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.

A description of the coagulopathy characteristics in amniotic fluid embolism: a case report.

Amniotic fluid embolism is frequently associated with coagulopathy. However, the exact nature and evolution of the bleeding disorder is incompletely understood. We report a case of clinically diagnosed amniotic fluid embolism associated with major haemorrhage and coagulopathy. We measured sequential levels of all individual clotting factors, thrombin generation, fibrinogen, and D-dimer levels over the course of the event, beginning shortly after the patient's initial collapse and during the subsequent resuscitation, to identify the specific abnormalities of coagulation from stored blood samples. A better understanding of amniotic fluid embolism and the associated coagulopathy is an important area of research to inform targeted treatment of the coagulopathy and improve outcomes for patients.

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.

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).

Pregnancy after heterotopic heart transplant removal.

Heterotopic heart transplants were introduced in 1974. The technique allows the patient's native heart to be preserved in situ, alongside the transplanted heterotopic donor heart. We present the case of a nulliparous woman who underwent heterotopic heart transplant in infancy, and subsequent explantation of the donor heart eleven years later, when her native heart function recovered. In adulthood the patient attended pre-pregnancy counselling and was awaiting cardiac magnetic resonance imaging when she presented pregnant at 6 weeks-of-gestation. She attended the joint cardiac obstetric and anaesthetic clinic, where she was reviewed monthly and had bi-monthly echocardiograms. At 35 weeks-of-gestation she was admitted to hospital with preeclampsia. After blood pressure control and steroid administration, a category 3 caesarean delivery under spinal anaesthesia was performed. To our knowledge this is the first case report describing pregnancy in a patient with a removed heterotopic heart transplant.

Platelet count and transfusion requirements during moderate or severe postpartum haemorrhage.

Limited data exist on platelet transfusion during postpartum haemorrhage. We retrospectively analysed a consecutive cohort from a single centre of 347 women with moderate or severe postpartum haemorrhage, transfused according to national guidelines. Twelve (3%) women required a platelet transfusion. There were no differences between women who did and did not receive platelets with respect to age, mode of initiation of labour or mode of delivery. Women receiving a platelet transfusion had a lower median (IQR [range]) platelet count at study entry than women who did not receive platelets before haemorrhage (135 (97-175 [26-259])×10(9) .l(-1) vs 224 (186-274 [91-1006])×10(9) .l(-1) ), respectively), and at diagnosis of postpartum haemorrhage (median 114 (78-153 [58-238])×10(9) .l(-1) vs 193 (155-243 [78-762])×10(9) .l(-1) respectively). Six women were thrombocytopenic pre-delivery. The cause of haemorrhage that was associated with the highest rate of platelet transfusion was placental abruption, with three of 14 women being transfused. If antenatal thrombocytopenia or consumptive coagulopathy were not present, platelets were only required for haemorrhage > 5000 ml. Early formulaic platelet transfusion would have resulted in many women receiving platelets unnecessarily. Using current guidelines, the need for platelet transfusion is uncommon without antenatal thrombocytopenia, consumptive coagulopathy or haemorrhage > 5000 ml. We found no evidence to support early fixed-ratio platelet transfusion.

A comparison of fibreoptic-guided tracheal intubation through the Ambu ® Aura-i ™, the intubating laryngeal mask airway and the i-gel ™: a manikin study.

We compared the Aura-i(™) , intubating laryngeal mask airway and i-gel(™) as conduits for fibreoptic-guided tracheal intubation in a manikin. Thirty anaesthetists each performed two tracheal intubations through each device, a total of 180 intubations. The median (IQR [range]) time to complete the first intubation was 40 (31-50 [15-162]) s, 37 (34-48 [25-75]) s and 28 (22-35 [14-59]) s for the Aura-i, intubating laryngeal mask airway and i-gel, respectively. Tracheal intubation through the i-gel was the quickest (p < 0.01). Resistance to railroading of the tracheal tube over the fibrescope was significantly greater through the Aura-i compared with the intubating laryngeal mask airway and the i-gel (p = 0.001). There were no failures to intubate through the intubating laryngeal mask airway or the i-gel but six intubation attempts through the Aura-i were unsuccessful, in five owing to a railroading failure and in one owing to accidental oesophageal intubation. We conclude that the Aura-i does not perform as well as the intubating laryngeal mask airway or the i-gel as an adjunct for performing fibreoptic-guided tracheal intubation.

Standard haemostatic tests following major obstetric haemorrhage.

BACKGROUND: Postpartum haemorrhage is an important cause of maternal morbidity and mortality. It is associated with haemostatic impairment which may exacerbate bleeding. METHODS: All deliveries over a 3-year period in a large UK unit were reviewed and cases of haemorrhage of 1500 mL or more identified. Laboratory records were reviewed and the lowest value for haemoglobin, platelet count and fibrinogen, and longest value for prothrombin time and activated partial thromboplastin time within 24h of delivery were recorded. RESULTS: Of 18,501 deliveries there were 456 bleeds of 1500 mL or more (2.5%). Fibrinogen levels correlated best with blood loss (r -0.48 P<0.01) and fell progressively as volume increased. Activated partial thromboplastin time was less sensitive (r 0.4 P<0.01) to increasing blood loss. Prothrombin time did not correlate with blood loss (r 0.01). Activated partial thromboplastin time and prothrombin time remained within the normal range in most women despite large bleeds. Similar results were observed in women who received four or more units of red blood cells. Haemoglobin level was adequately maintained irrespective of blood loss. Based on UK national guidelines only 13 of 456 (3%) women should have received fresh frozen plasma, although it was given to 45; despite this, fibrinogen levels below the pregnancy-related normal range were observed in most cases. CONCLUSION: Fibrinogen level was the parameter that best correlated with increasing volume of haemorrhage and was the most useful marker of developing haemostatic impairment. Guidelines for fresh frozen plasma use in major postpartum haemorrhage were rarely followed and should be reviewed.

Comparison of fibrescope guided intubation via the classic laryngeal mask airway and i-gel in a manikin.

We compared the classic laryngeal mask airway and i-gel as adjuncts to fibrescope guided intubation in a manikin. Two methods of intubation were compared with each device: the tracheal tube directly over the fibrescope; and the tracheal tube over an Aintree Intubation Catheter. Thirty-two anaesthetists took part in this randomised crossover study. Each anaesthetist performed two intubations with each method via each device. The mean (SD) time for the first intubation using the tracheal tube over the fibrescope was 43 (24) s with the classic laryngeal mask airway and 22 (9) s with the i-gel (95% CI for the difference 12-30 s, p < 0.0001). The mean (SD) times for the first intubation when using the Aintree Intubation Catheter was 46 (24) s with the classic laryngeal mask airway and 37 (9) s with the i-gel (95% CI for the difference 5-12 s, p < 0.0001). We recorded five (5/64, 8%) oesophageal intubations when using the classic laryngeal mask airway and none when using the i-gel. The participants rated the ease of railroading of the tracheal tube and railroading the Aintree Intubation Catheter over the fibrescope to be significantly easier (p < 0.0001 and p = 0.002 respectively) when using the i-gel than when using the classic laryngeal mask airway. Furthermore, 30/32 (94%) of anaesthetists reported preference for the i-gel over the classic laryngeal mask airway for fibrescope guided tracheal intubation when managing a difficult airway. We conclude that the i-gel is likely to be a more appropriate conduit than the classic laryngeal mask airway for fibrescope guided intubation irrespective of the intubation method used.