the perioperative period. In this review, based on a control group risk of 451 people per 1000, 194 fewer people per 1000 probably require ABT after receiving tranexamic acid (risk ratio (RR) 0.56, 95% confidence interval (CI) 0.46 to 0.68; 21 studies, 2148 participants; moderate-certainty evidence). We downgraded the certainty for possible publication bias. Review authors found that there was probably little or no difference in the risks of adverse events, reported as deep vein thrombosis (RR 1.16, 95% CI 0.74 to 1.81; 22 studies), pulmonary embolism (RR 1.01, 95% CI 0.36 to 2.86; 9 studies), myocardial infarction (RR 1.00, 95% CI 0.23 to 4.33; 8 studies), cerebrovascular accident (RR 1.45, 95% CI 0.56 to 3.70; 8 studies), or death (RR 1.01, 95% CI 0.70 to 1.46; 10 studies). We judged evidence from these outcomes to be moderate certainty, downgraded for imprecision. Another review, with a similarly broad inclusion criteria, included 10 studies, and found that tranexamic acid probably reduces the volume of transfused PRC (0.53 fewer units, 95% CI 0.27 to 0.80; 7 studies, 813 participants; moderate-certainty evidence). We downgraded the certainty because of unexplained high levels of statistical heterogeneity. No reviews reported outcomes of postoperative delirium, ADL, or HRQoL. Iron (9 reviews, 7 eligible RCTs) Whilst all reviews included studies in hip fracture populations, most also included other surgical populations. The most current, direct evidence was reported in two RCTs, with 403 participants with hip fracture; iron was given intravenously, starting preoperatively. This review did not include evidence for iron with erythropoietin. The methodological quality of this review was low. In this review, there was low-certainty evidence from two studies (403 participants) that there may be little or no difference according to whether intravenous iron was given in: the number of people who required ABT (RR 0.90, 95% CI 0.73 to 1.11), the volume of transfused blood (MD -0.07 units of PRC, 95% CI -0.31 to 0.17), infection (RR 0.99, 95% CI 0.55 to 1.80), or mortality within 30 days (RR 1.06, 95% CI 0.53 to 2.13). There may be little or no difference in delirium (25 events in the iron group compared to 26 events in control group; 1 study, 303 participants; low-certainty evidence). We are very unsure whether there was any difference in HRQoL, since it was reported without an effect estimate. The findings were largely consistent across reviews. We downgraded the evidence for imprecision, because studies included few participants, and the wide CIs indicated possible benefit and harm. No reviews reported outcomes of cognitive dysfunction, ADL, or HRQoL. Tranexamic acid probably reduces the need for ABT in adults undergoing hip fracture surgery, and there is probably little or no difference in adverse events. For iron, there may be little or no difference in overall clinical effects, but this finding is limited by evidence from only a few small studies. Reviews of these treatments did not adequately include patient-reported outcome measures (PROMS), and evidence for their effectiveness remains incomplete. We were unable to effectively explore the impact of timing and route of administration between reviews. A lack of systematic reviews for other types of pharmacological or any non-pharmacological interventions to reduce the need for ABT indicates a need for further evidence syntheses to explore this. Methodologically sound evidence syntheses should include PROMS within four months of surgery.

Lewis SR ，Pritchard MW ，Estcourt LJ ，Stanworth SJ ，Griffin XL ... -  《Cochrane Database of Systematic Reviews》

Treatment for women with postpartum iron deficiency anaemia.

