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Despite advances in hemorrhage detection and management, postpartum hemorrhage remains the single leading cause of maternal death worldwide. Within the United States, hemorrhage is the leading cause of maternal death on the day of delivery and within the first week after delivery. Blood transfusion after hemorrhage represents a large proportion of severe maternal morbidity during and after delivery. Blood loss during delivery has historically been assessed visually by inspecting soiled pads, linens, and laparotomy sponges. These methods underestimate the volume of blood loss by as much as 40%, becoming increasingly inaccurate as blood loss increases. Young, healthy obstetrical patients compensate for blood loss via peripheral vasoconstriction, maintaining heart rate and blood pressure in a normal range until over 1 L of blood has been lost. A significant decrease in blood pressure along with marked tachycardia (>120 bpm) may not be seen until 30% to 40% of blood volume has been lost, or 2.0 to 2.6 L in a healthy term pregnant patient, after which the patient may rapidly decompensate. In resource-poor settings especially, the narrow window between the emergence of significant vital sign abnormalities and clinical decompensation may prove catastrophic. Once hemorrhage is detected, decisions regarding blood product transfusion are routinely made on the basis of inaccurate estimates of blood loss, placing patients at risk of underresuscitation (increasing the risk of hemorrhagic shock and end-organ damage) or overresuscitation (increasing the risk of transfusion reaction, fluid overload, and alloimmunization). We will review novel technologies that have emerged to assist both in the early and accurate detection of postpartum hemorrhage and in decisions regarding blood product transfusion.
In the United States, obstetrical hemorrhage is the primary cause of approximately 11% of maternal deaths overall and is the leading cause of maternal death on the day of delivery and in the first week after delivery.
Young, healthy patients compensate for hemorrhage via peripheral vasoconstriction; when volume loss is profound, the resulting hypoperfusion can lead to multiorgan failure, hemorrhagic shock, and pituitary necrosis.
Subcommittees on Women’ s Health Issues in Thrombosis and Haemostasis and on Disseminated Intravascular Coagulation. Management of coagulopathy associated with postpartum hemorrhage: guidance from the SSC of the ISTH.
Protocols have been developed to improve early recognition of PPH and prioritize early transfusion to prevent end-organ damage and coagulopathy, but most continue to rely on visual estimation and/or changes in heart rate and blood pressure.
Blood loss at delivery or during surgery is routinely estimated visually by an obstetrician, midwife, obstetrical nurse, or anesthesiologist. These estimates correlate with transfusion, perhaps because the decision to transfuse is often based on clinician estimates of cumulative blood loss. However, such estimates are only weakly correlated with changes in hematocrit,
Obstetricians, anesthesiologists, and obstetrical nurses presented with conical drapes containing known volumes of blood consistently underestimated the amount of blood in each drape. With volumes of ≤1 L, they underestimated by <20%, but when the blood volume reached 2 L, the clinicians underestimated by 41%, or 830 mL.
Thus, it seems that underestimation is most pronounced in cases of severe hemorrhage, when estimation of blood loss is most crucial in planning interventions. Despite the established inaccuracy of visual estimation, this remains the most common method to estimate blood loss.
Acknowledging the inaccuracy of visual estimation, new technologies have been developed to quantify blood loss. One such technology is the Triton system, which uses an Apple iPad with proprietary software to estimate the amount of blood in laparotomy sponges. Blood-soaked laparotomy sponges are presented to the iPad camera 1 at a time, and the software calculates the amount of hemoglobin contained in each sponge.
A proprietary suction canister with a calibration mark has been introduced for use with this system. A staff member enters the volume of fluid in the suction canister into the Triton software. The iPad is used to capture an image of the fluid in the suction canister and of a calibration marker. The application (app) calculates the hemoglobin concentration of the fluid, the total amount of hemoglobin in the canister, and, by dividing by the patient's serum hemoglobin, the volume of blood lost.
Unfortunately, the Triton system's estimates of blood loss at cesarean delivery do not correlate well with changes in hemoglobin (r=0.26 and r=0.29 in 2 studies),
Assessing the association between blood loss and postoperative hemoglobin after cesarean delivery: a prospective study of 4 blood loss measurement modalities.
and the implementation of the Triton system for blood loss estimation at cesarean delivery does not seem to affect the rates of blood transfusion or length of stay.
