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ORIGINAL ARTICLE
Year : 2023  |  Volume : 17  |  Issue : 1  |  Page : 23-32

The role of point of care thromboelastography (TEG) and thromboelastometry (ROTEM) in management of Primary postpartum haemorrhage: A meta-analysis and systematic review


1 Department of Anaesthesia, Pain Medicine and Critical Care, AIIMS, New Delhi, India
2 Department of Anesthesia, AIIMS, Patna, Bihar, India
3 Department of Anesthesia, and Critical Care, AIIMS, Bhubaneswar, Odisha, India

Correspondence Address:
Soumya Sarkar
Department of Anesthesia, and Critical Care, AIIMS, Bhubaneswar - 751 019, Odisha
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/sja.sja_529_22

Rights and Permissions
Date of Submission18-Jul-2022
Date of Decision07-Sep-2022
Date of Acceptance11-Sep-2022
Date of Web Publication02-Jan-2023
 

  Abstract 


Background: The utility of instantaneous evaluation of coagulation during primary postpartum haemorrhage (PPH) is paramount in the context of empirical blood product transfusion-related risk of dilutional and consumptive coagulopathy and circulatory overload.
Methods: A profound screening of electronic databases till August 15, 2022 was carried out after being enlisted in PROSPERO (CRD42021275514). Randomized control studies, comparative cohort studies, and cross-sectional studies comparing point-of-care viscoelastic test guided blood product transfusion with empirical transfusion in patients with PPH were included.
Results: We retrieved five studies, with a total of 1914 parturient with PPH. Patients receiving transfusion based upon point of care viscoelastic tests had lesser risk of having emergency hysterectomy (Odds ratio (OR) = 0.55, 95% CI 0.32–0.95, I2 = 7%), transfusion-associated circulatory overload (TACO) (OR = 0.03, 95% CI 0.00–0.50), reduced transfusion of fresh frozen plasma (OR = 0.07, 95% CI 0.04–0.14, I2 = 89%), platelets (OR = 0.51, 95% CI 0.28–0.91, I2 = 89%), packed red blood cell transfusion (OR = 0.70, 95% CI 0.55–0.88, I2 = 89%), and had better cost-effective treatment [Mean difference (MD) = −357.5, 95% CI − 567.75 to −147.25, I2 = 93%] than patient received empirical transfusion. However, there was no significant difference in the requirement of ICU admissions (OR = 0.77, 95% CI = 0.46–1.29, I2 = 82%). No mortality was detected across the studies.
Conclusions: Point of care viscoelastic assessment guided transfusion in PPH confederates with reduced morbidity. Nevertheless, more studies on the triggering values for transfusion, long-term survival, and cost-benefit in patients with PPH are warranted to establish its utility.

Keywords: PPH, ROTEM, TEG


How to cite this article:
Khanna P, Sinha C, Singh AK, Kumar A, Sarkar S. The role of point of care thromboelastography (TEG) and thromboelastometry (ROTEM) in management of Primary postpartum haemorrhage: A meta-analysis and systematic review. Saudi J Anaesth 2023;17:23-32

How to cite this URL:
Khanna P, Sinha C, Singh AK, Kumar A, Sarkar S. The role of point of care thromboelastography (TEG) and thromboelastometry (ROTEM) in management of Primary postpartum haemorrhage: A meta-analysis and systematic review. Saudi J Anaesth [serial online] 2023 [cited 2023 Feb 3];17:23-32. Available from: https://www.saudija.org/text.asp?2023/17/1/23/364868




  Introduction Top


Primary postpartum hemorrhage (PPH) has been attributed to 27% of all maternal deaths.[1],[2] A woman dies every 4 minutes worldwide.[3],[4] It is also associated with significant maternal morbidity like transfusion-associated circulatory overload (TACO), renal failure, acute respiratory distress syndrome, shock, myocardial ischemia, hysterectomy etc. Identification of massive hemorrhage along with a prompt assessment of the patient's coagulation is necessary to improve the outcome. Results of conventional coagulation assessment often take a longer time.

