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. 2021 Dec 21;22(2):43–51. doi: 10.1016/j.bjae.2021.10.002

Management of patients with suspected placenta accreta spectrum

SC Reale 1, MK Farber 1,∗
PMCID: PMC8749385  PMID: 35035992

Learning objectives.

By reading this article, you should be able to:

  • •

    Identify patients at risk for placenta accreta spectrum (PAS).

  • •

    Describe all aspects of anaesthetic management for patients with suspected PAS.

  • •

    Develop a strategy to manage unexpected PAS.

Key points.

  • •

    It is critical to recognise the risk factors and identify patients with suspected placenta accreta spectrum (PAS); the most common risk factors for PAS are placenta praevia and previous Caesarean delivery.

  • •

    Multidisciplinary planning with experienced teams is critical, and women with suspected PAS should deliver at a tertiary care centre between 34 and 36 weeks' gestation.

  • •

    Prompt resuscitation and management of postpartum haemorrhage and coagulopathy are vital.

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    All centres should establish an algorithm for major postpartum haemorrhage to manage unanticipated cases of PAS.

  • •

    Neuraxial anaesthesia can be safe and effective for patients with PAS.

Placenta accreta spectrum (PAS) is an increasingly important source of maternal morbidity and mortality. Approximately one in 500–700 deliveries in the USA is complicated by PAS.1 The incidence has been increasing over the past 40 yrs, attributed in part to rising rates of Caesarean section (CS).2 Maternal morbidity from PAS is related to postpartum haemorrhage (PPH) and includes coagulopathy, acute kidney injury, gravid hysterectomy, anaemia, need for admission to intensive care and death.1,2 Placenta accreta spectrum is now the leading indication for peripartum hysterectomy.3

Placenta accreta spectrum disorders include placenta accreta, in which the placental villi adhere to the myometrium; placenta increta, invasion of the myometrium; and in its most severe form, placenta percreta, invasion through the myometrium to the serosa and surrounding organs. The aetiology of PAS is likely to be failure of decidualisation in the area of a previous uterine scar, leading to placental trophoblastic invasion of the myometrium.4 The frequency distributions of PAS disorders are 75% (placenta accreta), 18% (placenta increta) and 7% (placenta percreta).3 Although outcomes for PAS can be optimised at resourced tertiary centres, any anaesthetist caring for obstetric patients must be prepared to manage cases of unanticipated PAS.5 In this review, we highlight the key considerations for the anaesthestist in patients with suspected PAS, along with strategies to prepare for unanticipated PAS.

Before delivery

Identifying patients at risk of PAS

Risk stratification of patients with PAS is critically important for planning delivery. The most common risk factors for PAS are surgery or manipulation of the endometrium, including CS, myomectomy, curettage, hysteroscopy or endometrial ablation, with cumulative risk per procedure.3 Current placenta praevia with a history of prior CS is an important risk factor. In a large prospective cohort study of women with placenta praevia, the incidences of PAS were 11%, 40% and 61% with one, two and three previous Caesarean sections, respectively.2 Other established risk factors are in vitro fertilisation, Asherman's syndrome, multiparity and advanced maternal age.6

Women with risk factors for PAS should undergo imaging and diagnosis in the second or third trimester at centres with experience in the ultrasonographic diagnosis of PAS. In cases of suspected PAS by ultrasound (US), placenta praevia is present in over 80% cases and is therefore an important marker for potential PAS.3 Placental lacunae or ‘lakes’ with or without turbulent blood flow on Doppler imaging, abnormalities of the uterine–bladder or uteroplacental interface, and myometrial thickness of <1 mm are ultrasonographic features of PAS (Fig. 1). Placental lacunae on second trimester US confer the highest positive predictive value (75–100%) for PAS.7 Magnetic resonance imaging (MRI) findings suggestive of PAS include dark intraplacental bands thought to represent fibrin deposition with T2-weighted imaging, disruption between the uterus and placenta, and abnormal placental bulging. Ultrasound and MRI have similar sensitivity (74% for US; 94% for MRI) and specificity (95% for US; 84% for MRI) to screen for PAS, with no synergistic benefit from both investigations combined. In addition, as patients with clinical risk factors for PAS may be more likely to undergo serial imaging, selection bias may inflate the power of these tools for diagnosing PAS.7 Antenatal risk stratification for PAS allows for appropriate referral of high-risk patients to specialised obstetric centres with teams that are well versed in the clinical management of women with PAS, as discussed next.3,5

Fig 1.