Noninvasive measurement of intravascular hemoglobin
Another approach, popularized by Masimo Corporation (Irvine, CA), uses a device similar to a fingertip pulse oximeter to provide continuous noninvasive estimates of serum hemoglobin, earning this technology the abbreviation SpHb (analogous to SpO2). These devices emit several wavelengths of light, measure the light returning to the sensors, and use this information to estimate hemoglobin concentration.
compared laboratory hemoglobin readings with SpHb readings in patients undergoing cesarean delivery for placenta previa and found a correlation coefficient of 0.877 between the 2 variables, with a mean difference between SpHb and laboratory hemoglobin readings of 0.3 g/dL. The mean can be misleading; however, although the difference between SpHb and laboratory hemoglobin was <0.5 g/dL in 65% of patients, laboratory hemoglobin and SpHb differed by at least 1.5 g/dL in >10% of patients. In another study of pregnant and recently postpartum women, the device became increasingly inaccurate as pregnancy progressed: mean bias increased from −0.20 in nonpregnant patients to 1.32 in the third trimester of pregnancy. Particularly, the device overestimated hemoglobin levels by an average of 1.32 g/dL in the third trimester of pregnancy. Among recent postpartum patients, another population of interest in PPH research, the device continued to overestimate by an average of 1.10 g/dL. Among those in the second or third trimester of pregnancy or within 1 week after delivery (a reasonable proxy for the patient population experiencing PPH), the device overestimated hemoglobin by an average of 1.16 g/dL. Confidence intervals did not cross the line of equality, suggesting a significant bias toward overestimation, and the correlation between SpHb and laboratory hemoglobin in this group was weak (r=0.087).
tested a different SpHb device, the NBM-200, and found a mean difference of only 0.1 g/dL. However, the wide limits of agreement seen in that study indicate significant variation in the difference between the noninvasive measurement and laboratory measurement with only 95% of SpHb readings falling within −1.59 to +1.79 g/dL of the laboratory value.
The authors were unable to locate any large, prospective, randomized trials of SpHb among patients experiencing PPH; however, it seems from the existing data that further refinements are needed. The accuracy of these devices is likely compromised in ongoing obstetrical hemorrhage with significant vasoconstriction and decreased peripheral perfusion.
Assessing maternal response to volume loss
The quantification of external blood loss via visual estimation
Assessing the association between blood loss and postoperative hemoglobin after cesarean delivery: a prospective study of 4 blood loss measurement modalities.
Assessing the association between blood loss and postoperative hemoglobin after cesarean delivery: a prospective study of 4 blood loss measurement modalities.
Introduction of a novel system for quantitating blood loss after vaginal delivery: a retrospective interrupted time series analysis with concurrent control group.
Assessing the association between blood loss and postoperative hemoglobin after cesarean delivery: a prospective study of 4 blood loss measurement modalities.
Assessing the association between blood loss and postoperative hemoglobin after cesarean delivery: a prospective study of 4 blood loss measurement modalities.
Introduction of a novel system for quantitating blood loss after vaginal delivery: a retrospective interrupted time series analysis with concurrent control group.
Intraperitoneal bleeding, concealed abruption, or blood loss before the patient arrives at the hospital cannot be captured using these techniques. The SpHb technology described above seems unreliable in the delivering population.
Similarly, patient response to a set of volumes of hemorrhage is quite variable—data from outside of pregnancy show that approximately one-third of patients will progress to hypovolemic shock with much lower volumes of blood loss than the remainder of the population.
Thus, interest has emerged in using maternal physiological response to hemorrhage as the primary metric rather than attempting to quantify blood on sponges, pads, or linens. Such methods correlate with the need for transfusion in patients with trauma
and its quantitative assessment has emerged as a potential target for hemorrhage detection. The AccuFlow sensor (ThermaSENSE, Blacksburg, VA) is an investigational device that makes direct, quantitative measurements of perfusion at the skin surface. The device consists of sensors that are applied to the skin, which heat up to 39°C and measure the rate at which the heat dissipates. Thermal readings are transmitted via Bluetooth or cellular data signals to an iPad or other smart device, where the ThermaSENSE AccuFlow app calculates perfusion, allowing the device to measure vasoconstriction in real time.
