The collapsed parturient

This chapter covers a wide spectrum of causes for collapse on the labour ward or in the emergency department, for the first steps in management. The latest guidance on the management of cardiac arrest which the obstetric anaesthetist will be required to immediately attend and initiate in a pregnant woman is described in detail, with the steps needed to progress to perimortem caesarean delivery if resuscitation is not immediately effective. The serious complications of regional anaesthesia; high blocks, total spinals, and local anaesthesia toxicity are emphasized. Anaphylaxis, magnesium toxicity, and management of trauma in the obstetric patient are also outlined.

Hypertensive disease

Hypertension affects ~1 in 10 pregnant women in the UK, whilst pre-eclampsia (PET) complicates 2–8% of pregnancies. Hypertensive disease is the 4th leading cause of direct deaths, with recent triennium deaths due to intracerebral causes. This chapter explores the pathophysiology of hypertensive disease and its current management in pregnancy, including the treatment of eclampsia on labour ward. PET is a multi-system disease, which may present across a wide spectrum of organs. Therefore, the anaesthetic plan of management is greatly influenced by the extent of the disease process and which systems may be involved. This chapter provides detailed recommendations for the anaesthetic plan of care, whichever mode of delivery is indicated, and the peripartum critical care management required.

Major obstetric haemorrhageRachel Collis

Successful management of major obstetric haemorrhage requires a multi-professional team to work together to avoid catastrophic consequences: obstetricians, anaesthetists, midwives, ODPs, theatre scrub staff, porters, as well as blood bank technicians and specialist haematologists. The key pillars of management include; antenatal risk assessment of all women, early recognition of haemorrhage, measured blood loss, prompt escalation at specific trigger points, i.e. >500ml, >1000ml, and review by senior team members to ensure rapid source control. This chapter explores the causes of bleeding, management steps based on algorithms from current practice, and latest evidence for use of point of care testing with visco-elastography for goal-directed control of early clotting failure.

Obesity in pregnancy

Epidemiological studies show the incidence of obesity in pregnancy to be increasing, and the management of the morbidly obese woman on labour ward can be a challenge for anaesthetists. The chapter defines obesity, body mass index, classification, and prevalence, and reviews the physiological effects of obesity on the respiratory, cardiovascular, gastrointestinal, renal, endocrine, and haematological systems, as well as pharmacokinetic changes. Both fetal and maternal morbidities are listed followed by management proposals in the antenatal, peripartum, and postpartum periods. This includes antenatal screening, criteria for anaesthetic referral for assessment and what this should include to plan for delivery. Suggestions for management during labour and during an operative delivery are made. Attention is given to the ramped position and enhanced pre-oxygenation prior to induction of general anaesthesia with CPAP and THRIVE. Practical considerations and technical challenges are discussed and include manual handling, IV access, monitoring, regional techniques, and previous bariatric surgery.

Regional analgesia for Labour

Epidural analgesia is the most effective way of managing pain associated with labour. Pharmacological and technological advances, as well as a greater understanding of anatomy and physiology, have contributed to its safety and efficacy, with >25% of women receiving epidural analgesia during labour in the UK today. The pharmacokinetics of drugs administered into the epidural space are explained, and the evidence for using different methods of administration to establish optimum analgesia, i.e. intermittent top-ups vs continuous infusions vs patient controlled epidural analgesia, is discussed. How to accurately assess a block is emphasized. Epidurals that do not work are a source of anxiety and frustration to women and anaesthetists alike. Therefore understanding why an epidural may not behave as expected, and suggestions to trouble-shoot problematic epidurals are described based on authors’ experience.

Non-regional labour analgesia

Women may choose to deliver their baby in different places, e.g. obstetric-led units, midwife-led units, or at home, depending on their risk assessment and the mother’s own wishes. The way they manage their pain during labour will depend on where they deliver; however, it is essential that they are fully informed about the available options. This chapter explores the evidence base for both non-pharmacological and pharmacological options, e.g. complementary therapies, water immersion, TENS, inhalational analgesia, and systemic opioids. The use of patient-controlled analgesia (PCA) with ultra-short acting opioids, e.g. remifentanil, has been shown to be safe when used in a monitored environment and has high maternal satisfaction scores. The typical regimens and safe monitoring conditions for PCA remifentanil use are described.

Embolic disease

Venous thromboembolism is the leading direct cause of maternal death. Therefore an understanding of the risk factors, clinical presentation, appropriate investigations (i.e. echocardiogram, V/Q Scan, or CT pulmonary angiography) and the treatment options available for managing patients with suspected and confirmed pulmonary embolism (PE) are essential knowledge on an obstetric unit. The chapter includes information on anticoagulation treatment options and the management of life-threatening PE, when thrombolysis or pulmonary embolectomy may be indicated. Amniotic fluid embolism is discussed, reviewing aetiology, pathophysiology, clinical features, diagnosis, and supportive management. Finally air embolism is discussed, also looking at aetiology, pathophysiology, clinical features, diagnosis, and management, emphasizing, however, that prevention is key.

Anaesthesia for Caesarean section: Basic principles

Management of the woman for caesarean delivery requires meticulous planning and skill from the anaesthetist. The time available to plan and communicate with the woman will depend on the degree of urgency to deliver the baby. However, this chapter sets out the important basic principles which need to be adhered to, regardless of the time available. Information and consent for the planned technique is discussed, with a review of antacid prophylaxis and monitoring requirements for the woman and fetus prior to delivery. Enhanced recovery in obstetric surgery is considered the gold standard for elective caesarean delivery, with attention to the details of each aspect described. Caesarean section confers considerable cardio-vascular instability, therefore attention to maternal positioning to minimize aorto-caval compression, intravenous pre-loading, and current evidence to support the practice of differing vasopressor use is highlighted.

Ultrasound in obstetric practice

The use of ultrasound to aid location of the spinal and epidural space is not a new concept but has gained increasing popularity, particularly in woman who are obese, have abnormal spinal anatomy, or where regional placement has or is proving difficult. The benefits and challenges of spinal ultrasound imaging are discussed, with the methods to scan and obtain the right views or planes with the supporting images for spinal and epidural techniques. The use of ultrasound to perform a transversus abdominis plane (TAP) block is also illustrated. The chapter concludes with a section on the additional applications of ultrasound for vascular access and gastric volume estimation.

Maternal physiology

During pregnancy, maternal anatomy and physiology changes significantly. It is important to be aware of what is considered ‘normal’ for pregnancy, in order to promptly recognize and treat medical conditions that may subsequently develop in the antenatal, intrapartum, or postnatal time periods. This chapter sets out the anatomical and physiological changes according to each system: starting with a comprehensive review of the cardiovascular and respiratory changes, which have the most significant adaptations, through the renal, gastro-intestinal, haematological, and endocrine changes, and ending with the central nervous system. Altered anatomy and physiology will affect the conduct of general and regional anaesthesia. The difficulties associated with the obstetric airway, maternal oxygenation, and positioning during anaesthesia are clearly described.