Assessing changes in flow velocimetry and clinical outcome following use of an external aortic compression device in women with postpartum hemorrhage

External Aortic Compression in Noncompressible Truncal Hemorrhage and Traumatic Cardiac Arrest: A Scoping Review

External aortic compression has been investigated as a treatment for non-compressible truncal haemorrhage in trauma patients. We sought to systematically gather and tabulate the available evidence around external aortic compression. We were specifically interested in its ability to achieve hemostasis and aid in resuscitation of traumatic arrest and severe shock and to consider physiological changes and adverse effects. A scoping review approach was chosen due to the highly variable existing literature. We were guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, using the specific extension for scoping reviews. Searches were done on PubMed and Scopus databases in October 2020. We found that a range of studies have investigated external aortic compression in a variety of settings, including case reports and small case series, porcine hemorrhage models and effects on healthy volunteers. External aortic compression for postpartum hemorrhage in a single center provided some evidence of effectiveness. Overall the level of evidence is limited, however, external aortic compression does appear able to achieve cessation of distal blood flow. Furthermore, it appears to improve many relevant physiological parameters in the setting of hypovolemic shock. Application for more than 60 minutes appears to cause increasingly problematic complications. In conclusion we find that the role of external aortic compression warrants further research. The intervention may have a role as a bridge to definitive treatment of noncompressible truncal haemorrahge.

Prehospital aortic blood flow control techniques for non-compressible traumatic hemorrhage

Non-compressible hemorrhage in the junctional areas and torso could be life-threatening and its prehospital control remains extremely challenging. The aim of this review was to compare commonly used techniques for the control of non-compressible hemorrhage in prehospital settings, and thereby provide evidence for further improvements in emergency care of traumatic injuries. Three techniques were reviewed including external aortic compression (EAC), abdominal aortic junctional tourniquet (AAJT), and resuscitative endovascular balloon occlusion of the aorta (REBOA). In prehospital settings, all three techniques have demonstrated clinical effectiveness for the control of severe hemorrhage. EAC is a cost- and equipment-free, easy-to-teach, and immediately available technique. In contrast, AAJT and REBOA are expensive and require detailed instructions or systematic training. Compared with EAC, AAJT and REBOA have greater potentials in the management of traumatic hemorrhage. AAJT can be used not only in the junctional areas but also in pelvic and bilateral lower limb injuries. However, both AAJT and REBOA should be used for a limited time (less than 1 hour) due to possible consequences of ischemia and reperfusion. Compared with EAC and AAJT, REBOA is invasive, requiring femoral arterial access and intravascular guidance and inflation. Mortality from non-compressible hemorrhage could be reduced through the prehospital application of aortic blood flow control techniques. EAC should be considered as the first-line choice for many non-compressible injuries that cannot be managed with conventional junctional tourniquets. In comparison, AAJT or REBOA is recommended for better control of the aorta blood flow in prehospital settings. Although these three techniques each have advantages, their use in trauma is not widespread. Future studies are warranted to provide more data about their safety and efficacy.

Mechanical and surgical interventions for treating primary postpartum haemorrhage

BACKGROUND

Primary postpartum haemorrhage (PPH) is commonly defined as bleeding from the genital tract of 500 mL or more within 24 hours of birth. It is one of the most common causes of maternal mortality worldwide and causes significant physical and psychological morbidity. An earlier Cochrane Review considering any treatments for the management of primary PPH, has been split into separate reviews. This review considers treatment with mechanical and surgical interventions.