AccuFlow and its predecessor, the Combined Heat-Flux Temperature Sensor (CHFT+) sensor, detect altered perfusion in other conditions, including in explanted organs
The technology's ability to detect intrapartum hemorrhage has been assessed only in a small pilot study of 25 patients undergoing cesarean delivery, which was presented at the 2022 annual pregnancy meeting of the Society for Maternal-Fetal Medicine. Examples of sensor readings taken throughout a cesarean delivery are shown in Figure 1. In the pilot study, the change in perfusion at the wrist from delivery to the end of surgery was more strongly correlated with calculated blood loss than were the surgical team's blood loss estimates (r=−0.48 vs 0.087; P=.03). Furthermore, wrist perfusion at the end of the case was correlated with blood loss (r=0.22), suggesting that this approach may also be beneficial when patients present with a hemorrhage in progress.
Another related measure is the compensatory reserve, measured via either Compensatory Reserve Index or Compensatory Reserve Measurement (CRM) algorithms.
AI-enabled advanced development for assessing low circulating blood volume for emergency medical care: comparison of compensatory reserve machine-learning algorithms.
Predictors of the onset of hemodynamic decompensation during progressive central hypovolemia: comparison of the peripheral perfusion index, pulse pressure variability, and compensatory reserve index.
but its ability to detect obstetrical hemorrhage has not been evaluated. Further studies are planned.
Preventing hemorrhage-associated morbidity: the role of blood product transfusion
Fixed-ratio transfusion vs targeted transfusion for severe hemorrhage
Severe hemorrhage may result in massive transfusion (>4 units of packed RBCs in an hour with ongoing bleeding or >10 units of packed RBCs within 24 hours).
In such cases, the use of fixed-ratio transfusion protocols, such as a 1:1:1 ratio of RBCs to fresh frozen plasma (FFP) to platelets (PLTs), has been recommended.
Although lifesaving in the right clinical setting, massive transfusion does carry some risks. Hyperkalemia risk is related to the number of units transfused, and hyperkalemic arrests have been reported.
Citrate, used as an anticoagulant in blood products, binds serum calcium resulting in hypocalcemia and, potentially, hypotension and cardiac conduction abnormalities.
Transfusion of large volumes of refrigerated blood products without warming can also trigger hypothermia, which is associated with coagulopathy and worse outcomes after traumatic hemorrhage.
Analysis of transfusion-related acute lung injury and possible transfusion-related acute lung injury reported to the French Hemovigilance Network from 2007 to 2013.
Analysis of transfusion-related acute lung injury and possible transfusion-related acute lung injury reported to the French Hemovigilance Network from 2007 to 2013.
compared with nonpregnant women receiving blood transfusions. In addition, many massive transfusion protocols result in the transfusion of uncrossmatched RBCs, increasing the risk of RBC alloimmunization and hemolytic disease in future pregnancies.
These risks have prompted a renewed interest in targeted transfusion, that is, transfusing products individually based on predicted patient needs rather than transfusing set ratios of products to mimic whole blood. Massive transfusion protocols with set ratios of blood products remain a crucial component of early response to hemorrhage, but there may be a role for targeted transfusion in the ongoing response to hemorrhage.
The importance of fibrinogen
Studies of targeted transfusion have revealed a crucial role for fibrinogen in PPH. Severe PPH is associated with decreased fibrinogen levels,
Obstetric hemorrhage and coagulation: an update. Thromboelastography, thromboelastometry, and conventional coagulation tests in the diagnosis and prediction of postpartum hemorrhage.
Subcommittees on Women’ s Health Issues in Thrombosis and Haemostasis and on Disseminated Intravascular Coagulation. Management of coagulopathy associated with postpartum hemorrhage: guidance from the SSC of the ISTH.
Given the importance of fibrinogen replacement in hemorrhage response, and the favorable safety profile of fibrinogen replacement, some sources suggest that targeted blood product transfusion with an emphasis on replacement of fibrinogen and clotting factor replacement should be preferred over fixed-ratio transfusion.
Subcommittee on Perioperative and Critical Care. The utility of viscoelastic methods in the prevention and treatment of bleeding and hospital-associated venous thromboembolism in perioperative care: guidance from the SSC of the ISTH.
Subcommittee on Perioperative and Critical Care. The utility of viscoelastic methods in the prevention and treatment of bleeding and hospital-associated venous thromboembolism in perioperative care: guidance from the SSC of the ISTH.
The predictive value of modified computerized thromboelastography and platelet function analysis for postoperative blood loss in routine cardiac surgery.
