Haemostatic monitoring during postpartum haemorrhage and implications for management

C Solomon, R E Collis, P W Collins, C Solomon, R E Collis, P W Collins

Abstract

Postpartum haemorrhage (PPH) is a major risk factor for maternal morbidity and mortality. PPH has numerous causative factors, which makes its occurrence and severity difficult to predict. Underlying haemostatic imbalances such as consumptive and dilutional coagulopathies may develop during PPH, and can exacerbate bleeding and lead to progression to severe PPH. Monitoring coagulation status in patients with PPH may be crucial for effective haemostatic management, goal-directed therapy, and improved outcomes. However, current PPH management guidelines do not account for the altered baseline coagulation status observed in pregnant patients, and the appropriate transfusion triggers to use in PPH are unknown, due to a lack of high-quality studies specific to this area. In this review, we consider the evidence for the use of standard laboratory-based coagulation tests and point-of-care viscoelastic coagulation monitoring in PPH. Many laboratory-based tests are unsuitable for emergency use due to their long turnaround times, so have limited value for the management of PPH. Emerging evidence suggests that viscoelastic monitoring, using thrombelastography- or thromboelastometry-based tests, may be useful for rapid assessment and for guiding haemostatic therapy during PPH. However, further studies are needed to define the ranges of reference values that should be considered 'normal' in this setting. Improving awareness of the correct application and interpretation of viscoelastic coagulation monitoring techniques may be critical in realizing their emergency diagnostic potential.

Figures

Fig 1
Fig 1
Major risk factors associated with PPH. Conditions are classified according to pathophysiology. DIC, disseminated intravascular coagulation; vWD, von Willebrand's disease; PPH, postpartum haemorrhage.
Fig 2
Fig 2
Changes in haemostatic variables observed during normal, healthy pregnancy. The overall increase in pro-coagulant factors results in a typically hypercoagulable state which increases throughout pregnancy. Increases and decreases are relative to non-pregnancy. Positioning of factors is not indicative of the precise level of increase or decrease. FV, Factor V; FVII, Factor VII; FVIII, Factor VIII; FIX, Factor IX; FX, Factor X; FXI, Factor XI; FXII, Factor XII; FXIII, Factor XIII; PAI-1, plasminogen activator inhibitor 1; TAFI, thrombin activatible fibrinolysis inhibitor; TAT complex, thrombin–antithrombin complex; vWF, von Willebrand factor.
Fig 3
Fig 3
ROTEM®- and TEG®-based coagulation profiles in the peripartum period. Schematic representation of healthy (a) and coagulopathic (b) obstetric coagulation profiles for EXTEM and FIBTEM tests. Coagulation parameters which are typically reported for these tests are indicated in the top-left panel. The profiles reflect EXTEM and FIBTEM test results reported for healthy patients around the time of delivery, and for patients with PPH associated with poor fibrin-clot quality. Clot lysis parameters are not indicated; if (hyper)fibrinolysis is suspected, an APTEM test can be performed. APTEM profiles mirror EXTEM profiles under healthy conditions, and show enhanced coagulation vs EXTEM during fibrinolysis. Also presented (c) is a healthy, obstetric coagulation profile for kaolin-activated thrombelastography, with typically reported parameters indicated for this test. The profile reflects kaolin-TEG® values observed for healthy patients in the third trimester, and before elective Caesarean delivery. Owing to the lack of available evidence for typical test results, profiles are not presented for kaolin-TEG® during PPH, or for other TEG®-based tests in obstetric patients. α°, alpha angle; A5–A20, clot amplitude at 5–20 min after CT; CT, clotting time; MA, maximum amplitude; MCF, maximum clot firmness; PPH, postpartum haemorrhage; r, reaction time.

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