Fig 1

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Ultrasonographic evidence and specimen confirmation of placenta increta. (A) Ultrasonography at 30 weeks, 6 days demonstrating placenta praevia, placental lakes (star), increased vascularity at the bladder–myometrial border (arrow) and loss of distinction between the placental–myometrial border anteriorly and the myometrial–bladder border laterally. (B) Uterus and placenta post-Caesarean delivery/hysterectomy, with a densely adherent placenta and large circumferential placental bulge. The fundus has a classical hysterotomy closure (arrow). The hypervascularised placenta can be visualised in the low uterine segment, overlying the cervical os (star). Used with written consent from the patient.

Standardisation of nomenclature and grading for PAS is essential for appropriate risk stratification. The terminology PAS was originally proposed in 1966 to capture different grades of placental invasion of the myometrium (placenta accreta, increta and percreta) and has been incorporated into both the International Federation of Gynecology and Obstetrics (FIGO) and American College of Obstetricians and Gynecologists (ACOG) guidelines as the most comprehensive description of this disorder. The heterogeneity of alternative terminology (the terms ‘placental invasive disorders’, ‘advanced invasive placentation’, ‘abnormal myometrial invasion’, ‘abnormal placental adherence’ and ‘pernicious placenta’) is not as inclusive and has led to discrepancies in epidemiological, diagnostic and pathological studies, and should be discouraged. Furthermore, FIGO has advocated reporting guidelines to standardise clinical research reporting on PAS to facilitate systematic reviews, meta-analyses and overall understanding of comprehensive clinical outcomes for PAS.8

Planning for delivery

Timing of delivery is critical to optimise neonatal outcomes without compromising maternal risk of spontaneous labour and unscheduled complex CS. In general, obstetricians will plan delivery between 35+0 and 36+6 weeks' gestation in women strongly suspected to have PAS.9 A single course of antenatal glucocorticoids should be given to the mother between 34 and 36 weeks' gestation (or earlier if the risk of preterm delivery before 34 weeks is increased) to enhance fetal lung maturity.9 Scheduled delivery as late as 36+6 weeks' gestation has been advocated for women with suspected PAS but no risk factors for preterm birth, placenta increta or percreta, or previous CS.10 Amongst all patients with PAS, symptoms of bleeding or preterm labour may hasten the need for delivery, and such deliveries are associated with worse maternal and neonatal outcomes.4

Women with antenatally detectable risk factors for PAS, including placenta praevia, previous CS and uterine surgery and with suspected PAS, should undergo delivery at specialised maternal care centres with experience in managing PAS. In the USA, guidelines have been made to define maternal levels of care for every birthing unit, with the recommendation that women with suspected PAS be delivered at higher-acuity, higher-resourced Level 3 and 4 facilities.3 This general approach facilitates multidisciplinary collaboration between surgical subspecialties, obstetric anaesthesia and critical care teams as well as advanced resuscitation, including cell salvage and massive transfusion.11,12 A recent study demonstrated that 37% of women at risk for PAS delivered at non-specialised centres, considered inadequately equipped for PAS management.13 As PPH is the leading cause of preventable maternal morbidity and mortality, further evaluation of the outcomes in PAS across different level-of-care hospitals is warranted. In the meantime, there should be a low threshold to transfer a patient to a specialised centre for delivery when PAS is suspected. If increased regionalisation of obstetric care lowers the frequency of high-risk deliveries at non-specialised centres, it is important to prioritise emergency preparedness for unscheduled, unanticipated PAS at these centres, as discussed next.

It is also important to specify the location of planned delivery within the hospital, along with communication between staff and alignment of resources (Fig. 2). Options include the labour and delivery operating suite, the main operating theatre or a hybrid operating theatre with capabilities for interventional radiology. Caesarean section in the labour and delivery unit may allow for increased familiarity of teams and obstetric equipment, whereas delivery in the main operating theatre may offer better accommodation of a larger care team and advanced equipment. A recent US survey about choice of delivery location for suspected PAS reflects these nuances.15 Specific cited advantages to delivery in the labour and delivery unit were the ready availability of specialised obstetric surgical resources and personnel, and maintaining readiness to handle unanticipated cases at any time for patients too unstable to transfer. A limitation in staffing and technical resources was a cited disadvantage to delivery in the labour unit, a feature more commonly reported from lower-volume centres. Use of a hybrid operating theatre to facilitate interventional radiology procedures was variably reported, which likely reflects insufficient evidence of significant benefit. Systematically considering the anticipated acuity of the case, the logistics of multidisciplinary staffing and local resources within the operating theatres at both locations can enable the appropriate case- and centre-specific decision for the location of delivery. Further, given that patients with PAS may present for urgent, unscheduled surgery, the same logistics and a mechanism for activating the multidisciplinary team in unscheduled cases should also be clearly documented.