While the Viscoelastic coagulation methods 'Rotational thromboelastometry (ROTEM)' and 'thromboelastography (TEG)' provide a rapid assessment of blood hemostasis provide a coagulation profile in 5–10 minutes and help in the individualized management of bleeding patients the conventional coagulation test take much longer time.[5] It provides a point of care assessment of blood coagulation: clot formation, propagation, stabilization, and dissolution. It is a helpful guide in the treatment of coagulopathy. Its role has been confirmed in various setups like trauma, cardiac surgery and liver transplant.[6],[7],[8],[9],[10] Over the years, many studies highlighting their use in PPH have been published.[11],[12]

Previously administration of empirical fixed ratio of RBC: FFP: Platelet transfusion in trauma patients was advocated to minimize dilutional and consumptive coagulopathy.[13],[14],[15] A recent meta-analysis demonstrated a significant reduction in mortality in patients where transfusion was guided by viscoelastic testing compared to patients treated according to transfusion ratios in trauma.[16] This is in agreement with meta-analysis performed in other clinical settings.[17],[18] However, extrapolating these results to PPH patients might lead to complications like allergy and lung injury.[19]

This present study aimed to assess the utility of point of care a TEG/ROTEM guided transfusion in the management of PPH in comparison to the conventional liberal transfusion in terms of reduction in the requirement for transfusion of blood products, emergency hysterectomy, transfusion-related complications, and ICU admission.

The primary hypothesis was the point of care viscoelastic testing guided transfusion in PPH decreases inappropriate blood transfusion associated complications and is more cost-effective. We followed the “Preferred reporting items for systematic review and meta-analysis (PRISMA)” statement to carry out a systematic review and meta-analysis.[20]


  Methods Top


Protocol and registration

The imminent enrolment of the protocol of this study was done in PROSPERO (ID: CRD42021275514) date of registration: 29-09-2021, and there was no obvious digression.

Search strategy

A thorough literature search till 15th August 2022 was done in eminent electronic databases (“PubMe, d” “Medline,” “Embase,” and “Cochrane”), “Google Scholar (https://scholar.google.com),” preprint platforms “MedRxiv (https://www.medrxiv.org)” and “Clinical trial database (https://clinicaltrials.gov),” independently by AKS, SS, and PK with the following pre-defined keywords “TEG” OR “Thromboelastography” OR “ROTEM” OR “thromboelastometry” AND “PPH” OR “Postpartum haemorrhage” OR “Obstetrics.”

Inclusion and exclusion criteria

Randomized controlled trials (RCTs), controlled clinical trials, and comparative cohort studies, comparing point of care viscoelastic testing guided blood product transfusion with empiric transfusion in patients with PPH.

Case reports, letters to the editor, and case series in adults without any appropriate control group, without full retrievable text, were excluded [Figure 1]. PPH was defined as blood loss ≥1000 mL.
Figure 1: PRISMA-2009-Flow-Diagram

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Study selection

The potential articles were initially screened for the titles and abstracts from the databases, with the above MeSH (medical sub-heading) terminology, to avoid repetition and to exclude irrelevant articles. Then the full texts of the eligible studies were evaluated to satisfy the inclusion criteria by AKS, SS, and PK. Disagreements were settled after a discussion with CS.

Data extraction

Relevant data of each article regarding the first author, year of publication, place, population, mortality, blood loss, type and amount of transfused blood products, use of procoagulant interventions, acute lung injury, complications, period of hospital stay, in patients with PPH, and the per-capita expenditure were extracted independently by AKS and SS with a pre-conceived data extraction sheet. Supplementary data were searched for each article. A consensus among authors was reached when conflict occurred during a discussion with CS.

