Case Study
A 33-year-old gravida 4, para 3 woman was brought to the emergency room by her partner at 30 + 3/7 weeks’ gestation with vaginal bleeding and sporadic painful uterine contractions. She previously had one normal vaginal delivery, followed by one cesarean delivery for breech presentation and a second cesarean delivery for failed attempted vaginal birth after cesarean delivery 16 months ago. Her 22-week ultrasound scan demonstrated central placenta previa with suspected signs of a placenta accreta. She was booked at 34 weeks’ gestation for an elective cesarean delivery with hysterectomy, if needed, and was advised to come straight to hospital if she experienced vaginal bleeding.
Since the onset of vaginal bleeding 2 hours previously, she had used six heavy pads, and the bleeding had currently ceased. She was anxious and tired, and her contractions, although irregular (every 9–20 minutes) were very painful. In the emergency room, the resident obstetrician attached her to a continuous electrocardiogram monitor (heart rate 80 beats/min), noninvasive blood pressure monitoring (110/60 mmHg), pulse oximetry (SpO2 97% on room air), and fetal cardiotocography (normal). The obstetric trainee contacted the anesthesia team, who inserted a large-bore (14-gauge) IV cannula in her right antecubital fossa and sent blood for laboratory tests, including a complete blood count, coagulation profile, and blood cross-match. The anesthesia team assessed the patient, including airway, administered oxygen via a facemask, and administered 1 liter of crystalloid fluid. The patient was classed as American Society of Anesthesiologists (ASA) Class 1, body mass index (BMI) 24 kg/m2, with an unremarkable airway.
The obstetric trainee contacted her obstetric consultant to inform him that a patient with bleeding placenta previa and suspected accreta was in the emergency room with normal vital signs and that emergency delivery was likely to be required. A multidisciplinary team (MDT) gathered to discuss the optimal delivery strategy and timing for her cesarean delivery. This MDT comprised anesthesia, obstetrics, gynecology, neonatology, intensive care, interventional radiology, vascular surgery, urology, hematology, and nursing staff. Faced with this patient with a vaginal bleed and suspected placenta accreta with imminent labor, the decision was taken to perform an emergency cesarean delivery. The blood bank was alerted, and a postoperative ICU bed booked.
The obstetric trainee consented the patient for cesarean delivery and a hysterectomy, if needed. The anesthesia team discussed with the patient the advantages of general versus neuraxial anesthesia. The patient selected general anesthesia after discussion with her partner because she was very anxious and preferred to be “knocked out.” She was transferred to the OR, connected to routine anesthesia monitors, and positioned supine with left uterine displacement. Under local anesthesia, her radial artery was cannulated for direct blood pressure measurements, and a large-bore (7 French gauge) peripheral catheter was inserted into her left antecubital fossa. Blood products (four units each of red blood cells, fresh frozen plasma, and platelets) were ordered to the OR; a Cell Saver unit and a rapid warming infuser were also primed. General anesthesia was performed using a rapid-sequence induction technique with tracheal intubation. A cystoscopy performed before surgery revealed placental intrusion into the bladder. Given the strong evidence of placenta percreta, the surgical plan included hysterotomy and delivery of the fetus, followed by hysterectomy.
Key Points
A high index of suspicion is required for placenta accreta spectrum (PAS) in women with prior cesarean delivery and placenta previa.
Management of PAS requires a multidisciplinary team and suitable support facilities such as the blood bank and the ICU.
Cesarean hysterectomy may be planned and is associated with reduced blood loss, but uterine preservation strategies may be performed.
Preparations are required for massive hemorrhage, including rapid infuser and Cell Saver.
Patient blood management should include using a massive transfusion protocol and coagulation function assessments.
Neuraxial anesthesia may be suitable for all but emergency cases, and conversion to general anesthesia may be required.
