The History of Obstetric Anesthesia EPUB version of this bookEPUB version of this book

Editor’s Note: This chapter has remained intact since written for the first edition of the textbook published in 1994; the material continues to be as relevant today as it was then. Thus, the textbook editors have elected not to make revisions to the chapter, despite its age, but offer the following reflections.

In the last paragraph of the chapter, Dr. Caton noted that “only a fraction of the information available from basic sciences has been used to improve obstetric anesthesia care” and that “realizing the rewards from the clinical use of such information may be the most important lesson from the past and the greatest challenge for the future of obstetric anesthesia.”

In the 30 years that have passed since Dr. Caton wrote these words, much has changed in the practice of obstetrics and obstetric anesthesiology. Physicians and scientists have rigorously studied and promoted evidence-based care. Much of the knowledge resulting from this research is documented in the following pages of this textbook. Our understanding of the physiologic changes of pregnancy and their effects on anesthesia care has advanced. So too has our knowledge of the drugs used in pregnancy, including their effects on pregnancy and the effects of pregnancy on drug pharmacokinetics and pharmacodynamics. Ground-breaking research on the role and techniques of neuraxial labor analgesia in the care of parturients has enabled individualized care that minimizes adverse effects on the mother and fetus/neonate. Similarly, incremental, but significant advances in anesthesia for cesarean delivery have made anesthesia care safer. As women with significant comorbid medical conditions and advanced maternal age can now conceive and carry pregnancies past the age of fetal viability, anesthesia providers are extending the depth and duration of their care of these high-risk parturients to include prepartum optimization, and intra- and postpartum management of pain and stabilization of cardiopulmonary, hematologic, and critical care issues. Multidisciplinary, team-based care is increasingly recognized as an important contributor to patient outcomes, and anesthesia providers contribute significantly to these models of care on labor and delivery units.

But, as noted by Dr. Caton in his parting words, there is still much we do not know. We continue to rely on lessons from the past to improve care for women and their children and advance the science of obstetric anesthesiology.

“The position of woman in any civilization is an index of the advancement of that civilization; the position of woman is gauged best by the care given her at the birth of her child.” So wrote Haggard in 1929. If his thesis is true, Western civilization made a giant leap on January 19, 1847, when James Young Simpson used diethyl ether to anesthetize a woman with a deformed pelvis for delivery. This first use of a modern anesthetic for childbirth occurred a scant 3 months after Morton’s historic demonstration of the anesthetic properties of ether at the Massachusetts General Hospital in Boston. Strangely enough, Simpson’s innovation evoked strong criticism from contemporary obstetricians, who questioned its safety, and from many segments of the lay public, who questioned its wisdom. The debate over these issues lasted more than 5 years and influenced the future of obstetric anesthesia.

JAMES YOUNG SIMPSON

Few people were better equipped than Simpson to deal with controversy. Just 36 years of age, Simpson already had 7 years’ tenure as Professor of Midwifery at the University of Edinburgh, one of the most prestigious medical schools of its day ( Fig. 1.1 ). By that time, he had established a reputation as one of the foremost obstetricians in Great Britain, if not the world. On the day he first used ether for childbirth, he also received a letter of appointment as Queen’s Physician in Scotland. Etherization for childbirth was only one of Simpson’s contributions. He also designed obstetric forceps (which still bear his name), discovered the anesthetic properties of chloroform, made important innovations in hospital architecture, and wrote a textbook on the practice of witchcraft in Scotland that was used by several generations of anthropologists.

An imposing man, Simpson had a large head, a massive mane of hair, and the pudgy body of an adolescent. Contemporaries described his voice as “commanding,” with a wide range of volume and intonation. Clearly Simpson had “presence” and “charisma.” These attributes were indispensable to someone in his profession, because in the mid-19th century, the role of science in the development of medical theory and practice was minimal; rhetoric resolved more issues than facts. The medical climate in Edinburgh was particularly contentious and vituperative. In this milieu, Simpson had trained, competed for advancement and recognition, and succeeded. The rigor of this preparation served him well. Initially, virtually every prominent obstetrician, including Montgomery of Dublin, Ramsbotham of London, Dubois of Paris, and Meigs of Philadelphia, opposed etherization for childbirth. Simpson called on all of his professional and personal finesse to sway opinion in the ensuing controversy.

MEDICAL OBJECTIONS TO THE USE OF ETHER FOR CHILDBIRTH

Shortly after Simpson administered the first obstetric anesthetic, he wrote, “It will be necessary to ascertain anesthesia’s precise effect, both upon the action of the uterus and on the assistant abdominal muscles; its influence, if any, upon the child; whether it has a tendency to hemorrhage or other complications.” With this statement, he identified the issues that would most concern obstetricians who succeeded him and thus shaped the subsequent development of the specialty.