Fig 2.

Fig 2

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Algorithm for patients with suspected placenta accreta spectrum. FFP, fresh frozen plasma; PRBC, packed red blood cells; ROTEM, rotational thromboelastometry; TEG, thromboelastography; TOE, transoesophageal echocardiography; TTE, transthoracic echocardiography. Adapted with permission from King and colleagues.14

Assessment for anaesthesia

An obstetric anaesthesia consultation should be provided to patients with suspected PAS before delivery. Counselling before admission is essential, allowing adequate time not only to elicit a history of difficult intubation and to identify any contraindications to neuraxial anaesthesia, but also to discuss the more complex surgical management and anaesthetic options thoroughly. A general discussion about management of PAS can be tailored based on the presentation, surgical plan, mother's preferences and concerns. A thorough airway and physical examination and review of prior anaesthetic history to identify a potential difficult airway can guide decision making about choice of anaesthetic technique. Appropriate expectations about anaesthesia can mitigate anxiety for both the patient and their birthing partner. For example, although partners are frequently present for CS conducted under neuraxial anaesthesia, the use of general anaesthesia may require that the partner be asked to leave the operating theatre to allow the anaesthesia team to focus on the care of the mother.

Patients with suspected PAS should be counselled about the likelihood for blood transfusion associated with their delivery. Patients with concurrent placenta praevia and antepartum bleeding may be at higher risk of baseline anaemia and transfusion requirement. Detection and treatment of iron deficiency anaemia allow for predelivery haemoglobin to be optimised, and treatment with iron supplementation may be required weeks to months in advance of delivery.16 The option of cell salvage during CS with suspected PAS can be discussed, if it is readily available. Patients with suspected PAS who decline transfusion of blood products must be identified; delivery of such patients is a unique challenge, and modified cell salvage can be life saving when PPH occurs from PAS or other causes. Additional blood conservation strategies for PAS in patients who decline transfusion include use of erythropoietin, acute normovolaemic haemodilution, uterine artery embolisation and delayed hysterectomy, although there is a lack of clear evidence for the benefit of these techniques. Discussions about transfusion risk should be tailored to each patient based on their established risks and planned surgical approach.

Intraoperative management

Anaesthetic technique

Neuraxial anaesthesia

Before surgery, the mother's preferences and concerns discussed in consultation must be reviewed along with updates about any comorbidities, confirmation of the obstetric surgical plan and degree of concern for severe or uncontrolled PPH. Although several case series report the use of general anaesthesia for CS with suspected PAS, retrospective studies suggest that neuraxial anaesthesia can be safely performed either alone or in conjunction with general anaesthesia, even if Caesarean hysterectomy is anticipated or required.17,18 Neuraxial anaesthesia facilitates the patient's first-hand experience of the birth of her child; enhances intraoperative and postoperative pain control; and avoids complications associated with general anaesthesia in obstetrics, including difficult or failed intubation and pulmonary aspiration.

Conversion from neuraxial anaesthesia to general anaesthesia

Conversion from neuraxial to general anaesthesia may be required to secure the airway in the setting of worsening airway oedema from massive haemorrhage and large-volume resuscitation to facilitate surgical exposure and abdominal wall relaxation, or to preempt issues with pain control. In a large retrospective study of 129 patients with placenta praevia and suspected PAS, 21% of patients with primary neuraxial anaesthesia required conversion to general anaesthesia to facilitate surgical exposure or because of inadequate pain control.18 Elective conversion to general anaesthesia after delivery but before hysterectomy is offered by some providers to optimise the patient's delivery experience and pain control whilst also facilitating resuscitation during hysterectomy. Whether elective or planned, induction of general anaesthesia after neuraxial anaesthesia may be associated with hypotension from the combined effects of neuraxial anaesthesia-induced sympathectomy and the systemic response to i.v. anaesthetic agents; hypotension should therefore be anticipated and treated promptly. The generally recommended prophylactic use of a phenylephrine infusion after spinal anaesthesia for CS can be used and augmented for PAS under either neuraxial or general anaesthesia.

