Modern Anesthesia

Modern Anesthesia

Anesthesia has existed side by side with medicine from its beginnings. Because medicine is based on two actions: curing diseases and stopping pain. “Although it has not always been called anesthesia, the concept has been around for as long as people have been performing surgery -- no matter how primitive or crude” (Freeman, 6).  From the Incas who used to spit chewed coca into open wounds, to the Asians who used complicated mixtures of opium with many other plants, there is a considerable amount of evidence of ancient civilizations that used certain substances in order to stop pain, but anesthesia became as we know it today in the year 1846 (Freeman, 6).

Before 1846, surgeries were brutally performed. The most powerful countries used opium and alcohol as the most common substances for stopping pain. The problem was that both of these are highly addictive, and that the doses needed in order to repress the pain of a complex operation were more than enough to kill a person. Often people were even hit really hard in the head in order to be operated on them while they were unconscious. But despite all these “precautions”, before 1846, doctors had to deal with screaming patient through the whole procedure in operations (Freeman, 6).

a. - History of Anesthesia

i. – Discovery

In 1846, a dentist Dr. William Morton, extracted successfully a tumor from the jaw of one of his patients, what was amazing about this is that he did not use alcohol or cocaine, but instead he employed ether in order to induce his patient into a deep sleep stage. “Afterward, the patient claimed that he had no memory of the operation or any pain” (Freeman, 6). All doctors that witnessed this procedure were astonished by it, because they were aware that they had just witnessed something that would change medicine, and specially surgery, forever. After this event, advances and discoveries regarding anesthesia appeared exponentially. (Freeman, 6).

But, there was a little problem. Dr. Crawford Long, another well known doctor, assured the world that he was the pioneer of this new technique, by stating that he himself had used ether on a patient 5 years before Morton, and with the same results; he was never credited for his medical breakthrough. In 1846, another famous doctor, Horace Wells, came up with the name anesthesia from the Latin an that is “without” and aesthesis which means “sensation” (Wikipedia.org).

Later on, certain substances like the nitrous oxide and chloroform appeared and were used side by side with ethanol. In early 1900s, chloroform stopped being used because it was discovered that it had damaging effects in the organism. Though, nitrous oxide is still currently used. Modern anesthesiologists use morphine, a derivate from opium. But there are also a lot of anesthetics that are derivates from cocaine and as previously said, nitrous oxide. With this information it could be concluded that the same substances that were used by ancient civilizations have been used to create the substances used today.

ii. -Chemical composition

As any existent substance, anesthetics have their own unique chemical composition. Of course, there cannot be said that anesthesia has a single chemical composition, because there are several different types of anesthetics. Some are more used than others, but all of these anesthetics are still widely used. For example, the most used local anesthetics in the world, due to their benefits, are procaine, bupivacaine, lidocaine, and proparicaine. And each one of these has its own chemical composition. Local anesthetics, though, do share a common structure. They are all formed by a lipophilic part and a hydrophilic part joint by an intermediate alipathic chain. The link between the lipophilic part and the intermediate chain can either be of the amide-type and the ester-type. Because of this, local anesthetics are currently divided between esters and amides. (emedicine.medscape.com).

           

Procaine, commonly known as “Novocain” to its most common trade name, is a local anesthetic drug of the ester group, commonly used in dental surgeries. Its chemical formula is C₁₃H₂₀N₂O₂. (emedicine.medscape.com).The second anesthetic most commonly used by anesthetists is lidocaine. It is used as a local anesthetic for minor surgeries and also for dental surgeries. It is often used for stopping itching and other skin problems. It belongs to the amide group of local anesthetics and its chemical composition is C₁₄H₂₂N₂O. (emedicine.medscape.com). As we can see of the chemical formulas of both lidocaine and procaine, local anesthetics have a chemical composition made up of a certain number of atoms of Carbon, Hydrogen, Nitrogen and Oxygen.

b. - Types of Anesthesia

There are many different kinds of anesthetics, depending on the needed effect on the patient. For example, there is a muscular anesthesia that stops the sensation in muscles. Another type of anesthesia is the peripheral anesthesia that numbs the peripheral nerves. But, the types of anesthetics and how they are applied are divided between local and general anesthesia. What differences these two types of anesthesia is the area that is numbed. (Medical-dictionary.com).

i.-Local Anesthesia

Local anesthesia is the application of anesthetic drugs that produce a sense of numbness and lack of sensibility in a certain located area of the body (medical-dictionary.com). These drugs are applied directly into the desired zone using a simple injection. Depending on the quantity of space that wants to be numbed, this anesthesia could be divided into regional or local anesthesia.

Regional anesthesia (mepivacaine, lidocaine, etc.) is used in more complex procedures. These drugs are used, for example, in order to avoid any type of sensation above the waist. (Medical-dictionary.com)  On the other hand, local anesthetics (procaine, tetracaine, etc.) are used or applied in a more reduced area, like in a little injury in order to close it with stitches (Medical-dictionary.com). The most common procedures where this anesthesia is used are the following:

• “Biopsies in which skin or tissue samples are taken for diagnostic procedures
• Childbirth
• Surgeries on the arms, hands, legs, or feet
• Eye surgery
• Surgeries involving the urinary tract or sexual organs”.  (Medical-dictionary.com).