The occurrence and overall parturient in both the groups were noted as dichotomous data, and means and SD were attained as continuous data. Studies with insufficient data were delineated distinctly. For assessing the cost-effectiveness, the per-capita expenditure of incident was inflation-adjusted to 2022 USA dollars (USD) using the US Inflation Calculator.[21],[22]

Risk of bias assessment

Two independent researchers (SS, PK) ascertained any potential bias in selected RCTs with the RoB 2.0 tool,[23] and non-randomized studies were assessed by using the “Risk of Bias in Non-randomized Studies—of Interventions (ROBINS-I)” assessment tool.[24] Any difference of opinion was resolved by consulting with AK.

2.7. Quality of the evidence

SS and PK independently evaluated the quality of evidence by the “Grading of Recommendations Assessment, Development and Evaluation (GRADE)” tool,[25] comprising of “study limitations,” “indirectness,” “imprecision,” “consistency of effect,” and “publication bias.” They were categorized as “High,” “Moderate,” “Low,” or “Very Low,” The dissent was resolved after consulting with AK.

2.8. Data synthesis: Review Manager version 5.4 was utilized for this meta-analysis. Odds ratio (OR) was used for denoting the effect size measure of dichotomous data. The continuous variables were conveyed in mean differences (MDs) along with the 95% confidence intervals (CIs) in consonance with the “Cochrane Handbook for Systematic Reviews of Interventions.”[26] The I2 value of >50% was acknowledged as significant heterogeneity.


  Results Top


Basic characteristics

We included Four cohort studies[19],[27],[28],[29] and one randomized clinical trial[30] out of 251 identified publications in this review after satisfying the inclusion criteria. Six ongoing clinical trials (ClinicalTrials.gov) were excluded as their result is still awaited [Figure 1] and [Table 1]. Three of these studies included a comparison of point-of-care viscoelastic testing (PCVT) to empirical transfusion, while two compared PCVT to shock packs. PPH has been defined as a significant obstetric hemorrhage ranging in blood loss of more than 500–1500 ml across the studies. The overall risk of bias was low in the included studies [Figure 2].
Figure 2: (a) ROBINS-I assessment for the included non-randomized cohort studies. (b) ROB2 tool assessment for the included RCTs

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Table 1: Characteristics of included studies

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Meta-analysis

Emergency hysterectomy

The risk of having an emergency hysterectomy in PPH was assessed in four studies with 1290 patients. Patients receiving transfusion based on the point of care viscoelastic tests had a lesser risk of having an emergency hysterectomy than patients who received a liberal transfusion. [Odds ratio (OR) = 0.55, 95% CI 0.32–0.95, I2 = 7%] [Figure 3]a.
Figure 3: (a) Impact of viscoelastic testing guided transfusion in PPH on emergency hysterectomy. (b) The effect of viscoelastic testing guided transfusion in PPH on Transfusion-associated circulatory overload. (c) Impact of viscoelastic testing guided transfusion in PPH on ICU admission

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Transfusion-related circulatory overload

The risk of postoperative TACO was assessed in a single study with 255 patients. The odds of patient suffering were significantly lower in the intervention group than in the control group [OR = 0.03, 95% CI 0.00–0.50] [Figure 3]b.

ICU admission

Four studies with 1290 patients evaluated the risk of ICU admissions and found no significant reduction with the point of care viscoelastic tests guided transfusion. [OR = 0.77, 95% CI 0.46–1.29, I2 = 82%] [Figure 3]c.

FFP transfusion

A total of four studies having 1865 patients were assessed for the use of fresh frozen plasma (FFP). The use of FFP was significantly lower in the intervention group in comparison to the control group. [OR 0.07, 95% CI 0.04–0.14, I2 = 89%] [Figure 4]a.
Figure 4: (a) Efficacy of viscoelastic testing in PPH on FFP transfusion. (b)Efficacy of viscoelastic testing in PPH on platelet transfusion. (c) Efficacy of viscoelastic testing in PPH on PRBC transfusion. (d) Cost effectiveness of viscoelastic testing in PPH

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Platelets transfusion

A total of 1610 patients from three studies assessed the use of platelet transfusion. Patients in the experimental group required statistically lesser instances of platelets transfusion. [OR = 0.51, 95% CI 0.28–0.91, I2 = 89%] [Figure 4]b.

