Obstetric anesthesiology

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Obstetric anesthesia or obstetric anesthesiology, also known as ob-gyn anesthesia or ob-gyn anesthesiology, is a sub-specialty of anesthesiology that provides peripartum (time directly preceding, during or following childbirth) [1] pain relief (analgesia) for labor and anesthesia (suppress consciousness) for cesarean deliveries ('C-sections'). [2]

Contents

Other subspecialty options for anesthesiology include cardiac anesthesiology, pediatric anesthesiology, pain medicine, critical care, neuroanesthesia, regional anesthesia, transplant anesthesia and trauma anesthesia.[ citation needed ]

Scope

Obstetric anesthesiologists typically serve as consultants to ob-gyn physicians and provide pain management for both complicated and uncomplicated pregnancies. [3] An obstetric anesthesiologist's practice may consist largely of managing pain during vaginal deliveries and administering anesthesia for cesarean sections; however, the scope is expanding to involve anesthesia for both maternal as well as fetal procedures. [4]

Maternal-specific procedures include cerclage, external cephalic version (ECV), postpartum bilateral tubal ligation (BTL), and dilation and evacuation (D and E). [4] Fetus-specific procedures include fetoscopic laser photocoagulation and ex-utero intrapartum treatment (EXIT). [4] However, the majority of care given by anesthesiologists on most labor and delivery units is management of labor analgesia and anesthesia for cesarean section. [4]

History

The administration of general anesthesia in operative procedures was publicly demonstrated by William Thomas Green Morton (1819–1868) in Boston, October 1846 as the first successful practice of its kind. [5] This practice revealed the pain-annulling properties of ether inhalation during surgery. Pioneers of obstetric anesthesia extended these findings to cases of parturition or childbirth, notably including James Young Simpson of Scotland (1811–1870), John Snow of London (1813–1858) and Walter Channing of the United States (1786–1876).[ citation needed ]

Prior to the anesthetizing of Queen Victoria in 1853, the use of diethyl ether and chloroform as obstetric anesthetics faced social, religious, and medical opposition. [6] With the shift in social attitudes, women became less reserved towards this novel practice and began coercing physicians to administer powerful anesthetics during labor. Medical objections were similarly disintegrated with casebook publications that reflected the safety of obstetric anesthesia for both mother and child. Thus the advent of obstetric anesthesia facilitated the use of instruments during delivery as obstetricians were afforded greater scope in terms of these materials.[ citation needed ]

Following Morton's use of ether as an anesthetic, James Simpson conducted his own obstetric anesthetic trial on January 19, 1847 using an open-drop approach to administer ether. [7] [8] [9] However, due to its post-analgesic effect of nausea and vomiting, he later switched to using chloroform instead. [8] Simpson's later personal discovery of chloroform's anesthetic properties inspired subsequent trials with chloroform that he went on to make public in November 1847. The Medico Surgical Society publication of Simpson's findings was not well received and required significant defense thereafter. Three months later, on April 7, 1847, ether was used for the first time in American obstetrics. [7] [8] Following that initial administration documented in the Boston Medical and Surgical Journal by N.C Keep, Walter Channing described several obstetric cases in which he successfully employed sulfuric ether in the United States. [7]

John Snow was responsible for anesthetizing the Queen and is also attributed for influencing public and medical opinions on obstetric anesthesia through his various recorded experiences Though the birth of the Queen's 8th child Prince Leopold on April 7, 1853, was not generally publicized, the London social elite were aware of the use of chloroform in this delivery and found it appealing. [7] [8] [10] Until this time, there had been considerable public and religious opposition to obstetric anesthesia. [10] A woman, Eufame MacAlayne, was buried alive in Scotland in 1591 just for seeking pain relief for the birth of her two sons. [10] This societal aspect of childbirth was recognized by Dr. Churchill of Dublin and later published on the statistics of obstetric anesthesia. [11] Churchill suggested wealthier individuals were recorded to have easier births from the use of such drugs. In the practice of obstetric anesthesia, John Snow greatly differed from Simpson in that Snow emphasized proper quantity measurements and the delay of administration until the second stage of labor commenced. [12] Snow additionally disagreed with Simpson's argument that the laboring patient should be anesthetized to the level of unconsciousness. These differences among others are why the title "Father of Obstetric Anesthesia" has become so controversial. [13]

