Anesthetics Essay Example

as a gas form of anesthetic. Intravenous anesthesia involves injecting it directly into a vein using a needle, while infusion anesthesia is delivered through a catheter. These methods can be divided into four stages: premedication or induction, administration of anesthesia, full drug effect, and complete unconsciousness. Premedication includes giving sedatives or muscle relaxants before major surgery. The second stage induces deep yet pleasant unconsciousness in the patient. In the third stage, consciousness diminishes but reflexes and breathing may still be slightly irregular. Finally, in the fourth stage, the patient reaches complete unconsciousness with fully relaxed muscles and regular breathing patterns.
The use of anesthesia dates back to the 1700s when Joseph Priestley discovered nitrous oxide (also known as laughing gas). Although it was found in 1769, American dentist Horace Wells was the first to utilize it for dentistry purposes in 1844Anesthesia has gained popularity in the United States and England since its inception. In 1829, Michael Faraday discovered that inhaling ether could induce unconsciousness. However, it was not until 1842 that American doctor Crawford W. Long used ether as an anesthetic for tumor removal, leading to widespread acceptance. That same year, American dentist Thomas Green Morton collaborated with chemist Charles Thomas Jackson to use ether for painless tooth extractions. In 1831, Samuel Guthrie, an American physician and chemist, discovered chloroform. Unsatisfied with ether's effects during surgery, Scottish obstetrician Sir James Y. Simpson became the first to adopt chloroform as a useful anesthesia for surgical procedures. Sigmund Freud reported cocaine's anesthetic properties in 1884. Australian physician Karl Koller then applied this discovery to surgical procedures, marking the emergence of "local anesthesia". Cocaine served as the initial local

anesthesia used in surgeries. William Stewart Halsted was the first to inject cocaine into nerves for anesthesia at John Hopkins University in Baltimore. In 1898, Karl Gustav Bier achieved lower extremity paralysis by injecting cocaine into the vertebral canal.Spinal anesthesia, also known as spinal anesthesia, is widely used today. In 1901, J.L. Corning utilized cocaine to create novocaine and procaine for spinal anesthesia. In 1848, ethyl chloride was introduced as an analgesic but surgeons needed a safer option. In response, cyclopropane was introduced in 1929 but its flammability posed a problem. Trichlorethylene was then used in 1934 for pain reduction during childbirth while maintaining consciousness.

For intravenous anesthesia, Ore of Bordeaux achieved it using Chloral in 1874 and Emil Fischer performed Veronal synthesis in 1902 which gained wide acceptance. Muscle relaxants curare and succinylcholine were introduced after 1945 for anesthesia administration. Curare blocks nervous impulses at the neuromuscular junction while succinylcholine counteracts acetylcholine's action. These anesthetics are still used today along with derivatives.

Another method involves inducing hypothermia by cooling the patient with ice, wet sheets, and fans. However, shivering can still occur due to the body's natural responses controlled by the hypothalamus. To manage these responses, doctors administer chlorpromazine or promethazine which have tranquilizing effects. This process reduces tissue oxygen consumption and lowers demand for vital organs during surgery without causing permanent damage.

Anesthesia may cause fluctuations in blood pressure, either increasing or decreasing it. Shock and significant blood loss may lead to these changesNausea and vomiting can occur as side effects of certain anesthetics, while jaundice is a rare reaction that may be experienced with general anesthesia. The objective for doctors is to select an anesthetic

that induces rapid unconsciousness with minimal side effects. Different types of anesthetics are employed in hospitals throughout the region and country. Popular choices among general anesthetics include cyclopropane, ethylene, and halothane; however, caution should be exercised when using cyclopropane and ethylene due to their high explosiveness risk. Halothane is preferred as it does not pose a flammability or explosiveness hazard. Among intravenous anesthesia options, Pentothal sodium is frequently used due to its limited side effects during and after surgery. Block anesthesia, also known as local anesthesia, is the most commonly used type of anesthesia because it blocks specific nerves in targeted areas resulting in pain relief for patients in those particular regions. Two well-known forms of block anesthesia often utilized during childbirth are spinal anesthesia and caudal anesthesia. Procaine hydrochloride is the favored drug for these blocks. Xylocaine is extensively employed as a topical anesthetic especially in procedures involving stitches or simple dentistry. These anesthetics carry significant value within the field of anesthesia. Inhalation anesthesia has seen advancements over time with notable improvements including sevoflurane, desflurane, and xenonSevoflurane, a methylpropyl ether synthesized in 1960, is widely distributed for general use. It is highly insoluble and three times more soluble in blood compared to halothane. Its low solubility allows for faster anesthesia effects and rapid recovery without irritating the airways. Sevoflurane is popular among children but its production is limited due to high cost. Desflurane, synthesized around the same time as sevoflurane, has similar properties but causes irritation in the airways and laryngospasm in over 50% of users. However, its low cost allows for further research to improve it. Xenon, another important inhalant with anesthetic properties,

is currently prohibited for medical use since it was recently discovered. Despite having low potency on its own, xenon has the potential to replace nitrous oxide as a general anesthetic.