Discussion
Emergency hysterectomy is an infrequent but distressing outcome of pregnancy. Hysterectomy may be anticipated in such a case of suspected placenta accreta as presented here or may be a lifesaving procedure in order to mitigate severe maternal morbidity or even mortality. This patient had clinical features of antenatal suspected placenta accreta, placenta previa, previous cesarean delivery, and ultrasound signs of accreta, but her premature presentation with antepartum hemorrhage disrupted the plan for elective cesarean delivery.
This chapter discusses the causes and risk factors for emergency hysterectomy, with a special focus on PAS as a major cause. It reviews the management of emergency hysterectomy, which includes assembling a multidisciplinary team, hemorrhage management including IV access, blood products massive transfusion protocol, and use of the Cell Saver. The anesthesia choice may be clear in favor of general anesthesia if the patient is unstable, but neuraxial anesthesia is supported for PAS cases even when hysterectomy may be performed.1 Surgical and postoperative considerations are reviewed with a focus on material useful to the anesthesia practitioner managing an emergency hysterectomy.
Emergency Hysterectomy
The most common reasons for emergency cesarean hysterectomy are postpartum hemorrhage due to uterine atony and PAS (Table 35.1).
| Emergency hysterectomy |
|---|
| Placenta previa causing uncontrolled bleeding |
| Placenta accreta causing uncontrolled bleeding |
| Uterine atony |
| Trauma/uterine rupture |
| Uterine inversion |
| Nonemergency hysterectomy |
|---|
| Menorrhagia due to fibroids |
| Pelvic pain due to endometriosis |
| Pelvic inflammatory disease (PID) |
| Adenomyosis or fibroids |
| Pelvic organ prolapse |
| Cancer of uterus |
| Cancer of ovaries |
| Cancer of cervix |
Risk Factors for Emergency Hysterectomy
1. Uterine Atony. Postpartum hemorrhage due to uterine atony accounts for 21–43 percent of emergency hysterectomy cases.2, 3 An overdistended uterus due to multifetal gestation, fetal macrosomia, or polyhydramnios, preeclampsia, prolonged first- and second-stage of labor, induction, and nulliparity are all risk factors for uterine atony.
2. Uterine Rupture. This is primarily a complication following previous cesarean delivery.2
3. Placenta accreta spectrum. Thirty-eight percent of emergency hysterectomies are performed for abnormal adherent placenta,4 and cesarean hysterectomy is highly likely when placenta accreta is suspected. In one retrospective study, among 57 cases of antenatally suspected placenta accreta, 39 percent presented emergently with vaginal bleeding, and 98 percent underwent cesarean hysterectomy.5 In this chapter, management strategies for placenta accreta are emphasized, and all abnormal adherent placentas are referred to as placenta accreta spectrum (PAS).
Placenta Accreta Spectrum
1. Pathophysiology of Placenta Accreta Spectrum (PAS). Placenta accreta is caused by a partial/complete lack of the deciduas basalis and a defective fibrinoid layer. The depth of invasion is termed placenta accreta (placental villi attached to the myometrium), increta (invasion of placenta villi into the myometrium), or percreta (placental villi fully penetrating all layers of the myometrium to the serosal layer).6
2. Risk Factors for PAS. Women with PAS are usually asymptomatic,7 and up to 20 percent of PAS cases have no discernible risk factors.8, 9 Among risk factors for PAS are cumulative prior cesarean deliveries,10 placenta praevia, short time interval between cesarean deliveries, increasing maternal age, smoking, previous uterine surgery such as myomectomy or endometrial ablation, and prior dilatation and curettage.10
3. Epidemiology of PAS. In the United States over the last 30 years, a 10-fold increase in PAS cases has been reported, and in Western countries in general, the PAS rate ranges from 1 per 530 to 1 per 2,500 deliveries.7, 9, 11 The PAS incidence correlates with the increase in cesarean delivery rate.11, 12 In 2008, the cesarean delivery rate in the United States reached a peak – 32.8 percent of all births – and it remains at this high rate13 (Figure 35.1).