Simpson’s most articulate, persistent, and persuasive critic was Charles D. Meigs, Professor of Midwifery at Jefferson Medical College in Philadelphia ( Fig. 1.2 ). In character and stature, Meigs equaled Simpson. Born to a prominent New England family, Meigs’s forebears included heroes of the American Revolutionary War, the first governor of the state of Ohio, and the founder of the University of Georgia. His descendants included a prominent pediatrician, an obstetrician, and one son who served the Union Army as Quartermaster General during the Civil War.

A portrait of Charles D. Meigs. — Fig. 1.2

At the heart of the dispute between Meigs and Simpson was a difference in their interpretation of the nature of labor and the significance of labor pain. Simpson maintained that all pain, labor pain included, is without physiologic value. He said that pain only degrades and destroys those who experience it. In contrast, Meigs argued that labor pain has purpose, that uterine pain is inseparable from contractions, and that any drug that abolishes pain will alter contractions. Meigs also believed that pregnancy and labor are normal processes that usually end quite well. He said that physicians should therefore not intervene with powerful, potentially disruptive drugs ( Fig. 1.3 ). We must accept the statements of both men as expressions of natural philosophy, because neither had facts to buttress his position. Indeed, in 1847, physicians had little information of any sort about uterine function, pain, or the relationship between them. Studies of the anatomy and physiology of pain had just begun. It was only during the preceding 20 years that investigators had recognized that specific nerves and areas of the brain have different functions and that specialized peripheral receptors for painful stimuli exist.

A cover page of a medical book titled Obstetrics, The Science and the Art by Charles D Meigs with publication details and a symbol. — Fig. 1.3

In 1850, more physicians expressed support for Meigs’s views than for Simpson’s. For example, Baron Paul Dubois of the Faculty of Paris wondered whether ether, “after having exerted a stupefying action over the cerebrospinal nerves, could not induce paralysis of the muscular element of the uterus?” Similarly, Ramsbotham of London Hospital said that he believed the “treatment of rendering a patient in labor completely insensible through the agency of anesthetic remedies … is fraught with extreme danger.” These physicians’ fears gained credence from the report by a special committee of the Royal Medical and Chirurgical Society documenting 123 deaths that “could be positively assigned to the inhalation of chloroform.” Although none involved obstetric patients, safety was on the minds of obstetricians.

The reaction to the delivery of Queen Victoria’s eighth child in 1853 illustrated the aversion of the medical community to obstetric anesthesia. According to private records, John Snow anesthetized the Queen for the delivery of Prince Leopold at the request of her personal physicians. Although no one made a formal announcement of this fact, rumors surfaced and provoked strong public criticism. Thomas Wakley, the irascible founding editor of The Lancet , was particularly incensed. He “could not imagine that anyone had incurred the awful responsibility of advising the administration of chloroform to her Majesty during a perfectly natural labor with a seventh child.” (It was her eighth child, but Wakley had apparently lost count—a forgivable error considering the propensity of the Queen to bear children.) Court physicians did not defend their decision to use ether. Perhaps not wanting a public confrontation, they simply denied that the Queen had received an anesthetic. In fact, they first acknowledged a royal anesthetic 4 years later when the Queen delivered her ninth and last child, Princess Beatrice. By that time, however, the issue was no longer controversial.

PUBLIC REACTION TO ETHERIZATION FOR CHILDBIRTH

The controversy surrounding obstetric anesthesia was not resolved by the medical community. Physicians remained skeptical, but public opinion changed. Women lost their reservations, decided they wanted anesthesia, and virtually forced physicians to offer it to them. The change in the public’s attitude in favor of obstetric anesthesia marked the culmination of a more general change in social attitudes that had been developing over several centuries.

Before the 19th century, pain meant something quite different from what it does today. Since antiquity, people had believed that all manner of calamities—disease, drought, poverty, and pain—signified divine retribution inflicted as punishment for sin. According to Scripture, childbirth pain originated when God punished Eve and her descendants for Eve’s disobedience in the Garden of Eden. Many believed that it was wrong to avoid the pain of divine punishment. This belief was sufficiently prevalent and strong to retard acceptance of even the idea of anesthesia, especially for obstetric patients. Only when this tradition weakened did people seek ways to free themselves from disease and pain. In most Western countries, the transition occurred during the 19th century. Disease and pain lost their theologic connotations for many people and became biologic processes subject to study and control by new methods of science and technology. This evolution of thought facilitated the development of modern medicine and stimulated public acceptance of obstetric anesthesia.