Religious opposition

Labor analgesia was debated on the grounds of religion and morality, which John Simpson used as his own weapon against opposition. Biblical literalism led many to interpret labor pains as punishment for sin and deemed obstetric anesthesia impious with respect to the primeval curse. [14] Simpson advocated that “whosoever shall keep the whole law and yet offend in one point, is guilty of all”. In this sentiment he is referring to many of the medical practitioners who mitigate minor pains but avoid obstetric anesthetics for fear of opposition or religious persecution. [15] Critic Charles Meigs exemplified this belief of the physiological value in parturition pain, which the greater public supported throughout the mid 19th century.

The natural benefits of such labor pains which initially inhibited the practice of obstetrical analgesia, originated from another religious consideration of perfection. Religious opponents argued that individuals of God’s creation and His standard of perfection should not be in need of such obstetrical interference. Natural processes employed by the Almighty Himself should be left untouched. In support of this claim, M. Roussel advocated that the refinement of society through technical operations (i.e. anesthesia) causes more harm then good to the natural process of childbirth. [16]

Medical objections

Medical historian Richard Shyrock suggested that humanitarian sentiments motivated 19th century physicians, while science shaped their practice. [17] Victorian practitioners believed that if suffering was preventable it was their duty to abolish it in any way possible. Though physicians responsible for administering anesthesia were known to evade interfering in delivery if the mother was an uncivilized member of society. These individuals were left to their own resources, perhaps benefiting from midwife assistance. [18] The pathological process of childbirth was seen to be of necessity for successful delivery and dulling the pain of contractions would hinder this process, until Simpson was able to overturn this theory in 1854. The inhalation of anesthetic agents do not affect the act of labor or the mechanism by which uterine contractions occur, but rather renders the woman insensible to the high degree of pain. [19] With this finding, along with the statistical records of safely executed anesthetic administrations, the medical opposition to obstetric analgesia for pain annulment was suppressed.

The conflicting clinical interpretation of obstetric labor as natural pain, as opposed to discomfort induced by an abnormal or diseased condition, led obstetric practitioners and midwives alike to endorse laissez-faire treatment. Natural, animalistic functions of child rearing were determined thereafter not to require the assistance of obstetricians or subsequent labor analgesia. Following an era of natural philosophy, physicians evoked the ability of wild animals and ‘savaged individuals’ to deliver offspring in regions where the practice of child rearing had never been reduced to an art form. The likening of any obstetrical practice to mere pretend science, including the delivery of anesthetic agents, further prolonged the advancement of this field considerably throughout the 19th century. [20]

Social implications

The social distinction of labor analgesia practice strengthened the divide between savaged and civilized society, while highlighting gender roles in medical practice. The results of unassisted labor in uncivilized communities, specifically the vitality of both mom and fetus, were not documented well. The news of this ‘anti-obstetric’ practice failed to spread to the civilized community, allowing the means of obstetric interference through general and anesthetic intervention to persist. [21] Documentation and statistical evidence was favored throughout the development of obstetric anesthesia to determine the viability of physician strategies. The obstetric diary of midwife Martha Ballard (1735–1812) is historically valued for she documented the details of all midwife calls, as well as physician assistance, instrument usage, and symptoms. Being one of the first women to provide a history of obstetrical practice, Martha Ballard’s notes regarding the marginalization of women in medical practice and the arrogance of male physicians were taken into careful consideration.[ citation needed ]

Morphine

The isolation of morphine in the early 1800s was yet another milestone in obstetric anesthesia. [7] [8] However, the drug would not be widely used until the invention of the hypodermic needle in the 1850s. [7] [8] The first to use a hypodermic syringe in the United States was Fordyce Barker, who actually received the syringe from H.J Simpson as a gift during a visit to Edinburgh. [8] Eventually, the use of morphine for pain control during labor lost favor due to its effects of respiratory depression in the newborn and was replaced largely by meperidine, a synthetic narcotic, first made in Germany in 1939, that had less of an effect on respiratory depression. [7] [8] Meperidine is still popular in obstetrics today. [8]