4. Epidemiology of Placenta Accreta Spectrum. Ultrasound as a tool for the diagnosis of PAS has a sensitivity of 77–86 percent and a specificity of 96–98 percent.14 Additional benefits of MRI are unclear, with specificity and sensitivity similar to those of ultrasound.6, 10, 15 Combining ultrasound findings with known clinical risk factors such as placenta previa and prior cesarean delivery improves the diagnostic sensitivity for PAS.16, 17 In the absence of a radiologic diagnosis (ultrasound or MRI), PAS is a clinical or pathologic diagnosis.1
Management Considerations for Emergency Hysterectomy
1. Multidisciplinary Team Management. The involvement of a multidisciplinary team (MDT) can reduce blood loss, transfusion requirements, and maternal mortality and morbidity.10, 18 Close working relationships between anesthesiologists, obstetricians, midwives, neonatologists, blood bank, radiologists, oncogynecologists and other surgical subspecialties are important to optimize teamwork, communication, and planning7, 10 (Figure 35.2). Drills to simulate team management of hemorrhage and emergency cesarean delivery may improve patient outcome and team performance.19–21 A checklist may be useful to ensure that all MDT members are included and the necessary blood products ordered.11 In our practice, we order 4 units of red blood cells and 4 units of fresh frozen plasma to the OR and check them prior to anesthesia in cases of suspected placenta accreta.
2. Specialist Care Management. Consider transfer to a tertiary care center if your center lacks expertise or logistics such as blood bank and ICU1 (Table 35.2). Women managed with MDT in a tertiary center had reduced transfusion requirements and morbidity rates in one report.5
3. Timing of Delivery. Where possible, cesarean delivery is planned for PAS once the fetus has reached an appropriate gestational age – usually 34-36 weeks’ gestation22 – in order to avoid an emergency delivery with concomitant hemorrhage risk. The potential downside of early delivery is fetal immaturity, in particular lung development.18 Some physicians in the United States wait for 37 weeks’ gestation, considering that the risk of maternal hemorrhage is lower than fetal risk due to immaturity.23
Figure 35.2 Example checklist for preparation of placenta accreta caseSource: Use with permission from Belfort MA. Placenta accreta. Am J Obstet Gynecol 2010; 203(5):430–39.11
Table 35.2 Practice Surveys of Placenta Accreta Spectrum Management among Providers in the United States
| Jolley et al.57 | Wright et al.18 | Esakoff et al.23 | |
|---|---|---|---|
| Survey year | Survey collection period not reported; published 2011. | 2011 | 2009 |
| Survey population | Members of SMFM | Random sample of ACOG Fellows | Providers registered with SMFM |
| Number surveyed | 1,759 | 994 | 1,861 |
| Completed survey response | 27% | 51% | 19% |
| Number of survey items | 36 | 27 | Not reported |
| Survey tool | Online tool (surveymonkey) | Written mailed survey | Written mailed survey |
| Annual number of accreta cases | |||
| 0 | 26% | 18% | 9% |
| 45% | 45% | 69%a |
| 4–9 | 30% | 37% | 17%b |
| ≥10 | 3% | Not reported | 5%§ |
| Accreta patients not referred to tertiary unit | 95% | 33% | Not asked |
| Request for anesthesia consultation prior to surgery | 87% | Not asked | Not asked |
| Not asked |
| Not asked |
| Number that use cell salvage | 50% | Not asked | Not asked |
| Number that use intravascular balloon catheters | 35% | 28% | 36% |
Abbreviations: SMFM = Society of Maternal-Fetal Medicine; ACOG = American College of Obstetrics and Gynecologists.
aCategory was 1–5 cases per year.
bCategory was 6–10 cases per year.
cSubset of the 4–9 cases per year respondents.