There are some advantages of local anesthesia when compared to general anesthesia. For example, the patient never loses consciousness, so they do not suffer all the pain of waking up disoriented. Also, the effect of these drugs can be used longer without threatening the patient`s health. Finally, there is no blood lost with local anesthesia and there are no uncomfortable side effects. (Medical-dictionary.com)

“Local and regional anesthesia work by altering the flow of sodium molecules into nerve cells or neurons through the cell membrane.” (medical-dictionary.com). It is unknown how the drugs do this specifically, but scientists are certain that when the sodium molecules do not arrive to the neurons, the nerve impulses are not made by them and the feeling of pain is never produced (Gmyrek,1).

There are three types of general anesthesia. We have spinal anesthesia, where a little amount of these drugs are directly added into the cerebrospinal fluid surrounding the spinal cord. This stops the transmission of the pain sensation to the brain, as was discussed in Chapter 1. Secondly, there is the epidural anesthesia. In this case, a larger amount of drugs is placed around the cerebrospinal fluid, having the same results as the spinal anesthesia but it acts slower and is not followed by the normal blood pressure drop that usually comes along with spinal anesthesia. Finally, the third kind is the nerves block anesthesia. In this case, the drugs are applied in the area surrounding the nerves that give sensibility to the area that is about to be operated or cured. (Medical-dictionary.com)

ii. -General Anesthesia

As its name states, general anesthesia has a complete effect in the entire body. As it was previously explained, local anesthesia is used to numb a certain body part in order to carry out a certain procedure avoiding the pain that would be unbearable in most cases for the patients. General anesthesia has the same purpose, but since it affects the totality of the human organism, it is characterized for inducing the patient into an unconscious state; doing so, more complex procedures, such as long-lasting surgeries, can be performed without any kind of pain or discomfort of the patient.

How is this effect achieved? In the local anesthesia, as was explained, many anesthetics are used in order to achieve the same effect, but they are never used simultaneously. On the other hand, general anesthesia consists on a mixture of many anesthetics; normally, they are administrated both intravenously and inhaled, and this is called balanced anesthesia, this “is used because it takes advantage of the beneficial effects of each anesthetic agent to reach surgical anesthesia” (medical-dictionary.com).

           

Another notable difference between general and local anesthesia is that in local anesthesia, the drugs are administrated intravenously before the procedure and its effects last even after the operation is over. On the other hand, during a surgery where general anesthesia is used, the anesthetics are constantly being given to the patient. So, it is evident that the effects of the anesthetics of general anesthesia have a much shorter effect. That is why they have to be constantly administrated, and also why, if needed, the person could be easily awakened (emedicine.medscape.com).

           

If this is needed, it is as simple as reducing the level of anesthetics in the oxygen, and the patient can wake up almost immediately. But, the doctor must calculate the time because the anesthetics administrated intravenously last a little bit longer than the ones given along the oxygen.  Because of this, intravenous anesthetics are used at the beginning of the procedure in order to put the patient to sleep, and then he/she is maintained in that state with the anesthetics that are breathed. (Medical-dictionary.com)

           

Logically, as everything in the field of medicine, general anesthesia has its pros and its cons. Some of the advantages include the total control of the circulation and breathing processes. Because of this, it is necessary to provide the patient with oxygen at all times, but this enables the doctors to provide anesthetics by the airways. Also, it can be used if the patient has a sensibility towards local anesthesia. Finally, it is very confortable to work with this type of anesthesia because it is not necessary to move the patient in order to maintain him/her anesthetized. This anesthesia is adaptable, which means that if a procedure last longer than planned, it can easily be adjusted to sustain its effects longer. And, if needed, it can easily be stopped from working, just as easily as it is applied. (emedicine.medscape.com).

           

But, despite all these advantages, general anesthesia could be dangerous in some cases. It could be related with “serious complications such as nausea or vomiting, sore throat, headache, shivering, and delayed return to normal mental functioning” (emedicine.medscape.com). And some of its disadvantages are not only medical. Because it must be administrated continuously and also because it is composed by several different drugs, general anesthesia is quite expensive, and its prices are a considerable percentage of the whole operation costs.  Finally, general anesthesia is related to a very rare inherited muscular condition called malignant hyperthermia where the body temperature suddenly rises during the operation when exposed to the anesthesia and it could be lethal. (emedicine.medscape.com).

           

Another thing that must be considered is that general anesthesia is so powerful, that it does not only blocks pain, but it stops many vital processes, like breathing. Because of this, it is so hard to be an anesthetist, because they need to provide the adequate quantity of anesthetics throughout the whole procedure, but it is also their job to monitor their patient’s vital signs. So, anesthesiologists must be spectacular doctors, because for them, a single mistake could be unfixable, and their patients might never wake up again.

Without any doubt, modern anesthesia is one of the most important discoveries of our time. Without it, medicine would not be as it is today, and our way of living would not either. Just think about it. Imaging living with fear of getting hurt or sick, knowing that the operation has more probabilities of killing you than the sickness itself. Of course, anesthetics have existed since ancient times, but the real breakthrough of current anesthesia is the safety that it has now. Of course, it has certain side effects, and it is not uncommon to hear about people who die in the table due to a misusage of anesthesia.  But, it is certain that using anesthesia during an operation is currently the least of a patient’s concern.