Early viscoelastometric guided fibrinogen replacement combined with escalation of clinical care reduces progression in postpartum haemorrhage: a comparison of outcomes from two prospective observational studies.

BACKGROUND: Viscoelastometric haemostatic assays (VHA) give rapid information on coagulation status, allowing individualised resuscitation. METHODS: This paper compares outcomes from two observational studies of postpartum haemorrhage (PPH) in the same institution, before and after practice changed from fixed ratio empirical transfusion of coagulation products with laboratory coagulation testing to VHA-guided fibrinogen replacement incorporated into an enhanced PPH care bundle. In both studies, all blood samples were taken near 1000 mL qualitative blood loss (QBL). In Study One, QBL started once PPH was identified, and resuscitation with coagulation blood products was empirical or based on laboratory tests of coagulation. In Study Two, QBL started at delivery and VHA was used to guide fibrinogen replacement if FIBTEM A5 was <12 mm (Claus fibrinogen ≤2 g/L) or to withhold coagulation products if FIBTEM A5 was >12 mm. RESULTS: Improved PPH outcomes were observed in Study Two, with rates of measured blood loss ≥2500 mL, ≥4 units red blood cell (RBC) transfusion, fresh frozen plasma transfusion and ≥8 units of any blood product transfusion all reduced (P < 0.01). Clinically significant improvements occurred in women with fibrinogen ≤2 g/L at study entry, where the proportion of women who received ≥4 units RBC transfusion fell from 67% in Study One to 0% in Study Two (P = 0.0007). CONCLUSIONS: These results suggest that use of VHA as part of an early bundle of PPH care targeting fibrinogen ≤2 g/L with fibrinogen concentrate reduces PPH progression. The greatest benefit was seen when fibrinogen levels were ≤2 g/L at first testing.

ObsTIVA-UK: a service evaluation of obstetric total intravenous anaesthesia in the United Kingdom.

We conducted a prospective observational service evaluation across the United Kingdom on the use of total intravenous anaesthesia (TIVA) for obstetric surgery between November 2022 and June 2023. The primary aim was to describe the incidence of TIVA for obstetric surgery within participating units, with secondary aims to describe maternal and neonatal postoperative recovery indicators. Of 184 maternity units in the United Kingdom, 30 (16%) contributed data to the service evaluation. There were 104 patients who underwent caesarean delivery under TIVA and 19 patients had TIVA for other reasons. Infusions of propofol and remifentanil were used in 100% and 84% of cases, respectively. Fifty-nine out of 103 live neonates (57%) required some form of respiratory support. Of the neonates with recorded data, 73% and 17% had Apgar scores < 7 at 1 and 5 min respectively. No neonates were recorded to have Apgar scores < 7 at 10 min. Further prospective research is required to investigate the impact of obstetric TIVA on maternal and neonatal outcomes and inform best practice recommendations.

Comparison of haematological indices and transfusion management in severe and massive postpartum haemorrhage: analysis of a two-year national prospective observational study.

INTRODUCTION: This two-year prospective cohort study compared the management of women experiencing severe or massive postpartum haemorrhage (PPH) to explore the impact of targeted blood product administration on reducing PPH progression (from >1500 mL to ≥2500 mL blood loss). During the study, viscoelastic haemostatic assays (VHA) guided blood product transfusion. METHODS: All women experiencing blood loss after PPH >1000 mL were included in a national database. Haematological indices, transfusion and PPH aetiology were analysed in severe (>1500 mL blood loss or transfusion of any blood product) and massive PPH (≥2500 mL blood loss or transfusion ≥5 units red blood cells). RESULTS: Of the 61 094 maternities in Wales (2017 to 2018), 2111 had severe and 349 massive PPH. Red blood cells were transfused to 42.5% severe and 80.6% massive PPH cases. Hypofibrinogenaemia (fibrinogen <2 g/L and/or Fibtem A5 <12 mm) was the most frequent coagulation abnormality, occurring in 5.4% severe and 17.0% massive PPH, with blood coagulation products (fresh frozen plasma, platelets, cryoprecipitate and/or fibrinogen concentrate) administered to 3.6% and 22.9%. Women with hypofibrinogenaemia received targeted fibrinogen replacement in 97.8% severe and 93.6% massive PPH. The only aetiology with similar rates of hypofibrinogenaemia in severe and massive PPH was abruption (40.0% and 36.8%). CONCLUSION: Hypofibrinogenaemia was less frequent in severe PPH, although coagulopathy was observed across a range of PPH aetiologies, highlighting the importance of coagulation testing for all. Cases of abruption in severe and massive PPH had similar rates of hypofibrinogenaemia. Early VHA-guided fibrinogen replacement may reduce PPH progression in abruption and requires further evaluation.

The sensitivity and specificity of rotational thromboelastometry (ROTEM) to detect coagulopathy during moderate and severe postpartum haemorrhage: a prospective observational study.