Routine use of viscoelastic blood tests for diagnosis and treatment of coagulopathic bleeding in cardiac surgery: updated systematic review and meta-analysis.
Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis.
Using whole blood, VHAs assess the kinetics of coagulation at multiple stages from the initiation of clot formation until its proper lysis, providing a real-time computerized graphical representation and readout of crucial parameters (Table 1).
The 2 most common assays, thromboelastography (TEG) and rotational thromboelastometry (ROTEM), offer similar performance, although the reagents used and exact output parameters vary (Tables 1 and 2).
Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis.
In the laboratory version of both systems, sensors detect changes in resistance to the movement of a pin within a sample of whole blood, similar to the process first described in 1948.
Reference ranges for thromboelastography (TEG(®) ) and traditional coagulation tests in term parturients undergoing caesarean section under spinal anaesthesia*.
VHAs are moving out of the laboratory and to the point of care (POC), providing real-time information without the need to send specimens to a laboratory. Both of the major producers of VHA analyzers, ROTEM and TEG, have developed POC analyzers for use as close to the patient as possible: in the operating room, in the trauma bay, or in labor and delivery.
Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis.
ROTEM's cartridge-based POC system, ROTEM sigma, is pending US Food and Drug Administration approval but is in use in other countries. To use this system, a tube of blood is placed into a cartridge containing reagents, which is inserted into the machine and subjected to the same cup-and-pin technique used in previous machines.
Other POC devices have been developed by other manufacturers, but as only limited data are available on these devices, they are not discussed in detail in this article.
POC VHAs allow clinicians to test at the bedside, with results available in real time. The first clinically meaningful results are available in 5 to 10 minutes, although additional results can continue for up to 90 minutes with some systems.
Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis.
Obstetric hemorrhage and coagulation: an update. Thromboelastography, thromboelastometry, and conventional coagulation tests in the diagnosis and prediction of postpartum hemorrhage.
Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis.
Obstetric hemorrhage and coagulation: an update. Thromboelastography, thromboelastometry, and conventional coagulation tests in the diagnosis and prediction of postpartum hemorrhage.
Obstetric hemorrhage and coagulation: an update. Thromboelastography, thromboelastometry, and conventional coagulation tests in the diagnosis and prediction of postpartum hemorrhage.
potentially allowing clinicians to intervene earlier in cases of severe hemorrhage with emerging coagulopathy. These advantages have led to the rapid uptake of VHA in nonobstetrical massive hemorrhage settings, including cardiac surgery and trauma.
Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis.
The use of viscoelastic hemostatic tests in pregnancy and puerperium: review of the current evidence - communication from the Women's Health SSC of the ISTH.
The use of viscoelastic hemostatic tests in pregnancy and puerperium: review of the current evidence - communication from the Women's Health SSC of the ISTH.
profiles of nonlaboring pregnant patients are notably different from those observed in nonpregnant women. Key differences in TEG output between pregnant and nonpregnant subjects include a shorter R time (shorter time to begin clot formation),
These differences between pregnant and nonpregnant patients are summarized in Figure 2. In patients with emerging coagulopathy in other settings, the opposite changes are noted: R and K times increase (reflecting slower clot initiation and formation), alpha angle decreases as fibrin accumulation slows, and clot strength is decreased.
These relationships seem to persist in pregnancy; patients experiencing PPH have higher R and K times and lower alpha angle on TEG than patients delivering without hemorrhage, but this gap narrows when the hemorrhaging patients receive blood product transfusions.
Obstetric hemorrhage and coagulation: an update. Thromboelastography, thromboelastometry, and conventional coagulation tests in the diagnosis and prediction of postpartum hemorrhage.
Thus, tools, which can rapidly identify hypofibrinogenemia, are of critical importance. TEG 6s cartridge system results seem to correlate with laboratory fibrinogen results in obstetrical hemorrhage.
When the ROTEM delta was evaluated in a similar study population, FIBTEM results were only moderately correlated with laboratory fibrinogen (r=0.59). However, FIBTEM and laboratory fibrinogen had similar positive predictive values for progression to transfusion,
Obstetric hemorrhage and coagulation: an update. Thromboelastography, thromboelastometry, and conventional coagulation tests in the diagnosis and prediction of postpartum hemorrhage.