PRBC transfusion

Four studies with 1865 patients assessed PRBC transfusion found the transfusion was significantly lower in the intervention group in comparison to the control group. [OR = 0.70, 95% CI 0.55–0.88, I2 = 89%] [Figure 4]c.

However, one study (n = 258) has reported no significant difference in the requirement of >5 units of PRBC with the point of care viscoelastic tests guided transfusion [OR = 0.47, 95% CI 0.22–1.01].

Cost-effectiveness

Two studies with 213 patients found the point of care viscoelastic testing guided transfusion is more cost-effective in terms of lesser expenditure per patient than empirical transfusion. [Mean difference (MD) $ = −357.5, 95% CI −567.75 to −147.25, I2 = 93%] [Figure 4]d.

Mortality

Quantitative-analysis regarding mortality could not be performed as mortality in all studies included was zero.

Significant heterogeneity is found among studies assessing ICU admission, FFP, platelet, PRBC transfusion, and cost-effectiveness.

Quality of evidence

The quality of evidence on the utility of point-of-care viscoelastic tests guided transfusion in the management of PPH is low. Remarkable indirectness was found in terms of the difference in population and outcome measures [Table 2].
Table 2: GRADE evidence profile of point of care point of care a TEG/ROTEM guided transfusion in the management of PPH

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Publication bias

The publication bias was evaluated for the studies on the requirement of peripartum emergency hysterectomy. The Funnel plot indicates a publication bias is unlikely [Supplementary Figure 1].




  Discussion Top


This systematic review and meta-analysis found a low quality of evidence that using point of care viscoelastic test guided transfusion in PPH is associated with less FFP, platelet, and PRBC transfusion, TACO, and reduced risk of emergency hysterectomy.

Similarly, a recent multicentric interventional study (n = 61,094) also reported the incorporation of a PPH care bundle by means of Viscoelastometry guided transfusion resulted in a lesser incidence of progression from moderate to massive PPH in the last six months, reduced the requirement of blood product transfusion.[31] Several studies acknowledged its cost-effective role.[28],[32]

Multiple systematic reviews on adult patients undergoing cardiac surgery also reported a reduction in transfusion rates and blood loss with viscoelastic-guided transfusion in comparison to transfusion guided by clinical judgement and clotting tests.[33],[34]

A Cochrane review also found a decreased requirement for blood products and a reduction in morbidity and mortality in the resuscitation of bleeding adult and pediatric patients based on viscoelastic tests.[17]

The updated 2015 Health Technology Assessment (HTA) (Whiting 2015) by the National Health Service (NHS) focused on three subgroups of patients: cardiac surgery, trauma, and postpartum hemorrhage (obstetric bleeding) and found ROTEM results were associated with endpoints like lesser RBC, FFP, and platelet transfusions, invasive procedures, and coagulation disorders requiring treatment in PPH.[5]

The high turnover time of conventional coagulation tests often fails to become relevant in decision-making during dynamically evolving active bleeding patients.[11],[35]

A significant association has been found between fibrinogen level of <2g/l and severity of PPH independent of other laboratory parameters, sample collection time, mode of delivery, and other obstetric interventions.[36] The Royal College of Obstetricians and Gynaecologists also stressed that sustaining plasma fibrinogen >2 g/l in PPH.[37]

The fibrinogen level is gradually elevated during pregnancy, and at term reaches around 4–6 g/l. The Fresh frozen plasma retrieved from non-pregnant donors contains fibrinogen of around two g/l.[27],[38] The dramatic depletion of fibrinogen during PPH has mainly been attributed to blood loss-induced depletion of coagulation factors and consumption.[34] However, the fibrinogen level seems to be above the critical level in the majority of the cases of PPH. A recent study has advocated for withholding FFP in the absence of any real-time testing suggestive of coagulopathy.[39] A mathematical modelling also reported liberal use of FFP in obstetric hemorrhage may reduce the plasma fibrinogen level and exacerbate bleeding.[40]