INTRODUCTION: Point-of-care viscoelastic haemostatic assays such as rotational thromboelastometry (including ROTEM and TEG) have been used in the management of postpartum haemorrhage (PPH). This study compared results obtained from the automated ROTEM Sigma with laboratory tests of coagulation and platelet count during PPH. METHODS: A prospective observational cohort study recruited women with PPH ≥1000 mL (or clinical concern of bleeding). The Fibtem A5, Extem CT and Pltem (Extem A5 - Fibtem A5) results were compared with laboratory tests of fibrinogen, prothrombin time (PT), activated partial thromboplastin time (APTT) and platelet count. RESULTS: 521 women were recruited, including 274/277 (98.9%) of women with PPH ≥1500 mL. Fibtem A5 results were matched with laboratory fibrinogen in 552/644 (85.7%) samples. The incidence of abnormal laboratory results was low: fibrinogen ≤2 g/L 23/464 (5.0%), PT or APTT >1.5 × midpoint of reference range 4/464 (0.9%), and platelet count <75 × 109/L 11/477 (2.3%). Area-under-the-receiver operator characteristic curve for Fibtem A5 to detect fibrinogen ≤2 g/L was 0.96 (95% Confidence Interval (CI) 0.94 to 0.98, P<0.001), with sensitivity and specificity of Fibtem A5 ≤11 mm to detect fibrinogen ≤2 g/L of 0.76 and 0.96. Prolonged Extem CT results improved after treatment of hypofibrinogenaemia alone. Intervention points for platelet and fresh frozen plasma (FFP) transfusion based on ROTEM Sigma parameters could not be established. CONCLUSION: During PPH (≥1000 mL or cases of clinical concern about bleeding), ROTEM Sigma Fibtem A5 can detect fibrinogen ≤2 g/L and guide targeted fibrinogen replacement. Laboratory results should continue to be used to guide platelet and FFP transfusion.

Utility of viscoelastography with TEG 6s to direct management of haemostasis during obstetric haemorrhage: a prospective observational study.

BACKGROUND: The TEG 6s is an automated cartridge-based device with limited description of use in obstetric haemorrhage. The aim of this analysis was to describe the utility of TEG 6s in identifying abnormal laboratory results of coagulation and platelet count, and inform an interventional treatment algorithm for postpartum haemorrhage. METHODS: A prospective observational cohort study of 521 women with moderate to severe obstetric haemorrhage (>1000 mL blood loss), including 372 women with at least one TEG 6s test. A non-pregnant control group was used for reference. TEG 6s test parameters Citrated Functional Fibrinogen (CFF), Citrated Kaolin TEG (CK) and Citrated Rapid TEG (CRT) were compared with paired laboratory tests of fibrinogen, PT/aPTT and platelet count, obtained during haemorrhage. RESULTS: Among 456 TEG 6s tests, 389 were matched with laboratory coagulation results. The receiver operator characteristic area-under-the-curve (95% CI) for CFF amplitude by 10 min to detect Clauss fibrinogen ≤2 g/L was 0.95 (0.91 to 0.99) (P<0.0001, sensitivity 0.74 and specificity 0.97 at ≤17 mm). False positives had median (IQR) Clauss fibrinogen of 2.4 (2.3-2.7) g/L. The CK-R time had some utility for detecting prolonged PT/aPTT, however a threshold for fresh frozen plasma transfusion was not established. A CRT maximum amplitude <57 mm, when CFF was ≥15 mm, identified four of eight samples with platelet count <75 × 109/L. CONCLUSION: The TEG 6s CFF can be used to identify low fibrinogen during obstetric haemorrhage. A value to identify transfusion thresholds for PT/aPTT and platelets was not established, and laboratory results should continue to be used.

The incidence, aetiology, and coagulation management of massive postpartum haemorrhage: a two-year national prospective cohort study.

INTRODUCTION: Between 2017 and 2018 a national quality improvement initiative was introduced incorporating point-of-care viscoelastic haemostatic assays (VHA) to guide blood product transfusion. Laboratory coagulation profiles, use and results of VHA, and administration of blood products were investigated. METHODS: A two-year prospective cohort study of maternal outcomes of women experiencing massive postpartum haemorrhage (PPH) >1000 mL in Wales. In this study, cases of massive PPH (≥2500 mL and/or ≥5 units red blood cell (RBC) transfusion) were identified. RESULTS: Massive PPH occurred in 349 of 60 914 maternities (rate 5.7 per 1000). There were no deaths from PPH. Intensive care unit admission and/or hysterectomy occurred in 34/311 (10.9%) and 16/347 (4.6%), respectively. The leading cause of massive PPH was genital tract trauma (107/349, 30.6%). Two hundred and seventy-nine (80.6%) required RBC transfusion and 79/345 (22.9%) received at least one blood coagulation product. Results of VHA were recorded in 245/349 (70.2%), with 44/98 (44.9%) women tested in the first six months vs 63/77 (81.8%) in the final six months. Hypofibrinogenaemia (Clauss fibrinogen <2 g/L or FIBTEM A5 <12 mm) was observed in 56/328 (17.1%) of women, thrombocytopaenia (count <75 × 109/L) in 17/334 (5.1%) and either PT or aPTT >1.5×reference range in 10/293 (3.4%). CONCLUSION: In Wales, the use of VHA in cases of massive PPH increased over time, enabling clinicians to adopt a targeted, patient-specific approach to blood product administration, with only 22.9% of women receiving blood coagulation products and 17.1% having a documented clotting abnormality.