Anesthetic Considerations
1. Mode of Anesthesia. Neuraxial anesthesia has fewer associated maternal complications such as failed intubation, aspiration of gastric contents, hypoxia, awareness, and maternal death.24–26 Regarding the anesthesia mode for PAS Lilker et al.24 reported that over one-fifth of cases required conversion to general anesthesia due to patient discomfort and/or inadequate surgical conditions in a series of 23 placenta accreta cases.
2. Emergency Obstetric Hemorrhage. Bleeding placenta accreta or uterine atony may be an indication to consider general anesthesia due to the high risk of hypotension and coagulopathy.9 Neuraxial anesthesia causes sympathectomy, potentially worsening hemodynamic instability from hemorrhage.7 Factors that may influence the decision for neuraxial or general anesthesia include degree of placental invasion, predicted blood loss, length or difficulty of surgery, planned cesarean delivery versus attempted placental separation,6 and difficult maternal airway. Regardless of anesthesia mode, blood products and vasoactive drugs such as phenylephrine, ephedrine, dopamine, and epinephrine should be available.1 A plan for immediate conversion to general anesthesia should be in place, including a discussion with the patient to prepare her for the possibility that this may occur rapidly.
3. Vascular Access. We recommend insertion of two large-bore IV cannulas and invasive direct arterial monitoring of blood pressure9 for women at high risk for massive transfusion and hemodynamic instability. The internal jugular vein is in closer anatomic proximity to the carotid artery in a pregnant woman. In our practice, we insert a 14- and a 7F-gauge peripheral cannula and reserve central venous access for special cases. In women undergoing neuraxial anesthesia, we insert these lines under local anesthetic infiltration, but we may place the lines following induction in elective cases under general anesthesia.
Transfusion Considerations
1. Blood Loss. Increased plasma volume in pregnancy makes routine vital sign monitoring unreliable for blood loss assessments. An invasive arterial line allows beat-to-beat hemodynamic assessments and serial point-of-care assessments for thrombolelastography and hemoglobin.27–29 A recent survey of postpartum hemorrhage (PPH) management in the United States reported wide variation in blood loss estimation techniques. Visual estimates from suction bottles and the surgical field were used by 98 percent of the units, and only one-fifth added or used an objective measure of blood loss such as surgical swab weights or laboratory assessments.30 Visual estimates are notably inaccurate, but training can improve the precision of these estimates.31 The 2013 European guidelines for management of severe perioperative bleeding recommend performing coagulation assessments to guide blood management,32 including a thromboelastogram. Normal fibrinogen levels in pregnancy are high, and therefore, a concentration below 2 g/liter is considered very low in pregnancy and may be associated with severe hemorrhage.32
2. Massive Transfusion Protocol (MTP). Recent transfusion policies stem from data on severely injured military personnel in armed conflicts. In 2005, the United States Army Institute of Surgical Research suggested a “damage control resuscitation” technique with a 1:1:1 red blood cell (RBC), fresh frozen plasma (FFP), platelets (PLTs) transfusion ratio.7, 10 Adherence to a MTP was associated with increased survival33, 34 and a drop in mortality from 65 to 19 percent. Similar figures have been published from civilian trauma centers.35
Obstetric transfusion protocols are derived largely from trauma MTPs. A recent US survey reported that at least 20 percent of academic centers lack PPH protocols. Among units with a PPH protocol, 95 percent also had a MTP. Blood loss greater than 1,500 ml was the usual trigger to activate a MTP in obstetric hemorrhage management, and 35 percent of units use a predefined 1:1:1 RBC-FFP-PLT transfusion ratio.30
3. Cell Salvage. Cell salvage using a Cell Saver appears safe despite the potential risks of amniotic fluid embolization36 and maternal alloimmunization34, 37 and may reduce allogeneic transfusion requirements.37–39 In our practice, we use the Cell Saver for PAS cesarean delivery. In the United Kingdom, one-third of the labor and delivery units used the Cell Saver, and most of these promoted cell salvage in their PPH protocols.40
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