Case Study
A healthy primiparous woman with a body mass index (BMI) of 20 kg/m2 presented at 41 + 5 weeks’ gestation to the delivery suite following induction of labor for postdates. After a prolonged latent phase, her labor progressed slowly. She requested epidural analgesia, which was sited successfully without problems, after which labor was augmented with oxytocin. After a further 8 hours, the patient remained dilated at 9 cm despite adequate uterine contractions, and the decision was made to perform an emergency cesarean delivery.
Both the anesthesiologist and obstetrician had 5 years of specialty training, and consultants in both specialties were available to attend within 30 minutes from home because it was outside routine hours. The patient’s baseline full blood count (FBC) showed a hemoglobin (Hb) of 101 g/liter, white cell count (WCC) of 18 × 109/liter, and platelet count of 220 × 109/liter. Two group and save samples had been sent to the blood bank earlier in the day, confirming blood group and no abnormal antibodies, which meant that should blood be required, it could be immediately issued without delay and further cross-matching.
The epidural block the patient had for labor analgesia was successfully topped up to provide anesthesia for her cesarean delivery using 20 ml 0.5% l-bupivacaine and 100 µg fentanyl. Following delivery, a slow IV bolus of 5 IU oxytocin was administered, and an oxytocin infusion was started at 10 IU/h. Almost immediately, the patient complained of feeling unwell, with a fall in blood pressure from 105/65 to 70/40 mmHg and an increase in heart rate from 105 to 125 beats/min noted. The anesthesiologist also noticed that there was already 1,200 ml of blood in the suction bottle and a number of heavily blood-soaked swabs, which had not yet been weighed, and blood loss appeared to be continuing. Discussion with the obstetrician revealed that bleeding was mainly traumatic from an extension of the uterine incision with some uterine atony.
A major obstetric hemorrhage (MOH) was declared, alerting the blood bank to issue 4 units of packed red cells (PRCs) and to defrost fresh frozen plasma (FFP) but to delay transportation of the FFP until point-of-care (POC) testing results were available. Consultant anesthesiologist and obstetric staff were called from home. A second large-bore IV cannula was inserted and blood taken at the same time for a FBC, near-patient thromboelastometry FIBTEM, coagulation profile and venous blood gas analysis, including hemoglobin (Hb) and lactate estimation. Hb estimation on the blood gas analysis was 84 g/liter, lactate 3 mmol/liter, with a base deficit of –6 mmol/liter. The FIBTEM amplitude at 5 minutes (A5) was 25 mm, indicating adequate fibrinogen levels and implying normal coagulation despite the significant postpartum hemorrhage (PPH) of around 1,800 ml at this time. The local FIBTEM POC algorithm was followed (Figure 33.1), and the FFP was held in the blood bank rather than being delivered to the OR. The PRCs were available in the OR 15 minutes after request, and 2 units were transfused via a warming device. As part of the standard local practice 1 g tranexamic acid was given intravenously.
Surgical bleeding was brought under surgical control, and uterine atony was managed by repeating the 5-IU bolus of oxytocin, and after antiemetic prophylaxis with 8 mg ondansetron, 500 µg ergometrine (diluted in 20 ml saline) was given by slow IV injection. After the very brisk initial bleeding, 35 minutes after recognition of the major PPH, the bleeding slowed significantly, and after closing the uterus, hemostasis was secured. Most of the management was undertaken by resident medical staff, but attendance by the consultant obstetrician and anesthesiologist confirmed hemostasis and adequate resuscitation. The final measured blood loss was 2,600 ml. Initial fluid resuscitation was with 1 liter of balanced salt solution followed by 500 ml of a modified fluid gelatin in the first 25 minutes. Two units of PRCs were given when the blood loss was around 2 liters, followed by a further 1 liter of balanced salt solution over the next 30 minutes. After the initial dramatic fall in blood pressure, which was treated with fluid boluses and a 50-µg bolus of IV phenylephrine, the patient’s systolic blood pressure remained above 100 mmHg. Her heart rate fell from the initial value of 125 beats/min to around 105 beats/min, probably reflecting mild hypoperfusion and anemia.
Repeat bloods taken toward the end of the procedure after transfusion of 2 units PRCs showed a Hb of 85 g/liter and a FIBTEM A5 value that had fallen to 14 mm, reflecting the significant bleed, but in the face of hemostasis still above the FFP FIBTEM transfusion trigger. The corrected calcium on blood gas analysis indicated a level of 0.9 mmol/liter, which was treated by administering 10 ml 10% calcium gluconate by slow IV infusion
The patient was sent to a high-dependency area for recovery, with hourly urine output and observations recorded every 15 minutes on a modified early obstetric warning score (MEOWS) chart. She received one further unit of PRCs on the first postnatal day because she was symptomatic with a Hb of 76 g/liter, but otherwise recovered well.
Key Points
Despite being healthy, this woman had multiple risk factors for significant postpartum hemorrhage (PPH). Her prolonged latent labor stage, pharmacologically augmented contractions with oxytocin, and obstructed labor put her at a high risk of uterine atony. She was additionally vulnerable to the effects of hemorrhage because of preexisting anemia and low BMI. Her estimated blood volume was around 5 liters, and total blood loss was therefore over 50 percent of her circulating volume. This compares with a woman with a BMI of 24 kg/m2 with an estimated blood volume of 6 liters, in whom the same blood loss would represent around 40 percent of her blood volume.
