Control of Pain
Management of discomfort and pain during labor is an essential part of good obstetric practice. Some patients tolerate pain by using techniques learned in childbirth preparation programs. It is important that bedside staff be knowledgeable about these pain management techniques and be supportive of the patient’s decisions. Unless con-traindicated, pharmacologic analgesics to ameliorate pain of contractions should be made available on request to women in labor.
During the first stage of labor, pain results from the contraction of the uterus and dilation of the cervix. This pain travels along the visceral afferents, which accompany sympathetic nerves entering the spinal cord at T-10, T-11, T-12, and L-1. As the fetal head descends, there is also dis-tension of the lower birth canal and perineum. This pain is transmitted along somatic afferents that comprise por-tions of the pudendal nerves that enter the spinal cord at S-2, S-3, and S-4. To provide relief from obstetric pain, the following methods of anesthesia and analgesia are used.
· Epidural block: infusion of local anesthetics or narcoticsthrough a catheter into the epidural space. The most effective form of intrapartum pain relief in the United States, it can be used in either vaginal or abdominal deliv-eries and in postpartum procedures such as tubal ligation.
· Spinal anesthesia: a single injection of anesthetic
· Combined spinal–epidural: combination of the abovetwo techniques
· Local block: local injection of anesthetic into theperineum or vagina. A pudendal block is a local block (Fig. 8.7).
· General anesthesia: inhaled or intravenous administra-tion of anesthetic agents that results in a loss of mater-nal consciousness. This technique is reserved only for cesarean deliveries in selected cases.
To determine which method of obstetric pain control should be used, the positive and negative aspects of each should be considered. Of the regional modes of analgesia, epidural anesthesia is superior to spinal anesthesia in that it can be left as a continuous source of analgesia and anesthe-sia during both the labor and delivery process. The advan-tage of this technique is its ability to provide analgesia during labor as well as excellent anesthesia for delivery, yet main-tain the patient’s sense of touch, facilitating participation in the birth process. Spinal anesthesia provides good pain relief for procedures of limited duration, such as cesarean delivery or vaginal delivery when labor is rapidly progressing. Combined spinal–epidural anesthesia has advantages: the epidural catheter to titrate medications throughout labor and the rapid onset associated with spinal techniques. All of these types of regional anesthesia may be associated with a postdural puncture headache. However, combined spinal–epidural anesthesia avoids the risk of spinal headache in the mother and reduces the risk of sympathetic blockade, which could lead to hypotension. There is also less motor blockade than with spinal anesthesia. Local block may pro-vide anesthesia for episiotomy and repair of vaginal and per-ineal lacerations; however, paracervical block may result in fetal bradycardia. General anesthesia is associated with complications such as maternal aspiration and neonatal depression. If properly administered, it is effective for most cesarean deliveries, but regional anesthesia is preferable.