General anaesthesia

General anaesthesia may be chosen for patients with suspected PAS if the anaesthetist prefers to secure the airway before surgery. This may be justified for cases of known or suspected difficult airway, or if a lengthy surgical procedure or massive haemorrhage is anticipated. The advantage of a planned general anaesthetic is the ability to secure the airway in a controlled setting, before the onset of haemodynamic instability, airway oedema or coagulopathy. Videolaryngoscopy is recommended for tracheal intubation in obstetric patients because of the increased incidence of difficult intubation, faster rate of deoxygenation, airway friability at term gestation and increased risk of aspiration. However, if general anaesthesia is used at the onset of surgery, placental transfer of anaesthetic medications may depress neonatal alertness at birth; this possibility should be communicated clearly to the paediatric team attending the delivery.

Choice of vascular access

Adequate vascular access is essential for patients with suspected PAS in anticipation of PPH, unstable haemodynamics and need for rapid resuscitation. At minimum, patients should have two large-bore peripheral i.v. lines (14- or 16-gauge [g]), placed before surgery. Central venous access may not be universally required, given that large volumes can be infused via large-bore peripheral i.v. cannulae. Of note, standard multilumen central venous catheters (CVCs) are of smaller diameter and longer than large peripheral i.v. cannulae and do not facilitate rapid transfusion. An in-vitro comparison of flow rate for a 1:1 mixture of red blood cells and fresh frozen plasma pressurised to 300 mmHg demonstrated comparable flow through an 18g peripheral i.v. and a multilumen CVC (183 and 198 ml min−1, respectively), and superior flow rates through 16g and 14g peripheral i.v. cannulae (448 and 728 ml min−1, respectively).19 Central venous access may be warranted if peripheral access is difficult, there is need for ongoing infusion of vasopressor drugs, there is concern for catheter infiltration with high flow rates via a rapid infuser or there is concurrent cardiac comorbidity or need for central venous pressure measurement. If a CVC is used for cases of suspected PAS, selection of a multilumen access catheter (MAC) or a sheath introducer provides the advantage of flow rates—close to 500 ml min−1. In addition to venous access, radial arterial cannulation allows continuous haemodynamic monitoring in cases with suspected PAS and facilitates frequent blood draws for serial analysis of arterial blood gases, haemoglobin, coagulation tests and electrolytes.

Echocardiography in the operating theatre

Point-of-care transthoracic echocardiography (TTE) or transoesophageal echocardiography (TOE) can be an adjunctive diagnostic tool to assess maternal volume status in the operating theatre.20 Left ventricular end-diastolic volume can be measured in conjunction with other parameters (HR, BP and central venous pressure) to guide resuscitation and evaluate response to therapy. Although acquisition and interpretation of TTE or TOE usually involve a cardiologist or cardiac anaesthetist, point-of-care skills are increasingly part of obstetric anaesthesia, and critical care fellowship training and mechanisms for certification may increase the application of this important skill in obstetric anaesthesia practice.

Surgical interventions

It is essential to discuss the planned surgical approach with the obstetrician before delivery to allow the anaesthetist to anticipate the potential risks of unstable bleeding and establish appropriate arterial/venous access, mode of anaesthesia and a plan for postpartum analgesia. The most common surgical approach to PAS is Caesarean hysterectomy without attempted placental separation to avoid haemorrhage resulting from the failed attempt to remove the placenta. With the common presentation of invasive placenta and concurrent placenta praevia, hypervascularity of the placenta is frequently visible upon inspection of the exterior uterine wall of the low uterine segment, and a fundal vertical (classical) hysterotomy can be made for CS before hysterectomy.3 Positioning the patient in the dorsal lithotomy position aids visualisation during surgery, and a calibrated under-buttocks ‘v-drape’ can capture intrauterine blood loss after hysterotomy closure before hysterectomy. Placement of ureteric stents before delivery by the urology team may be requested by the obstetrician to lower the risk of ureteric injury, although the benefit of this intervention is unknown. Uterine preservation measures including removal of placental tissue without hysterectomy, leaving the entire placenta in situ, and delayed interval hysterectomy are largely investigational and may be considered for select patients who decline transfusion or prioritise fertility preservation.3