Postpartum iron deficiency anaemia is caused by antenatal iron deficiency or excessive blood loss at delivery and might affect up to 50% of labouring women in low- and middle-income countries. Effective and safe treatment during early motherhood is important for maternal well-being and newborn care. Treatment options include oral iron supplementation, intravenous iron, erythropoietin, and red blood cell transfusion. To assess the benefits and harms of the available treatment modalities for women with postpartum iron deficiency anaemia. These include intravenous iron, oral iron supplementation, red blood cell transfusion, and erythropoietin. A Cochrane Information Specialist searched for all published, unpublished, and ongoing trials, without language or publication status restrictions. We searched databases including CENTRAL, MEDLINE, Embase, CINAHL, LILACS, WHO ICTRP, and ClinicalTrials.gov, together with reference checking, citation searching, and contact with study authors to identify eligible studies. We applied date limits to retrieve new records since the last search on 9 April 2015 until 11 April 2024. We included published, unpublished, and ongoing randomised controlled trials (RCTs) that compared treatments for postpartum iron deficiency anaemia with placebo, no treatment, or alternative treatments. Cluster-randomised trials were eligible for inclusion. We included RCTs regardless of blinding. Participants were women with postpartum haemoglobin ≤ 12 g/dL, treated within six weeks after childbirth. We excluded non-randomised, quasi-randomised, and cross-over trials. The critical outcomes of this review were maternal mortality and fatigue. The important outcomes included persistent anaemia symptoms, persistent postpartum anaemia, psychological well-being, infections, compliance with treatment, breastfeeding, length of hospital stay, serious adverse events, anaphylaxis or evidence of hypersensitivity, flushing/Fishbane reaction, injection discomfort/reaction, constipation, gastrointestinal pain, number of red blood cell transfusions, and haemoglobin levels. We assessed risk of bias in the included studies using the Cochrane RoB 1 tool. Two review authors independently performed study screening, risk of bias assessment, and data extraction. We contacted trial authors for supplementary data when necessary. We screened all trials for trustworthiness and scientific integrity using the Cochrane Trustworthiness Screening Tool. We conducted meta-analyses using a fixed-effect model whenever feasible to synthesise outcomes. In cases where data were not suitable for meta-analysis, we provided a narrative summary of important findings. We evaluated the overall certainty of the evidence using GRADE. We included 33 RCTs with a total of 4558 postpartum women. Most trials were at high risk of bias for several risk of bias domains. Most of the evidence was of low or very low certainty. Imprecision due to few events and risk of bias due to lack of blinding were the most important factors. Intravenous iron versus oral iron supplementation The evidence is very uncertain about the effect of intravenous iron on mortality (risk ratio (RR) 2.95, 95% confidence interval (CI) 0.12 to 71.96; P = 0.51; I² = not applicable; 3 RCTs; 1 event; 572 women; very low-certainty evidence). One woman died of cardiomyopathy, and another developed arrhythmia, both in the groups treated with intravenous iron. Intravenous iron probably results in a slight reduction in fatigue within 8 to 28 days (standardised mean difference -0.25, 95% CI -0.42 to -0.07; P = 0.006; I² = 47%; 2 RCTs; 515 women; moderate-certainty evidence). Breastfeeding was not reported. Oral iron probably increases the risk of constipation compared to intravenous iron (RR 0.12, 95% CI 0.06 to 0.21; P < 0.001; I² = 0%; 10 RCTs; 1798 women; moderate-certainty evidence). The evidence is very uncertain about the effect of intravenous iron on anaphylaxis or hypersensitivity (RR 2.77, 95% CI 0.31 to 24.86; P = 0.36; I² = 0%; 12 RCTs; 2195 women; very low-certainty evidence). Three women treated with intravenous iron experienced anaphylaxis or hypersensitivity. The trials that reported on haemoglobin at 8 to 28 days were too heterogeneous to pool. However, 5 of 6 RCTs favoured intravenous iron, with