Thus, although VHA results do not correlate exactly with laboratory fibrinogen levels, VHAs seem as useful in identifying the need for fibrinogen replacement, in a fraction of the time needed for traditional assays. Given the morbidity associated with overtransfusion, determining who should not be transfused is equally valuable. In 5 minutes, ROTEM can identify patients with PPH who do not benefit from fibrinogen replacement,
and 10-minute TEG readings are 74% sensitive and 97% specific (area under the receiver operating curve, 0.95) for a laboratory fibrinogen level below 200.
Unfortunately, the assessment of other coagulation parameters has been less reliable. TEG 6s had a sensitivity of only 50% for PLTs of <75,000 and <30% sensitivity for prolonged prothrombin time and activated partial thromboplastin time.
Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis.
National Institute for Health and Care Excellence. Detecting, managing and monitoring haemostasis: viscoelastometric point‑of‑care testing (ROTEM, TEG and Sonoclot systems). 2014. Available at: https://www.nice.org.uk/guidance/dg13. Accessed April 14, 2022.
Subcommittee on Perioperative and Critical Care. The utility of viscoelastic methods in the prevention and treatment of bleeding and hospital-associated venous thromboembolism in perioperative care: guidance from the SSC of the ISTH.
Subcommittee on Perioperative and Critical Care. The utility of viscoelastic methods in the prevention and treatment of bleeding and hospital-associated venous thromboembolism in perioperative care: guidance from the SSC of the ISTH.
than the use of standard laboratory analysis or clinician discretion. Among patients who underwent a liver transplant, TEG-guided transfusion decreased the use of FFP,
and ROTEM-based transfusion was associated with decreased reoperation because of bleeding, postoperative hemodynamic instability, retransplantation, and acute kidney injury.
In trauma, VHA-guided transfusion is associated with increased fibrinogen replacement, decreased RBC and PLT transfusion, and decreased risk of multiorgan failure and hemorrhage-related mortality, without changing posttrauma hemoglobin.
Dynamic use of fibrinogen under viscoelastic assessment results in reduced need for plasma and diminished overall transfusion requirements in severe trauma.
Although prospective, randomized controlled trials are lacking, retrospective studies indicate that total blood loss, time to cessation of bleeding, and total blood products transfused seem to be decreased when VHAs are used to guide hemorrhage management.
supporting the theory that pregnant patients with hemorrhage need fibrinogen in greater quantities than other blood components, that continued use of a set 1:1:1 ratio may result in overtransfusion of other components, and that VHAs can aid clinicians in selecting appropriate products for transfusion.
Although promising, further data are needed before VHAs are widely adopted into obstetrical hemorrhage protocols. We recommend that in the presence of severe active obstetrical hemorrhage, activation of massive transfusion protocols should not be delayed while awaiting the results of any coagulation assessment, including VHAs. During the resuscitation process, VHAs may guide clinicians in targeting transfusion of blood products.
Cost-effectiveness of viscoelastic hemostatic assays
The use of POC VHAs in trauma saves >$900 per patient, largely in transfusion-associated costs.
Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis.
In obstetrics, the ROTEM-guided transfusion protocol summarized in Figure 3 resulted in a cost savings of more than $8000 per patient compared with routine laboratory monitoring.
Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis.
The implementation of hemorrhage protocols seems to reduce or even eliminate Black-White disparities in severe maternal morbidity, suggesting a benefit from the use of objective measures rather than clinician impression.
By providing early, objective data to guide transfusion, the implementation of VHA-based protocols may be able to reduce disparities in maternal outcomes after PPH.
Table 3Final recommendations
Lord. New technology for postpartum hemorrhage. Am J Obstet Gynecol MFM 2023.
Topic of interest
Recommendations
Novel sensors for early detection of PPH
Although many sensors are under investigation, no commercially available technology provides sufficiently accurate estimates of blood loss to justify routine clinical use.
Further studies should be performed, and the algorithms behind these technologies may be refined to improve test performance in an obstetrical population.
As obstetrical hemorrhage outcomes depend not only on the actual volume of blood loss or the hemoglobin nadir but also on the patient's response to hemorrhage, alternative endpoints should be considered in such studies.
Application of viscoelastic tests to guide management of PPH
Pregnancy-specific reference ranges should be established for the existing viscoelastic assays.
Prospective, randomized trials are needed to confirm the clinical use and cost savings associated with this technology.
If viscoelastic hemostatic assays are used, fibrinogen assessment seems to be more reliable in obstetrical hemorrhage than other viscoelastic parameters.