In 1984, propofol was introduced as a newer intravenous drug and has contributed to advancements in intravenous anesthesia. Significant progress has been made in administering, distributing,and maintaining propofol.This drug offers rapid recovery and induction with minimal side effects like slight nausea and drowsiness.However,it can be challenging to manually control the infusion rate to achieve desired plasma concentration.Frequent adjustments are necessary for consistent flow maintenance.Anesthesiologists can overcome this obstacle by using the target controlled infusion rate technique with software within the infusion pump. This technique manages the infusion rate based on complex but standard pharmacokinetic equations. Remifentanil, a highly potent synthetic opioid ideal for continuous infusion during anesthesia, undergoes rapid metabolism in the body due to its methyl ester structure. While currently used as a neuroanesthetic, it is expected that remifentanil will also have applications in cardiac and cardiovascular anesthesia in the future.

Significant progress has been made regarding local anesthetics. Bupivacaine and ropivacaine are the most popular options, providing fast induction and postoperative pain relief lasting several hours depending on dosage administered. Bupivacaine consists of R(+)bupivacaine and S(-)bupivacaine enantiomers due to stereoisomerism. It has been discovered that the R(+) form is more likely to cause cardiovascular toxicity in rabbits, sheep, and humans. On the other hand, ropivacaine only exists as the S(-) isomer and clinical studies have shown it to be safer than bupivacaine.

Anesthesia exhibits a unique property known as the cutoff phenomenon where anesthetic potency decreases in alkanes and their derivatives when they become too large

in size. Typically, anesthetic potency increases with chain length until reaching fourteen carbons before becoming ineffective.The potency increases rapidly from ethanol (a two-carbon chain) to decanol (a ten-carbon chain), but remains constant from eleven carbon chains to thirteen carbon chains. However, once the carbon chain reaches fourteen carbons, the potency suddenly disappears. This phenomenon may be attributed to either the binding site being too small for long-chained alcohols or because longer 1-alkanols have low water solubility, limiting their access to the action site. To further investigate this issue, scientists conducted studies on the 1-alkanol series by converting it into DPPC using hydrogen bonding. This process resulted in transitional phases occurring during which specific temperature ranges caused changes in the state of matter. It has been observed that within this transition, DPPC remains unaffected while water macromolecules are primarily affected by anesthetics. Consequently, compounds with carbon chains ranging from C2 to C10 are classified as anesthetics in anesthesia, whereas those with carbon chains of C14 and above are categorized as nonanesthetics. The mechanism of anesthesia involves disruption of hydrogen bonds through high polarizability demonstrated by cyclopropane. Additionally, anesthesia is facilitated by increased hydrophobicity and relaxation of membranes and proteins.The benefits of anesthetics include their effectiveness in relieving pain before, during, and after surgeries, making procedures more manageable. Anesthetics also induce relaxation and tranquility in patients. Scientists have extensively studied anesthetics since the early 1700s, resulting in a wealth of information in this field. Throughout history, humans have sought ways to alleviate pain, leading to exploration of various techniques. However, currently the most advanced method for pain relief is through the use of anesthetics. Advancements in anesthesia

are crucial for our progressing world and economy despite potential side effects. The future may bring new methods of administering and distributing anesthetics, especially within the United States as we enter into the new millennium.Insights into different aspects of anesthesia can be obtained from various sources. These include W. Bradford Swift's article in Cats Magazine (January 1990), Carol Saline's piece in Philadelphia Magazine (November 1988), Chiou's article published in Science on May 4th, 1990, Brown's paper featured in Nature on October 19th, 1989, Wiklund's two-part article published in The New England Journal of Medicine on October 16th, 1997, and Schapera's article in The Journal of Occupational Medicine November issue from 1993. Ludovici's book titled "Cone of Oblivion," which was published in New York in1961 also provides valuable information on the subject matter. Furthermore, located in Yonkers, New York is The United States Pharmacopeia Complete Drug Reference. This reference book was published by the United States Pharmacopeial Convention Inc. and was released in 1992.