OBJECTIVES

To determine the effectiveness and safety of mechanical and surgical interventions used for the treatment of primary PPH.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (26 July 2019) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of mechanical/surgical methods for the treatment of primary PPH compared with standard care or another mechanical/surgical method. Interventions could include uterine packing, intrauterine balloon insertion, artery ligation/embolism, or uterine compression (either with sutures or manually). We included studies reported in abstract form if there was sufficient information to permit risk of bias assessment. Trials using a cluster-RCT design were eligible for inclusion, but quasi-RCTs or cross-over studies were not.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion and risk of bias, independently extracted data and checked data for accuracy. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included nine small trials (944 women) conducted in Pakistan, Turkey, Thailand, Egypt (four trials), Saudi Arabia, Benin and Mali. Overall, included trials were at an unclear risk of bias. Due to substantial differences between the studies, it was not possible to combine any trials in meta-analysis. Many of this review's important outcomes were not reported. GRADE assessments ranged from very low to low, with the majority of outcome results rated as very low certainty. Downgrading decisions were mainly based on study design limitations and imprecision; one study was also downgraded for indirectness. External uterine compression versus normal care (1 trial, 64 women) Very low-certainty evidence means that we are unclear about the effect on blood transfusion (risk ratio (RR) 2.33, 95% confidence interval (CI) 0.66 to 8.23). Uterine arterial embolisation versus surgical devascularisation plus B-Lynch (1 trial, 23 women) The available evidence for hysterectomy to control bleeding (RR 0.73, 95% CI 0.15 to 3.57) is unclear due to very low-certainty evidence. The available evidence for intervention side effects is also unclear because the evidence was very low certainty (RR 1.09; 95% CI 0.08 to 15.41). Intrauterine Tamponade Studies included various methods of intrauterine tamponade: the commercial Bakri balloon, a fluid-filled condom-loaded latex catheter ('condom catheter'), an air-filled latex balloon-loaded catheter ('latex balloon catheter'), or traditional packing with gauze. Balloon tamponade versus normal care (2 trials, 356 women) One study(116 women) used the condom catheter. This study found that it may increase blood loss of 1000 mL or more (RR 1.52, 95% CI 1.15 to 2.00; 113 women), very low-certainty evidence. For other outcomes the results are unclear and graded as very low-certainty evidence: mortality due to bleeding (RR 6.21, 95% CI 0.77 to 49.98); hysterectomy to control bleeding (RR 4.14, 95% CI 0.48 to 35.93); total blood transfusion (RR 1.49, 95% CI 0.88 to 2.51); and side effects. A second study of 240 women used the latex balloon catheter together with cervical cerclage. Very low-certainty evidence means we are unclear about the effect on hysterectomy (RR 0.14, 95% CI 0.01 to 2.74) and additional surgical interventions to control bleeding (RR 0.20, 95% CI 0.01 to 4.12). Bakri balloon tamponade versus haemostatic square suturing of the uterus (1 trial, 13 women) In this small trial there was no mortality due to bleeding, serious maternal morbidity or side effects of the intervention, and the results are unclear for blood transfusion (RR 0.57, 95% CI 0.14 to 2.36; very low certainty). Bakri balloon tamponade may reduce mean 'intraoperative' blood loss (mean difference (MD) -426 mL, 95% CI -631.28 to -220.72), very low-certainty evidence. Comparison of intrauterine tamponade methods (3 trials, 328 women) One study (66 women) compared the Bakri balloon and the condom catheter, but it was uncertain whether the Bakri balloon reduces the risk of hysterectomy to control bleeding due to very low-certainty evidence (RR 0.50, 95% CI 0.05 to 5.25). Very low-certainty evidence also means we are unclear about the results for the risk of blood transfusion (RR 0.97, 95% CI 0.88 to 1.06). A second study (50 women) compared Bakri balloon, with and without a traction stitch. Very low-certainty evidence means we are unclear about the results for hysterectomy to control bleeding (RR 0.20, 95% CI 0.01 to 3.97). A third study (212 women) compared the condom catheter to gauze packing and found that it may reduce fever (RR 0.47, 95% CI 0.38 to 0.59), but again the evidence was very low certainty. Modified B-Lynch compression suture versus standard B-Lynch compression suture (1 trial, 160 women) Low-certainty evidence suggests that a modified B-Lynch compression suture may reduce the risk of hysterectomy to control bleeding (RR 0.33, 95% CI 0.11 to 0.99) and postoperative blood loss (MD -244.00 mL, 95% CI -295.25 to -192.75).

