Pain Relief and Anesthesia in Obstetrics

Abstract

Pain Relief and Anesthesia in Obstetrics, A. Van Zundert and G. W. Ostheimer, editors. New York: Churchill Livingstone, 1996, ISBN 0-443-04474-0, 1062 pp, $89.95. It is common to see multiauthored books; this one is unusual in that it has almost 200 contributors. In spite of this, repetitious discussions are infrequent. The contributors come from many parts of the world and give the book a true international flavor. The contributors to this book include some of the most prominent names in obstetrical anesthesia: Ezzat Abouleish, John Bonica, Philip Bromage, David Chestnut, Michael Cousins, Benjamin Covino, Sanjay Datta, Mieczyslaw Finster, Barbara Leighton, Gertie Marx, Daniel Moore, Mark Norris, Gerard Ostheimer, Michael Rosen, and Sol Shnider. After the introduction by Gertie Marx and Phil Bromage, there is a chapter on the history of pain relief for childbirth. This chapter is illuminating in mentioning many people and various attempts at pain relief in childbirth that are not commonly known. It is surprising that few references are given for those who might wish to follow up on these leads. The chapter on pain, written by the late and revered John J. Bonica, reviews the current concepts of the mechanisms of pain transmission and inhibition. The roles of endorphins and enkephalins, psychological and emotional factors, anxiety, attention, and motivation are explained at length. The information is widely applicable, not only in an obstetrical context. The idea that childbirth is natural and painless in primitive people is refuted by reports of actual observers. The nature and details of childbirth pain are explored and explained in great detail. The harmful effects of labor pain on the mother, the fetus, and the observing father are described in such a way as to justify and emphasize the need for pain relief. An unusual idea is presented by the late Sol Shnider, who leaves us with the word that, contrary to common belief, anesthesia is not harmful but good for the mother and fetus. Those who advocate natural childbirth and those who repeat biblical admonitions that pain is to be expected must rethink their stand. The anxiety, suffering, and pain of the parturient cause an outpouring of stress hormones that reduce uteroplacental blood flow and cause acidosis, hypoxia, and cardiac malfunctions in the fetus. Analgesia prevents and corrects these problems. Hawdon cites favorable fetal effects of epidural anesthesia: avoidance of drugs that are depressants for the fetus, minimization of the duration and stress of a complicated labor, prevention of changes in the mother that would have adverse effects on the fetus, improvement of maternal status and uterine blood flow when pregnancy-induced hypertension is present, a decrease in the incidence of retinal hemorrhages and improvement of the outcome for premature, breech, and twin deliveries. Lastly, the mother-infant relationship is improved, with fewer negative reactions, a greater sense of involvement, and more rapid bonding and establishment of breast feeding. In the chapter on neonatal assessment by pediatricians, it is pointed out that many factors influence neonatal behavior. The older literature found major depressant effects by large doses of morphine, meperidine, barbiturates, and general anesthesia. The change in practice, reducing doses and emphasizing small-dose regional anesthesia, is recognized as better, but there is reluctance to endorse the safety of pain relief measures. The authors bemoan that there are so many factors to consider and that neonatal development is so difficult to assess, so that valid conclusions are possible only at extremes. Pain relief is associated with "disruption of maternal functioning" and "an accumulation of possible indirect negative effects …" and the mother's "sense of failure" and "altered selfesteem after delivery." The references they select seem to point out that the mother who suffers thinks more highly of herself and her baby; both get medals for bravery. The ancient curse has not been completely discarded. The chapter on physiologic considerations reviews the current knowledge of maternal metabolism, respiration, hematology, cardiovascular function, and gastrointestinal function. It ends with the implications of these physiologic changes, for both general and regional anesthetics. This is followed by chapters discussing assessment of the mother, fetus, infant, placental perfusion, placental transfer of drugs, and drug interactions. A large section is devoted to epidural analgesia for labor and delivery. In this section, all aspects of care of patients with epidurals are covered. Dan Moore gives us the benefit of his vast experience and clear thinking in his analysis of systemic toxicity due to local anesthetics for epidural anesthesia. It contains a remarkably succinct and organized evaluation of cause, prevention, and treatment. This is followed by a section with chapters on alternatives for epidural analgesia: natural childbirth; hypnosis; acupuncture; transcutaneous electrical nerve stimulation; opioids; caudal, paracervical, and pudendal blocks; spinal anesthesia; spinal headaches; and inhalational analgesia. Among the 101 chapters, a wide variety of additional topics are covered, including pre-, intra-, and postpartum concerns: anesthetic techniques for cesarean and operative deliveries; surgery during pregnancy; the high-risk parturient and her fetus; obstetrical problems and monitoring; hydration; and vaginal birth after a cesarean section. A chapter is devoted to each pre- and coexisting problem of the pregnant woman: diseases of various body organs and systems, diabetes, autoimmune disease, hematologic disease, morbid obesity, difficult airway, malignant hyperthermia, drug addiction, herpes, human immunodeficiency virus, sepsis, trauma, carbon monoxide poisoning, organ transplant, in vitro fertilization, and other assorted subjects. A small chapter is devoted to venous air embolism, which is increasingly recognized during cesarean section, and may occur in half the patients. A negative pressure gradient of 5 cm allows a significant amount of air to enter the veins. This occurs most often during the hysterotomy and its repair, especially if the uterus is exteriorized and the patient is in Trendelenburg's position. Diagnosis, prevention, and treatment are described. There is a chapter on the use of the laryngeal mask airway in obstetric anesthesia. It is not recommended as a first choice for obstetric patients, who are at risk for aspiration. However, it has been effective when there was failed endotracheal intubation. It can also serve as a guide for tracheal tube insertion. Details of its use are discussed. The inner city parturient has a chapter, mostly devoted to illicit drug effects and acquired immune deficiency syndrome (AIDS). Cocaine and crack cross the placenta and affect the fetus. The mother may die of arrhythmia, cardiac infarction, asystole, convulsions, stroke, aspiration, and pulmonary edema. Regional anesthesia is recommended as safer than general anesthesia, but it poses the problem of hypotension, which is refractory to ephedrine treatment. Recommendation is for a dilute solution of phenylephrine. During general anesthesia these patients develop hypertensive crises, arrhythmia, and ischemia. Labetalol is preferred to hydralazine or propranolol; ketamine and halothane should be avoided. Other drugs considered include amphetamines, alcohol, narcotics, marijuana, solvent vapors, and tobacco. Anesthetic implications of AIDS include reduced functional residual capacity leading to faster desaturation, tonsil and adenoid hypertrophy causing difficult intubation, increased intracranial pressure, arrhythmias and chronic heart failure, coagulation disorders, and neuropathies. AIDS therapy causes an assortment of problems for the anesthesiologist, and their details are outlined. Social and organizational concerns have many chapters devoted to them: socioeconomics, the situation in developing countries, finances in various countries, who should administer anesthesia, resuscitation of infants, legal liability, education, organization and standards, and ethical problems such as care of Jehovah's Witnesses. A remarkable amount of material has been assembled into a single volume of more than 1000 pages. The illustrations are ample and excellent. The print is easily legible. The headings and subheadings keep the flow of material orderly and avoid confusion. There is an excellent index. The only adverse comment is that the date of publication seems to be omitted from the references, until realization dawns that the date is placed between the author's name and the title of the article. The book is highly recommended for all who have an interest in obstetrical anesthesia. Jay Jacoby, MD, PhD Department of Anesthesiology The Ohio State University Columbus, OH 43210