Brief History of Anesthesia

Surgical anesthesia with inhaled ether was first performed in 1842 by Dr. Crawford W. Long in rural Georgia. In 1846, Dr. William T. Morton, a dentist, successfully administered ether for a mandibular tumor removal in front of an audience at Massachusetts General Hospital. A newspaper reporter was present in the audience, and thus, the discovery of surgical anesthesia soon spread worldwide. Beginning in 1847, ether was used in England for labor pain, and chloroform gained public acceptance when it was successfully administered to Queen Victoria in 1853 during the birth of Prince Leopold.

Another American dentist, Dr. Horace Wells, recognized the anesthetic potential of nitrous oxide after a painless tooth extraction on himself. However, an attempt to use nitrous oxide during a demonstration procedure at Massachusetts General Hospital failed, and it wasn’t until a Chicago surgeon, Dr. Edmond W. Andrews, used nitrous oxide with oxygen in 1868 that the possibility of using this gas as an anesthetic began to be accepted.

Ether, chloroform, and nitrous oxide were the primary anesthetics until the 1920s, when drugs with greater flexibility and fewer side effects began to be preferred. Other inhaled anesthetics were developed over the next 30 years, but these had the unfortunate drawbacks of either being explosive when in contact with oxygen, or toxic. Ironically, the science used to develop the atomic bomb led to the discovery of fluorinated inhaled anesthetics in the 1950s. The first, fluroxene, had a low blood solubility and minimal cardiovascular depression; however, it often caused nausea and vomiting, was possibly hepatotoxic and carcinogenic, and was flammable at high concentrations; thus, it was withdrawn from the market in 1975. Research then focused on methyl ethyl ether derivatives because these don’t cause cardiac dysrhythmias. Currently, nitrous oxide, isoflurane, desflurane, and sevoflurane are the most commonly used inhaled anesthetics.

Cocaine was the first injectable anesthetic used, beginning in the 1880s. In 1905, procaine replaced cocaine for regional anesthesia. Currently, lidocaine, bupivacaine, ropivacaine, and tetracaine are the most frequently used local anesthetics.

In 1934, thiopental was introduced for rapid intravenous induction of anesthesia. In 1989, propofol was developed, providing a similar onset time to thiopental, but with a quicker and more complete reversal of drug effects.


Types of Anesthesia

There are different categories of anesthesia.

Infiltration: Local anesthetic is injected directly into the tissue at the site of operation.

Regional: Local anesthetic is injected around a major nerve bundle, causing temporary numbness in a limited area of the body. Regional anesthesia includes peripheral nerve blocks, which involve a small area such as a hand or foot, and spinals and epidurals, which can numb only half of the body.

General: General anesthesia is accomplished with inhaled and/or intravenous anesthetic, making the patient completely unaware. General anesthesia acts directly on the brain and spinal cord, whereas infiltration and regional anesthesia act on the nerves. Muscle relaxing drugs (for example, succinylcholine) may also be used for paralysis to eliminate body movement during surgery. Because all muscles are affected, including the diaphragm, endotracheal intubation and ventilatory assistance are required. Also, muscle relaxing drugs don't have any analgesic or anesthetic effects, so they should only be used with other drugs that do provide those effects. Paralysis without adequate anesthesia is a cause of intraoperative awareness, which is discussed below.

Sedation: During short or outpatient procedures, sedation with opioids, propofol, or midazolam (Versed) may be used to decrease patient anxiety and limit patient recall of the procedure.


General Statistics

Injuries can result from anesthesia or associated procedures.

Patients are often afraid of anesthetic complications, sometimes more so than operative complications. Since nurses are involved in preparing patients for surgery, it's helpful for them to be aware of the actual statistics of anesthetic complications. Each year in the United States, anesthesia/anesthetics are reported as the underlying cause in approximately 34 deaths and contributing factors in another 281 deaths, with excess mortality risk in the elderly and men (Guohua et al, 2009). Anesthesiologists have been at the forefront in developing new technology that has improved patient safety during surgery 25-fold in the last 20 years.

Injuries can also result from anesthesia or associated procedures, including peripheral nerve damage, eye damage, dental or oral trauma from intubation, fetal/newborn injury, pulmonary aspiration, allergic reaction/anaphylaxis, and intraoperative awareness. (Each of these will be discussed in detail later.) Anesthesiologists identify difficult airway management as the greatest patient safety issue (Stoelting & Miller, 2006). When adverse events do occur, it can be difficult to differentiate between an event due to anesthesiologist error (breach in the standard of care) and an unavoidable event that occurred in spite of optimal care.

\In 1985, the American Society of Anesthesiologists started the Anesthesia Patient Safety Foundation to "assure that no patient shall be harmed by anesthesia." This group provides research grants to promote a better understanding of preventable injuries related to anesthesia, and endorses national and international communication about the causes and solutions for preventable harm. Anesthesiology is the only medical specialty with a foundation specifically dedicated to patient safety (Stoelting & Miller, 2006).



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