AUTHORS' CONCLUSIONS

There is currently insufficient evidence from RCTs to determine the relative effectiveness and safety of mechanical and surgical interventions for treating primary PPH. High-quality randomised trials are urgently needed, and new emergency consent pathways should facilitate recruitment. The finding that intrauterine tamponade may increase total blood loss > 1000 mL suggests that introducing condom-balloon tamponade into low-resource settings on its own without multi-system quality improvement does not reduce PPH deaths or morbidity. The suggestion that modified B-Lynch suture may be superior to the original requires further research before the revised technique is adopted. In high-resource settings, uterine artery embolisation has become popular as the equipment and skills become more widely available. However, there is little randomised trial evidence regarding efficacy and this requires further research. We urge new trial authors to adopt PPH core outcomes to facilitate consistency between primary studies and subsequent meta-analysis.

Development of an assessment and intervention protocol for postpartum hemorrhage in the mainland of China: an evidence-based method and Delphi consult

Objective

Postpartum hemorrhage (PPH) is a leading cause of maternal death. Although guidelines have been updated, those with detailed protocols are limited for nursing practice. This study aims at establishing an early assessment and intervention protocol as a toolkit for PPH for midwives and obstetrical nurses.

Methods

Employing the evidence-based method, a systematic Internet search of guidelines was conducted and appraisal of literatures was conducted with AGREE system and Oxman-Guyatt Overview Quality Assessment Questionnaire (OQAQ), according to which a protocol draft was therefore developed. Then, a two-round modified Delphi method was utilized to reach a consensus of the protocol built on best practices. Selection criteria for each intervention measure included consensus level with a threshold of 70%, mean of importance (M) >3.5, and coefficient of variation (CV) <0.25. Reliability of experts’ opinion was calculated by positive coefficient and authoritative coefficient. Items without consistency were enlisted in the second-round consult. When all items met the selection criteria, the protocol would be finally formulated.

Results

A 122-measure protocol was established, including prevention, assessment, and intervention of PPH. With a panel of 14 experts participated in the consult, the positivity coefficient was 0.93 and 1.00 for two rounds, respectively, and the authority coefficient was 0.88. After a two-round consult and revision of the draft, the final program was formulated, containing 5 first-level indexes and 14 second-level indexes with a total item of 120.

Conclusions

The PPH protocol, based on high-quality evidences, was formulated with a two-round Delphi method, which can provide insight for midwives and obstetrical nurses to effectively deal with PPH.

Proximal External Aortic Compression for Life-Threatening Abdominal-Pelvic and Junctional Hemorrhage: An Ultrasonographic Study in Adult Volunteers

Introduction: Following life-threatening junctional trauma, the goal is to limit blood loss while expediting transfer to operative rescue. Unfortunately, life-threatening abdominal-pelvic or junctional hemorrhage is often not amenable to direct compression and few temporizing strategies are available beyond hemostatic dressings, hypotensive resuscitation, and balanced transfusion. Objectives: In this study, we evaluated proximal external aortic compression to arrest blood flow in healthy adult men. Methods: This was a simulation trial of proximal external aortic compression, for life-threatening abdominal-pelvic and junctional hemorrhage, in a convenience sample of healthy adult male volunteers. The primary end points were cessation of femoral blood flow as assessed by pulse wave Doppler ultrasound at the right femoral artery, caudal to the inguinal ligament. Secondary end points were discomfort and negative sequelae. Results: Aortic blood flow was arrested in 12 volunteers. Median time to blood flow cessation was 12.5 seconds. Median reported discomfort was 5 out of 10. No complications or negative sequelae were reported. Conclusion: This trial suggests that it may be reasonable to attempt temporization of major abdominal-pelvic and junctional hemorrhage using bimanual proximal external aortic compression. In the absence of immediate alternatives for this dangerous and vexing injury pattern, there appear to be few downsides to prehospital proximal external aortic compression while concomitantly expediting definite care.

Optimization of indirect pressure in order to temporize life-threatening haemorrhage: A simulation study

BACKGROUND

Minimizing haemorrhage using direct pressure is intuitive and widely taught. In contrast, this study examines the use of indirect-pressure, specifically external aortic compression (EAC). Indirect pressure has great potential for temporizing bleeds not amenable to direct tamponade i.e. abdominal-pelvic, junctional, and multi-site trauma. However, it is currently unclear how to optimize this technique.