For a woman at risk of PPH, plans should be made to make delivery as safe as possible. Such plans include
Antenatal: Identification and treatment of anemia. If very high risk (e.g., placenta accrete), arrange interventional radiology at planned cesarean delivery.
Peripartum: Team awareness and planning, large-bore IV access, blood availability.
Operating Room: Cell salvage, fluid and patient warming, and rapid fluid infusion devices.
Timely recognition of major PPH is comparatively easy in the OR, where blood loss should be routinely measured and the mother actively observed. Early recognition in all situations is essential so that etiology-specific treatments can be initiated, blood products ordered, and relevant senior staff can attend.
Near-side blood testing (venous blood gas and thromboelastometery) can be used safely to optimize use of blood and other blood products such as FFP, removing the need for formulaic replacement even in high-risk patients.
Discussion
Major obstetric hemorrhage (MOH) is classified as moderate (1,500–2,500 ml) or severe (>2,500 ml) blood loss. In the Scottish study of severe maternal morbidity, MOH was 80 percent of the reported maternal morbidity, with a rate of 5.8 per 1,000 births.1 PPH remains a leading cause of maternal morbidity and mortality in the United Kingdom, and in 2014, the UK confidential enquiries into maternal deaths reported a mortality rate from obstetric hemorrhage of 0.49 per 100,000 maternities, where substandard care due to delayed recognition was frequently implicated.2
Late recognition of PPH may be due in part to the physiologic adaptations of pregnancy, which enable patients to compensate well for moderate levels of hypovolemia, and the fact that most pregnant woman are young and healthy. The classical signs of shock consequently may manifest only once substantial hemorrhage has already occurred, at around 30 percent of blood volume. Additionally, hemorrhage may be concealed, further obscuring the diagnosis. MEOWS observation charts, which are specifically adapted to highlight physiologic deterioration in pregnant women, should be used whenever obstetric patients are cared for both before and after delivery, and when scores indicate clinical deterioration, hemorrhage must be considered.
The most common causes of PPH are uterine atony and trauma secondary to vaginal or cesarean birth, which account for 80 percent of cases. The 4 T’s mnemonic is helpful when attending a mother so that a rapid diagnosis can be made and appropriate interventions initiated.
1. Uterine Tone. Thirty percent of blood volume goes to the uterus at term, and at delivery, physical constriction through uterine contraction of the vessels is required to prevent PPH.
2. Tissue Retained within the Uterine Cavity. Any retained products (placenta/membranes) must be removed to allow uterine contraction and hemostasis. Women with placenta accreta/percreta are at very high risk of major PPH.
3. Trauma. Bleeding can be rapid and requires prompt surgical intervention. Common sites and causes include perineal or genital tract trauma and lateral extension of the lower uterine segment at emergency cesarean, which is more common if the fetal head is engaged in the pelvis.
4. Thrombin: Disorders of Coagulation. Coagulopathy may precede hemorrhage and be causal or develop secondary to hemorrhage. Severe obstetric coagulopathy with consumption of clotting factors and platelets is associated with placental abruption, HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets), severe sepsis, and amniotic fluid embolus. Dilution of coagulation factors by resuscitation with non-plasma-based fluids will also lead to coagulopathy, but this occurs late in obstetric hemorrhage because of increased baseline levels of fibrinogen and other clotting factors.
Management of Postpartum Hemorrhage
Early recognition is vital to allow a rapid structured response. When abnormal bleeding is noticed (>500 ml at vaginal birth and 1,000 ml after cesarean birth), medical staff should attend, if not already there, and therapeutic maneuvers should be initiated based on the cause of the PPH. This is facilitated by ensuring the routine weighing of all surgical swabs, pads, and bed linen because this correlates closely with a fall in hemoglobin. Visually estimating blood loss can lead to significant underestimation and subsequent delay in initiating interventions.3 It is important to have a high index of suspicion because repeated small amounts of blood loss postpartum may be overlooked, and bleeding may be concealed.
Resuscitation should follow a structured ABC approach and identification and treatment of the cause using the 4 T’s mnemonic. Adequate IV access should be established, with blood taken for FBC, laboratory-based coagulation, and blood bank specimens. POC measurements of Hb and lactate using a blood gas machine (which is available on many delivery suites) can be very helpful, allowing early recognition of anemia and metabolic acidosis, although a normal hemoglobin early in a PPH does not rule out a significant bleed. In addition, POC testing of coagulation using thromboelastography techniques can help the clinician make a decision about the administration of coagulation products based on actual rather than estimated need. Within 10 minutes it is possible to know if the bleeding is purely obstetric in origin and therefore will not improve until the underlying cause has been managed or if the bleeding is being caused or exacerbated by an underlying coagulation deficiency.
Fluid resuscitation should start immediately with warmed crystalloid, and efforts should be made to maintain normothermia because hypothermia can worsen coagulopathy. Blood products should be requested immediately so that they are ready for transfusion when required because there is often a significant delay. When bleeding is not rapidly controlled and the patient is in a delivery room, she must be moved urgently to the OR for examination under anesthesia.
The antifibrinolytic agent tranexamic acid has been shown to be of benefit in the bleeding trauma patient administered as a 1-g loading dose followed by subsequent infusion of 1 g, and its role in the bleeding parturient is under investigation.4
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