Ethylene Oxygen: The History of a Midwestern Obstetric Anesthetic Technique
Abstract Number: S-46
Abstract Type: Other
Suitable options for pain control during childbirth were limited until the introduction of ether as the first obstetric anesthetic in 1847. Subsequently, chloroform, narcotic and scopolamine techniques, rectal analgesic mixtures and nitrous oxide emerged as potential anesthetics and analgesics, however each had significant complications and undesirable side effects for both mother and baby. In the 1920s, ethylene oxygen emerged as an option for obstetric anesthesia. Ethylene had been introduced into general anesthetic practice in 1923 by Drs. Luckhardt and Carter in Chicago (1) and quickly became an attractive alternative to the other available anesthetic agents at the time. It was notable for smooth inductions, with a rapid and generally pleasant emergence. Side effects such as cyanosis, post-operative nausea and vomiting, increased secretions and sweating were minimal as compared to its counterparts. Ethylene was therefore quickly adopted for use in obstetric anesthesia and analgesia. Of particular importance to the practice of obstetrics, ethylene oxygen anesthesia provided cardiopulmonary stability and resulted in sufficient relaxation for both operative and routine deliveries (2). Intermittent brief inhalation of ethylene oxygen provided analgesia, while still allowing parturients to actively participate in their labor. Ethylene had minimal effect on fetal heart tones and uterine contractions as compared to chloroform and ether and did not appreciably alter the duration of the second stage of labor or result in increased blood loss (3). Babies delivered to mothers using ethylene were noted to have less cyanosis and asphyxia than with other anesthetics, even when exposed to ethylene oxygen for fairly long durations (4). Compared with nitrous oxide, anesthetic providers were able to use significantly less agent to achieve desired operative conditions and rarely required the addition of ether (5). Ethylene did, however, have disadvantages, most notably its potential for explosiveness. This required considerable vigilance and precaution on the part of the anesthetic provider in addition to specialized equipment in order to deliver it safely. Thus, its use was limited to appropriately equipped hospital settings, making it essentially unavailable to women laboring at home. The danger of significant explosions was ultimately responsible for ethylene’s fall from routine use. Additionally, advancements in the use of regional and local anesthetic techniques for obstetric anesthesia led to a decline in the use of ethylene oxygen for this purpose.
1. Luckhardt AB and Carter JB. (1923) Anes Analg 2(6): 221-232.
2. Rucker MP. (1926) Anes Analg 5: 235-246.
3. Blevins WJ. (1929) California and Western Medicine XXX(2): 106-108.
4. Plass ED and Swanson CN. (1926) JAMA 87(21): 1716-1719.
5. Heaney NS. (1924) JAMA 83(26): 2061-2062.