METHODS

We designed a model of central vessel compression using the Malbrain intra-abdominal pressure monitor and digital weigh scale. Forty participants performed simulated external aortic compression on the ground, on a stretcher mattress, and with and without a backboard.

RESULTS

The greater the rescuer's bodyweight the greater was their mean compression (Pearson's correlation 0.93). Using one-hand, a mean of 28% participant bodyweight (95% CI, 26-30%) could be transmitted at sustainable effort, waist-height, and on a stretcher. A second compressing hand increased the percentage of rescuer bodyweight transmission 10-22% regardless of other factors (i.e. presence/absence or a backboard; rescuer position) (p<0.001). Adding a backboard increased transmission of rescuer bodyweight 7-15% (p<0.001). Lowering the patient from waist-height backboard to the floor increased transmission of rescuer bodyweight 4-9% (p<0.001). Kneeling on the model was the most efficient method and transmitted 11% more weight compared to two-handed maximal compression (p<0.001).

CONCLUSIONS

Efficacy is maximized with larger-weight rescuers who use both hands, position themselves atop victims, and compress on hard surfaces/backboards. Knee compression is most effective and least fatiguing, thus assisting rescuers of lower weight and lesser strength, where no hard surfaces exist (i.e. no available backboard or trauma on soft ground), or when lengthy compression is required (i.e. remote locations). Our work quantifies methods to optimize indirect pressure as a temporizing measure following life-threatening haemorrhage not amenable to direct compression, and while expediting compression devices or definitive treatment.

Treatment for primary postpartum haemorrhage

BACKGROUND

Primary postpartum haemorrhage (PPH) is one of the top five causes of maternal mortality in both developed and developing countries.

OBJECTIVES

To assess the effectiveness and safety of any intervention used for the treatment of primary PPH.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2013).

SELECTION CRITERIA

Randomised controlled trials comparing any interventions for the treatment of primary PPH.

DATA COLLECTION AND ANALYSIS

We assessed studies for eligibility and quality and extracted data independently. We contacted authors of the included studies to request more information.

MAIN RESULTS

Ten randomised clinical trials (RCTs) with a total of 4052 participants fulfilled our inclusion criteria and were included in this review.Four RCTs (1881 participants) compared misoprostol with placebo given in addition to conventional uterotonics. Adjunctive use of misoprostol (in the dose of 600 to 1000 mcg) with simultaneous administration of additional uterotonics did not provide additional benefit for our primary outcomes including maternal mortality (risk ratio (RR) 6.16, 95% confidence interval (CI) 0.75 to 50.85), serious maternal morbidity (RR 0.34, 95% CI 0.01 to 8.31), admission to intensive care (RR 0.79, 95% CI 0.30 to 2.11) or hysterectomy (RR 0.93, 95% CI 0.16 to 5.41).  Two RCTs (1787 participants) compared 800 mcg sublingual misoprostol versus oxytocin infusion as primary PPH treatment; one trial included women who had received prophylactic uterotonics, and the other did not. Primary outcomes did not differ between the two groups, although women given sublingual misoprostol were more likely to have additional blood loss of at least 1000 mL (RR 2.65, 95% CI 1.04 to 6.75). Misoprostol was associated with a significant increase in vomiting and shivering.Two trials attempted to test the effectiveness of estrogen and tranexamic acid, respectively, but were too small for any meaningful comparisons of pre-specified outcomes.One study compared lower segment compression but was too small to assess impact on primary outcomes.We did not identify any trials evaluating surgical techniques or radiological interventions for women with primary PPH unresponsive to uterotonics and/or haemostatics.

AUTHORS' CONCLUSIONS

Clinical trials included in the current review were not adequately powered to assess impact on the primary outcome measures. Compared with misoprostol, oxytocin infusion is more effective and causes fewer side effects when used as first-line therapy for the treatment of primary PPH. When used after prophylactic uterotonics, misoprostol and oxytocin infusion worked similarly. The review suggests that among women who received oxytocin for the treatment of primary PPH, adjunctive use of misoprostol confers no added benefit.The role of tranexamic acid and compression methods requires further evaluation. Furthermore, future studies should focus on the best way to treat women who fail to respond to uterotonic therapy.