The thromboelastography parameters correlate linearly with fibrinogen concentration. The application of “TEG functional fibrinogen” or “ROTEM fibrin-based thromboelastometry” amplitude at 5, 10 min is useful for rapid detection of hypofibrinogenemia (≤2 g/l).[41]

A “FibTEM A5” of 12 mm generally corresponds with a plasma fibrinogen level of 2.2 g/l[42],[43] While a recent study reported a sensitivity of 74% and a specificity of 97% for “TEG 6S functional fibrinogen assay” of ≤17 mm, 42 another study found a TEG functional fibrinogen maximum amplitude value of ≤2.7 mm possessed 100% sensitivity and 92% specificity.[44]

Gillissen et al.[45] reported a better correlation between fibrin-based thromboelastometry parameters and plasma fibrinogen level in the “ROTEM Sigma” analyzer than on the “ROTEM Delta” (amplitude at 5 min: r = 0.85; 95% CI 0.651–0.935 and 0.70; 95% CI 0.377–0.867, respectively)

Similarly, reduced maximum amplitude and α angle in the kaolin-activated TEG assay were also found to be a good predictor of severe PPH >2500 ml, and the requirement of transfusion of >4 U of red blood cells and FFP.[44]

Multiple studies have acknowledged the role of point of care viscoelastic guided transfusion in not only reduction in the total volume of blood products transfused but also lower overall estimated blood loss[27],[28],[29] along with a reduction in acute kidney injury (AKI) and mortality.[16],[18]

Although several international guidelines[46],[47] advocates for a point of care viscoelastic testing guided transfusion in PPH, the role of prepartum Visco elastic assessments in predicting PPH is still debatable.[48],[49]

Limitations

We found no significant reduction in ICU admission of the parturient with PPH with the use of point of care viscoelastic test guided transfusion and significant heterogeneity in terms of requirement of different blood products and cost-effectiveness.

The probable explanation quite possibly is multi-factorial. Lack of standardized criteria for severe PPH, different baseline hematocrit levels, transfusion trigger, presence of comorbidities, and the patient's condition at the time of intervention across the studies, and inadequate size (power) of few studies could be the significant attributing factors.

Due to a lack of data and zero maternal mortality reported in all studies included in this meta-analysis, we could not analyze mortality. In contrast to the WOMAN Trial,[50] which has been performed in low-income countries and reported a mortality of 2.4%, all studies included in this meta-analysis have been performed in very experience obstetric hospitals and reported zero mortality. Six ongoing clinical trials are still running and yet to publish their results. However, it is even unlikely to demonstrate a significant reduction in mortality with such studies performed in experienced obstetric hospitals since maternal mortality in the UK was 6.5 per 100,000 live births (0.0065%) in 2018.[51]


  Conclusion Top


In conclusion, point-of-care viscoelastic assays are more effective in terms of rapid decision making, avoidance of excessive transfusion of blood products, and associated complications than conventional formula-driven liberal transfusion during primary postpartum hemorrhage. However, larger RCTs, stepped-wedge cluster randomized trials, and real-world cohort studies on quality improvement in PPH according to gestational age or trimester during pregnancy are necessary to substantiate the efficacy and cost-effectiveness of viscoelastic testing guided bleeding management in obstetric hemorrhage.

Author's individual contribution

Dr. Puneet Khanna (PK): Conceptualization, Search strategy, Study selection, Risk of bias assessment, Quality of the evidence assessment, and Editing.

Dr. Chandni Sinha (CS): Study selection, Data extraction., and Drafted the manuscript.

Dr. Akhil Kant Singh (AKS): Study selection, Data extraction.

Dr. Ajeet Kumar (AK): Risk of bias assessment, Quality of the evidence assessment.

Dr. Soumya Sarkar (SS): Conceptualization, Search strategy, Study selection, Data extraction, Data synthesis, Risk of bias assessment, Quality of the evidence assessment Drafted the manuscript, and Editing.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

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