mean changes in haemoglobin ranging from 0.73 to 2.10 g/dL (low-certainty evidence). Red blood cell transfusion versus intravenous iron No women died in the only trial that reported on mortality (1 RCT; 7 women; very low-certainty evidence). The evidence is very uncertain about the effect of red blood cell transfusion on fatigue at 8 to 28 days (mean difference (MD) 1.20, 95% CI -2.41 to 4.81; P = 0.51; I² = not applicable; 1 RCT; 13 women; very low-certainty evidence) and breastfeeding more than six weeks postpartum (RR 0.43, 95% CI 0.12 to 1.57; P = 0.20; I² = not applicable; 1 RCT; 13 women; very low-certainty evidence). Constipation and anaphylaxis were not reported. Red blood cell transfusion may result in little to no difference in haemoglobin within 8 to 28 days (MD -1.00, 95% CI -2.02 to 0.02; P = 0.05; I² = not applicable; 1 RCT; 12 women; low-certainty evidence). Intravenous iron and oral iron supplementation versus oral iron supplementation Mortality and breastfeeding were not reported. One trial reported a greater improvement in fatigue in the intravenous and oral iron group, but the effect size could not be calculated (1 RCT; 128 women; very low-certainty evidence). Intravenous iron and oral iron may result in a reduction in constipation compared to oral iron alone (RR 0.21, 95% CI 0.07 to 0.69; P = 0.01; I² = not applicable; 1 RCT; 128 women; low-certainty evidence). There were no anaphylaxis or hypersensitivity events in the trials (2 RCTs; 168 women; very low-certainty evidence). Intravenous iron and oral iron may result in little to no difference in haemoglobin (g/dL) at 8 to 28 days (MD 0.00, 95% CI -0.48 to 0.48; P = 1.00; I² = not applicable; 1 RCT; 60 women; low-certainty evidence). Red blood cell transfusion versus no transfusion Mortality, fatigue at day 8 to 28, constipation, anaphylaxis, and haemoglobin were not reported. Red blood cell transfusion may result in little to no difference in breastfeeding more than six weeks postpartum (RR 0.91, 95% CI 0.78 to 1.07; P = 0.24; I² = not applicable; 1 RCT; 297 women; low-certainty evidence). Oral iron supplementation versus placebo or no treatment Mortality, fatigue, breastfeeding, constipation, anaphylaxis, and haemoglobin were not reported. Two trials reported on gastrointestinal symptoms, but did not report results by study arm. Intravenous iron probably reduces fatigue slightly in the early postpartum weeks (8 to 28 days) compared to oral iron tablets, but probably results in little to no difference after four weeks. It is very uncertain if intravenous iron has an effect on mortality and anaphylaxis/hypersensitivity. Breastfeeding was not reported. Intravenous iron may increase haemoglobin slightly more than iron tablets, but the data were too heterogeneous to pool. However, changes in haemoglobin levels are a surrogate outcome, and treatment decisions should preferentially be based on patient-relevant outcomes. Iron tablets probably result in a large increase in constipation compared to intravenous iron. The effect of red blood cell transfusion compared to intravenous iron on mortality, fatigue, and breastfeeding is very uncertain. No studies reported on constipation or anaphylaxis/hypersensitivity. Red blood cell transfusion may result in little to no difference in haemoglobin at 8 to 28 days. The effect of intravenous iron and oral iron supplementation on mortality, fatigue, breastfeeding, and anaphylaxis/hypersensitivity is very uncertain or unreported. Intravenous iron and oral iron may result in a reduction in constipation compared to oral iron alone, and in little to no difference in haemoglobin. The effect of red blood cell transfusion compared to non-transfusion on mortality, fatigue, constipation, anaphylaxis/hypersensitivity, and haemoglobin is unreported. Red blood cell transfusion may result in little to no difference in breastfeeding. The effect of oral iron supplementation on mortality, fatigue, breastfeeding, constipation, anaphylaxis/hypersensitivity, and haemoglobin is unreported. This Cochrane review had no dedicated funding. Protocol and previous versions are available: Protocol (2013) [DOI: 10.1002/14651858.CD010861] Original review (2004) [DOI: 10.1002/14651858.CD004222.pub2] Review update (2015) [DOI: 10.1002/14651858.CD010861.pub2].