The reluctance that physicians felt about the administration of anesthesia for childbirth pain stands in stark contrast to the enthusiasm expressed by early obstetric patients. In 1847, Fanny Longfellow, wife of the American poet Henry Wadsworth Longfellow and the first woman in the United States anesthetized for childbirth, wrote:

I am very sorry you all thought me so rash and naughty in trying the ether. Henry’s faith gave me courage, and I had heard such a thing had succeeded abroad, where the surgeons extend this great blessing more boldly and universally than our timid doctors. … This is certainly the greatest blessing of this age.

Queen Victoria, responding to news of the birth of her first grandchild in 1860 and perhaps remembering her own recent confinement, wrote, “What a blessing she [Victoria, her oldest daughter] had chloroform. Perhaps without it her strength would have suffered very much.” The new understanding of pain as a controllable biologic process left no room for Meigs’s idea that pain might have physiologic value. The eminent 19th-century social philosopher John Stuart Mill stated that the “hurtful agencies of nature” promote good only by “inciting rational creatures to rise up and struggle against them.”

Simpson prophesied the role of public opinion in the acceptance of obstetric anesthesia, a fact not lost on his adversaries. Early in the controversy he predicted, “Medical men may oppose for a time the superinduction of anesthesia in parturition but they will oppose it in vain; for certainly our patients themselves will force use of it upon the profession. The whole question is, even now, one merely of time.” By 1860, Simpson’s prophecy came true; anesthesia for childbirth became part of medical practice by public acclaim, in large part in response to the demands of women.

OPIOIDS AND OBSTETRICS

The next major innovation in obstetric anesthesia came approximately 50 years later. Dämmerschlaff , which means “twilight sleep,” was a technique developed by von Steinbüchel of Graz and popularized by Gauss of Freiberg. It combined opioids with scopolamine to make women amnestic and somewhat comfortable during labor ( Fig. 1.4 ). Until that time, opioids had been used sparingly for obstetrics. Although opium had been part of the medical armamentarium since the Roman Empire, it was not used extensively, in part because of the difficulty of obtaining consistent results with the crude extracts available at that time. Therapeutics made a substantial advance in 1809 when Sertürner, a German pharmacologist, isolated codeine and morphine from a crude extract of the poppy seed. Methods for administering the drugs remained unsophisticated. Physicians gave morphine orally or by a method resembling vaccination, in which they placed a drop of solution on the skin and then made multiple small puncture holes with a sharp instrument to facilitate absorption. In 1853, the year Queen Victoria delivered her eighth child, the syringe and hollow metal needle were developed. This technical advance simplified the administration of opioids and facilitated the development of twilight sleep approximately 50 years later.

A title panel displays two German obstetric paper titles by V. Steinbüchel and Oskar Kreis, each with author names and affiliations. — Fig. 1.4

Although reports of labor pain relief with hypodermic morphine appeared as early as 1868, few physicians favored its use. For example, in an article published in Transactions of the Obstetrical Society of London , Sansom listed the following four agents for relief of labor pain: (1) carbon tetrachloride, the use of which he favored; (2) bichloride of methylene, which was under evaluation; (3) nitrous oxide, which had been introduced recently by Klikgowich of Russia; and (4) chloroform. He did not mention opioids, but neither did he mention diethyl ether, which many physicians still favored. Similarly, Gusserow, a prominent German obstetrician, described using salicylic acid but not morphine for labor pain. (Von Baeyer did not introduce acetylsalicylic acid to medical practice until 1899.) In retrospect, von Steinbüchel’s and Gauss’s descriptions of twilight sleep in the first decade of the century may have been important more for popularizing morphine than for suggesting that scopolamine be given with morphine.

Physicians reacted to twilight sleep as they had reacted to diethyl ether several years earlier. They resisted it, questioning whether the benefits justified the risks. Patients also reacted as they had before. Not aware of, or perhaps not concerned with, the technical considerations that confronted physicians, patients harbored few doubts and persuaded physicians to use it, sometimes against the physicians’ better judgment. The confrontation between physicians and patients was particularly strident in the United States. Champions of twilight sleep lectured throughout the country and published articles in popular magazines. Public enthusiasm for the therapy subsided slightly after 1920, when a prominent advocate of the method died during childbirth. She was given twilight sleep, but her physicians said that her death was unrelated to any complication from its use. Whatever anxiety this incident may have created in the minds of patients, it did not seriously diminish their resolve. Confronted by such firm insistence, physicians acquiesced and used twilight sleep with increasing frequency.

Although the reaction of physicians to twilight sleep resembled their reaction to etherization, the medical milieu in which the debate over twilight sleep developed was quite different from that in which etherization was deliberated. Between 1850 and 1900, medicine had changed, particularly in Europe. Physiology, chemistry, anatomy, and bacteriology became part of medical theory and practice. Bright students from America traveled to leading clinics in Germany, England, and France. They returned with new facts and methods that they used to examine problems and critique ideas. These developments became the basis for the revolution in American medical education and practice launched by the Flexner report published in 1914.