Vascular occlusion techniques

In a systematic review and meta-analysis of 29 studies and over 2,000 patients, prophylactic balloon occlusion of the internal iliac arteries for placenta praevia or PAS was associated with lower intraoperative blood loss and rates of hysterectomy.21 Use of a resuscitative endovascular balloon occlusion of the aorta (REBOA) catheter has also been increasingly reported for the management of PAS with large volume, unstable PPH.22 If a neuraxial anaesthetic is planned, epidural placement must precede internal iliac or REBOA catheter insertion, as flexion of the lower extremities is precluded after either occlusive vascular catheter technique. Placement of a REBOA catheter can be prophylactic or emergent. The complication of local thrombosis after REBOA use has been reported in conjunction with the use of tranexamic acid (TXA).23 Vascular occlusion techniques may be deployed in patients who desire future fertility or who refuse blood product transfusion.

Management of PPH

As haemorrhage is the leading cause of morbidity and mortality related to PAS CS with or without hysterectomy, a focus on haemorrhage resuscitation is essential.9 Blood loss for Caesarean hysterectomy for PAS can exceed 2 L, but the degree of bleeding acuity and ultimate transfusion requirement is highly variable. Ongoing monitoring of the surgical field and clear communication with the obstetric surgical team are mandatory for appropriate resuscitation throughout CS and possible hysterectomy for PAS. The operating theatre for such cases should be prepared for massive transfusion with fluid warmers, blood filters, rapid infusion devices and cell salvage devices. It has been recommended that cross-matched blood products, including a minimum of 4 units of packed red blood cells and 4 units of fresh frozen plasma, should be immediately available in the operating theatre, with an additional 8 units of packed red blood cells, 4 units of fresh frozen plasma and 2 apheresis units of platelets available and cross-matched in the blood bank for use as needed.24 Frequent communication with the blood bank can help ensure availability of further blood products. Activation of a massive transfusion protocol (MTP) should occur in cases of rapid, unstable bleeding. Massive transfusion protocols typically release a defined ratio of packed red blood cells, fresh frozen plasma and platelets from the blood bank, in similar ratios as described, and may additionally include cryoprecipitate. In cases in which blood products are quickly consumed, having obstetric MTPs in place provides the anaesthesia team ready access to adequate quantities and types of blood products until surgical and haemostatic control has been obtained. For ongoing obstetric bleeding, more concentrated fibrinogen sources should also be considered, including fibrinogen concentrate or cryoprecipitate, along with surveillance for coagulopathy (discussed next). The use of greater than 4 L of crystalloid or colloid is independently associated with adverse maternal outcomes, even when stratified for severity of bleeding, and should be avoided when possible.25 If blood loss exceeds 1,500 ml, prophylactic antibiotics should be redosed.3

As PAS is confirmed intraoperatively and surgical interventions have varying complexity, the degree and acuity of blood loss for PAS are less predictable in the operating theatre than for routine CS. Mechanisms to measure cumulative blood loss can be helpful, as accuracy of visual blood loss estimation has been shown to worsen with increasing volume lost. Quantitative blood loss (QBL) methods include gravimetry, calibrated under-buttocks v-drapes and colorimetric technologies. Use of QBL in PAS is warranted to help guide appropriate resuscitation from PPH. However, studies are needed to evaluate whether using QBL techniques lowers maternal morbidity from PPH. Furthermore, relying on QBL during PAS cases may delay resuscitation if cervical or vaginal blood loss is not appreciated or quantitated in real time. Therefore, QBL methods are encouraged but best done in conjunction with monitoring patient physiological and laboratory indices, along with communication with the surgical team about the rate and magnitude of blood loss and surgical control of bleeding.

Although the use of first- and second-line uterotonics for atonic bleeding during CS is a mainstay of the management of PPH, there are no definitive data on prophylactic uterotonic drugs for patients with suspected or confirmed PAS. The literature to date shows variation in use of uterotonics during CS for PAS, which may reflect a surgical plan for uterine preservation with the placenta left in situ, predominantly non-atonic bleeding, or coding omission.26 Although there are no comparative studies, expert consensus supports the avoidance of giving prophylactic uterotonic drugs routinely in cases of suspected PAS unless there is placental removal or separation with associated atonic bleeding.11 The use of uterotonics must be a collaborative decision by the anaesthetist and surgeon, particularly in cases of focal accreta and planned hysterectomy, in which uterine contraction may compound bleeding from partial placental separation with atonic blood loss before hysterectomy.

Cell salvage has been used with increasing frequency for PPH given its established safety profile.27 In a report of 884 cases of PPH in which cell salvage was utilised, only 21% had adequate blood collection for reinfusion.27 Cell salvage was most beneficial for cases of ongoing bleeding during CS and Caesarean hysterectomy; hence, consideration for cases in which PAS is suspected is warranted. Cell salvage for patients with PAS has been reported with good success.28 Using cell salvage for suspected PAS cases can lower or avoid risks of allogeneic blood transfusion.

Management of coagulopathy

Whilst PPH is ongoing, point-of-care coagulation testing with devices such as rotational thromboelastometry (ROTEM) or thromboelastography (TEG) can provide valuable, real-time information about global coagulation status to guide transfusion. Standard coagulation tests, such as activated partial thromboplastin time and prothrombin time, can remain within normal laboratory ranges during PPH until blood loss exceeds 4–5 L.29 Low serum fibrinogen (<200 mg dl−1) is a predictor for progression to severe PPH, and monitoring of serum fibrinogen helps guide fibrinogen concentrate or cryoprecipitate dosing.3 However, the turnaround time for serum fibrinogen testing is typically longer than 30 min. Rotational thromboelastometry or TEG can offer more nuanced, timely information than standard coagulation testing or serum fibrinogen to enable coagulopathy detection and tailored treatment during PPH. Importantly, point-of-care testing may eliminate provider reliance on fixed ratio transfusion that may not be appropriate during PPH and may lower overall transfusion rate and incidence of transfusion-associated circulatory overload.30 Hypothermia-induced coagulopathy and acidosis should be avoided with use of forced air warmers and fluid warmers and maintaining adequate perfusion, respectively.

Treatment with TXA 1 g i.v. at the onset of PPH decreased the risk of death from PPH with no increase in thrombotic complications in a large RCT.31 Tranexamic acid should be considered for PAS with PPH. A second dose of TXA 1 g can be given if bleeding is ongoing at 30 min. Treatment with TXA should not preclude or delay standard therapy for PPH, including giving uterotonics before hysterectomy, transfusion, and surgical interventions. As discussed previously, TXA should be used with caution if REBOA or other vascular occlusion devices are in use or anticipated. In addition, renal cortical necrosis and persistent renal insufficiency have been reported with the use of high-dose TXA postpartum.32 High-dose TXA should be avoided in obstetric patients, and TXA should be used with caution in women at risk for acute kidney injury. Prophylactic use of TXA, even in the setting of PAS, is not currently recommended, as it has not been well studied.

Unexpected PAS

Patients without classical risk factors or those whose risk is unrecognised can present with unanticipated PAS discovered at the time of CS. Thus, all anaesthetists who care for obstetric patients should be prepared for the emergency management of PAS. A team-based crisis management protocol for PPH should be established in addition to ongoing education about the protocol. The protocol can emphasise a system to rapidly activate an MTP, fibrinogen-rich products and clear mechanisms to escalate care by mobilising available members of the multidisciplinary team. Stabilising patients for transfer to a better-equipped centre should be considered but is not always possible. Anaesthetic goals for the emergency management of PPH from unanticipated PAS include maintenance of haemodynamic stability, massive transfusion, QBL, regular blood tests and close communication with the obstetrician about surgical control of bleeding. Activation of an obstetric MTP for emergency release of blood products can be life saving. Rapid additional peripheral i.v. and arterial access should be obtained for resuscitation. The patient's airway should be secured if large amounts of blood products are being given or if there is haemodynamic instability. Additional resources should be simultaneously mobilised, including critical care, general surgical, gynaecological or interventional radiology teams. Use of a pre-established multidisciplinary management plan (Fig. 2) can be helpful for rapid coordination during unanticipated cases of PAS.

Postoperative management

Surveillance and management of complications

Patients with PAS require vigilant monitoring after surgery for ongoing bleeding, anaemia, fluid overload and multi-organ dysfunction.3 Appropriateness for recovery on the labour and delivery unit can depend on staffing models and expertise of the labour and delivery teams.

Admission to ICU after CS for PAS can be determined by the need for ongoing vasoactive infusions, tracheal intubation, high quantity of fluids and blood products given, anticipated need for additional transfusion and pulmonary oedema or coagulopathy.

At the completion of surgery for PAS, a team debriefing should occur irrespective of whether the case was routine or unscheduled, and particularly when outcomes are poor. The multidisciplinary team (obstetricians, anaesthetists, nurses and other specialists involved) should take part in the postoperative debriefing. Debriefing topics for discussion should include a summary of the procedure, what went well, what could have gone better, communication or safety concerns and plans for postoperative management.33 Training and audit in the conduct of these debriefings should occur regularly to generate information and to make system improvements accordingly.

Venous thromboembolism (VTE) prophylaxis is indicated in patients who have complex CS with or without hysterectomy, including patients with PAS. Although anticoagulants should be avoided if there is concern for ongoing bleeding or coagulopathy, there is concern that patients with PAS are at increased risk for VTE given their surgical complexity and relative postoperative immobilisation. If the patient has an epidural catheter in situ, VTE prophylaxis should take into account national established guidelines about anticoagulant timing and epidural catheter removal to minimise the risk of neuraxial haematoma.34 Close communication between the obstetric and anaesthesia teams for optimisation of anticoagulation and timing of neuraxial discontinuation is important.

Pain management

Patients recovering from CS with PAS have increased postoperative pain because of the complexity of the required surgery, which commonly requires larger incisions, significant soft tissue dissection, longer operative times and greater tissue trauma.35 A multimodal approach, including paracetamol, NSAIDs, neuraxial analgesia with intrathecal opioids and truncal blocks (such as transversus abdominis plane block or quadratus lumborum block) can be offered. Whilst truncal blocks give no added benefit when intrathecal morphine is given for routine CS, pain from more complex CS or hysterectomy may justify using truncal blocks, although there are no data to support this.36 There is also no evidence that routine use of ketamine, clonidine or gabapentin significantly enhances analgesia after CS for PAS. Postoperative epidural local anaesthetics causing significant sensory block may warrant close neurological monitoring if a uterine artery balloon remains in situ.

Conclusions

Women with risk factors for PAS, particularly prior uterine surgery and current placenta praevia, should receive a thorough assessment of PAS before delivery. High clinical risk with or without ultrasonographic or MRI findings for PAS in the second trimester warrants referral to a tertiary centre for planned CS. The delivery plan should designate a multidisciplinary care team that includes obstetricians who are familiar with the management of PAS, an experienced gynaecological surgeon, obstetric anaesthetists and a blood bank that can provide facilities for massive transfusion. Women with suspected PAS should receive thorough antepartum counseling about their options for anaesthesia and the associated risks of PPH requiring transfusion, increased vascular access and potential need for general anaesthesia. Anaesthetists should be prepared to manage massive transfusion and correction of coagulopathy, with systems in place to activate resuscitation for PPH in both anticipated and unanticipated cases of PAS.

Declaration of interests

The authors declare that they have no conflicts of interest.

MCQs

The associated MCQs (to support CME/CPD activity) will be accessible at www.bjaed.org/cme/home by subscribers to BJA Education.

Biographies

Sharon C. Reale MD is an attending anaesthesiologist at Brigham and Women's Hospital and an assistant professor of anaesthesia at Harvard Medical School. She is the director of the Obstetric Anesthesiology Fellowship programme at Brigham and Women's Hospital. Her major clinical and research interests are education in obstetric anaesthesia, post-partum haemorrhage and analysis of epidemiological databases.

Michaela K. Farber MD MS is an attending anaesthesiologist at Brigham and Women's Hospital, assistant professor of anaesthesia at Harvard Medical School and chief of the Division of Obstetric Anesthesiology at Brigham and Women's Hospital. Her major clinical and research interests are post-partum haemorrhage, point-of-care coagulation testing and management of placenta accreta spectrum.

Matrix codes: 1I02, 2A03, 2A05, 3B00

Footnotes

Supplementary references to this article can be found online at https://doi.org/10.1016/j.bjae.2021.10.002.

Supplementary Material

The following is the Supplementary data to this article:

Multimedia component 1
mmc1.docx (18KB, docx)

References

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