Why Mothers Die — Report on Confidential Enquiries into Maternal Deaths in the United Kingdom 1994–96

This is the fifteenth Report in this series on maternal deaths and is the fourth reporting on deaths in the UK as a whole. Since the first Report included Anaesthesia as an entity in 1952, obstetric anaesthetists in most parts of the world have used the data as benchmarks of safety of anaesthetic and analgesic procedures administered in pregnancy. In those 50-odd years, anaesthesia in pregnancy and the puerperium has undergone a transformation from general anaesthesia with ether, chloroform or cyclopropane to today's low-dose, regional techniques which have minimal impact on maternal mortality. In the ‘Anaesthesia’ section of the Report (Chapter 9), there is one Direct death, which is discussed below. Eight of the nine mortalities associated with anaesthesia received general anaesthesia; all had serious pre-existing medical conditions and, on the data provided, at least two of these could have had regional anaesthesia, which reflects a lack of planning and/or early communication between obstetricians, physicians and anaesthetists. It is most distressing therefore to see an increase in the absolute numbers of Direct and Indirect deaths in this Report. Of the 268 Direct and Indirect deaths in this triennium, 67 are due to improved case ascertainment. The new baseline maternal mortality rate of 12.2 per 100 000 maternities contrasts with 9.8 per 100 000 in the previous Report [1]. The fact remains that substandard care is the real message of this Report. The Report highlights many interesting features of present-day obstetric practice. One is the increasing numbers of Caesarean deliveries, now up to 30% in some specialised units. Ninety-three deaths were associated with Caesarean section compared with 98 in the 1991–93 Report. It is unfortunate therefore that the traditional chapter on Caesarean sections has been omitted. Another is increasing maternal age, and with it the incidence of diseases and complex medical problems, all of which complicate anaesthesia, especially in emergencies. For women 35 years or older, the Caesarean section rate is now 25%. For primiparas it is 33% (Table 1). Recent publicity concerning Caesarean section ‘on demand’ may increase these rates further [2]. Caesarean-hysterectomy is also increasing in frequency in line with the increased prevalence of abdominal delivery, and is often predictable. The chance of hysterectomy increases almost exponentially with the number of previous Caesarean sections [3], so it goes without saying that women at risk of repeat Caesarean section should be cared for by experienced consultants. Management plans, including anaesthesia, should be formulated and documented during the last trimester. With increasing maternal age and intervention rates, such as induction of labour and Caesarean delivery, and rising demands for labour analgesia it is clear that the 20-year-old recommendation for one consultant anaesthetist session per 500 deliveries is no longer adequate [4]. Whilst general anaesthesia has not been directly responsible for any deaths in this triennium, it is associated with many deaths, all of which patients were seriously ill. Although no denominator data for anaesthesia are available for the country as a whole, it is widely recognised that in the UK the use of general anaesthesia for delivery has declined to a small percentage of all obstetric anaesthesia. Indeed, obstetric anaesthetists, exhorted by the recommendations in previous Reports, other audits and studies, have striven successfully to minimise the use of general anaesthesia, which today is largely reserved for only those cases where regional methods are contraindicated or considered to be more hazardous. This Report reflects that trend. It is axiomatic therefore that the sole, Direct anaesthetic death should have been caused by a regional technique. This tragic death, like the epidural death in the previous triennium [1], is yet another reminder that regional techniques, improperly administered, can be as hazardous as any other anaesthetic procedure. Combined spinal-epidural (CSE) anaesthesia was first reported in 1937 [5], and has been extensively researched and developed to the point where it is now in widespread use throughout the world. Along with the use of synergistic, low-dose mixtures of local anaesthetics and opioids, and the introduction of fine-gauge, pencil-point spinal needles, CSE is being increasingly recognised as an important addition to the armamentarium of the anaesthetist. ‘The CSE technique offers many advantages over continuous epidural or subarachnoid methods alone, not the least of which are a reduction in drugs dosage, the ability to eliminate motor blockade and to achieve highly selective sensory blockade and optimal analgesia. These features hold great promise for minimising the hazards and side-effects of traditional epidural or intrathecal catheter techniques’ [6]. In obstetrics, CSE is used for analgesia and anaesthesia, in both the delivery suite and the operating theatre. To suggest that the CSE technique per se was a critical factor in this death is absurd. The fault lies not in the method but in the way it was used. For Caesarean delivery, CSE anaesthesia can be achieved with less than half the usual dose of hyperbaric bupivacaine [7]. But in this case, a full intrathecal bupivacaine dose (11.25 mg) was used, together with clonidine (150 μg) and alfentanil (125 μg). Total volume and resulting baricity of the intrathecal