Obstetrics also changed. During the years preceding World War I, it had earned a reputation as one of the most exciting and scientifically advanced specialties. Obstetricians experimented with new drugs and techniques. They recognized that change entails risk, and they examined each innovation more critically. In addition, they turned to science for information and methods to help them solve problems of medical management. Developments in obstetric anesthesia reflected this change in strategy. New methods introduced during this time stimulated physicians to reexamine two important but unresolved issues, the effects of drugs on the child, and the relationship between pain and labor.

THE EFFECTS OF ANESTHESIA ON THE NEWBORN

Many physicians, Simpson included, worried that anesthetic drugs might cross the placenta and harm the newborn. Available information justified their concern. The idea that gases cross the placenta appeared long before the discovery of oxygen and carbon dioxide. In the 16th century, English physiologist John Mayow suggested that “nitro-aerial” particles from the mother nourish the fetus. By 1847, physiologists had corroborative evidence. Clinical experience gave more support. John Snow observed depressed neonatal breathing and motor activity and smelled ether on the breath of neonates delivered from mothers who had been given ether. In an early paper, he surmised that anesthetic gases cross the placenta. Regardless, some advocates of obstetric anesthesia discounted the possibility. For example, Harvard Professor Walter Channing denied that ether crossed the placenta because he could not detect its odor in the cut ends of the umbilical cord. Oddly enough, he did not attempt to smell ether on the child’s exhalations as John Snow had done.

In 1874, Swiss obstetrician Paul Zweifel published an account of work that finally resolved the debate about the placental transfer of drugs ( Fig. 1.5 ). He used a chemical reaction to demonstrate the presence of chloroform in the umbilical blood of neonates. In a separate paper, Zweifel used a light-absorption technique to demonstrate a difference in oxygen content between umbilical arterial and venous blood, thereby establishing the placental transfer of oxygen. Although clinicians recognized the importance of these data, they accepted the implications slowly. Some clinicians pointed to several decades of clinical use “without problems.” For example, Otto Spiegelberg, Professor of Obstetrics at the University of Breslau, wrote in 1887, “as far as the fetus is concerned no unimpeachable clinical observation has yet been published in which a fetus was injured by chloroform administered to its mother.” Experience lulled them into complacency, which may explain their failure to appreciate the threat posed by twilight sleep.

Dangers from twilight sleep probably developed insidiously. The originators of the method, von Steinbüchel and Gauss, recommended conservative doses of drugs. They suggested that 0.3 mg of scopolamine be given every 2 to 3 hours to induce amnesia and that no more than 10 mg of morphine be administered subcutaneously for the whole labor. Gauss, who was especially meticulous, even advised physicians to administer a “memory test” to women in labor to evaluate the need for additional scopolamine. However, as other physicians used the technique, they changed it. Some gave larger doses of opioid—as much as 40 or 50 mg of morphine during labor. Others gave additional drugs (e.g., as much as 600 mg of pentobarbital during labor and inhalation agents for delivery). Despite administering these large doses to their patients, some physicians said they had seen no adverse effects on the infants. They probably spoke the truth, but this probability says more about their powers of observation than the safety of the method.

Two situations eventually made physicians confront problems associated with placental transmission of anesthetic drugs. The first was the changing use of morphine. In the latter part of the 19th century (before the enactment of laws governing the use of addictive drugs), morphine was a popular ingredient of patent medicines and a drug frequently prescribed by physicians. As addiction became more common, obstetricians saw many pregnant women who were taking large amounts of morphine daily. When they tried to decrease their patients’ opioid use, several obstetricians noted unexpected problems (e.g., violent fetal movements, sudden fetal death), which they correctly identified as signs of withdrawal. Second, physiologists and anatomists began extensive studies of placental structure and function. By the turn of the century, they had identified many of the physical and chemical factors that affect rates of drug transfer. Thus, even before twilight sleep became popular, physicians had clinical and laboratory evidence to justify caution. As early as 1877, Gillette described 15 instances of neonatal depression that he attributed to morphine given during labor. Similarly, in a review article published in 1914, Knipe identified stillbirths and neonatal oligopnea and asphyxia as complications of twilight sleep and gave the incidence of each problem as reported by other writers.

When the studies of obstetric anesthesia published between 1880 and 1950 are considered, four characteristics stand out. First, few of them described effects of anesthesia on the newborn. Second, those who did report newborn apnea, oligopnea, or asphyxia seldom defined these words. Third, few used controls or compared one mode of treatment with another. Finally, few writers used their data to evaluate the safety of the practice that they described. In other words, by today’s standards, even the best of these papers lacked substance. They did, however, demonstrate a growing concern among physicians about the effects of anesthetic drugs on neonates. Perhaps even more important, their work prepared clinicians for the work of Virginia Apgar ( Fig. 1.6 ).