Jensen MCH ，Holm C ，Jørgensen KJ ，Schroll JB ... -  《Cochrane Database of Systematic Reviews》

Ultrasound and shockwave therapy for acute fractures in adults.

The morbidity and socioeconomic costs of fractures are considerable. The length of time to healing is an important factor in determining a person's recovery after a fracture. Ultrasound may have a therapeutic role in reducing the time to union after fracture by stimulating osteoblasts and other bone-forming proteins. This is an update of a review previously published in February 2014.   OBJECTIVES: To assess the effects of low-intensity ultrasound (LIPUS), high-intensity focused ultrasound (HIFUS) and extracorporeal shockwave therapies (ECSW) as part of the treatment of acute fractures in adults.  SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase (1980 to March 2022), Orthopaedic Proceedings, trial registers and reference lists of articles. We included randomised controlled trials (RCTs) and quasi-RCTs including participants over 18 years of age with acute fractures (complete or stress fractures) treated with either LIPUS, HIFUS or ECSW versus a control or placebo-control. We used standard methodology expected by Cochrane. We collected data for the following critical outcomes: participant-reported quality of life, quantitative functional improvement, time to return to normal activities, time to fracture union, pain, delayed or non-union of fracture. We also collected data for treatment-related adverse events. We collected data in the short term (up to three months after surgery) and in the medium term (later than three months after surgery).   MAIN RESULTS: We included 21 studies, involving 1543 fractures in 1517 participants; two studies were quasi-RCTs. Twenty studies tested LIPUS and one trial tested ECSW; no studies tested HIFUS. Four studies did not report any of the critical outcomes. All studies had unclear or high risk of bias in at least one domain. The certainty of the evidence was downgraded for imprecision, risk of bias and inconsistency. LIPUS versus control (20 studies, 1459 participants) We found very low-certainty evidence for the effect of LIPUS on Health-related quality of life (HRQoL) measured by SF-36 at up to one year after surgery for lower limb fractures (mean difference (MD) 0.06, 95% confidence interval (CI) -3.85 to 3.97, favours LIPUS; 3 studies, 393 participants). This result was compatible with a clinically important difference of 3 units with both LIPUS or control. There may be little to no difference in time to return to work after people had complete fractures of the upper or lower limbs (MD 1.96 days, 95% CI -2.13 to 6.04, favours control; 2 studies, 370 participants; low-certainty evidence).  There is probably little or no difference in delayed union or non-union up to 12 months after surgery (RR 1.25, 95% CI 0.50 to 3.09, favours control; 7 studies, 746 participants; moderate-certainty evidence). Although data for delayed and non-union included both upper and lower limbs, we noted that there were no incidences of delayed or non-union in upper limb fractures. We did not pool data for time to fracture union (11 studies, 887 participants; very low-certainty evidence) because of substantial statistical heterogeneity which we could not explain. In upper limb fractures, MDs ranged from 0.32 to 40 fewer days to fracture union with LIPUS. In lower limb fractures, MDs ranged from 88 fewer days to 30 more days to fracture union. We also did not pool data for pain experienced at one month after surgery in people with upper limb fractures (2 studies, 148 participants; very low-certainty evidence) because of substantial unexplained statistical heterogeneity. Using a 10-point visual analogue scale, one study reported less pain with LIPUS (MD -1.7, 95% CI -3.03 to -0.37; 47 participants), and the effect was less precise in the other study (MD -0.4, 95% CI -0.61 to 0.53; 101 participants). We found little or no difference in skin irritation (a possible treatment-related adverse event) between groups but judged the certainty of the evidence from this small study to be very low (RR 0.94, 95% CI 0.06 to 14.65; 1 study, 101 participants). No studies reported data for functional recovery. Data for treatment adherence were inconsistently reported across studies, but was generally described to be good. Data for costs were reported for one study, with higher direct costs, as well as combined direct and indirect costs, for LIPUS use. ECSW versus control (1 study, 56 participants) We are uncertain whether ECSW reduces pain at 12 months after surgery in fractures of the lower limb (MD -0.62, 95% CI -0.97 to -0.27, favours ECSW); the difference between pain scores was unlikely to be clinically important, and the certainty of the evidence was very low. We are also uncertain of the effect of ECSW on delayed or non-union at 12 months because the certainty of this evidence is very low (RR 0.56, 95% CI 0.15 to 2.01; 1 study, 57 participants). There were no treatment-related adverse events. This study reported no data for HRQoL, functional recovery, time to return to normal activities, or time to fracture union. In addition, no data were available for adherence or cost. We were uncertain of the effectiveness of ultrasound and shock wave therapy for acute fractures in terms of patient-reported outcome measures (PROMS), for which few studies reported data. It is probable that LIPUS makes little or no difference to delayed union or non-union. Future trials should be double-blind, randomised, placebo-controlled trials recording validated PROMs and following up all trial participants. Whilst time to union is difficult to measure, the proportion of participants achieving clinical and radiographic union at each follow-up point should be ascertained, alongside adherence with the study protocol and cost of treatment in order to better inform clinical practice.

Searle HKC ，Lewis SR ，Coyle C ，Welch M ，Griffin XL ... -  《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》

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》