injection are unknown. All of these doses are excessive in the context of a parturient of short stature and CSE. To date, both clonidine and alfentanil have not been widely researched in CSE or pregnancy, so their use as adjuvants must be questionable. The epidural dose of bupivacaine was also excessive in context. Indeed, it is difficult to understand why epidural bupivacaine was required at all. In eight of the 21 cases discussed in the Anaesthesia chapter, a consultant anaesthetist was not present, and two of those were known to have significant anaesthesia risk factors in the prenatal period. Substandard care was apparent in 13 cases. In three, a senior house officer was responsible for anaesthetic care. Clearly more senior, experienced anaesthetists need to be readily available for obstetrics. In the UK, almost all pregnant women receive comprehensive antenatal care and education by midwives and obstetricians. It is during this period that risk factors are identified and assessed. Anaesthetists should educate and exhort general practitioners, obstetricians and midwives to consult them during pregnancy so that when anaesthesia is required, even in an emergency, the most appropriate techniques are understood and can be instituted. Although no comprehensive data are available, it is known that such communication and consultation is becoming standard practice. In 1992, one of us (J.C.) reported in Australia that ALL pregnant women are potential candidates for our attention and, in practice, 70% or more parturients will receive an anaesthetic or analgesic procedure — usually regional [8]. This principle cannot be ignored by any obstetric team member, and it is especially important in smaller units where anaesthesia and intensive care services are not readily available. Today, identification of anaesthetic and other risk factors during pregnancy and appropriate consultation with an experienced anaesthetist during pregnancy should be regarded as mandatory for all at-risk mothers. In other words, teamwork in caring for pregnant women throughout the pregnancy, not just in labour or at delivery, is essential. It is disturbing that it is again a lack of teamwork and planning which underpins much of the substandard care associated with 67% of the 134 Direct deaths and many of the others (Table 2). The clinical roles of anaesthetists in obstetrics have long extended beyond the operating theatre. Resuscitation, appropriate physiological monitoring and intravenous fluid and blood-products administration are all activities at which anaesthetists excel. Sadly, substandard care in these areas features in many of the deaths associated with haemorrhage, hypertensive and thromboembolic disease, amniotic fluid embolism and ectopic pregnancy (Table 2). The Report recommends that better planning, guidelines and management of these conditions is required. The four principal categories of maternal death are: Thromboembolism, Pre-eclampsia and eclampsia, Haemorrhage and Early (including ectopic) pregnancy. Local guidelines for improving the management of these situations are recommended in the Report [9]. Such guidelines should include early and continued involvement of anaesthetists, but the Report stops short of stating this clearly. In parturients requiring thromboprophylaxis, early team planning is essential to minimise the prophylactic regimen compromising anaesthetic management. In at least one death, in a patient with pulmonary hypertension, general anaesthesia was implicated as an associated factor because the anticoagulation regimen precluded the use of a regional technique [10]. Recent reports from the United States of problems with low-molecular-weight heparins should alert all practitioners to these hazards [11–13]. With teamwork and planning, anticoagulation should not compromise anaesthetic technique. Thromboprophylaxis can be expected to become more prevalent with increasing age, medical complexity and operative delivery. Arguably, regional anaesthesia permits better analgesia, earlier mobilisation and other advantages in the obese, older and other parturients at risk of thromboembolism. In pre-eclampsia, early, planned delivery is commonplace, and regional anaesthesia has been shown to improve uteroplacental (and almost certainly other organ) blood flow, eliminate the pain and stress of labour, and simplify hypertensive management [14]. Recommended guidelines for the planning and management of such cases should always involve anaesthetists so that regional analgesia/anaesthesia can be provided [1]. It is somewhat heartening that deaths attributed to haemorrhage have declined during this triennium. Nevertheless, substandard care was identified in eight of the 12 Direct haemorrhage deaths. The key recommendations (Report p. 48) should include early consultation with the duty anaesthetist to institute appropriate resuscitation, monitoring and planning for delivery/surgery. As general anaesthesia is most likely to be required in these cases, early assessment is paramount. The Report has many minor, irritating, numerical and arithmetic errors and is presented in an enlarged format yet printed in only 8 and 9 point type size; but despite these criticisms it is recommended reading for anaesthetists and all who care for women in pregnancy. Improved staffing, availability, communications and teamwork involving anaesthetists are required to minimise the unacceptable substandard care cited.

Topic: Cardiac, Anesthesia and Surgical Outcomes
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences