The aim of this chapter is to introduce the anesthesia technician to the care provided to obstetric patients by the anesthesia team in the delivery suite. The unique environment, the unique condition of pregnancy, and the particular challenges of provision of safe anesthesia care in this specialty area are considered.

When elderly women are asked to name the most memorable day of their lives, the most common response is the day of delivery of their first child. The birth of a child is usually a joyful time, although the experience may be attended with fear, anxiety, and severe pain. Historically, and in parts of the world still, childbirth is associated with a high maternal mortality rate and an even higher neonatal mortality rate. The safety of childbirth has improved considerably in developed countries (Fig. 47.1). Nonetheless, for the fetus, delivery remains a time of high risk. Delivery may be complicated by known or previously unknown congenital medical problems, in utero growth problems, placental or umbilical cord accidents, obstruction of passage through the birth canal, and related injuries. For the mother, childbirth remains a significant cause of mortality and morbidity even in wealthy countries. Complications occur related to preexisting medical conditions in the mother, especially cardiac disease, and medical conditions arising as a result of pregnancy, such as venous thromboembolism, as well as diseases unique to pregnancy such as preeclampsia and amniotic fluid embolus. Hemorrhage remains a major cause of maternal mortality, even in the best of settings. There are also increased risks associated with anesthesia during pregnancy to be considered.

The role of the anesthesia team on the labor and delivery suite is to provide labor analgesia, safe anesthesia for surgical procedures, both elective and unplanned, and to respond to any emergencies as they arise, to ensure the safety of both the mother and child. Careful planning and preparation is the key to safe provision of anesthesia services on the delivery suite.

Obstetric units are often remote from the main operating suite; indeed, they may be in distant buildings. Staffing assignments must ensure that adequate anesthesia coverage and technical support are available day and night. In rural settings and in small hospitals, anesthesia providers may not always be in-house at night. There will be a clear local policy as to acceptable times for delivery of anesthesia services, but the American Society of Anesthesiologists (ASA), American College of Obstetricians and Gynecologists (ACOG), and Joint Commission standard that must be met is that for emergency cesarean sections equipment and personnel should be adequate to ensure that a decision to incision interval of less than 30 minutes can be achieved. This means that anesthesia supplies must be ready and accessible at all times, operating rooms (ORs) must be prepared to receive a patient requiring an emergency cesarean section, and the anesthesia team should be prepared to provide anesthesia, including general anesthesia, at short notice. Although anesthesia technicians are an important part of the anesthesia team, many institutions do not provide a dedicated anesthesia technician to cover the obstetric suite. The delivery suite is usually set up with delivery rooms, in which the anesthesia team may be involved in providing labor analgesia for labor and forceps or vacuum deliveries, and ORs in which both elective and emergency procedures are performed, including cesarean section, manual removal of placenta, tubal ligation, cervical suture, and in some centers fetal in utero
procedures. In some units, ORs may be shared with the main operating area.

Facilities for monitoring in delivery rooms may be limited to noninvasive monitoring including noninvasive blood pressure and pulse oximetry. Obstetric nursing staff routinely monitor these parameters during labor, along with cardiotocography, which measures both the fetal heart rate and uterine contractions (Fig. 47.2). Fetal heart rate monitoring (analysis of cardiotocography patterns) allows assessment of the adequacy of uterine contraction and fetal well-being during labor. A normal fetal heart rate is between 110 and 160 beats per minute, with variability, and with “accelerations.” The monitor may also show “decelerations” of various types, the most ominous of which are frequent late decelerations, which means that the deceleration occurs after the peak of the contraction. This suggests that uteroplacental perfusion is compromised during the contraction and the fetus may be at increased risk of a poor outcome including neurologic damage and even death (Fig. 47.3). The decision to proceed with urgent cesarean section is frequently made on the basis of this monitoring. A sustained fetal bradycardia suggests that the supply of oxygen to the fetus remains impaired and is a clear emergency requiring immediate delivery.

Advanced monitoring such as electrocardiogram (ECG), and arterial or central venous pressure monitoring, may be possible in the delivery room, although the training of obstetric nursing staff may limit its use. In addition, the supplies for these procedures are usually stocked in the OR, and not the delivery suite. During labor and delivery, there are very large changes in physiologic parameters as a result of pain and the metabolic demands of the contracting uterus; for example, cardiac output, already increased 50% percent by pregnancy itself, increases another 40% during labor and delivery. While labor analgesia is known to reduce such changes, for some patients safe delivery requires additional monitoring. Other options are the use of specialist obstetric nursing staff with additional training, intensive care nursing support, or the continuous presence of the anesthesiologist. It may be preferable for patients requiring invasive monitoring to deliver in an OR or an intensive care unit (ICU) setting. When invasive monitoring is required for labor, it is usually for patients with severe cardiac or other underlying disease. Arterial lines and central lines are used more frequently than pulmonary artery catheters. Occasionally, arterial pressure monitoring may be required for women with severe hypertension.

The risks associated with general anesthesia are increased during pregnancy because of major physiologic changes occurring in the mother as
a result of the pregnancy. These changes include the following:

Neuraxial analgesia is both the most effective and least invasive option for labor analgesia. Lumbar epidurals are commonly used. Other options are spinals or combined spinal and epidural techniques (combined spinal epidural [CSE]). Optimal labor analgesia gives pain relief without motor blockade.

Labor is divided into three stages. The first stage occurs when the uterus is contracting regularly and painfully and the cervix dilates. The second stage occurs when the baby descends through the birth canal and the mother actively pushes. The third stage is the delivery of the placenta. The pain of the first stage of labor is transmitted via nerves supplying the fundus and body of the uterus, from T10-L1, whereas the pain of the second stage of labor is transmitted via nerves supplied by sacral nerve roots S2-S4.

The pain of labor is described as being among the most severe of all types of pain. Women’s expectations of the pain of labor are varied, as are their attitudes to analgesia. Some women plan for as much analgesia as possible, while others aim for minimal analgesia, or only noninvasive techniques (Table 47.1). Labor pain is particularly severe in the later first stage, as the cervix approaches full dilation. This may coincide with both mental and physical exhaustion, leading many to request epidural analgesia at this stage.

The pain of labor is unique in pain treatment, in that provision of as much analgesia as possible is not necessarily what the patient desires. Many women want to feel contractions to be able to time pushing. The labor epidural rate is approximately 60%. Some women, particularly with psychological preparation, do very well with minimal analgesia. However, others benefit enormously from neuraxial analgesia. Some women will be advised that a labor epidural is the safest option for them, particularly if they are
at high risk of needing to be delivered by cesarean section, or if they have particular medical conditions.