Local anesthetics

Probably the most important discovery in obstetric anesthesia was the introduction of regional anesthesia, [8] in which local anesthetics are used to block pain from a large area (or nerve distribution). Cocaine, the first local anesthetic [9] was used topically in ophthalmology in 1884 by Carl Koller. [8] [9] William Halstead completed the first nerve block; [8] August Bier, the first clinical spinal anesthesia; [8] Sicard and Cathlein, the caudal approach to epidural anesthesia in 1901; [8] and Fidel Pages, the lumbar epidural approach in 1921. [7] [8] In 1921, the first vaginal delivery under spinal analgesia was reported by Kreiss in Germany. [8] George Pitkin is credited with popularizing obstetric spinal anesthesia in the United States. [8] Charles B. Odom introduced lumbar epidural analgesia to obstetrics in 1935. [7] [8]

Investigations

The anesthesiologist relies on several patient monitors intraoperatively to safely care for the patient. These include, but are not limited to, pulse oximetry, capnography, electrocardiogram, non-invasive blood pressure cuff monitoring and temperature. [22] In some cases, arterial blood gas monitoring may be used. [22]

Treatments

Anesthesia for labor and vaginal delivery includes various modalities including pharmacological and non-pharmacological techniques. [23]

Non-pharmacological

Non-pharmacological techniques include Lamaze breathing, acupuncture, acupressure, LeBoyer technique, transcutaneous nerve stimulation, massage, hydrotherapy, vertical positioning, presence of a support person, intradermal water injections, and biofeedback amongst many more. [24]

Water immersion in the first stage of labor may reduce women's use of epidural. [25] A meta analysis showed there may be benefits to the presence of a support individual (doula, family member) including lower use of pharmacologic analgesia, decreased length of labor, and lower incidence of cesarian section. [24] [26] Hypnosis warrants further investigation. [23]

Medications

Obstetric anesthesiologists employ the following pharmacological agents and techniques:

Anesthesia for cesarean sections (C-sections) most commonly uses neuraxial (regional) anesthesia due to its better safety profile for both mother and baby. [24] [27] However, for emergencies or cases where neuraxial anasthesia cannot be used, general anesthesia is used instead. [24] Drugs used to induce general anesthesia include thiopental, propofol, etomidate, and ketamine. [24] Unconsciousness is maintained using inhalation agents, and muscle relaxing agents are used as needed. [24] Opioids are less commonly used prior to delivery due to fear of adverse effects on the neonate. However under certain circumstances it is important to attenuate the hypertensive responses to induction and incision and ultra-short acting opioids (remifentanil and alfentanil) appear to be efficacious and safe. [28]

Training

United States

In the United States, obstetric anesthesiology is a sub-specialty of anesthesiology (i.e., an anesthesiologist trains for an additional year as a fellow to qualify as an obstetric anesthesiologist). [ citation needed ]

After earning a four-year undergraduate bachelor's degree, students enroll in a four-year graduate education leading to a degree in medicine (the Doctor of Medicine degree (M.D.)) or in osteopathic medicine (the Doctor of Osteopathic Medicine degree (D.O.)). [29] After receiving a medical degree, students must complete a four-year residency training at an approved anesthesiology program [30] and pass certification exams to become a board-certified, general anesthesiologist. [29] Obstetric anesthesiologists then complete an additional year of study (fellowship) to gain specialized experience. [29] Currently, obstetric anesthesia is not associated with an additional certification period over being board-certified in anesthesiology. [30]

Ethical and medicolegal issues

Anesthesiologists use safe blood transfusions in certain situations as a therapy for patients with low oxygen carrying capacity or to correct coagulation problems. [31] Certain religions (e.g., Jehovah's Witnesses) prohibit the use of blood transfusions based on their religious beliefs. [32] Medical ethics stand on the four pillars of autonomy, beneficence, non-maleficence and justice. [33] Based on the basis of patient autonomy, a person who is deemed to have capacity and refuses a blood transfusion for religious reason has the right to do so. [34] [35]

Related Research Articles

<span class="mw-page-title-main">Caesarean section</span> Surgical procedure in which a baby is delivered through an incision in the mothers abdomen

Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen. It is often performed because vaginal delivery would put the baby or mother at risk. Reasons for the operation include obstructed labor, twin pregnancy, high blood pressure in the mother, breech birth, shoulder presentation, and problems with the placenta or umbilical cord. A caesarean delivery may be performed based upon the shape of the mother's pelvis or history of a previous C-section. A trial of vaginal birth after C-section may be possible. The World Health Organization recommends that caesarean section be performed only when medically necessary.

<span class="mw-page-title-main">Anesthesia</span> State of medically-controlled temporary loss of sensation or awareness

Anesthesia or anaesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia, paralysis, amnesia, and unconsciousness. An individual under the effects of anesthetic drugs is referred to as being anesthetized.

<span class="mw-page-title-main">General anaesthesia</span> Medically induced loss of consciousness

General anaesthesia (UK) or general anesthesia (US) is a method of medically inducing loss of consciousness that renders a patient unarousable even with painful stimuli. This effect is achieved by administering either intravenous or inhalational general anaesthetic medications, which often act in combination with an analgesic and neuromuscular blocking agent. Spontaneous ventilation is often inadequate during the procedure and intervention is often necessary to protect the airway. General anaesthesia is generally performed in an operating theater to allow surgical procedures that would otherwise be intolerably painful for a patient, or in an intensive care unit or emergency department to facilitate endotracheal intubation and mechanical ventilation in critically ill patients.

<span class="mw-page-title-main">Anesthesiology</span> Medical specialty concerned with anesthesia and perioperative care

Anesthesiology, anaesthesiology, or anaesthesia is the medical specialty concerned with the total perioperative care of patients before, during and after surgery. It encompasses anesthesia, intensive care medicine, critical emergency medicine, and pain medicine. A physician specialized in anesthesiology is called an anesthesiologist, anaesthesiologist, or anaesthetist, depending on the country. In some countries the terms are synonymous, while in other countries they refer to different positions and anesthetist is only used for non-physicians, such as nurse anesthetists.

<span class="mw-page-title-main">Spinal anaesthesia</span> Form of neuraxial regional anaesthesia

Spinal anaesthesia, also called spinal block, subarachnoid block, intradural block and intrathecal block, is a form of neuraxial regional anaesthesia involving the injection of a local anaesthetic or opioid into the subarachnoid space, generally through a fine needle, usually 9 cm (3.5 in) long. It is a safe and effective form of anesthesia usually performed by anesthesiologists that can be used as an alternative to general anesthesia commonly in surgeries involving the lower extremities and surgeries below the umbilicus. The local anesthetic with or without an opioid injected into the cerebrospinal fluid provides locoregional anaesthesia: true analgesia, motor, sensory and autonomic (sympathetic) blockade. Administering analgesics in the cerebrospinal fluid without a local anaesthetic produces locoregional analgesia: markedly reduced pain sensation, some autonomic blockade, but no sensory or motor block. Locoregional analgesia, due to mainly the absence of motor and sympathetic block may be preferred over locoregional anaesthesia in some postoperative care settings. The tip of the spinal needle has a point or small bevel. Recently, pencil point needles have been made available.

Awareness under anesthesia, also referred to as intraoperative awareness or accidental awareness during general anesthesia (AAGA), is a rare complication of general anesthesia where patients regain varying levels of consciousness during their surgical procedures. While anesthesia awareness is possible without resulting in any long-term memory of the experience, it is also possible for victims to have awareness with explicit recall, where they can remember the events related to their surgery.

<span class="mw-page-title-main">Epidural administration</span> Medication injected into the epidural space of the spine

Epidural administration is a method of medication administration in which a medicine is injected into the epidural space around the spinal cord. The epidural route is used by physicians and nurse anesthetists to administer local anesthetic agents, analgesics, diagnostic medicines such as radiocontrast agents, and other medicines such as glucocorticoids. Epidural administration involves the placement of a catheter into the epidural space, which may remain in place for the duration of the treatment. The technique of intentional epidural administration of medication was first described in 1921 by Spanish military surgeon Fidel Pagés.

<span class="mw-page-title-main">James Young Simpson</span> Scottish obstetrician (1811–1870)

Sir James Young Simpson, 1st Baronet,, was a Scottish obstetrician and a significant figure in the history of medicine. He was the first physician to demonstrate the anaesthetic properties of chloroform on humans and helped to popularise its use in medicine.