Management of postpartum haemorrhage: from research into practice, a narrative review of the literature and the Cardiff experience.

Postpartum haemorrhage (PPH) is caused by obstetric complications but may be exacerbated by haemostatic impairment. In a 10-year programme of research we have established that haemostatic impairment is uncommon in moderate PPH and that fibrinogen falls earlier than other coagulation factors. Laboratory Clauss fibrinogen and the point-of-care surrogate measure of fibrinogen (FIBTEM A5 measured on the ROTEM® machine) are predictive biomarkers for progression from early to severe PPH, the need for blood transfusion and invasive procedures to control haemorrhage. Fibrinogen replacement is not required in PPH unless the plasma level falls below 2 g/L or the FIBTEM A5 is below 12 mm. Deficiencies of coagulation factors other than fibrinogen are uncommon even during severe PPH, and ROTEM® monitoring can inform withholding FFP safely in most women. In the absence of placental abruption, clinically significant thrombocytopenia is uncommon unless the platelet count is low before the bleed started, or very large bleeds (>5000 mL) occur. Measuring blood loss is feasible in routine practice during PPH and is more accurate than estimation. These research findings have been collated to design an ongoing quality improvement programme for all maternity units in Wales called OBS Cymru (Wales) (The Obstetric Bleeding Strategy for Wales).

A randomised crossover trial comparing a single-use polyvinyl chloride laryngeal mask airway with a single-use silicone laryngeal mask airway.

We compared insertion rates of single-use polyvinyl chloride laryngeal mask airways (LMAs) vs single-use silicone LMAs in 72 anaesthetised patients. Both airways were produced by Flexicare Medical. Laryngeal mask airway insertion was successful on the first attempt in 68/72 (94%) polyvinyl chloride LMAs vs 64/72 (89%) silicone LMAs (p = 0.39). Overall insertion rates were 72/72 (100%) for the polyvinyl chloride LMAs and 71/72 (99%) for the silicone LMAs (p = 1.0). Mean (SD) insertion times were similar for polyvinyl chloride and silicone LMAs: 24.3 (5.1)s vs 24.8 (7.8)s (p = 0.64). Laryngeal mask airway position, as assessed using a fibrescope, was not different (p = 0.077). The median (IQR [range]) leak pressure was 16 (12-20 [6-30]) cmH(2) O for the polyvinyl LMA and 18 (13-22 [6-30]) cmH(2) O or the silicone LMA (p = 0.037). In conclusion, we did not find any important differences between polyvinyl chloride and silicone laryngeal mask airways.

The use of fibrinogen concentrate to correct hypofibrinogenaemia rapidly during obstetric haemorrhage.

Haemorrhage is a common complication of childbirth with 0.65% of deliveries associated with significant (>1500 mL) peripartum blood loss. Hypofibrinogenaemia secondary to dilutional and consumptive coagulopathies can be challenging to correct quickly with conventional blood and plasma therapy. Fibrinogen concentrate offers rapid restoration of fibrinogen levels with a small volume infusion and minimal preparation time. It is effective in treating patients with congenital hypofibrinogenaemia, but there are few reports of its use in association with continuing obstetric haemorrhage. Six cases of obstetric haemorrhage, associated with hypofibrinogenaemia, treated with fibrinogen concentrate in conjunction with platelets, fresh frozen plasma, packed red blood cells, uterotonics and obstetric intervention are described. In all cases, laboratory assessed coagulation was rapidly normalised and severe haemorrhage improved. These cases suggest that fibrinogen concentrate may be an effective addition to conventional treatments for obstetric haemorrhage associated with hypofibrinogenaemia.

The electrical effect of two commonly used clinical stimulators on traumatic edema in rats.

The purposes of this study were to determine the effect of electrical stimulation on traumatic rat hind-paw edema and to establish whether there would be a difference in edema reduction when two types of stimulators were used. The animals were divided into a control group (n = 15) and two experimental groups, one group receiving monophasic pulsed current (MPC group, n = 15) and the other group receiving symmetrical biphasic pulsed current (SBPC group, n = 14). The right hind-paw volume of all groups was measured prior to traumatization and at 24, 48, 72, and 96 hours posttrauma. Following the 24-, 48-, and 72-hour measurements, 1 hour of electrical stimulation was administered to the experimental groups. The control group received sham treatment. Results revealed significant edema reduction in all groups over the 96-hour period, with each group's greatest change in paw volume occurring 48 hours posttrauma. At the final paw volume measurement, there was no significant difference between the MPC and control groups or between the MPC and SBPC groups. The SBPC group, however, showed less reduction in edema than did the control group. One hour of electrical stimulation per day over 3 consecutive days failed to demonstrate significant edema reduction in either the MPC group or the SBPC group as compared with the control group. The results of this study demonstrated that the electrical stimulation characteristics and procedures currently used in the clinic do not significantly reduce extant edema caused by trauma in rat hind limbs.