In case of heavy bleeding, hypotension, or tachycardia, massive transfusion protocols should be initiated and blood products transfused while awaiting results of further testing. Once available, the results of viscoelastic hemostatic assays may be used to guide transfusion of additional blood products.
Despite many promising technologies on the horizon for early detection of PPH, none have yet met the standards of reliability needed for clinical application beyond a research setting. This remains an active area of research, as techniques in use in other surgical fields are translated into obstetrics. Although the exact role of VHAs in obstetrical hemorrhage remains to be determined, it seems that they may aid clinicians in targeting transfusion of blood products in the setting of severe obstetric hemorrhage. Though perhaps not a replacement for fixed-ratio massive transfusion protocols in the immediate response to acute, life-threatening hemorrhage, VHA-guided transfusion protocols have the potential to optimize blood product utilization, decrease healthcare costs, and improve patient outcomes. The authors' recommendations for initial steps in integrating these technologies into clinical practice are summarized in Table 3.
References
Say L
Chou D
Gemmill A
et al.
Global causes of maternal death: a WHO systematic analysis.
Subcommittees on Women’ s Health Issues in Thrombosis and Haemostasis and on Disseminated Intravascular Coagulation. Management of coagulopathy associated with postpartum hemorrhage: guidance from the SSC of the ISTH.
Assessing the association between blood loss and postoperative hemoglobin after cesarean delivery: a prospective study of 4 blood loss measurement modalities.
Introduction of a novel system for quantitating blood loss after vaginal delivery: a retrospective interrupted time series analysis with concurrent control group.
AI-enabled advanced development for assessing low circulating blood volume for emergency medical care: comparison of compensatory reserve machine-learning algorithms.
Predictors of the onset of hemodynamic decompensation during progressive central hypovolemia: comparison of the peripheral perfusion index, pulse pressure variability, and compensatory reserve index.
Analysis of transfusion-related acute lung injury and possible transfusion-related acute lung injury reported to the French Hemovigilance Network from 2007 to 2013.
Obstetric hemorrhage and coagulation: an update. Thromboelastography, thromboelastometry, and conventional coagulation tests in the diagnosis and prediction of postpartum hemorrhage.
Subcommittee on Perioperative and Critical Care. The utility of viscoelastic methods in the prevention and treatment of bleeding and hospital-associated venous thromboembolism in perioperative care: guidance from the SSC of the ISTH.
The predictive value of modified computerized thromboelastography and platelet function analysis for postoperative blood loss in routine cardiac surgery.
Routine use of viscoelastic blood tests for diagnosis and treatment of coagulopathic bleeding in cardiac surgery: updated systematic review and meta-analysis.
Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis.
Reference ranges for thromboelastography (TEG(®) ) and traditional coagulation tests in term parturients undergoing caesarean section under spinal anaesthesia*.
The use of viscoelastic hemostatic tests in pregnancy and puerperium: review of the current evidence - communication from the Women's Health SSC of the ISTH.
National Institute for Health and Care Excellence. Detecting, managing and monitoring haemostasis: viscoelastometric point‑of‑care testing (ROTEM, TEG and Sonoclot systems). 2014. Available at: https://www.nice.org.uk/guidance/dg13. Accessed April 14, 2022.
Dynamic use of fibrinogen under viscoelastic assessment results in reduced need for plasma and diminished overall transfusion requirements in severe trauma.
M.G.L. has no financial conflict of interest. M.G.L. is involved in research on the AccuFlow sensor but has no financial relationship with the makers of that device. The AccuFlow sensor is discussed in this manuscript alongside its major competitors.
J.A.C. has no conflict of interest.
H.K.A.’s research makes use of a rotational thromboelastometry (ROTEM) delta analyzer, which is on loan from the device manufacturer, Instrumentation Laboratory Company, Bedford, Massachusetts. She does not receive any direct funding from the Instrumentation Laboratory Company, and the Instrumentation Laboratory Company is not involved in any way in the design or conduct of her research. The ROTEM delta analyzer is discussed in this manuscript alongside its major commercial competitor (thromboelastography), with equal time spent in the discussion of both products. Furthermore, H.K.A. participated in consulting work for HemoSonics on 1 occasion in the past. No device produced or designed by HemoSonics is discussed in this manuscript.
L.D.P. is part of the medical consultant board of Coagulant Therapeutics. No product produced or designed by Coagulant Therapeutics is discussed in this manuscript.
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