<span class="mw-page-title-main">Bupivacaine</span> Local anaesthetic drug

Bupivacaine, marketed under the brand name Marcaine among others, is a medication used to decrease feeling in a specific area. In nerve blocks, it is injected around a nerve that supplies the area, or into the spinal canal's epidural space. It is available mixed with a small amount of epinephrine to increase the duration of its action. It typically begins working within 15 minutes and lasts for 2 to 8 hours.

<span class="mw-page-title-main">Chloroprocaine</span> Local anaesthetic drug

Chloroprocaine is a local anesthetic given by injection during surgical procedures and labor and delivery. Chloroprocaine vasodilates; this is in contrast to cocaine which vasoconstricts. Chloroprocaine is an ester anesthetic.

<span class="mw-page-title-main">Methoxyflurane</span> Chemical compound

Methoxyflurane, sold under the brand name Penthrox among others, is an inhaled medication primarily used to reduce pain following trauma. It may also be used for short episodes of pain as a result of medical procedures. Onset of pain relief is rapid and of a short duration. Use is only recommended with direct medical supervision.

<span class="mw-page-title-main">Patient-controlled analgesia</span> Administration of pain relief medication by a patient

Patient-controlled analgesia (PCA) is any method of allowing a person in pain to administer their own pain relief. The infusion is programmable by the prescriber. If it is programmed and functioning as intended, the machine is unlikely to deliver an overdose of medication. Providers must always observe the first administration of any PCA medication which has not already been administered by the provider to respond to allergic reactions.

<span class="mw-page-title-main">History of general anesthesia</span>

Throughout recorded history, attempts at producing a state of general anesthesia can be traced back to the writings of ancient Sumerians, Babylonians, Assyrians, Egyptians, Indians, and Chinese. Despite significant advances in anatomy and surgical technique during the Renaissance, surgery remained a last-resort treatment largely due to the pain associated with it. However, scientific discoveries in the late 18th and early 19th centuries paved the way for the development of modern anesthetic techniques.

The following outline is provided as an overview of and topical guide to anesthesia:

<span class="mw-page-title-main">History of neuraxial anesthesia</span>

The history of neuraxial anaesthesia dates back to the late 1800s and is closely intertwined with the development of anaesthesia in general. Neuraxial anaesthesia, in particular, is a form of regional analgesia placed in or around the Central Nervous System, used for pain management and anaesthesia for certain surgeries and procedures.

<span class="mw-page-title-main">No Pain Labor & Delivery – Global Health Initiative</span> Non-for-profit organization

No Pain Labor & Delivery – Global Health Initiative is a non-for-profit organization. Founded in 2006, the program focuses on correcting the unnecessarily high caesarean delivery rate and the poor utilization of neuraxial labor analgesia in China.

<span class="mw-page-title-main">Pain management during childbirth</span>

Pain management during childbirth is the treatment or prevention of pain that a woman may experience during labor and delivery. The amount of pain a woman feels during labor depends partly on the size and position of her baby, the size of her pelvis, her emotions, the strength of the contractions, and her outlook. Tension increases pain during labor. Virtually all women worry about how they will cope with the pain of labor and delivery. Childbirth is different for each woman and predicting the amount of pain experienced during birth and delivery can not be certain.

Gertie Florentine Marx (1912-2004) was an obstetric anesthesiologist, "internationally known as 'the mother of obstetric anaesthesia'". Marx pioneered the use of epidural analgesia during childbirth, and was the founding editor of the quarterly Obstetric Anesthesia Digest.

<span class="mw-page-title-main">Caudal anaesthesia</span> Form of neuraxial regional anaesthesia

Caudal anaesthesia is a form of neuraxial regional anaesthesia conducted by accessing the epidural space via the sacral hiatus. It is typically used in paediatrics to provide peri- and post-operative analgesia for surgeries below the umbilicus. In adults it is used for chronic low back pain management.

References

  1. ↑ "Medical Definition of PERIPARTUM". www.merriam-webster.com.
  2. ↑ Stoelting RK, Miller RD (2007). Basics of anesthesia. Philadelphia: Churchill Livingstone. p. 515. ISBN   978-81-312-2898-2.{{cite book}}: CS1 maint: location missing publisher (link)
  3. ↑ Ramanathan, Sivam (1988). Obstetric Anesthesia. Philadelphia, PA: Lee & Febiger. pp. vii. ISBN   978-0-8121-1118-7.
  4. 1 2 3 4 Aaronson, Jaime; Goodman, Stephanie (2014). "Obstetric anesthesia: Not just for cesareans and labor". Seminars in Perinatology. 38 (6, October 2014): 378–385. doi:10.1053/j.semperi.2014.07.005. ISSN   0146-0005. PMID   25146107.
  5. ↑ Gordon, Henry L. Sir James Young Simpson and Chloroform (1811-1870). Ed. Ernest Hart. Pasternoster Square, London: Urwin, 1897. Masters of Medicine. Web. 2017.
  6. ↑ Whitfield A (2014). "A short history of Obstetric Anaesthesia". Res Medica. 3 (1). doi: 10.2218/resmedica.v3i1.972 . ISSN   2051-7580.
  7. 1 2 3 4 5 6 7 8 9 Marx, Gertie F.; Bassell, Gerard M. (1980). Obstetric Analgesia and Anaesthesia. The Netherlands: Elsevier/North-Holland Biomedical Press. pp. 1, 5–8, 10, 12–13. ISBN   978-0-444-80137-1.
  8. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Ramanathan, Sivam (1988). Obstetric anesthesia. Philadelphia, PA: Lea & Febiger. pp. 3–4. ISBN   978-0-8121-1118-7.
  9. 1 2 3 Miller, Ronald D.; Pardo, Manuel C. Jr. (2012). Basics of anesthesia (6th ed.). Elsevier/Saunders. pp. 5–6. ISBN   978-81-312-2898-2. OCLC   742301032.
  10. 1 2 3 Tolmie, John D.; Birch, Alexander (1986). Anesthesia for the uninterested (2nd ed.). Rockville, Md: Aspen Publishers. p. 163. ISBN   978-0871892966.
  11. ↑ Swayne, J. G. (1875). "Obstetrical Statistics". The British Medical Journal. 2 (777): 635–638. doi:10.1136/bmj.2.777.635. JSTOR   25242218. PMC   2297735 . PMID   20748025.
  12. ↑ Snow, John (1853). "On the Administration of Chloroform during Parturition". Association Medical Journal. 1 (23): 500–502. doi:10.1136/bmj.s3-1.23.500. JSTOR   25494691. PMC   2449612 . PMID   20740854.
  13. ↑ Gordon, Henry L. Sir James Young Simpson and Chloroform (1811-1870). Ed. Ernest Hart.
  14. ↑ Simpson, J. Y. (1853). "The Propriety and Morality of Using Anæsthetics in Instrumental and Natural Parturition". Association Medical Journal. 1 (27): 582–589. JSTOR   25494769.
  15. ↑ Simpson, J.Y. (January 1959). "Answer to the Religious Objections Advanced against the Employment of Anaesthetic Agents in Midwifery and Surgery". British Journal of Anaesthesia. 31 (1): 35–43. doi: 10.1093/bja/31.1.35 . PMC   5199347 .
  16. ↑ Beatty, Thomas Edward (1869). "Address In Midwifery, Delivered At The Thirty-Seventh Annual Meeting Of The British Medical Association, Held In Leeds, July 27th, 28th, 29th, And 30th, 1869". The British Medical Journal. 2 (449): 137–143. doi:10.1136/bmj.2.449.137. JSTOR   25217099. S2CID   71208772.
  17. ↑ Caton, Donald (1 January 2000). "John Snow's Practice of Obstetric Anesthesia". Anesthesiology. 92 (1): 247–252. doi: 10.1097/00000542-200001000-00037 . PMID   10638922. S2CID   8117674.
  18. ↑ "Obstetrical Society Of London". The British Medical Journal. 1 (105): 15–17. 1859. JSTOR   25192989.
  19. ↑ Simpson, J. Y. (1848). "Letter in Reply to Dr. Collins, on the Duration of Labour as a Cause of Danger and Mortality to the Mother and Infant". Provincial Medical and Surgical Journal. 12 (22): 601–606. JSTOR   25500540.
  20. ↑ Camann W, Lim MN, Ong S, Yeh PS (July 2002). "Has medicalisation of childbirth gone too far?". BMJ. 325 (7355): 103–104. doi:10.1136/bmj.325.7355.103. JSTOR   25451822. PMC   1123599 . PMID   12114249.
  21. ↑ Leavitt JW (1983). ""Science" enters the birthing room: obstetrics in America since the eighteenth century". J Am Hist. 70 (2): 281–304. doi:10.2307/1900205. JSTOR   1900205. PMID   11614690.
  22. 1 2 Miller, Ronald D.; Pardo, Manuel C. (2011-01-01). Basics of anesthesia . Elsevier/Saunders. pp.  22–23, 337–338. ISBN   978-8131228982. OCLC   742301032.
  23. 1 2 3 4 H., Davies, N. J.; N., Cashman, Jeremy; B.)., Rushman, G. B. Geoffrey (2005-01-01). Lee's synopsis of anaesthesia. Elsevier/Butterworth Heinemann. pp. 660–662. OCLC   61303532.{{cite book}}: CS1 maint: multiple names: authors list (link)
  24. 1 2 3 4 5 6 7 8 9 10 Miller, Ronald D.; Pardo, Manuel C. Jr. (2011-01-01). Basics of anesthesia . Elsevier/Saunders. pp.  521–529. ISBN   978-81-312-2898-2. OCLC   742301032.
  25. ↑ Cluett, ER; Burns, E; Cuthbert, A (16 May 2018). "Immersion in water during labour and birth". The Cochrane Database of Systematic Reviews. 5 (6): CD000111. doi:10.1002/14651858.CD000111.pub4. PMC   6494420 . PMID   29768662.
  26. ↑ Hodnett, Ellen D.; Gates, Simon; Hofmeyr, G. Justus; Sakala, Carol (2012-10-17). Hodnett, Ellen D (ed.). "Continuous support for women during childbirth". The Cochrane Database of Systematic Reviews. 10: CD003766. doi:10.1002/14651858.CD003766.pub4. ISSN   1469-493X. PMC   4175537 . PMID   23076901.
  27. ↑ White, Leigh D.; Thang, Christopher; Hodsdon, Anthony; Melhuish, Thomas M.; Barron, Fiona A.; Godsall, M. Guy; Vlok, Ruan (January 2020). "Comparison of Supraglottic Airway Devices With Endotracheal Intubation in Low-Risk Patients for Cesarean Delivery". Anesthesia & Analgesia: 1. doi: 10.1213/ANE.0000000000004618 . PMID   31923002. S2CID   210149430.
  28. ↑ White, L.D.; Hodsdon, A.; An, G.H.; Thang, C.; Melhuish, T.M.; Vlok, R. (May 2019). "Induction opioids for caesarean section under general anaesthesia: a systematic review and meta-analysis of randomised controlled trials". International Journal of Obstetric Anesthesia. 40: 4–13. doi: 10.1016/j.ijoa.2019.04.007 . hdl: 10072/416502 . PMID   31230994.
  29. 1 2 3 "American Society of Anesthesiologists - How to Prepare for a Career in Anesthesiology". www.asahq.org. Retrieved 2016-12-08.
  30. 1 2 Miller, Ronald D.; Pardo, Manuel C. Jr. (2011-01-01). Basics of anesthesia . Elsevier/Saunders. pp.  12–13. ISBN   9788131228982. OCLC   742301032.
  31. ↑ Miller, Ronald; Pardo, Manuel (2012). Basics of anesthesia . Elsevier/Saunders. pp.  372–373. ISBN   9781437716146. OCLC   742301032.
  32. ↑ "Why Don't Jehovah's Witnesses Accept Blood Transfusions?" . Retrieved 2016-12-16.
  33. ↑ "Essential learning: Law and ethics" . Retrieved 2016-12-16.
  34. ↑ Dixon, J. Lowell; Smalley, MG (27 November 1981). "Jehovah's Witnesses: The Surgical/Ethical Challenge". JAMA. 246 (21): 2471–2472. doi:10.1001/jama.1981.03320210037021. PMID   7299971.
  35. ↑ "How Can Blood Save Your Life?" . Retrieved 2016-12-16.
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